在TV开发中RecycleView的使用是最让人头疼的经常会出现焦点丢失。因为当item未显示时不能获取焦点。所以当我们按上下键时经常丢失焦点或者焦点乱跳。要解决这个问题我们必须要手动控制RecyclerView 的按键和焦点移动。
所以我们这里需要需要自定义RecycleView。
代码如下，各个方法作用在注视中已添加：
public class TvRecyclerView extends RecyclerView
{
//正常跟随滚动
private static final int SCROLL_NORMAL = 0;
//居中滚动
private static final int SCROLL_FOLLOW = 1;
//滚动模式
private int scrollModel;
//当前选中的position
private int mSelectedPosition = 0;
//下一个聚焦的View
private View mNextFocused;
public TvRecyclerViewNew(Context context)
{
this(context, null);
}
public TvRecyclerViewNew(Context context, AttributeSet attrs)
{
this(context, attrs, -1);
}
public TvRecyclerViewNew(Context context, AttributeSet attrs, int defStyle)
{
super(context, attrs, defStyle);
init(context, attrs, defStyle);
}
/**
* 初始化
*
* @param context
* @param attrs
* @param defStyle
*/
private void init(Context context, AttributeSet attrs, int defStyle)
{
initView();
initAttr(attrs);
}
/**
* 初始化View
* 为避免recycleview焦点混乱常用的一些设置
*/
private void initView()
{
setDescendantFocusability(FOCUS_AFTER_DESCENDANTS);
setHasFixedSize(true);
setWillNotDraw(true);
setOverScrollMode(View.OVER_SCROLL_NEVER);
setChildrenDrawingOrderEnabled(true);
setClipChildren(false);
setClipToPadding(false);
setClickable(false);
setFocusable(true);
setFocusableInTouchMode(true);
/**
防止RecyclerView刷新时焦点不错乱bug的步骤如下:
(1)adapter执行setHasStableIds(true)方法
(2)重写getItemId()方法,让每个view都有各自的id
(3)RecyclerView的动画必须去掉
*/
setItemAnimator(null);
}
/**
* 初始化样式
* 是否居中滚动
* @param attrs
*/
private void initAttr(AttributeSet attrs)
{
TypedArray typeArray = getContext().obtainStyledAttributes(attrs, R.styleable.TvRecyclerView);
scrollModel = typeArray.getInteger(R.styleable.TvRecyclerView_scrollMode, 0);
}
/**
* 恢复回收之前的状态
* @param state
*/
@Override
protected void onRestoreInstanceState(Parcelable state)
{
Bundle bundle = (Bundle) state;
Parcelable superData = bundle.getParcelable("super_data");
super.onRestoreInstanceState(superData);
setItemSelected(bundle.getInt("select_pos", 0));
}
/**
* 回收之前保存状态
* @return
*/
@Override
protected Parcelable onSaveInstanceState()
{
Bundle bundle = new Bundle();
Parcelable superData = super.onSaveInstanceState();
bundle.putParcelable("super_data", superData);
bundle.putInt("select_pos", mSelectedPosition);
return bundle;
}
/**
* 解决4.4版本抢焦点的问题
* @return
*/
@Override
public boolean isInTouchMode()
{
if (Build.VERSION.SDK_INT == 19)
{
return !(hasFocus() && !super.isInTouchMode());
} else
{
return super.isInTouchMode();
}
}
@Override
public void requestChildFocus(View child, View focused)
{
super.requestChildFocus(child, focused);
}
@Override
public boolean requestChildRectangleOnScreen(View child, Rect rect, boolean immediate)
{
final int parentLeft = getPaddingLeft();
final int parentRight = getWidth() - getPaddingRight();
final int parentTop = getPaddingTop();
final int parentBottom = getHeight() - getPaddingBottom();
final int childLeft = child.getLeft() + rect.left;
final int childTop = child.getTop() + rect.top;
final int childRight = childLeft + rect.width();
final int childBottom = childTop + rect.height();
final int offScreenLeft = Math.min(0, childLeft - parentLeft);
final int offScreenRight = Math.max(0, childRight - parentRight);
final int offScreenTop = Math.min(0, childTop - parentTop);
final int offScreenBottom = Math.max(0, childBottom - parentBottom);
final boolean canScrollHorizontal = getLayoutManager().canScrollHorizontally();
final boolean canScrollVertical = getLayoutManager().canScrollVertically();
// Favor the "start" layout direction over the end when bringing one side or the other
// of a large rect into view. If we decide to bring in end because start is already
// visible, limit the scroll such that start won't go out of bounds.
