Question

我正在尝试使Recyclerview中的项目在向上或向下滚动时移动，这取决于子视图的Y坐标。但是，我似乎无法获得孩子们的坐标。如何获得Y坐标？我在onBindViewHolder方法中需要它，以便我可以根据它设置子视图的布局参数。

Answer 1

在您的活动/片段中：

 RecyclerView yourRecyclerView;
 FansAdapter yourRecyclerAdapter;

........

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    yourRecyclerView = (RecyclerView) findViewById(R.id.recycler_view);
    yourRecyclerView.setLayoutManager(new LinearLayoutManager(this));
    yourRecyclerView.setHasFixedSize(true);
    yourRecyclerAdapter = new YourAdapter (populateYourList(), this);
    yourRecyclerView.setAdapter(yourRecyclerAdapter);
    yourRecyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
        @Override
        public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
            super.onScrolled(recyclerView, dx, dy);
            View firstVisibleChild = recyclerView.getChildAt(0);//change if necessary. determine that item(items) you need to find 
            final ImageView imageView = (ImageView) firstVisibleChild.findViewById(R.id.item_image);
            if (null != imageView) {
             imageView.getViewTreeObserver().addOnGlobalLayoutListener(new  ViewTreeObserver.OnGlobalLayoutListener() {
                @Override
                public void onGlobalLayout() {         
                int[] locationsFrom = new int[2];
                imageView.getLocationInWindow(locationsFrom);
                int  xStart = locationsFrom[0];
                int yStart = locationsFrom[1];
                Log.d("LOG_TAG", "your item xEnd=" + xStart +" yEnd=" + yStart);
                if (null != yourRecyclerAdapter) {
                    yourRecyclerAdapter.setX(xStart);
                    yourRecyclerAdapter.setY(yStart);
                }
            }
          }
        }
    });
}

@Override
protected void onDestroy() {
    super.onDestroy();
    if (null != yourRecyclerView) {
        yourRecyclerView.clearOnScrollListeners();
    }

}

和适配器：

public class YourAdapter extends RecyclerView.Adapter<YourAdapter.YouViewHolder> {

ArrayList<String> fansList;
Context mContext;
private int x;
private int y;

public YourAdapter(ArrayList<String> fansList, Context context) {
    this.fansList = fansList;
    this.mContext = context;
}

public void setX(int x) {
    this.x = x;
}

public void setY(int y) {
    this.y = y;
}

@Override
public YouViewHolder onCreateViewHolder(ViewGroup viewGroup, int viewType) {
    if (viewGroup instanceof RecyclerView) {
        View view = LayoutInflater.from(viewGroup.getContext()).inflate(R.layout.recycle_item_fans, viewGroup, false);
        view.setFocusable(true);
        return new YouViewHolder(view);
    } else {
        throw new RuntimeException("Not bound to RecyclerView");
    }

}

@Override
public void onBindViewHolder(YouViewHolder holder, int position) {
    holder.itemName.setText(fansList.get(position));
    Log.v("LOG_TAG","x="+x+" y="+y);// use y or x
}

@Override
public int getItemCount() {
    return fansList.size();
}


//holder
public final class YouViewHolder extends RecyclerView.ViewHolder  {

    public final TextView itemName;
    public final ImageView imageView;

    public YouViewHolder(View rowView) {
        super(rowView);
        this.itemName = (TextView) rowView.findViewById(R.id.text_fan_name);
        this.imageView = (ImageView) rowView.findViewById(R.id.image_second_free);
    }
}

}

得到回收物项绝对坐标

1 个答案: