Android触摸事件总结
Android触摸事件总结如下：
1、触摸事件分发顺序
dispatchTouchEvent：触摸事件从上向下分发
onInterTouchEvent：拦截事件，返回true表示拦截成功，交由自己的onTouchEvent处理。
onTouchEvent：消费事件，如果消费返回true，否则返回false，事件再依次向上传递。
2、层级顺序
Activity--------layout中的根节点------ViewGroup-----当前targetView.
1.1 Activity中
dispatchTouchEvent
public boolean dispatchTouchEvent(MotionEvent ev) {
if (ev.getAction() == MotionEvent.ACTION_DOWN) {
onUserInteraction();
}
if (getWindow().superDispatchTouchEvent(ev)) { //交由view处理
return true;
}
return onTouchEvent(ev); //如果view不消费事件，则交给自己的onTouchEvent处理.
}onTouchEvent
消费事件
1.2 ViewGroup中
dispatchTouchEvent
ViewGroup重写了View中的dispatchTouchEvent
// Check for interception.
final boolean intercepted;
if (actionMasked == MotionEvent.ACTION_DOWN
|| mFirstTouchTarget != null) {
final boolean disallowIntercept = (mGroupFlags & FLAG_DISALLOW_INTERCEPT) != 0; //targetView是否设置了requestDisallowInterceptTouchEvent(true)
if (!disallowIntercept) {
intercepted = onInterceptTouchEvent(ev); //执行事件拦截
ev.setAction(action); // restore action in case it was changed
} else {
intercepted = false; //targetView不允许父容器拦截事件
}
} else {
// There are no touch targets and this action is not an initial down
// so this view group continues to intercept touches.
intercepted = true;
}onInterceptTouchEvent
拦截事件
onTouchEvent
消费事件，同View
1.3 子View中
dispatchTouchEvent
if (li != null && li.mOnTouchListener != null
&& (mViewFlags & ENABLED_MASK) == ENABLED
&& li.mOnTouchListener.onTouch(this, event)) { //如果当前View enabled，则优先执行onTouchListener，如果返回true，则不再执行onTouchEvent
result = true;
}
if (!result && onTouchEvent(event)) { //执行onTouchEvent
result = true;
}onTouchEvent
public boolean onTouchEvent(MotionEvent event) {
final float x = event.getX();
final float y = event.getY();
final int viewFlags = mViewFlags;
final int action = event.getAction();
//如果当前View.setEnabled(false);
if ((viewFlags & ENABLED_MASK) == DISABLED) {
if (action == MotionEvent.ACTION_UP && (mPrivateFlags & PFLAG_PRESSED) != 0) {
setPressed(false); //还原按下状态
}
// A disabled view that is clickable still consumes the touch
// events, it just doesn't respond to them.
return (((viewFlags & CLICKABLE) == CLICKABLE
|| (viewFlags & LONG_CLICKABLE) == LONG_CLICKABLE)
|| (viewFlags & CONTEXT_CLICKABLE) == CONTEXT_CLICKABLE);
}
if (mTouchDelegate != null) {
if (mTouchDelegate.onTouchEvent(event)) { //事件委托处理
return true;
}
}
//可点击或长按可点击
if (((viewFlags & CLICKABLE) == CLICKABLE ||
(viewFlags & LONG_CLICKABLE) == LONG_CLICKABLE) ||
(viewFlags & CONTEXT_CLICKABLE) == CONTEXT_CLICKABLE) {
switch (action) {
case MotionEvent.ACTION_UP:
boolean prepressed = (mPrivateFlags & PFLAG_PREPRESSED) != 0;
if ((mPrivateFlags & PFLAG_PRESSED) != 0 || prepressed) {
// take focus if we don't have it already and we should in
// touch mode.
boolean focusTaken = false;
if (isFocusable() && isFocusableInTouchMode() && !isFocused()) {
focusTaken = requestFocus();
}
if (prepressed) {
// The button is being released before we actually
// showed it as pressed. Make it show the pressed
// state now (before scheduling the click) to ensure
// the user sees it.
setPressed(true, x, y);
}
//如果还未执行长按事件(按下的时间不够或者没有设置LongClickListener
if (!mHasPerformedLongPress && !mIgnoreNextUpEvent) {
// This is a tap, so remove the longpress check
removeLongPressCallback();//移除长按回调
// Only perform take click actions if we were in the pressed state
if (!focusTaken) {
// Use a Runnable and post this rather than calling
// performClick directly. This lets other visual state
// of the view update before click actions start.
if (mPerformClick == null) {
mPerformClick = new PerformClick();
}
if (!post(mPerformClick)) {
performClick(); //执行点击事件
}
}
}
if (mUnsetPressedState == null) {
mUnsetPressedState = new UnsetPressedState();
}
if (prepressed) {
postDelayed(mUnsetPressedState,
ViewConfiguration.getPressedStateDuration());
} else if (!post(mUnsetPressedState)) {
// If the post failed, unpress right now
mUnsetPressedState.run();
}
removeTapCallback();
}
mIgnoreNextUpEvent = false;
break;
case MotionEvent.ACTION_DOWN:
mHasPerformedLongPress = false;
if (performButtonActionOnTouchDown(event)) {
break;
}
// Walk up the hierarchy to determine if we're inside a scrolling container.
boolean isInScrollingContainer = isInScrollingContainer();
// For views inside a scrolling container, delay the pressed feedback for
// a short period in case this is a scroll.
if (isInScrollingContainer) {
mPrivateFlags |= PFLAG_PREPRESSED;
if (mPendingCheckForTap == null) {
mPendingCheckForTap = new CheckForTap();
}
mPendingCheckForTap.x = event.getX();
mPendingCheckForTap.y = event.getY();
postDelayed(mPendingCheckForTap, ViewConfiguration.getTapTimeout());
} else {
// Not inside a scrolling container, so show the feedback right away
setPressed(true, x, y);
checkForLongClick(0);
}
break;
case MotionEvent.ACTION_CANCEL:
setPressed(false);
removeTapCallback();
removeLongPressCallback();
mInContextButtonPress = false;
mHasPerformedLongPress = false;
mIgnoreNextUpEvent = false;
break;
case MotionEvent.ACTION_MOVE:
drawableHotspotChanged(x, y);
// Be lenient about moving outside of buttons
if (!pointInView(x, y, mTouchSlop)) { //如果触摸点不在当前View上,则移除点击事件回调
// Outside button
removeTapCallback();
if ((mPrivateFlags & PFLAG_PRESSED) != 0) {
// Remove any future long press/tap checks
removeLongPressCallback();
setPressed(false);
}
}
break;
}
return true;
}
return false;
}dispatchTouchEvent、onTouchEvent、OnTouchListener、onClickListener的执行优先级？
这个要分二种情况：
1）如果点击的是容器类ViewGroup
dispatchTouchEvent----onInterceptTouchEvent-----onTouchListener----onTouchEvent（ACTION_UP时检测执行OnClickListener）
2）如果点击的是非容器类View，比如TextView
dispatchTouchEvent中执行onTouchListener，onTouch返回false，才执行onTouchEvent（ACTION_UP时检测执行OnClickListener）