Recyclerview smoothScrollToPosition()无效问题

自定义布局管理器实现平滑滚动

最新推荐文章于 2024-07-15 22:07:50 发布

原创最新推荐文章于 2024-07-15 22:07:50 发布 · 1.2k 阅读

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文章标签：

#android #java #android studio

文章展示了如何在Android中对`SmoothCalendarLayoutManager`和`GridLayoutManager`进行重写，以实现更平滑的滚动效果。通过对`LinearSmoothScroller`的`calculateSpeedPerPixel`方法调整，控制滑动速度，使滚动看起来更自然。

对layoutmanaer重写 smoothScrollToPosition方法
参照:源码: smoothScrollToPosition

package com.google.android.material.datepicker;

import android.content.Context;
import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.LinearSmoothScroller;
import androidx.recyclerview.widget.RecyclerView;
import android.util.DisplayMetrics;

/**
 * Layout manager for {@link MaterialCalendar} that slows the scroll down to appear smoother for
 * months.
 */
class SmoothCalendarLayoutManager extends LinearLayoutManager {

  /** Default value in {@link LinearSmoothScroller} is 25f */
  private static final float MILLISECONDS_PER_INCH = 100f;

  SmoothCalendarLayoutManager(Context context, int orientation, boolean reverseLayout) {
    super(context, orientation, reverseLayout);
  }

  @Override
  public void smoothScrollToPosition(
      RecyclerView recyclerView, RecyclerView.State state, int position) {
    final LinearSmoothScroller linearSmoothScroller =
        new LinearSmoothScroller(recyclerView.getContext()) {

          @Override
          protected float calculateSpeedPerPixel(DisplayMetrics displayMetrics) {
            return MILLISECONDS_PER_INCH / displayMetrics.densityDpi;
          }
        };
    linearSmoothScroller.setTargetPosition(position);
    startSmoothScroll(linearSmoothScroller);
  }
}

   GridLayoutManager manager = new GridLayoutManager(getContext(), 2, LinearLayoutManager.VERTICAL, false){
            @Override
            public void smoothScrollToPosition(RecyclerView recyclerView, RecyclerView.State state, int position) {
                super.smoothScrollToPosition(recyclerView, state, position);
                LinearSmoothScroller smoothScroller =
                        new LinearSmoothScroller(recyclerView.getContext()) {
                            @Override
                            protected float calculateSpeedPerPixel(DisplayMetrics displayMetrics) {
                                // 返回：滑过1px时经历的时间(ms)。
                                return 150f / displayMetrics.densityDpi;
                            }

                            @Override
                            public int calculateDtToFit(int viewStart, int viewEnd, int boxStart, int boxEnd, int snapPreference) {
                                return boxStart  - viewStart;
                            }
                        };

                smoothScroller.setTargetPosition(position);
                startSmoothScroll(smoothScroller);
            }
        };