RecyclerView使用——点击按钮返回顶部

recyclerView下滑到某个position,按钮显示,点击按钮返回recyclerView的顶部;

1.xml布局:

<ImageView android:id="@+id/iv_batch_top" android:layout_width="40dp" android:layout_height="40dp" android:src="@mipmap/fragment_batch_back" />

2.position>20时,将按钮显示;小于等于则隐藏;

private RecyclerView mFolderRv; .... GridLayoutManager llm = new GridLayoutManager(getMainActivity(), 1); llm.setSpanSizeLookup(new GridLayoutManager.SpanSizeLookup() { @Override public int getSpanSize(int i) { if (i <= 20) { mBackTopIv.setVisibility(View.GONE); } else { mBackTopIv.setVisibility(View.VISIBLE); } return 1;//返回 1 } }); mFolderRv.setLayoutManager(llm);

3.按钮的点击事件:

.... case R.id.iv_import_top: mFolderRv.scrollToPosition(0);//返回到顶部 即position=0; break; ...