文章目录
GitHub:https://github.com/AnJiaoDe/TabLayoutNiubility
该轮子特异功能如下：
使用方法
注意：该轮子适用于androidx中的ViewPager2和ViewPager
注意：如果轮子死活下载不下来，说明maven地址有毛病，你需要找到jitpack的官网首页，查看最新的官网地址
注意：记得去gayhub查看最新版本，最新版本最niubility
详细使用如下
Tab均分不滑动(ViewPager、ViewPager2均支持)
Tab滑动、 indicator蠕动、多布局(ViewPager、ViewPager2均支持)
根据item个数动态设置Tab均分还是滑动
Tab文字颜色渐变(ViewPager、ViewPager2均支持)
自定义Indicator如三角形(ViewPager、ViewPager2均支持)
ViewPager双层嵌套(建议不要使用ViewPager2进行双层嵌套，ViewPager2嵌套滑动冲突几乎无法处理，贼鸡儿坑)
仿微信主页Tab
相关API
TabMediator
FragmentPageAdapter
TabAdapter
TabLayoutScroll、TabLayoutNoScroll、TabLayoutMulti、IndicatorLineView 、 IndicatorTriangleView
TabLayoutScroll和 indicator style设置
自定义indicator
实现原理剖析
说真的，这自定义控件还真不简单
涉及到的难点场景
搞清楚ViewPager监听的onPageSelected、onPageScrolled和onPageScrollStateChanged回调执行特点
自定义HorizontalRecyclerView实现TabLayout
源码如下
TabLayout的item宽度均分
RecyclerView的item刷新如何做到不闪烁
UML类图如下
面向接口编程（面向多态编程）的**
欢迎联系、指正、批评
GitHub:https://github.com/AnJiaoDe/TabLayoutNiubility
该轮子特异功能如下：
Tab均分不滑动(ViewPager、ViewPager2均支持)
Tab滑动、 indicator蠕动、多布局(ViewPager、ViewPager2均支持)
根据item个数动态设置Tab均分还是滑动
Tab文字颜色渐变(ViewPager、ViewPager2均支持)
自定义Indicator如三角形(ViewPager、ViewPager2均支持)
ViewPager双层嵌套(建议不要使用ViewPager2进行双层嵌套，ViewPager2嵌套滑动冲突几乎无法处理，贼鸡儿坑)
仿微信主页Tab
使用方法
注意：该轮子适用于androidx中的ViewPager2和ViewPager
1.工程目录下的build.gradle中添加代码：
注意：如果轮子死活下载不下来，说明maven地址有毛病，你需要找到jitpack的官网首页，查看最新的官网地址
allprojects {
repositories {
maven { url 'https://www.jitpack.io' }
}
}2.直接在需要使用的模块的build.gradle中添加代码：
dependencies {
api 'com.github.AnJiaoDe:TabLayoutNiubility:V1.1.1'
api 'androidx.recyclerview:recyclerview:1.1.0'//版本必须>=1.1.0
}注意：记得去gayhub查看最新版本，最新版本最niubility
3.如果你想使用ViewPager2,那么添加代码：
api 'androidx.viewpager2:viewpager2:1.0.0'//版本必须>=1.0.04.混淆：
-keepclasseswithmembers class * {# 保持自定义控件类不被混淆
public <init>(android.content.Context, android.util.AttributeSet);
#这行不能加，加了就会失败
# public <init>(android.content.Context, android.util.AttributeSet, int);
}
-keep class androidx.** {*;}详细使用如下
Tab均分不滑动(ViewPager、ViewPager2均支持)
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<com.cy.tablayoutniubility.TabLayoutNoScroll
android:id="@+id/tablayout"
android:layout_width="match_parent"
android:layout_height="40dp"
app:space_horizontal="0dp"
android:background="#fff">
<com.cy.tablayoutniubility.IndicatorLineView
android:layout_width="match_parent"
app:width_indicator_max="80dp"
app:width_indicator_selected="30dp"
android:layout_height="wrap_content" />
</com.cy.tablayoutniubility.TabLayoutNoScroll>
<androidx.viewpager2.widget.ViewPager2
android:id="@+id/view_pager"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:overScrollMode="never" />
</LinearLayout>tab_item布局：
<?xml version="1.0" encoding="utf-8"?>
<TextView xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/tv"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:gravity="center"
android:textColor="#444444"
android:textSize="16sp" >
</TextView>JAVA代码：
ViewPager2 viewPager2 = findViewById(R.id.view_pager);
TabLayoutNoScroll tabLayoutLine = findViewById(R.id.tablayout);
// tabLayoutLine.setSpace_horizontal(0).setSpace_vertical(0);
FragPageAdapterVp2NoScroll<String> fragmentPageAdapter = new FragPageAdapterVp2NoScroll<String>(this) {
@Override
public Fragment createFragment(String bean, int position) {
return FragmentTab2.newInstance(FragmentTab2.TAB_NAME2, getList_bean().get(position));
}
@Override
public void bindDataToTab(TabNoScrollViewHolder holder, int position, String bean, boolean isSelected) {
TextView textView = holder.getView(R.id.tv);
if (isSelected) {
textView.setTextColor(0xffe45540);
textView.setTypeface(Typeface.defaultFromStyle(Typeface.BOLD));
} else {
textView.setTextColor(0xff444444);
textView.setTypeface(Typeface.defaultFromStyle(Typeface.NORMAL));
}
textView.setText(bean);
}
@Override
public int getTabLayoutID(int position, String bean) {
return R.layout.item_tab_center;
}
};
TabAdapterNoScroll<String> tabAdapter = new TabMediatorVp2NoScroll<String>(tabLayoutLine, viewPager2).setAdapter(fragmentPageAdapter);
List<String> list = new ArrayList<>();
list.add("关注");
list.add("推荐");
list.add("上课");
list.add("抗疫");
fragmentPageAdapter.add(list);
tabAdapter.add(list);Tab滑动、 indicator蠕动、多布局(ViewPager、ViewPager2均支持)
多布局：
@Override
public int getTabLayoutID(int position, String bean) {
if (position == 0) {
return R.layout.item_tab_msg;
}
return R.layout.item_tab;
}
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<com.cy.tablayoutniubility.TabLayoutScroll
android:id="@+id/tablayout"
android:layout_width="match_parent"
android:layout_height="40dp"
android:background="#fff">
<com.cy.tablayoutniubility.IndicatorLineView
android:layout_width="match_parent"
android:layout_height="wrap_content" />
</com.cy.tablayoutniubility.TabLayoutScroll>
<androidx.viewpager2.widget.ViewPager2
android:id="@+id/view_pager"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:overScrollMode="never" />
</LinearLayout>tab item布局：
<?xml version="1.0" encoding="utf-8"?>
<TextView xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:gravity="center"
android:textSize="16sp"
android:textColor="#444444"
android:id="@+id/tv">
</TextView>JAVA代码：
ViewPager2 viewPager2 = findViewById(R.id.view_pager);
TabLayoutScroll tabLayoutLine = findViewById(R.id.tablayout);
// tabLayoutLine.setSpace_horizontal(dpAdapt(20)).setSpace_vertical(dpAdapt(8));
FragPageAdapterVp2<String> fragmentPageAdapter = new FragPageAdapterVp2<String>(this) {
@Override
public Fragment createFragment(String bean, int position) {
return FragmentTab2.newInstance(FragmentTab2.TAB_NAME2, getList_bean().get(position));
}
@Override
public void bindDataToTab(TabViewHolder holder, int position, String bean, boolean isSelected) {
TextView textView = holder.getView(R.id.tv);
if (isSelected) {
textView.setTextColor(0xffe45540);
textView.setTypeface(Typeface.defaultFromStyle(Typeface.BOLD));
