Android RecyclerView item選中放大被遮擋問題詳解

2019-10-22 18:12:37

字體：大中小

來源：轉載

供稿：網友

在Android TV上一般選中某個View, 都會有焦點突出放大的效果, 但是當在RecyclerView中(ListView或GridView)實現當item View執行放大動畫后會被其他的item View遮擋.

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

在實現針對TV端的自定義控件 TvRecyclerView 時遇到此問題, 最后的解決方案是:

自定義RecyclerView, 重寫getChildDrawingOrder方法, 讓選中的item最后繪制, 這樣就不會讓其他view遮擋.

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() {    //啟用子視圖排序功能    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;  }}

最好還需要設置RecyclerView的父類的屬性: clipChildren = false, clipToPadding = false, 避免邊緣的子view被父類遮擋.

<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>

使用介紹:

(1) 自定具有放大縮小的布局:

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) 放大動畫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) 子視圖的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;    }  }}

效果圖如下:

Android,RecyclerView,item,遮擋,被遮擋