final int dx;
if (canScrollHorizontal)
{
if (ViewCompat.getLayoutDirection(this) == ViewCompat.LAYOUT_DIRECTION_RTL)
{
dx = offScreenRight != 0 ? offScreenRight
: Math.max(offScreenLeft, childRight - parentRight);
} else
{
dx = offScreenLeft != 0 ? offScreenLeft
: Math.min(childLeft - parentLeft, offScreenRight);
}
} else
{
dx = 0;
}
// Favor bringing the top into view over the bottom. If top is already visible and
// we should scroll to make bottom visible, make sure top does not go out of bounds.
final int dy;
if (canScrollVertical)
{
dy = offScreenTop != 0 ? offScreenTop : Math.min(childTop - parentTop, offScreenBottom);
} else
{
dy = 0;
}
if (dx != 0 || dy != 0)
{
if (immediate)
{
scrollBy(dx, dy);
} else
{
smoothScrollBy(dx, dy);
}
postInvalidate();
return true;
}
return false;
}
/**
* 判断是垂直，还是横向.
*/
private boolean isVertical()
{
LayoutManager manager = getLayoutManager();
if (manager != null)
{
LinearLayoutManager layout = (LinearLayoutManager) getLayoutManager();
return layout.getOrientation() == LinearLayoutManager.VERTICAL;
}
return false;
}
/**
* 滚动的相关响应
* computeScroll在父控件执行drawChild时，会调用这个方法
*/
@Override
public void computeScroll()
{
super.computeScroll();
//滚动后更新当前选中的position
if (mNextFocused != null)
{
mSelectedPosition = getChildAdapterPosition(mNextFocused);
} else
{
mSelectedPosition = getChildAdapterPosition(getFocusedChild());
}
}
/**
* 返回迭代的绘制子类索引。如果你想改变子类的绘制顺序就要重写该方法
* 提示：为了能够调用该方法，你必须首先调用setChildrenDrawingOrderEnabled(boolean)来允许子类排序
*
* @param childCount 子类个数
* @param i 当前迭代顺序
* @return 绘制该迭代子类的索引
*/
@Override
protected int getChildDrawingOrder(int childCount, int i)
{
View view = getFocusedChild();
if (null != view)
{
int position = getChildAdapterPosition(view) - getFirstVisiblePosition();
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;
}
@Override
public boolean dispatchKeyEvent(KeyEvent event)
{
boolean result = super.dispatchKeyEvent(event);
View focusView = this.getFocusedChild();
if (focusView == null)
{
return result;
} else
{
if (event.getAction() == KeyEvent.ACTION_UP)
{
//不能拦截KeyEvent.KEYCODE_BACK
//否则onBackPress不会触发
if(event.getKeyCode() == KeyEvent.KEYCODE_BACK){
return super.dispatchKeyEvent(event);
}else {
return true;
}
} else
{
switch (event.getKeyCode())
{
case KeyEvent.KEYCODE_DPAD_RIGHT:
View rightView = mNextFocused = FocusFinder.getInstance().findNextFocus(this, focusView, View.FOCUS_RIGHT);
setViewPosition(mNextFocused);
if (rightView != null)
{
rightView.requestFocus();
return true;
} else
{
return false;
}
case KeyEvent.KEYCODE_DPAD_LEFT:
View leftView = mNextFocused = FocusFinder.getInstance().findNextFocus(this, focusView, View.FOCUS_LEFT);
setViewPosition(mNextFocused);
if (leftView != null)
{
mSelectedPosition = getChildAdapterPosition(leftView);
} else
{
mSelectedPosition = getChildAdapterPosition(getFocusedChild());
}
if (leftView != null)
{
leftView.requestFocus();
return true;
} else
{
return false;
}
case KeyEvent.KEYCODE_DPAD_DOWN:
View downView = mNextFocused = FocusFinder.getInstance().findNextFocus(this, focusView, View.FOCUS_DOWN);
setViewPosition(mNextFocused);
if (downView != null)
{
downView.requestFocus();
if (scrollModel == SCROLL_NORMAL)
{
//跟随滚动直接返回true
return true;
} else
{
//居中滚动计算出滚动距离，将view滚动到中间
int downOffset = downView.getTop() + downView.getHeight() / 2 - getHeight() / 2;