} else {
textView.setTextColor(0xff444444);
textView.setTypeface(Typeface.defaultFromStyle(Typeface.NORMAL));
}
textView.setText(bean);
}
@Override
public int getTabLayoutID(int position, String bean) {
if (position == 0) {
return R.layout.item_tab_msg;
}
return R.layout.item_tab;
}
};
TabAdapter<String> tabAdapter = new TabMediatorVp2<String>(tabLayoutLine, viewPager2).setAdapter(fragmentPageAdapter);
List<String> list = new ArrayList<>();
list.add("关注");
list.add("推荐");
list.add("视频");
list.add("抗疫");
list.add("酷玩");
list.add("彩票");
list.add("漫画");
fragmentPageAdapter.add(list);
tabAdapter.add(list);根据item个数动态设置Tab均分还是滑动
使用TabLayoutMulti
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<com.cy.tablayoutniubility.TabLayoutMulti
android:id="@+id/tablayout"
android:layout_width="match_parent"
android:layout_height="40dp"
app:space_horizontal="0dp"
android:background="#fff">
<com.cy.tablayoutniubility.IndicatorLineView
android:layout_width="match_parent"
app:width_indicator_max="80dp"
app:width_indicator_selected="30dp"
android:layout_height="wrap_content" />
</com.cy.tablayoutniubility.TabLayoutMulti>
<androidx.viewpager2.widget.ViewPager2
android:id="@+id/view_pager"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:overScrollMode="never" />
</LinearLayout>
JAVA代码：
ViewPager2 viewPager2 = findViewById(R.id.view_pager);
TabLayoutMulti tabLayoutMulti = findViewById(R.id.tablayout);
// tabLayoutLine.setSpace_horizontal(0).setSpace_vertical(0);
List<String> list = new ArrayList<>();
list.add("关注");
list.add("推荐");
list.add("上课");
list.add("抗疫");
list.add("文化");
// list.add("经济");
// list.add("幸福里");
//根据item个数设置是否需要滚动
if (list.size() > 6) tabLayoutMulti.setScrollable(true);
BaseFragPageAdapterVp2 fragmentPageAdapter;
if (tabLayoutMulti.isScrollable()) {
fragmentPageAdapter = new FragPageAdapterVp2<String>(this) {
@Override
public Fragment createFragment(String bean, int position) {
return FragmentTab2.newInstance(FragmentTab2.TAB_NAME2, getList_bean().get(position));
}
@Override
public void bindDataToTab(TabViewHolder holder, int position, String bean, boolean isSelected) {
TextView textView = holder.getView(R.id.tv);
if (isSelected) {
textView.setTextColor(0xffe45540);
textView.setTypeface(Typeface.defaultFromStyle(Typeface.BOLD));
} else {
textView.setTextColor(0xff444444);
textView.setTypeface(Typeface.defaultFromStyle(Typeface.NORMAL));
}
textView.setText(bean);
}
@Override
public int getTabLayoutID(int position, String bean) {
return R.layout.item_tab_center;
}
};
}else {
fragmentPageAdapter = new FragPageAdapterVp2NoScroll<String>(this) {
@Override
public Fragment createFragment(String bean, int position) {
return FragmentTab2.newInstance(FragmentTab2.TAB_NAME2, getList_bean().get(position));
}
@Override
public void bindDataToTab(TabNoScrollViewHolder holder, int position, String bean, boolean isSelected) {
LogUtils.log("bindDataToTab");
TextView textView = holder.getView(R.id.tv);
if (isSelected) {
textView.setTextColor(0xffe45540);
textView.setTypeface(Typeface.defaultFromStyle(Typeface.BOLD));
} else {
textView.setTextColor(0xff444444);
textView.setTypeface(Typeface.defaultFromStyle(Typeface.NORMAL));
}
textView.setText(bean);
}
@Override
public int getTabLayoutID(int position, String bean) {
return R.layout.item_tab_center;
}
};
}
ITabAdapter tabAdapter = new TabMediatorMulti<String>(tabLayoutMulti).setAdapter(viewPager2, fragmentPageAdapter);
fragmentPageAdapter.add(list);
tabAdapter.add(list);
//或者
// if(tabLayoutMulti.isScrollable()){
// TabAdapter tabAdapt= (TabAdapter) tabAdapter.getAdapter();
// tabAdapt.add(list);
// }else {
// TabAdapterNoScroll tabAdapt= (TabAdapterNoScroll) tabAdapter.getAdapter();
// tabAdapt.add(list);
// }Tab文字颜色渐变(ViewPager、ViewPager2均支持)
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:orientation="vertical"
android:layout_width="match_parent"
android:background="#fff"
android:layout_height="match_parent" >
<com.cy.tablayoutniubility.TabLayoutScroll
android:layout_width="match_parent"
android:background="#fff"
android:layout_height="40dp"
android:id="@+id/tablayout">
<com.cy.tablayoutniubility.IndicatorLineView
android:layout_width="match_parent"
android:layout_height="wrap_content"/>
</com.cy.tablayoutniubility.TabLayoutScroll>
<View
android:layout_width="match_parent"
android:layout_height="1dp"
android:background="#eee"/>
<androidx.viewpager2.widget.ViewPager2
android:id="@+id/view_pager"
android:overScrollMode="never"
android:layout_width="match_parent"
android:layout_height="match_parent"/>
</LinearLayout>tab item布局：
<?xml version="1.0" encoding="utf-8"?>
<com.cy.tablayoutniubility.TabGradientTextView xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:id="@+id/tv"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:gravity="center"
android:textSize="16sp"
app:textColorNormal="#ff444444"
app:textColorSelected="#ffe45540">
</com.cy.tablayoutniubility.TabGradientTextView>JAVA代码：
ViewPager2 viewPager2= findViewById(R.id.view_pager);
TabLayoutScroll tabLayoutLine= findViewById(R.id.tablayout);
// tabLayoutLine.setSpace_horizontal(dpAdapt(20)).setSpace_vertical(dpAdapt(8));
FragPageAdapterVp2<String> fragmentPageAdapter = new FragPageAdapterVp2<String>(this) {
@Override
public Fragment createFragment(String bean, int position) {
return FragmentTab2.newInstance(FragmentTab2.TAB_NAME2, getList_bean().get(position));
}
@Override
public void bindDataToTab(TabViewHolder holder, int position, String bean, boolean isSelected) {
TabGradientTextView textView = holder.getView(R.id.tv);
if (isSelected) {
textView.setTypeface(Typeface.defaultFromStyle(Typeface.BOLD));
//因为 public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
//positionOffset没有为1的时候
//必须
textView.setProgress(1);
} else {
textView.setTypeface(Typeface.defaultFromStyle(Typeface.NORMAL));
//因为快速滑动时， public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
//positionOffset不会出现0
//必须
textView.setProgress(0);
}
textView.setText(bean);
}
@Override
public int getTabLayoutID(int position, String bean) {
return R.layout.item_tab_gradient;
}
@Override
public void onTabScrolled(TabViewHolder holderCurrent, int positionCurrent, boolean fromLeft2RightCurrent, float positionOffsetCurrent, TabViewHolder holder2, int position2, boolean fromLeft2Right2, float positionOffset2) {
super.onTabScrolled(holderCurrent, positionCurrent, fromLeft2RightCurrent, positionOffsetCurrent, holder2, position2, fromLeft2Right2, positionOffset2);
TabGradientTextView textViewCurrent = holderCurrent.getView(R.id.tv);
TabGradientTextView textView2= holder2.getView(R.id.tv);
LogUtils.log("onTabScrolled");
textViewCurrent.setDirection(fromLeft2RightCurrent?TabGradientTextView.DIRECTION_FROM_LEFT:TabGradientTextView.DIRECTION_FROM_RIGHT)
.setProgress(positionOffsetCurrent);
textView2.setDirection(fromLeft2Right2?TabGradientTextView.DIRECTION_FROM_LEFT:TabGradientTextView.DIRECTION_FROM_RIGHT)
.setProgress(positionOffset2);
}
};
TabAdapter<String> tabAdapter = new TabMediatorVp2<String>(tabLayoutLine, viewPager2).setAdapter(fragmentPageAdapter);
List<String> list = new ArrayList<>();
list.add("关注");
list.add("推荐");
list.add("视频");
list.add("抗疫");
list.add("彩票");
list.add("漫画");
fragmentPageAdapter.add(list);
tabAdapter.add(list);自定义Indicator如三角形(ViewPager、ViewPager2均支持)
可以在布局或者代码中设置三角形的选中宽度和最大宽度，使三角形宽度不改变
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:orientation="vertical"
android:layout_width="match_parent"
android:background="#fff"
android:layout_height="match_parent" >
<com.cy.tablayoutniubility.TabLayoutScroll
android:layout_width="match_parent"
android:background="#fff"
android:layout_height="40dp"
android:id="@+id/tablayout">
<com.cy.tablayoutniubility.IndicatorTriangleView
android:layout_width="match_parent"
android:layout_height="wrap_content"/>
</com.cy.tablayoutniubility.TabLayoutScroll>
<View
android:layout_width="match_parent"
android:layout_height="1dp"
android:background="#eee"/>
<androidx.viewpager2.widget.ViewPager2
android:id="@+id/view_pager"
android:overScrollMode="never"
android:layout_width="match_parent"
android:layout_height="match_parent"/>
</LinearLayout>
tab item布局：
<?xml version="1.0" encoding="utf-8"?>
<TextView xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:gravity="center"
android:textSize="16sp"
android:textColor="#444444"
android:id="@+id/tv">
</TextView>JAVA代码：
ViewPager2 viewPager2= findViewById(R.id.view_pager);
TabLayoutScroll tabLayoutNiubility= findViewById(R.id.tablayout);
// tabLayoutTriangle.setSpace_horizontal(dpAdapt(20)).setSpace_vertical(dpAdapt(8));
FragPageAdapterVp2<String> fragmentPageAdapter = new FragPageAdapterVp2<String>(this) {
@Override
public Fragment createFragment(String bean, int position) {
return FragmentTab2.newInstance(FragmentTab2.TAB_NAME2, getList_bean().get(position));
}
@Override
public void bindDataToTab(TabViewHolder holder, int position, String bean, boolean isSelected) {
TextView textView = holder.getView(R.id.tv);
if (isSelected) {
textView.setTextColor(0xffe45540);
textView.setTypeface(Typeface.defaultFromStyle(Typeface.BOLD));
} else {
textView.setTextColor(0xff444444);
textView.setTypeface(Typeface.defaultFromStyle(Typeface.NORMAL));
}
textView.setText(bean);
}
@Override
public int getTabLayoutID(int position, String bean) {
return R.layout.item_tab;
}
};
TabAdapter<String> tabAdapter = new TabMediatorVp2<String>(tabLayoutNiubility, viewPager2).setAdapter(fragmentPageAdapter);
List<String> list = new ArrayList<>();
list.add("关注");
list.add("推荐");
list.add("彩票");
list.add("漫画");
fragmentPageAdapter.add(list);
tabAdapter.add(list);ViewPager双层嵌套(建议不要使用ViewPager2进行双层嵌套，ViewPager2嵌套滑动冲突几乎无法处理，贼鸡儿坑)
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<com.cy.tablayoutniubility.TabLayoutScroll
android:id="@+id/tablayout"
android:layout_width="match_parent"
android:layout_height="40dp"
android:background="#fff">
<com.cy.tablayoutniubility.IndicatorLineView
android:layout_width="match_parent"
android:layout_height="wrap_content" />
</com.cy.tablayoutniubility.TabLayoutScroll>
<androidx.viewpager.widget.ViewPager
android:id="@+id/view_pager"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:overScrollMode="never" />
</LinearLayout>
activity代码：
ViewPager viewPager= findViewById(R.id.view_pager);
TabLayoutScroll tabLayoutLine= findViewById(R.id.tablayout);
// tabLayoutLine.setSpace_horizontal(dpAdapt(20)).setSpace_vertical(dpAdapt(8));
FragPageAdapterVp<String> fragmentPageAdapter = new FragPageAdapterVp<String>(getSupportFragmentManager(),
FragmentStatePagerAdapter.BEHAVIOR_RESUME_ONLY_CURRENT_FRAGMENT) {
@Override
public Fragment createFragment(String bean, int position) {
return FragmentTab1.newInstance(FragmentTab1.TAB_NAME1, getList_bean().get(position));
}
@Override
public void bindDataToTab(TabViewHolder holder, int position, String bean, boolean isSelected) {
TextView textView = holder.getView(R.id.tv);
if (isSelected) {
textView.setTextColor(0xffe45540);
textView.setTypeface(Typeface.defaultFromStyle(Typeface.BOLD));
} else {
textView.setTextColor(0xff444444);
textView.setTypeface(Typeface.defaultFromStyle(Typeface.NORMAL));
}
textView.setText(bean);
}
@Override
public int getTabLayoutID(int position, String bean) {
if (position == 0) {
return R.layout.item_tab_msg;
}
return R.layout.item_tab;
}
};
TabAdapter<String> tabAdapter = new TabMediatorVp<String>(tabLayoutLine, viewPager).setAdapter(fragmentPageAdapter);
List<String> list = new ArrayList<>();
list.add("关注");
list.add("推荐");
list.add("酷玩");
list.add("彩票");
list.add("漫画");
fragmentPageAdapter.add(list);
tabAdapter.add(list);Fragment代码：
viewPager = view.findViewById(R.id.view_pager);
tabLayoutLine = view.findViewById(R.id.tablayout);
FragPageAdapterVp<String> fragmentPageAdapter = new FragPageAdapterVp<String>(getChildFragmentManager(),
FragmentStatePagerAdapter.BEHAVIOR_RESUME_ONLY_CURRENT_FRAGMENT) {
@Override
public Fragment createFragment(String bean, int position) {
return FragmentTab2.newInstance(FragmentTab2.TAB_NAME2, getList_bean().get(position));
}
@Override
public void bindDataToTab(TabViewHolder holder, int position, String bean, boolean isSelected) {
TextView textView = holder.getView(R.id.tv);
if (isSelected) {
LogUtils.log("bindDataToTabisSelected",position);
textView.setTextColor(0xffe45540);
textView.setTypeface(Typeface.defaultFromStyle(Typeface.BOLD));
} else {
LogUtils.log("bindDataToTab",position);
textView.setTextColor(0xff444444);
textView.setTypeface(Typeface.defaultFromStyle(Typeface.NORMAL));
}
textView.setText(bean);
}
@Override
public int getTabLayoutID(int position, String bean) {
return R.layout.item_tab;
}
};
TabAdapter<String> tabAdapter = new TabMediatorVp<String>(tabLayoutLine, viewPager).setAdapter(fragmentPageAdapter);
if (getArguments() != null) {
String tab_name1 = getArguments().getString(TAB_NAME1);
List<String> list = new ArrayList<>();
list.add(tab_name1 + "0");
list.add(tab_name1 + "1");
list.add(tab_name1 + "2");
list.add(tab_name1 + "3");
list.add(tab_name1 + "4");
list.add(tab_name1 + "5");
list.add(tab_name1 + "6");
list.add(tab_name1 + "7");
list.add(tab_name1 + "8");
list.add(tab_name1 + "9");
list.add(tab_name1 + "10");
list.add(tab_name1 + "11");
list.add(tab_name1 + "12");
list.add(tab_name1 + "13");
fragmentPageAdapter.add(list);
tabAdapter.add(list);
}仿微信主页Tab
activity布局：
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<androidx.viewpager2.widget.ViewPager2
android:id="@+id/view_pager"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="1"
android:overScrollMode="never" />
<com.cy.tablayoutniubility.TabLayoutNoScroll
android:id="@+id/tablayout"
android:layout_width="match_parent"
android:layout_height="60dp"
android:background="#fff">
<com.cy.tablayoutniubility.IndicatorNullView
android:layout_width="match_parent"
android:layout_height="wrap_content" />
</com.cy.tablayoutniubility.TabLayoutNoScroll>
</LinearLayout>
item布局：
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:gravity="center"
android:orientation="vertical">
<ImageView
android:id="@+id/iv"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:scaleType="centerInside" />
<TextView
android:id="@+id/tv"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="4dp"
android:gravity="center"
android:textSize="12sp"></TextView>
</LinearLayout>
JAVA代码：
ViewPager2 viewPager2= findViewById(R.id.view_pager);
TabLayoutNoScroll tabLayoutNoScroll= findViewById(R.id.tablayout);
FragPageAdapterVp2NoScroll<TabBean> fragmentPageAdapter = new FragPageAdapterVp2NoScroll<TabBean>(this) {
@Override
public Fragment createFragment(TabBean bean, int position) {
return FragmentTab2.newInstance(FragmentTab2.TAB_NAME2, getList_bean().get(position).getText());
}
@Override
public void bindDataToTab(TabNoScrollViewHolder holder, int position, TabBean bean, boolean isSelected) {
TextView textView = holder.getView(R.id.tv);
if (isSelected) {
textView.setTextColor(0xff00ff00);
holder.setImageResource(R.id.iv,bean.getResID_selected());
} else {
textView.setTextColor(0xff444444);
holder.setImageResource(R.id.iv,bean.getResID_normal());
}
textView.setText(bean.getText());
}
@Override
public int getTabLayoutID(int position, TabBean bean) {
if (position == 2) {
return R.layout.item_tab_main_circle;
}
return R.layout.item_tab_main;
}
};
TabAdapterNoScroll<TabBean> tabAdapter = new TabMediatorVp2NoScroll<TabBean>(tabLayoutNoScroll, viewPager2).setAdapter(fragmentPageAdapter);
List<TabBean> list = new ArrayList<>();
list.add(new TabBean("消息",R.drawable.msg,R.drawable.msg_selected));
list.add(new TabBean("通讯录",R.drawable.friends,R.drawable.friends_selected));
list.add(new TabBean("朋友圈",R.drawable.circle,R.drawable.circle_selected));
list.add(new TabBean("我",R.drawable.my,R.drawable.my_selected));
fragmentPageAdapter.add(list);
tabAdapter.add(list);相关API
TabMediator
TabMediatorVp
TabMediatorVp2
TabMediatorVp2NoScroll(不可滚动)
TabMediatorVpNoScroll(不可滚动)
TabMediatorMulti(可用于ViewPager和ViewPager2,可根据item个数动态设置是否滚动)
FragmentPageAdapter
拥有一系列add、remove函数
FragmentPageAdapterVp2（Tab可滑动，ViewPager2使用）
FragmentPageAdapterVp（Tab可滑动，ViewPager使用）
FragmentPageAdapterVp2NoScroll（Tab不可滑动，ViewPager2使用）
FragmentPageAdapterVpNoScroll（Tab不可滑动，ViewPager使用）
TabAdapter
TabAdapter(Tab的Adapter，继承自RecyclerView的Adapter)
拥有一系列add、remove函数
TabAdapterNoScroll(Tab的Adapter，不能滚动)
TabLayoutScroll、TabLayoutNoScroll、TabLayoutMulti、IndicatorLineView 、 IndicatorTriangleView
TabLayoutScroll是可滚动tab,TabLayoutNoScroll是不可滚动tab,里面需要嵌套indicatorview,可以选择IndicatorLineView线条indicator、IndicatorTriangleView三角形indicator,
TabLayoutMulti用于需要根据item个数动态设置是否滚动
<com.cy.tablayoutniubility.TabLayoutNiubility
android:id="@+id/tablayout"
android:layout_width="match_parent"
android:layout_height="40dp"
android:background="#fff">
<com.cy.tablayoutniubility.IndicatorLineView
android:layout_width="match_parent"
android:layout_height="wrap_content" />
</com.cy.tablayoutniubility.TabLayoutNiubility>TabLayoutScroll和 indicator style设置
TabLayoutNiubility可设置space
indicator可设置颜色、选中长度、最大长度、高度、radius等
可在布局中使用 比如：
<com.cy.tablayoutniubility.IndicatorLineView
android:layout_width="match_parent"
app:width_indicator_max="80dp"
app:width_indicator_selected="30dp"
android:layout_height="wrap_content" /><?xml version="1.0" encoding="utf-8"?>
<resources>
<attr name="height_indicator" format="dimension|reference" />
<attr name="width_indicator_selected" format="dimension|reference"/>
<attr name="width_indicator_max" format="dimension|reference"/>
