how to get past 1 month data?

[yoshimaa]

I want to know how to get google fit past 30days data.
I use this way, 'aggregate, DataType.AGGREGATE_STEP_COUNT_DELTA',and 'bucketByTime(1, TimeUnit.DAYS)'
but I can not get whole 30days, only get 15 or 16days.

long aDayMills = 1000 * 60 * 60 * 24;

DataSource ESTIMATED_STEP_DELTAS = new DataSource.Builder()
                    .setDataType(DataType.TYPE_STEP_COUNT_DELTA)
                    .setType(DataSource.TYPE_DERIVED)
                    .setStreamName("estimated_steps")
                    .setAppPackageName("com.google.android.gms")
                    .build();

            for (int i = 1; i < 30; i++) {

                long start = start - (aDayMills * i);
                long end = start - (aDayMills * (i - 1)) - 1; 

                DataReadRequest readRequest = new DataReadRequest.Builder()
                        .aggregate(ESTIMATED_STEP_DELTAS, DataType.AGGREGATE_STEP_COUNT_DELTA)
                        .aggregate(DataType.TYPE_DISTANCE_DELTA, DataType.AGGREGATE_DISTANCE_DELTA)
                        .aggregate(DataType.TYPE_CALORIES_EXPENDED, DataType.AGGREGATE_CALORIES_EXPENDED)
                        .aggregate(DataType.TYPE_ACTIVITY_SEGMENT, DataType.AGGREGATE_ACTIVITY_SUMMARY)
                        .bucketByTime(1, TimeUnit.DAYS)
                        .setTimeRange(start, end, TimeUnit.MILLISECONDS)
                        .build();

                Fitness.HistoryApi.readData(googleApiClient, readRequest).setResultCallback(new com.google.android.gms.common.api.ResultCallback<DataReadResult>() {
                    @Override
                    public void onResult(@NonNull DataReadResult dataReadResult) {
                        com.google.android.gms.common.api.Status status = dataReadResult.getStatus();
                        if (status.isSuccess()) {
                            printData(dataReadResult);
                        } else {
                            Log.d(TAG, "statusCode:" + status.getStatusCode() + ",message:" + status.getStatusMessage());
                        }
                    }
                });
            }

I cannot get correct data if get whole 30days data by one request.

please tell me how to get whole past 30days fit data.
thanks.