this.smoothScrollBy(0, downOffset);
return true;
}
} else
{
return isBottomEdge(getLayoutManager().getPosition(this.getFocusedChild()));
}
case KeyEvent.KEYCODE_DPAD_UP:
View upView = mNextFocused = FocusFinder.getInstance().findNextFocus(this, focusView, View.FOCUS_UP);
setViewPosition(mNextFocused);
if (upView != null)
{
upView.requestFocus();
if (scrollModel == SCROLL_NORMAL)
{
return true;
} else
{
int upOffset = getHeight() / 2 - (upView.getBottom() - upView.getHeight() / 2);
this.smoothScrollBy(0, -upOffset);
return true;
}
} else
{
return isTopEdge(getLayoutManager().getPosition(this.getFocusedChild())) ;
}
}
}
}
return result;
}
private void setViewPosition(View mNextFocused){
if(mNextFocused != null){
mSelectedPosition = getChildAdapterPosition(mNextFocused);
}else {
mSelectedPosition = getChildAdapterPosition(getFocusedChild());
}
}
//防止Activity时,RecyclerView崩溃
@Override
protected void onDetachedFromWindow()
{
if (getLayoutManager() != null)
{
super.onDetachedFromWindow();
}
}
/**
* 设置选中的item
* @param position
*/
public void setItemSelected(int position)
{
if (mSelectedPosition == position)
{
return;
}
if (position >= getAdapter().getItemCount())
{
position = getAdapter().getItemCount() - 1;
}
mSelectedPosition = position;
requestLayout();
}
/**
* 是否是最右边的item，如果是竖向，表示右边，如果是横向表示下边
*
* @param childPosition
* @return
*/
public boolean isRightEdge(int childPosition)
{
LayoutManager layoutManager = getLayoutManager();
if (layoutManager instanceof GridLayoutManager)
{
GridLayoutManager gridLayoutManager = (GridLayoutManager) layoutManager;
GridLayoutManager.SpanSizeLookup spanSizeLookUp = gridLayoutManager.getSpanSizeLookup();
int totalSpanCount = gridLayoutManager.getSpanCount();
int totalItemCount = gridLayoutManager.getItemCount();
int childSpanCount = 0;
for (int i = 0; i <= childPosition; i++)
{
childSpanCount += spanSizeLookUp.getSpanSize(i);
}
if (isVertical())
{
if (childSpanCount % gridLayoutManager.getSpanCount() == 0)
{
return true;
}
} else
{
int lastColumnSize = totalItemCount % totalSpanCount;
if (lastColumnSize == 0)
{
lastColumnSize = totalSpanCount;
}
if (childSpanCount > totalItemCount - lastColumnSize)
{
return true;
}
}
} else if (layoutManager instanceof LinearLayoutManager)
{
if (isVertical())
{
return true;
} else
{
return childPosition == getLayoutManager().getItemCount() - 1;
}
}
return false;
}
/**
* 是否是最左边的item，如果是竖向，表示左方，如果是横向，表示上边
*
* @param childPosition
* @return
*/
public boolean isLeftEdge(int childPosition)
{
LayoutManager layoutManager = getLayoutManager();
if (layoutManager instanceof GridLayoutManager)
{
GridLayoutManager gridLayoutManager = (GridLayoutManager) layoutManager;
GridLayoutManager.SpanSizeLookup spanSizeLookUp = gridLayoutManager.getSpanSizeLookup();
int totalSpanCount = gridLayoutManager.getSpanCount();
int childSpanCount = 0;
for (int i = 0; i <= childPosition; i++)
{
childSpanCount += spanSizeLookUp.getSpanSize(i);
}
if (isVertical())
{
if (childSpanCount % gridLayoutManager.getSpanCount() == 1)
{
return true;
}
} else
{
if (childSpanCount <= totalSpanCount)
{
return true;
}
}
} else if (layoutManager instanceof LinearLayoutManager)
{
if (isVertical())
{
return true;
} else
{
return childPosition == 0;
}
}
return false;
