Android RecyclerView item选中放大被遮挡问题详解

在Android TV上一般选中某个View, 都会有焦点突出放大的效果, 但是当在RecyclerView中(ListView或GridView)实现当item View执行放大动画后会被其他的item View遮挡.

原因是: RecyclerView的机制是越靠后的View z-order越高, 所以bringToFront方法是不管用的.

在实现针对TV端的自定义控件 TvRecyclerView 时遇到此问题, 最后的解决方案是:

自定义RecyclerView, 重写getChildDrawingOrder方法, 让选中的item最后绘制, 这样就不会让其他view遮挡.

public class ScaleRecyclerView extends RecyclerView {

  private int mSelectedPosition = 0;

  public ScaleRecyclerView(Context context) {
    super(context);
    init();
  }

  public ScaleRecyclerView(Context context, @Nullable AttributeSet attrs) {
    super(context, attrs);
    init();
  }

  public ScaleRecyclerView(Context context, @Nullable AttributeSet attrs, int defStyle) {
    super(context, attrs, defStyle);
    init();
  }

  private void init() {
    //启用子视图排序功能
    setChildrenDrawingOrderEnabled(true);
  }

  @Override
  public void onDraw(Canvas c) {
    mSelectedPosition = getChildAdapterPosition(getFocusedChild());
    super.onDraw(c);
  }

  @Override
  protected int getChildDrawingOrder(int childCount, int i) {
    int position = mSelectedPosition;
    if (position < 0) {
      return i;
    } else {
      if (i == childCount - 1) {
        if (position > i) {
          position = i;
        }
        return position;
      }
      if (i == position) {
        return childCount - 1;
      }
    }
    return i;
  }
}

最好还需要设置RecyclerView的父类的属性: clipChildren = false, clipToPadding = false, 避免边缘的子view被父类遮挡.

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
  android:layout_width="match_parent"
  android:layout_height="match_parent"
  android:clipChildren="false"
  android:clipToPadding="false">

  <android.support.v7.widget.RecyclerView
    android:layout_width="match_parent"
    android:layout_height="245dp"
    android:layout_centerInParent="true" />

</RelativeLayout>

使用介绍:

(1) 自定具有放大缩小的布局:

public class FocusRelativeLayout extends RelativeLayout {

  private Animation scaleSmallAnimation;
  private Animation scaleBigAnimation;

  public FocusRelativeLayout(Context context) {
    super(context);
  }

  public FocusRelativeLayout(Context context, AttributeSet attrs) {
    super(context, attrs);
  }

  public FocusRelativeLayout(Context context, AttributeSet attrs, int defStyleAttr) {
    super(context, attrs, defStyleAttr);
  }

  @Override
  protected void onFocusChanged(boolean gainFocus, int direction, Rect previouslyFocusedRect) {
    super.onFocusChanged(gainFocus, direction, previouslyFocusedRect);
    if (gainFocus) {
      getRootView().invalidate();
      zoomOut();
    } else {
      zoomIn();
    }
  }

  private void zoomIn() {
    if (scaleSmallAnimation == null) {
      scaleSmallAnimation = AnimationUtils.loadAnimation(getContext(), R.anim.anim_scale_small);
    }
    startAnimation(scaleSmallAnimation);
  }

  private void zoomOut() {
    if (scaleBigAnimation == null) {
      scaleBigAnimation = AnimationUtils.loadAnimation(getContext(), R.anim.anim_scale_big);
    }
    startAnimation(scaleBigAnimation);
  }
}

(2) 放大动画xml配置如下:

<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android"
  android:fillAfter="true"
  android:shareInterpolator="false">
  <scale
    android:duration="150"
    android:fromXScale="1.0"
    android:fromYScale="1.0"
    android:interpolator="@android:anim/accelerate_decelerate_interpolator"
    android:pivotX="50.0%"
    android:pivotY="50.0%"
    android:repeatCount="0"
    android:toXScale="1.08"
    android:toYScale="1.08" />
</set>

(3) 主布局xml:

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
  android:layout_width="match_parent"
  android:layout_height="match_parent"
  android:clipChildren="false"
  android:clipToPadding="false">

  <com.app.tvviewpager.ScaleRecyclerView
    android:id="@+id/main_recyclerView"
    android:layout_width="match_parent"
    android:layout_height="210dp"
    android:layout_centerInParent="true"/>

</RelativeLayout>

(4) 子视图的xml:

<FocusRelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
  android:id="@+id/rl_main_layout"
  android:layout_width="300dp"
  android:layout_height="210dp"
  android:focusable="true">

  <TextView
    android:layout_width="300dp"
    android:layout_height="30dp"
    android:layout_alignParentBottom="true" />
</FocusRelativeLayout>

(5) adapter配置:

public class MyAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> {
  private Context mContext;
  private OnItemStateListener mListener;
  private static int[] mColorIds = {R.color.amber, R.color.brown, R.color.cyan,
      R.color.deepPurple, R.color.green, R.color.lightBlue, R.color.lightGreen,
      R.color.lime, R.color.orange, R.color.pink, R.color.cyan, R.color.deepPurple};
  MyAdapter(Context context) {
    mContext = context;
  }

  public void setOnItemStateListener(OnItemStateListener listener) {
    mListener = listener;
  }

  @Override
  public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
    return new RecyclerViewHolder(View.inflate(mContext, R.layout.item_recyclerview, null));
  }

  @Override
  public void onBindViewHolder(RecyclerView.ViewHolder holder, final int position) {
    final RecyclerViewHolder viewHolder = (RecyclerViewHolder) holder;
    viewHolder.mRelativeLayout.setBackgroundColor(ContextCompat.getColor(mContext, mColorIds[position]));
  }

  @Override
  public int getItemCount() {
    return mColorIds.length;
  }

  private class RecyclerViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener {

    FocusRelativeLayout mRelativeLayout;

    RecyclerViewHolder(View itemView) {
      super(itemView);
      mRelativeLayout = (FocusRelativeLayout) itemView.findViewById(R.id.rl_main_layout);
      mRelativeLayout.setOnClickListener(this);
    }

    @Override
    public void onClick(View v) {
      if (mListener != null) {
        mListener.onItemClick(v, getAdapterPosition());
      }
    }
  }

  public interface OnItemStateListener {
    void onItemClick(View view, int position);
  }
}

(6) Activity中的配置:

public class RecyclerActivity extends AppCompatActivity {
  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_recycler);
    final ScaleRecyclerView recyclerView = (ScaleRecyclerView) findViewById(R.id.main_recyclerView);
    GridLayoutManager manager = new GridLayoutManager(RecyclerActivity.this, 1);
    manager.setOrientation(LinearLayoutManager.HORIZONTAL);
    manager.supportsPredictiveItemAnimations();
    recyclerView.setLayoutManager(manager);
    int itemSpace = getResources().
        getDimensionPixelSize(R.dimen.recyclerView_item_space);
    recyclerView.addItemDecoration(new SpaceItemDecoration(itemSpace));
    final MyAdapter mAdapter = new MyAdapter(RecyclerActivity.this);
    recyclerView.setAdapter(mAdapter);
  }

  private class SpaceItemDecoration extends RecyclerView.ItemDecoration {
    private int space;
    SpaceItemDecoration(int space) {
      this.space = space;
    }

    @Override
    public void getItemOffsets(Rect outRect, View view, RecyclerView parent,
                  RecyclerView.State state) {
      outRect.left = space;
    }
  }
}

效果图如下:

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