android.view.View#getOnFocusChangeListener ( )源码实例Demo

@NonNull
@Override
public ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
    Presenter presenter = mPresenters.get(viewType);
    Presenter.ViewHolder presenterVh = presenter.onCreateViewHolder(parent);
    View view = presenterVh.view;
    ViewHolder viewHolder = new ViewHolder(presenter, view, presenterVh);
    if (mAdapterListener != null) {
        mAdapterListener.onCreate(viewHolder);
    }
    View presenterView = viewHolder.mHolder.view;
    if (presenterView != null) {
        viewHolder.mFocusChangeListener.mChainedListener = presenterView.getOnFocusChangeListener();
        presenterView.setOnFocusChangeListener(viewHolder.mFocusChangeListener);
    }
    if (mFocusHighlight != null) {
        mFocusHighlight.onInitializeView(view);
    }
    return viewHolder;
}
 

@Override
public void onChildAttachedToWindow(View child) {
    // 设置单击事件，修复.
    if (!child.hasOnClickListeners()) {
        child.setOnClickListener(mItemListener);
    }
    // 设置焦点事件，修复.
    if (child.getOnFocusChangeListener() == null) {
        child.setOnFocusChangeListener(mItemListener);
    }
}
 

@Override
public void onChildAttachedToWindow(View child) {
    if (!ViewCompat.hasOnClickListeners(child)) {
        child.setOnClickListener(mItemListener);
    }
    child.setOnLongClickListener(mItemListener);
    if (child.getOnFocusChangeListener() == null) {
        child.setOnFocusChangeListener(mItemListener);
    }

}
 

@Override
public void onChildAttachedToWindow(View child) {
    // 设置单击事件，修复.
    if (!child.hasOnClickListeners()) {
        child.setOnClickListener(mItemListener);
    }
    // 设置焦点事件，修复.
    if (child.getOnFocusChangeListener() == null) {
        child.setOnFocusChangeListener(mItemListener);
    }
}
 

/**
 * {@link View.OnFocusChangeListener} that assigned in
 * {@link Presenter#onCreateViewHolder(ViewGroup)} may be chained, user should never change
 * {@link View.OnFocusChangeListener} after that.
 */
@Override
public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
    if (DEBUG) Log.v(TAG, "onCreateViewHolder viewType " + viewType);
    Presenter presenter = mPresenters.get(viewType);
    Presenter.ViewHolder presenterVh;
    View view;
    if (mWrapper != null) {
        view = mWrapper.createWrapper(parent);
        presenterVh = presenter.onCreateViewHolder(parent);
        mWrapper.wrap(view, presenterVh.view);
    } else {
        presenterVh = presenter.onCreateViewHolder(parent);
        view = presenterVh.view;
    }
    ViewHolder viewHolder = new ViewHolder(presenter, view, presenterVh);
    if (mAdapterListener != null) {
        mAdapterListener.onCreate(viewHolder);
    }
    View presenterView = viewHolder.mHolder.view;
    if (presenterView != null) {
        viewHolder.mFocusChangeListener.mChainedListener = presenterView.getOnFocusChangeListener();
        presenterView.setOnFocusChangeListener(viewHolder.mFocusChangeListener);
    }
    if (mFocusHighlight != null) {
        mFocusHighlight.onInitializeView(view);
    }
    return viewHolder;
}
 

@Override
protected void onLayout(boolean changed, int left, int top, int right, int bottom) {
	// To prevent undesired "focus" and "blur" events during layout caused
	// by ListView temporarily taking focus, we will disable focus events until
	// layout has finished.
	// First check for a quick exit. listView can be null, such as if window closing.
	// Starting with API 18, calling requestFocus() will trigger another layout pass of the listview,
	// resulting in an infinite loop. Here we check if the view is already focused, and stop the loop.
	if (listView == null || (Build.VERSION.SDK_INT >= 18 && listView != null && !changed && viewFocused)) {
		viewFocused = false;
		super.onLayout(changed, left, top, right, bottom);
		return;
	}
	OnFocusChangeListener focusListener = null;
	View focusedView = listView.findFocus();
	int cursorPosition = -1;
	if (focusedView != null) {
		OnFocusChangeListener listener = focusedView.getOnFocusChangeListener();
		if (listener != null && listener instanceof TiUIView) {
			//Before unfocus the current editText, store cursor position so
			//we can restore it later
			if (focusedView instanceof EditText) {
				cursorPosition = ((EditText)focusedView).getSelectionStart();
			}
			focusedView.setOnFocusChangeListener(null);
			focusListener = listener;
		}
	}
	
	//We are temporarily going to block focus to descendants 
	//because LinearLayout on layout will try to find a focusable descendant
	if (focusedView != null) {
		listView.setDescendantFocusability(ViewGroup.FOCUS_BLOCK_DESCENDANTS);
	}
	super.onLayout(changed, left, top, right, bottom);
	//Now we reset the descendant focusability
	listView.setDescendantFocusability(ViewGroup.FOCUS_AFTER_DESCENDANTS);

	TiViewProxy viewProxy = proxy;
	if (viewProxy != null && viewProxy.hasListeners(TiC.EVENT_POST_LAYOUT)) {
		viewProxy.fireEvent(TiC.EVENT_POST_LAYOUT, null);
	}

	// Layout is finished, re-enable focus events.
	if (focusListener != null) {
		// If the configuration changed, we manually fire the blur event
		if (changed) {
			focusedView.setOnFocusChangeListener(focusListener);
			focusListener.onFocusChange(focusedView, false);
		} else {
			//Ok right now focus is with listView. So set it back to the focusedView
			viewFocused = true;
			focusedView.requestFocus();
			focusedView.setOnFocusChangeListener(focusListener);
			//Restore cursor position
			if (cursorPosition != -1) {
				((EditText)focusedView).setSelection(cursorPosition);
			}
		}
	}
}