}
/**
* 是否是最上边的item，以recyclerview的方向做参考
*
* @param childPosition
* @return
*/
public boolean isTopEdge(int childPosition)
{
LayoutManager layoutManager = getLayoutManager();
if (layoutManager instanceof GridLayoutManager)
{
GridLayoutManager gridLayoutManager = (GridLayoutManager) layoutManager;
GridLayoutManager.SpanSizeLookup spanSizeLookUp = gridLayoutManager.getSpanSizeLookup();
int totalSpanCount = gridLayoutManager.getSpanCount();
int childSpanCount = 0;
for (int i = 0; i <= childPosition; i++)
{
childSpanCount += spanSizeLookUp.getSpanSize(i);
}
if (isVertical())
{
if (childSpanCount <= totalSpanCount)
{
return true;
}
} else
{
if (childSpanCount % totalSpanCount == 1)
{
return true;
}
}
} else if (layoutManager instanceof LinearLayoutManager)
{
if (isVertical())
{
return childPosition == 0;
} else
{
return true;
}
}
return false;
}
/**
* 是否是最下边的item，以recyclerview的方向做参考
*
* @param childPosition
* @return
*/
public boolean isBottomEdge(int childPosition)
{
LayoutManager layoutManager = getLayoutManager();
if (layoutManager instanceof GridLayoutManager)
{
GridLayoutManager gridLayoutManager = (GridLayoutManager) layoutManager;
GridLayoutManager.SpanSizeLookup spanSizeLookUp = gridLayoutManager.getSpanSizeLookup();
int itemCount = gridLayoutManager.getItemCount();
int childSpanCount = 0;
int totalSpanCount = gridLayoutManager.getSpanCount();
for (int i = 0; i <= childPosition; i++)
{
childSpanCount += spanSizeLookUp.getSpanSize(i);
}
if (isVertical())
{
//最后一行item的个数
int lastRowCount = itemCount % totalSpanCount;
if (lastRowCount == 0)
{
lastRowCount = gridLayoutManager.getSpanCount();
}
if (childSpanCount > itemCount - lastRowCount)
{
return true;
}
} else
{
if (childSpanCount % totalSpanCount == 0)
{
return true;
}
}
} else if (layoutManager instanceof LinearLayoutManager)
{
if (isVertical())
{
return childPosition == getLayoutManager().getItemCount() - 1;
} else
{
return true;
}
}
return false;
}
/**
* 判断是否已经滑动到底部
*
* @param recyclerView
* @return
*/
private boolean isVisBottom(RecyclerView recyclerView)
{
LinearLayoutManager layoutManager = (LinearLayoutManager) recyclerView.getLayoutManager();
int lastVisibleItemPosition = layoutManager.findLastVisibleItemPosition();
int visibleItemCount = layoutManager.getChildCount();
int totalItemCount = layoutManager.getItemCount();
if (visibleItemCount > 0 && lastVisibleItemPosition == totalItemCount - 1)
{
return true;
} else
{
return false;
}
}
public int getFirstVisiblePosition()
{
if (getChildCount() == 0)
return 0;
else
return getChildAdapterPosition(getChildAt(0));
}
public int getLastVisiblePosition()
{
final int childCount = getChildCount();
if (childCount == 0)
return 0;
else
return getChildAdapterPosition(getChildAt(childCount - 1));
}
private int getFreeWidth()
{
return getWidth() - getPaddingLeft() - getPaddingRight();
}
private int getFreeHeight()
{
return getHeight() - getPaddingTop() - getPaddingBottom();
}
public int getSelectedPosition()
{
return mSelectedPosition;
}
public void setSelectionPostion(int selectionPostion)
{
mSelectedPosition = selectionPostion;
}
}
复制代码最后一点不要忘记在attrs.xml中添加TvRecycelview样式：
"scrollMode" >
"normalScroll" value="0"/>
"followScroll" value="1"/>
<declare-styleable name="TvRecyclerView">
"scrollMode"/>
declare-styleable>
复制代码