<attr name="color_indicator" format="color|reference"/>
<declare-styleable name="TabGradientTextView">
<attr name="textColorNormal" format="color|reference" />
<attr name="textColorSelected" format="color|reference"/>
</declare-styleable>
<declare-styleable name="TabLayoutNiubility">
<attr name="space_vertical" format="dimension|reference"/>
<attr name="space_horizontal" format="dimension|reference"/>
</declare-styleable>
<declare-styleable name="IndicatorLineView">
<attr name="height_indicator" />
<attr name="width_indicator_selected"/>
<attr name="width_indicator_max"/>
<attr name="radius_indicator" format="dimension|reference"/>
<attr name="color_indicator" />
</declare-styleable>
<declare-styleable name="IndicatorTriangleView">
<attr name="height_indicator" />
<attr name="width_indicator_selected"/>
<attr name="width_indicator_max"/>
<attr name="color_indicator" />
</declare-styleable>
</resources>可在代码中使用 比如：
tabLayoutScroll.getIndicatorView().getIndicator().setColor_indicator();/**
* 设置indicator进度
* @param progress
* @return
*/
public Indicator setProgress(int progress) {
this.progress = progress;
viewIndicator.invalidate();
return this;
}
public int getProgress() {
return progress;
}
public int getWidth_indicator_max() {
return width_indicator_max;
}
/**
* 设置indicator最大长度
* @param width_indicator_max
* @return
*/
public Indicator setWidth_indicator_max(int width_indicator_max) {
this.width_indicator_max = width_indicator_max;
return this;
}
/**
* 设置indicator颜色
* @param color_indicator
* @return
*/
public Indicator setColor_indicator(int color_indicator) {
paint_indicator.setColor(color_indicator);
return this;
}
/**
* 设置indicator高度
* @param height_indicator
* @return
*/
public Indicator setHeight_indicator(int height_indicator) {
this.height_indicator = height_indicator;
return this;
}
public int getHeight_indicator() {
return height_indicator;
}
public Paint getPaint_indicator() {
return paint_indicator;
}
/**
* 设置indicator选中时的长度
* @param width_indicator_selected
* @return
*/
public Indicator setWidth_indicator_selected(int width_indicator_selected) {
this.width_indicator_selected = width_indicator_selected;
return this;
}
public int getWidth_indicator_selected() {
return width_indicator_selected;
}
public int getWidth_indicator() {
return width_indicator;
}
/**
* 设置indicator当前长度
* @param width_indicator
* @return
*/
public Indicator setWidth_indicator(int width_indicator) {
this.width_indicator = Math.min(width_indicator_max, width_indicator);
return this;
}自定义indicator
1.实现IIndicatorView 接口
2.创建Indicator 对象、设置基本默认参数
3.实现draw方法，根据progress和width_indicator绘制自己想要的样式
比如库里提供的IndicatorTriangleView
public class IndicatorTriangleView extends View implements IIndicatorView {
private Path path;
private Indicator indicator;
private int height;
public IndicatorTriangleView(Context context, @Nullable AttributeSet attrs) {
super(context, attrs);
indicator=new Indicator(this);
//实例化路径
path = new Path();
indicator=new Indicator(this);
TypedArray typedArray = context.obtainStyledAttributes(attrs, R.styleable.IndicatorTriangleView);
indicator.setWidth_indicator_selected(typedArray.getDimensionPixelSize(R.styleable.IndicatorTriangleView_width_indicator_selected, ScreenUtils.dpAdapt(context,12)));
indicator.setWidth_indicator_max(typedArray.getDimensionPixelSize(R.styleable.IndicatorTriangleView_width_indicator_max, ScreenUtils.dpAdapt(context,48)));
indicator.setHeight_indicator(typedArray.getDimensionPixelSize(R.styleable.IndicatorTriangleView_height_indicator, ScreenUtils.dpAdapt(context,6)));
indicator.setColor_indicator(typedArray.getColor(R.styleable.IndicatorTriangleView_color_indicator, 0xffe45540));
indicator.setWidth_indicator(ScreenUtils.dpAdapt(context,30));
typedArray.recycle();
}
@Override
protected void onLayout(boolean changed, int left, int top, int right, int bottom) {
super.onLayout(changed, left, top, right, bottom);
height=getHeight();
}
@Override
public <T extends View> T getView() {
return (T) this;
}
@Override
public Indicator getIndicator() {
return indicator;
}
@Override
protected void onDraw(Canvas canvas) {
path.reset();
path.moveTo(indicator.getProgress(), height);// 此点为多边形的起点
path.lineTo(indicator.getProgress() + indicator.getWidth_indicator() * 1f / 2, height - indicator.getHeight_indicator());
path.lineTo(indicator.getProgress() + indicator.getWidth_indicator(), height);
path.close(); // 使这些点构成封闭的多边形
indicator.getPaint_indicator().setStyle(Paint.Style.FILL);
canvas.drawPath(path, indicator.getPaint_indicator());
}
}实现原理剖析
说真的，这自定义控件还真不简单
涉及到的难点场景
搞清楚ViewPager监听的onPageSelected、onPageScrolled和onPageScrollStateChanged回调执行特点
/**
* This method will be invoked when the current page is scrolled, either as part
* of a programmatically initiated smooth scroll or a user initiated touch scroll.
*
* @param position Position index of the first page currently being displayed.
* Page position+1 will be visible if positionOffset is nonzero.
* @param positionOffset Value from [0, 1) indicating the offset from the page at position.
* @param positionOffsetPixels Value in pixels indicating the offset from position.
*/
public void onPageScrolled(int position, float positionOffset,
@Px int positionOffsetPixels) {
}
/**
* This method will be invoked when a new page becomes selected. Animation is not
* necessarily complete.
*
* @param position Position index of the new selected page.
*/
public void onPageSelected(int position) {
}
/**
* Called when the scroll state changes. Useful for discovering when the user begins
* dragging, when a fake drag is started, when the pager is automatically settling to the
* current page, or when it is fully stopped/idle. {@code state} can be one of {@link
* #SCROLL_STATE_IDLE}, {@link #SCROLL_STATE_DRAGGING} or {@link #SCROLL_STATE_SETTLING}.
*/
public void onPageScrollStateChanged(@ScrollState int state) {
}首次进入viewPager,回调如下：
onPageSelected: ----------------------------------->>>>0
onPageScrolled: ----------------------------------->>>>0手指向左拖动，viewapger从index切换到第index+1,回调如下：
可以发现当手指松开，ViewPager从SCROLL_STATE_DRAGGING到达SCROLL_STATE_SETTLING（自动滚动状态），onPageSelected先执行，onPageScrolled position从index 慢慢到index+1
LOG_E: ----------------------------------->>>>onPageScrollStateChangedSCROLL_STATE_DRAGGING
onPageScrolled: ----------------------------------->>>>0
onPageScrolled: ----------------------------------->>>>0
LOG_E: ----------------------------------->>>>onPageScrollStateChangedSCROLL_STATE_SETTLING
onPageSelected: ----------------------------------->>>>1
onPageScrolled: ----------------------------------->>>>0
onPageScrolled: ----------------------------------->>>>0
onPageScrolled: ----------------------------------->>>>0
onPageScrolled: ----------------------------------->>>>0
onPageScrolled: ----------------------------------->>>>0
onPageScrolled: ----------------------------------->>>>0
onPageScrolled: ----------------------------------->>>>0
onPageScrolled: ----------------------------------->>>>0
onPageScrolled: ----------------------------------->>>>0
onPageScrolled: ----------------------------------->>>>0
onPageScrolled: ----------------------------------->>>>0
onPageScrolled: ----------------------------------->>>>0
onPageScrolled: ----------------------------------->>>>0
onPageScrolled: ----------------------------------->>>>1
LOG_E: ----------------------------------->>>>onPageScrollStateChangedSCROLL_STATE_IDLE
手指向右拖动，viewapger从index切换到第index-1,回调如下：
onPageScrolled: ----------------------------------->>>>1
LOG_E: ----------------------------------->>>>onPageScrollStateChangedSCROLL_STATE_IDLE
LOG_E: ----------------------------------->>>>onPageScrollStateChangedSCROLL_STATE_DRAGGING
onPageScrolled: ----------------------------------->>>>0
onPageScrolled: ----------------------------------->>>>0
onPageScrolled: ----------------------------------->>>>0
onPageScrolled: ----------------------------------->>>>0
onPageScrolled: ----------------------------------->>>>0
onPageScrolled: ----------------------------------->>>>0
onPageScrolled: ----------------------------------->>>>0
onPageScrolled: ----------------------------------->>>>0
onPageScrolled: ----------------------------------->>>>0
onPageScrolled: ----------------------------------->>>>0
onPageScrolled: ----------------------------------->>>>0
LOG_E: ----------------------------------->>>>onPageScrollStateChangedSCROLL_STATE_SETTLING
onPageSelected: ----------------------------------->>>>0
onPageScrolled: ----------------------------------->>>>0
onPageScrolled: ----------------------------------->>>>0
onPageScrolled: ----------------------------------->>>>0
onPageScrolled: ----------------------------------->>>>0
onPageScrolled: ----------------------------------->>>>0
onPageScrolled: ----------------------------------->>>>0
onPageScrolled: ----------------------------------->>>>0
LOG_E: ----------------------------------->>>>onPageScrollStateChangedSCROLL_STATE_IDLE
可以发现当手指开始拖动，onPageScrolled position从index 直接变成index-1,
当手指松开，ViewPager从SCROLL_STATE_DRAGGING到达SCROLL_STATE_SETTLING（自动滚动状态），onPageSelected执行，onPageScrolled position不再改变，直到SCROLL_STATE_IDLE（自动滚动停止）
总结：onPageSelected先执行（粗略来说），手指向左拖动,onPageScrolled position是当前item的position+1,手指向右拖动,onPageScrolled position是当前item的position-1,搞懂这点是关键。
自定义HorizontalRecyclerView实现TabLayout
之所以选择RecyclerView做tabLayout，是因为RecyclerView最适用于多item的布局，不仅因为它有缓存的功能、还因为使用起来极其方便简单，个人觉得，android里recyclerView的设计是超级奶思的。
因为TabLayout需要根据ViewPager的滑动来滑动，但RecyclerView的scrollTo函数是空的，没有任何作用，这样滑动控制就会变得困难。不过我们可以override，自己实现它，通过scrollBy函数滑动，设置滑动监听事件，记录偏移量offsetX，这样，我们就可以做到scrollTo是有作用的。
public class HorizontalRecyclerView extends RecyclerView {
private LinearItemDecoration linearItemDecoration;
//永远<=0
private int offsetX = 0;
public HorizontalRecyclerView(Context context) {
this(context, null);
}
public HorizontalRecyclerView(Context context, @Nullable AttributeSet attrs) {
super(context, attrs);
addOnScrollListener(new OnScrollListener() {
@Override
public void onScrolled(@NonNull RecyclerView recyclerView, int dx, int dy) {
super.onScrolled(recyclerView, dx, dy);
offsetX -= dx;
}
});
SimpleItemAnimator simpleItemAnimator = (SimpleItemAnimator) getItemAnimator();
if (simpleItemAnimator != null) simpleItemAnimator.setSupportsChangeAnimations(false);
}
/**
* x为正，表示手指往左滑,x为负，表示手指往右滑
*
* @param x
* @param y
*/
@Override
public void scrollBy(int x, int y) {
super.scrollBy(x, y);
}
/**
* x<=0
* 比如 x=0,表示滑动到RecyclerView最左边，完全显示第一个item,
* 比如 x=-100,表示RecyclerView左边100像素的界面被隐藏
*
* @param x
* @param y
*/
@Override
public void scrollTo(int x, int y) {
scrollBy(offsetX - x, y);
}
public int getOffsetX() {
return offsetX;
}
@Override
public void setAdapter(Adapter adapter) {
setLayoutManager(new LinearLayoutManager(getContext(), LinearLayoutManager.HORIZONTAL, false));
super.setAdapter(adapter);
}
}手指滑动ViewPager，保证选中的TabLayout的item在正中间
手指滑动ViewPager,TabLayout跟着滑动
手指点击TabLayout,ViewPager跟着滑动
手指滑动TabLayout,再点击TabLayout
手指滑动TabLayout,再触摸ViewPager
手指滑动TabLayout,再滑动ViewPager
今日头条存在一个体验不好的场景：快速滑动TabLayout,ViewPager在TabLayout停止滑动之前就停止了滑动，这时，将看不到indicator，然而小编的TabLayoutNiubility解决了这个问题
源码如下
package com.cy.tablayoutniubility;
import androidx.annotation.NonNull;
import androidx.recyclerview.widget.RecyclerView;
import androidx.viewpager2.widget.ViewPager2;
import static androidx.viewpager2.widget.ViewPager2.SCROLL_STATE_IDLE;
/**
* @Description:
* @Author: cy
* @CreateDate: 2020/7/29 18:42
* @UpdateUser:
* @UpdateDate: 2020/7/29 18:42
* @UpdateRemark:
* @Version:
*/
public class TabLayoutMediatorVp2<T> {
private TabLayoutNiubility tabLayout;
private ViewPager2 viewPager2;
private TabAdapter<T> tabAdapter;
private int position_scroll_last = 0;
private int diff = 0;
private int diff_click = 0;
