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:

来源：https://blog.csdn.net/lbcab/article/details/54576425