九宫格的RecycleView高度封装：VerticalGridFragment
解决的问题：
- TV焦点丢失的问题
- 动画不被遮盖的的问题
拆解前先看下布局：
布局名称为： lb_vertical_grid_fragment.xml
布局代码如下：
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/browse_dummy"
android:layout_width="match_parent"
android:layout_height="match_parent" >
<android.support.v17.leanback.widget.BrowseFrameLayout
android:id="@+id/grid_frame"
android:focusable="true"
android:focusableInTouchMode="true"
android:descendantFocusability="afterDescendants"
android:layout_width="match_parent"
android:layout_height="match_parent" >
<FrameLayout
android:id="@+id/browse_grid_dock"
android:layout_width="match_parent"
android:layout_height="match_parent" />
<include layout="@layout/lb_browse_title" />
</android.support.v17.leanback.widget.BrowseFrameLayout>
</FrameLayout>
VerticalGridFragment： onCreateView 生命周期做的View绑定
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
/**
* 引入布局 lb_vertical_grid_fragment.xml
*/
ViewGroup root = (ViewGroup) inflater.inflate(R.layout.lb_vertical_grid_fragment,
container, false);
/**
* 给TitleView 设置文案和监听等
*/
setTitleView((TitleView) root.findViewById(R.id.browse_title_group));
return root;
}
VerticalGridView 是对RecycleView的封装
好吧 重点来了
@Override
public void onViewCreated(View view, Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
/**
*browse_grid_dock 九宫格容器
*/
ViewGroup gridDock = (ViewGroup) view.findViewById(R.id.browse_grid_dock);
/**
* mGridViewHolder 为VerticalGridView的ViewHolder
*/
mGridViewHolder = mGridPresenter.onCreateViewHolder(gridDock);
/**
* 将VerticalGridView 加入 gridDock
*/
gridDock.addView(mGridViewHolder.view);
/***
* 在BaseGridView 中当一个子布局在摆放好,注册回调,getGridView()就是VerticalGridView
*/
mGridViewHolder.getGridView().setOnChildLaidOutListener(mChildLaidOutListener);
mSceneAfterEntranceTransition = sTransitionHelper.createScene(gridDock, new Runnable() {
@Override
public void run() {
setEntranceTransitionState(true);
}
});
updateAdapter();
}
mGridPresenter.onCreateViewHolder(gridDock)做了一些事情，我们一起来看下VerticalGridPresenter这个类的onCreateViewHolder方法：
@Override
public final ViewHolder onCreateViewHolder(ViewGroup parent) {
/**
* 创建了VerticalGridView ViewHolder
*/
ViewHolder vh = createGridViewHolder(parent);
vh.mInitialized = false;
/**
* 创建了VerticalGridItemBridgeAdapter 适配器也创建了
*/
vh.mItemBridgeAdapter = new VerticalGridItemBridgeAdapter();
initializeGridViewHolder(vh);
if (!vh.mInitialized) {
throw new RuntimeException("super.initializeGridViewHolder() must be called");
}
return vh;
}
/**
* Subclass may override this to inflate a different layout.
*/
protected ViewHolder createGridViewHolder(ViewGroup parent) {
View root = LayoutInflater.from(parent.getContext()).inflate(
R.layout.lb_vertical_grid, parent, false);
return new ViewHolder((VerticalGridView) root.findViewById(R.id.browse_grid));
}
MVP设计思想深入人心啊，来来我们一起看下 VerticalGridPresenter
略看了下，我突然发现没什么放大动画及焦点状态的监听。继续看，在源码中看到了这个方法，其中有个适配器 ItemBridgeAdapter,使用还挺频繁，小样就是你了
@Override
public void onBindViewHolder(Presenter.ViewHolder viewHolder, Object item) {
if (DEBUG) Log.v(TAG, "onBindViewHolder " + item);
ViewHolder vh = (ViewHolder) viewHolder;
vh.mItemBridgeAdapter.setAdapter((ObjectAdapter) item);
vh.getGridView().setAdapter(vh.mItemBridgeAdapter);
}
进入 ItemBridgeAdapter 瞧瞧去
final class OnFocusChangeListener implements View.OnFocusChangeListener {
View.OnFocusChangeListener mChainedListener;
@Override
public void onFocusChange(View view, boolean hasFocus) {
if (DEBUG) Log.v(TAG, "onFocusChange " + hasFocus + " " + view
+ " mFocusHighlight" + mFocusHighlight);
if (mWrapper != null) {
view = (View) view.getParent();
}
/**
* 获取焦点的的状态处理
*/
if (mFocusHighlight != null) {
mFocusHighlight.onItemFocused(view, hasFocus);
}
if (mChainedListener != null) {
mChainedListener.onFocusChange(view, hasFocus);
}
}
}
这个方法，大胆猜测就是获取焦点后的动画处理，跳进去看一下，找到了FocusHighlightHelper
static class BrowseItemFocusHighlight implements FocusHighlightHandler {
private static final int DURATION_MS = 150;
private int mScaleIndex;
private final boolean mUseDimmer;
BrowseItemFocusHighlight(int zoomIndex, boolean useDimmer) {
if (!isValidZoomIndex(zoomIndex)) {
throw new IllegalArgumentException("Unhandled zoom index");
}
mScaleIndex = zoomIndex;
mUseDimmer = useDimmer;
}
private float getScale(Resources res) {
return mScaleIndex == ZOOM_FACTOR_NONE ? 1f :
res.getFraction(getResId(mScaleIndex), 1, 1);
}
@Override
public void onItemFocused(View view, boolean hasFocus) {
view.setSelected(hasFocus);
getOrCreateAnimator(view).animateFocus(hasFocus, false);
}
@Override
public void onInitializeView(View view) {
getOrCreateAnimator(view).animateFocus(false, true);
}
private FocusAnimator getOrCreateAnimator(View view) {
FocusAnimator animator = (FocusAnimator) view.getTag(R.id.lb_focus_animator);
if (animator == null) {
animator = new FocusAnimator(
view, getScale(view.getResources()), mUseDimmer, DURATION_MS);
view.setTag(R.id.lb_focus_animator, animator);
}
return animator;
}
}
说了这么多，总结下 VerticalGridView 放入了lb_vertical_grid_fragment.xml中的browse_grid_dock并且还创建了ViewHolder,将视图和VerticalGridFragment绑定，适配器ItemBridgeAdapter ，动画处理FocusHighlightHelper，这似乎还少一个GridLayoutManager，这个非v7里的，而是v17里的，继承RecyclerView.LayoutManager。从封装上看，v17将GridLayoutManager封到了抽象类BaseGridView,BaseGridView 继承自RecyclerView