private int toScroll = 0;
private int offsetX_last = 0;
private int offsetX_last_click = 0;
private int offsetX_touch = 0;
private boolean rvScrolledByVp = false;
private boolean rvScrolledByTouch = false;
private boolean scrolledByClick = false;
private int position_selected_last = 0;
private boolean op_click_last = false;
private int click_position_last = -1;
public TabLayoutMediatorVp2(TabLayoutNiubility tabLayout, final ViewPager2 viewPager2) {
this.tabLayout = tabLayout;
this.viewPager2 = viewPager2;
}
public TabAdapter<T> setAdapter(final FragmentPageAdapterVp2<T> fragmentPageAdapter) {
tabAdapter = new TabAdapter<T>() {
@Override
public void bindDataToView(TabViewHolder holder, int position, T bean, boolean isSelected) {
fragmentPageAdapter.bindDataToTab( holder, position, bean, isSelected);
}
@Override
public int getItemLayoutID(int position, T bean) {
return fragmentPageAdapter.getTabLayoutID(position, bean);
}
@Override
public void onItemClick(TabViewHolder holder, int position, T bean) {
//点击tabLayout的item,会先回调onPageSelected,然后回调onPageScrolled
//标志复位
rvScrolledByTouch = false;
offsetX_touch = 0;
//标志：tablayout的滑动是由点击item触发的
scrolledByClick = true;
position_selected_last = viewPager2.getCurrentItem();
viewPager2.setCurrentItem(position);
//让indicator立马指向currentItem
RecyclerView.ViewHolder viewHolder = tabLayout.getHorizontalRecyclerView().findViewHolderForAdapterPosition(viewPager2.getCurrentItem());
if (viewHolder != null) {
tabLayout.getIndicatorView().getIndicator().setWidth_indicator(tabLayout.getIndicatorView().getIndicator().getWidth_indicator_selected())
.setProgress((int) (viewHolder.itemView.getLeft()
+ viewHolder.itemView.getWidth() * 1f / 2
- tabLayout.getIndicatorView().getIndicator().getWidth_indicator() / 2));
} else {
//不可见，width_indicator为0
tabLayout.getIndicatorView().getIndicator().setWidth_indicator(0).invalidate();
}
fragmentPageAdapter.onTabClick( holder, position, bean);
}
};
tabLayout.getHorizontalRecyclerView().addOnScrollListener(new RecyclerView.OnScrollListener() {
@Override
public void onScrolled(@NonNull RecyclerView recyclerView, int dx, int dy) {
super.onScrolled(recyclerView, dx, dy);
//如果是手指滑动tabLayout，需要记录滑动的距离
if (!rvScrolledByVp) {
rvScrolledByTouch = true;
offsetX_touch -= dx;
}
//indicator需要跟着滑动
RecyclerView.ViewHolder viewHolder = tabLayout.getHorizontalRecyclerView().findViewHolderForAdapterPosition(viewPager2.getCurrentItem());
if (viewHolder != null) {
tabLayout.getIndicatorView().getIndicator().setWidth_indicator(tabLayout.getIndicatorView().getIndicator().getWidth_indicator_selected())
.setProgress((int) (viewHolder.itemView.getLeft()
+ viewHolder.itemView.getWidth() * 1f / 2
- tabLayout.getIndicatorView().getIndicator().getWidth_indicator() / 2));
} else {
//不可见，width_indicator为0
tabLayout.getIndicatorView().getIndicator().setWidth_indicator(0).invalidate();
}
}
});
viewPager2.registerOnPageChangeCallback(new ViewPager2.OnPageChangeCallback() {
@Override
public void onPageSelected(int position) {
super.onPageSelected(position);
//通知tabAdapter更新选中项
tabAdapter.setPositionSelected(viewPager2.getCurrentItem());
}
/**注意：滑动很快的时候，即使到了另外的page,positionOffsetPixels不一定会出现0
* @param position
* @param positionOffset
* @param positionOffsetPixels
*/
@Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
super.onPageScrolled(position,positionOffset,positionOffsetPixels);
int centerX = (int) (tabLayout.getWidth() * 1f / 2);
//说明上次手指滑动了tabLayout，现在手指滑动viewpager,需要将tablayout复位
if (rvScrolledByTouch && offsetX_touch != 0) {
tabLayout.getHorizontalRecyclerView().stopScroll();
//标志不是由手指滑动tablayout
rvScrolledByVp = true;
tabLayout.getHorizontalRecyclerView().scrollBy(offsetX_touch, 0);
rvScrolledByVp = false;
//立刻复位
rvScrolledByTouch = false;
offsetX_touch = 0;
//这里不能修改position_scroll_last，因为只要上次手指滑动了tablayout,然后手指滑动viewapger，onPageScrolled会被回调多次
//在后面去修改position_scroll_last即可
// position_scroll_last = position;
return;
}
//点击item后，onPageSelected先回调，然后还会继续回调onPageScrolled，直到onPageScrolled=position_selected，从page index 滑动到 page index+1，
//position == viewPager2.getCurrentItem() - 1说明点击的item在当前position之后
//position == viewPager2.getCurrentItem()说明点击的item在当前position之前
//viewpager滑动中，才处理，
if (scrolledByClick) {
if ((position == viewPager2.getCurrentItem() - 1 || position == viewPager2.getCurrentItem())) {
RecyclerView.ViewHolder viewHolder = tabLayout.getHorizontalRecyclerView().findViewHolderForAdapterPosition(viewPager2.getCurrentItem());
if (viewHolder != null) {
//indicator想要指向正中间，计算TabLayout需要滑动的距离
if (diff_click == 0)
diff_click = (int) (viewHolder.itemView.getLeft() + viewHolder.itemView.getWidth() * 1f / 2 - centerX);
//获取tablayout的偏移量，永远<=0
if (offsetX_last_click == 0)
offsetX_last_click = tabLayout.getHorizontalRecyclerView().getOffsetX();
if (positionOffset != 0) {
//scrollBy调用一次，onScrolled回调一次
//标志不是由手指滑动tablayout
rvScrolledByVp = true;
//往右滑
if (position_selected_last < viewPager2.getCurrentItem()) {
tabLayout.getHorizontalRecyclerView().scrollTo((int) (offsetX_last_click - (diff_click * positionOffset)), 0);
} else {
//往左滑
tabLayout.getHorizontalRecyclerView().scrollTo((int) (offsetX_last_click - (diff_click * (1 - positionOffset))), 0);
}
rvScrolledByVp = false;
}
} else {
//不可见，width_indicator为0
tabLayout.getIndicatorView().getIndicator().setWidth_indicator(0).invalidate();
}
}
position_scroll_last = position;
return;
}
/**
* 手指左右滑动Viewpager，触发下面所有代码
*/
TabViewHolder viewHolder = (TabViewHolder) tabLayout.getHorizontalRecyclerView().findViewHolderForAdapterPosition(position);
if (viewHolder != null) {
int width_half = (int) (viewHolder.itemView.getWidth() * 1f / 2);
int left = viewHolder.itemView.getLeft();
int space = tabLayout.getHorizontalRecyclerView().getItemDecoration().getSpace_horizontal();
TabViewHolder viewHolder_behind = (TabViewHolder) tabLayout.getHorizontalRecyclerView().findViewHolderForAdapterPosition(position + 1);
if (position == 0) {
