我正在尝试通过RecyclerView和ItemTouchHelper实现“滑动删除”功能。我遇到了一个奇怪的问题,但我无法找到问题所在。当我将一个项目从顶部(而不是第一个)向左滑动时,它会消失,目前为止一切正常。当我滚动并返回时,在被滑动掉的项上方有一个伪像。看起来该行未被绘制(或者可能是x轴平移?)。视频展示了这个问题。
视频步骤:
视频步骤:
- 我滑动删除第二个项目
- 向下滚动到底部
- 回来
- 项目1不再可见
- 我再次向下滚动到底部
- 我向上滚动回来
- 现在一切都好了
- 再次,但使用从顶部开始的第三个(而不是第二个)项目,同样的问题
- 再次,使用第一个项目,没有问题
public class MainActivity extends AppCompatActivity {
RecyclerView mRecyclerView;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
mRecyclerView = (RecyclerView) findViewById(R.id.recycler_view);
mRecyclerView.setLayoutManager(new LinearLayoutManager(this));
mRecyclerView.setAdapter(new TestAdapter());
setUpItemTouchHelper();
}
private void setUpItemTouchHelper() {
ItemTouchHelper.SimpleCallback simpleItemTouchCallback = new ItemTouchHelper.SimpleCallback(0, ItemTouchHelper.LEFT) {
@Override
public boolean onMove(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder, RecyclerView.ViewHolder target) {
return false;
}
@Override
public void onSwiped(RecyclerView.ViewHolder viewHolder, int swipeDir) {
int swipedPosition = viewHolder.getAdapterPosition();
TestAdapter adapter = (TestAdapter)mRecyclerView.getAdapter();
adapter.remove(swipedPosition);
}
};
ItemTouchHelper itemTouchHelper = new ItemTouchHelper(simpleItemTouchCallback);
itemTouchHelper.attachToRecyclerView(mRecyclerView);
}
static class TestAdapter extends RecyclerView.Adapter {
List<String> items;
public TestAdapter() {
items = new ArrayList<>();
// this should give us a couple of screens worth
for (int i=1; i<= 15; i++) {
items.add("Item " + i);
}
}
@Override
public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
return new TestViewHolder(parent);
}
@Override
public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) {
TestViewHolder viewHolder = (TestViewHolder)holder;
String item = items.get(position);
viewHolder.titleTextView.setText(item);
}
@Override
public int getItemCount() {
return items.size();
}
public void remove(int position) {
if (position < 0 || position >= items.size()) {
return;
}
items.remove(position);
notifyItemRemoved(position);
}
}
static class TestViewHolder extends RecyclerView.ViewHolder {
TextView titleTextView;
public TestViewHolder(ViewGroup parent) {
super(LayoutInflater.from(parent.getContext()).inflate(R.layout.row_view, parent, false));
titleTextView = (TextView) itemView.findViewById(R.id.title_text_view);
}
}
}
编辑:
我有一个解决这个问题的方法,但是我想知道它的原因以及如何真正地解决这个问题。我的方法是调用notifyDataSetChanged(),但要在动画完成后再调用(否则动画会被终止)。基本上,我添加了一个ItemDecorator并找出了动画何时结束。
mRecyclerView.addItemDecoration(new RecyclerView.ItemDecoration() {
boolean running;
@Override
public void onDraw(Canvas c, RecyclerView parent, RecyclerView.State state) {
if (parent.getItemAnimator().isRunning()) {
running = true;
}
if (running == true && !parent.getItemAnimator().isRunning()) {
// first time it's not running
running = false;
parent.getAdapter().notifyDataSetChanged();
}
super.onDraw(c, parent, state);
}
});