//TabLayout刚显示，indicator会指向第0个item
diff = 0;
offsetX_last = 0;
if (viewHolder_behind != null)
//计算indicator指向下一个item需要滑动的距离
toScroll = (int) (width_half
+ tabLayout.getHorizontalRecyclerView().getItemDecoration().getSpace_horizontal()
+ viewHolder_behind.itemView.getWidth() * 1f / 2);
} else if (position_scroll_last < position) {
//说明从page index 滑动到了page index+1,
if (viewHolder_behind != null) {
//indicator想要指向正中间，计算TabLayout需要滑动的距离
diff = (int) (viewHolder_behind.itemView.getLeft() + viewHolder_behind.itemView.getWidth() * 1f / 2 - centerX);
//下一个item都在正中间的前面，无需滑动，而且可以避免出现负数导致recyclerView抖动
if (diff < 0) diff = 0;
//获取上次tablayout的偏移量，永远<=0
offsetX_last = tabLayout.getHorizontalRecyclerView().getOffsetX();
//计算indicator指向下一个item需要滑动的距离
toScroll = (int) (width_half
+ tabLayout.getHorizontalRecyclerView().getItemDecoration().getSpace_horizontal()
+ viewHolder_behind.itemView.getWidth() * 1f / 2);
}
} else if (position_scroll_last > position) {
//说明从page index 滑动到了page index-1
//indicator想要指向正中间，计算TabLayout需要滑动的距离
diff = (int) (left + width_half - centerX);
//position的item在正中间的后面，无需滑动，而且可以避免出现正数导致recyclerView抖动
if (diff > 0) diff = 0;
//获取上次tablayout的偏移量，永远<=0
offsetX_last = tabLayout.getHorizontalRecyclerView().getOffsetX();
if (viewHolder_behind != null)
//计算indicator指向position的item需要滑动的距离
toScroll = (int) (width_half
+ tabLayout.getHorizontalRecyclerView().getItemDecoration().getSpace_horizontal()
+ viewHolder_behind.itemView.getWidth() * 1f / 2);
} else if (op_click_last) {
//如果position_scroll_last==position,并且上次操作是点击item,
if (position == click_position_last) {
//说明现在是正要从page index 滑动到page index+1
if (viewHolder_behind != null) {
//indicator想要指向正中间，计算TabLayout需要滑动的距离
diff = (int) (viewHolder_behind.itemView.getLeft() + viewHolder_behind.itemView.getWidth() * 1f / 2 - centerX);
//获取上次tablayout的偏移量，永远<=0
offsetX_last = tabLayout.getHorizontalRecyclerView().getOffsetX();
//计算indicator指向position的item需要滑动的距离
toScroll = (int) (width_half
+ tabLayout.getHorizontalRecyclerView().getItemDecoration().getSpace_horizontal()
+ viewHolder_behind.itemView.getWidth() * 1f / 2);
}
}
op_click_last = false;
}
//diff==0,无需滑动，positionOffset==0,无需滑动，当前position和上次滑动的position相等，才执行滑动操作
if (diff != 0 && positionOffset != 0 && position_scroll_last == position) {
//标志，tabLayout滑动，不是因为手指滑动tablayout导致的
rvScrolledByVp = true;
if (diff > 0) {
//scrollBy调用一次，onScrolled回调一次
//手指往左滑动，positionOffset由小变大
tabLayout.getHorizontalRecyclerView().scrollTo((int) (offsetX_last - (diff * positionOffset)), 0);
} else {
//手指往右滑动，positionOffset由大变小
tabLayout.getHorizontalRecyclerView().scrollTo((int) (offsetX_last - (diff * (1 - positionOffset))), 0);
}
//标志复位
rvScrolledByVp = false;
}
//计算Width_indicator,Width_indicator由小变大再变小，2个item中间时最大
tabLayout.getIndicatorView().getIndicator().setWidth_indicator(Math.max(tabLayout.getIndicatorView().getIndicator().getWidth_indicator_selected(),
(int) (tabLayout.getIndicatorView().getIndicator().getWidth_indicator_selected() +
(positionOffset == 0 ? 0 : tabLayout.getIndicatorView().getIndicator().getWidth_indicator_max() * (0.5 - Math.abs(0.5 - positionOffset))))))
.setProgress((int) (left
+ width_half
- tabLayout.getIndicatorView().getIndicator().getWidth_indicator() / 2
+ (toScroll * positionOffset)));
if (toScroll != 0)
//手指往左滑动，positionOffset由小变大
//手指往右滑动，positionOffset由大变小
if (viewHolder_behind != null)
fragmentPageAdapter.onTabScrolled(viewHolder, position, false, 1 - positionOffset,
viewHolder_behind, position + 1, true, positionOffset);
} else {
//viewpager嵌套viewpager的时候，内层viewpager向右滑动了以后又向左滑动，会导致tablayout
//position对应的item不可见，所以要滑动到对应的position
tabLayout.getHorizontalRecyclerView().scrollToPosition(position);
viewHolder = (TabViewHolder) tabLayout.getHorizontalRecyclerView().findViewHolderForAdapterPosition(position);
//scrollToPosition一调用，不会立马滑动完毕，所以还会有存在null的时候，
if(viewHolder!=null){
int width_half = (int) (viewHolder.itemView.getWidth() * 1f / 2);
int left = viewHolder.itemView.getLeft();
tabLayout.getIndicatorView().getIndicator().setWidth_indicator(tabLayout.getIndicatorView().getIndicator().getWidth_indicator_selected())
.setProgress((int) (left
+ width_half
- tabLayout.getIndicatorView().getIndicator().getWidth_indicator() / 2));
}else {
tabLayout.getIndicatorView().getIndicator().setWidth_indicator(0).invalidate();
}
}
position_scroll_last = position;
}
@Override
public void onPageScrollStateChanged(int state) {
switch (state) {
case SCROLL_STATE_IDLE:
//记录上次操作的是点击item
if (scrolledByClick) {
click_position_last = viewPager2.getCurrentItem();
op_click_last = true;
}
//标志复位
scrolledByClick = false;
diff_click = 0;
offsetX_last_click = 0;
break;
}
}
});
tabLayout.setAdapter(tabAdapter);
viewPager2.setAdapter(fragmentPageAdapter);
return tabAdapter;
}
}处理过程超鸡儿复杂，千万别想着能看懂，要是能看懂，只能说明你是万中无一的绝世高手，能知道大概干了些什么就可以了。
TabLayout的item宽度均分
用LinearLayout做tablayout，每个item的weight设置为1
removeAllViews();
for (int i = 0; i < tabNoScrollAdapter.getItemCount(); i++) {
TabNoScrollViewHolder tabNoScrollViewHolder = tabNoScrollAdapter.onCreateViewHolder(i, tabNoScrollAdapter.getList_bean().get(i), this);
tabNoScrollViewHolder.setPositionAdapter(i);
sparseArrayViewHolder.put(i, tabNoScrollViewHolder);
addView(tabNoScrollViewHolder.itemView, new LinearLayout.LayoutParams(0, ViewGroup.LayoutParams.MATCH_PARENT, 1));
ItemChanged(i);
}RecyclerView的item刷新如何做到不闪烁
禁用默认的刷新动画
SimpleItemAnimator simpleItemAnimator = (SimpleItemAnimator) getItemAnimator();
if (simpleItemAnimator != null) simpleItemAnimator.setSupportsChangeAnimations(false);UML类图如下
面向接口编程（面向多态编程）的**
小编特别喜欢JAVA这门语言，小编个人认为JAVA将面向对象编程的**展现的淋漓尽致。
整个轮子用得最多的编程**就是多态，多态是设计模式和框架的基础。
接口和泛型是实现多态的2把利器。
编程**暂且稍微透露，后面小编会专门出一个SDK开发入门教程，详细讲述设计模式和多态，敬请关注。
欢迎联系、指正、批评
Github:https://github.com/AnJiaoDe
简书：https://www.jianshu.com/u/b8159d455c69
CSDN：https://blog.csdn.net/confusing_awakening
ffmpeg入门教程:https://www.jianshu.com/p/042c7847bd8a
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