setEnabled
设置为true,相当于激活事件,对触摸产生反应,而设置成false。
无论是否设置setClickable
为false
还是true都不可点击,无法响应事件.
Button click = findViewById(R.id.click);
//click.setClickable(false);
//click.setEnabled(true);
//设置false无法响应任何点击事件
//click.setEnabled(false);
click.setOnClickListener(this);
//只有在onClickListener事件之后设置clickable为false才可以不能点击,不响应事件,否则之前设置还是可以点击,但是设置false之后,但是还会产生一闪一闪变化 click.setClickable(false);
public boolean dispatchTouchEvent(MotionEvent event) {
// If the event should be handled by accessibility focus first.
if (event.isTargetAccessibilityFocus()) {
// We don't have focus or no virtual descendant has it, do not handle the event.
if (!isAccessibilityFocusedViewOrHost()) {
return false;
}
// We have focus and got the event, then use normal event dispatch.
event.setTargetAccessibilityFocus(false);
}
boolean result = false;
if (mInputEventConsistencyVerifier != null) {
mInputEventConsistencyVerifier.onTouchEvent(event, 0);
}
final int actionMasked = event.getActionMasked();
if (actionMasked == MotionEvent.ACTION_DOWN) {
// Defensive cleanup for new gesture
stopNestedScroll();
}
//onFilterTouchEventForSecurity判断当前View是否被遮盖
if (onFilterTouchEventForSecurity(event)) {
if ((mViewFlags & ENABLED_MASK) == ENABLED && handleScrollBarDragging(event)) {
result = true;
}
//noinspection SimplifiableIfStatement
ListenerInfo li = mListenerInfo;
//li对象不会为空,但mOnTouchListener对象是不是为空根据该控件是否注册类setOnTouchListener监听
if (li != null && li.mOnTouchListener != null
//如果控件不是enabled的那么onTouch方法就不会执行
&& (mViewFlags & ENABLED_MASK) == ENABLED
//mOnTouchListener.onTouch是否返回true,根据onTouch方法是否返回为true有关
&& li.mOnTouchListener.onTouch(this, event)) {
result = true;
}
//如果上面都成立,此时result为true,那么下面onTouchEvent就不会执行,否则只要上面有一个不成立,并且onTouchEvent
//返回true就会执行result=true方法,如果onTouchEvent返回false就不执行,dispatchTouchEvent就返回false,
//dispatchTouchEvent返回结果与上面代码与下面代码是否成立有关
if (!result && onTouchEvent(event)) {
result = true;
}
}
if (!result && mInputEventConsistencyVerifier != null) {
mInputEventConsistencyVerifier.onUnhandledEvent(event, 0);
}
// Clean up after nested scrolls if this is the end of a gesture;
// also cancel it if we tried an ACTION_DOWN but we didn't want the rest
// of the gesture.
if (actionMasked == MotionEvent.ACTION_UP ||
actionMasked == MotionEvent.ACTION_CANCEL ||
(actionMasked == MotionEvent.ACTION_DOWN && !result)) {
stopNestedScroll();
}
return result;
}
dispatchTouchEvent
源码分析总结:dispatchTouchEvent
方法开始进行分发的onTouchListener
方法,后执行onTouchEvent
方法,也就是onTouch
方法优先于onClick
方法执行,原因由于onClick方法在onTouchEvent
方法之调用performClick
获取,而onTouchListener
方法优先于onTouchevent
方法,所以onTouch
优先于onClick
方法执行onTouchListener
返回false就是控件没有设置setOnTouchListener
方法,或者控件enabled属性为false,就执行onTouchEvent
方法,否则不执行onTouchEvent
方法,最后dispatchEvent
方法返回值也就是onTouchEvent方法返回值dispatchEvent
就返回true,而onTouchEvent
方法就不会执行public boolean onTouchEvent(MotionEvent event) {
final float x = event.getX();
final float y = event.getY();
final int viewFlags = mViewFlags;
final int action = event.getAction();
final boolean clickable = ((viewFlags & CLICKABLE) == CLICKABLE
|| (viewFlags & LONG_CLICKABLE) == LONG_CLICKABLE)
|| (viewFlags & CONTEXT_CLICKABLE) == CONTEXT_CLICKABLE;
//如果当前view是disabled并且可以点击则消费事件
if ((viewFlags & ENABLED_MASK) == DISABLED) {
if (action == MotionEvent.ACTION_UP && (mPrivateFlags & PFLAG_PRESSED) != 0) {
setPressed(false);
}
mPrivateFlags3 &= ~PFLAG3_FINGER_DOWN;
// A disabled view that is clickable still consumes the touch
// events, it just doesn't respond to them.
return clickable;
}
if (mTouchDelegate != null) {
//这里调用了TouchDelegate类中的onTouchEvent方法,该方法是dispatchEvent返回为true时,才返回true,此时
onTouchEvent就返回true,将事件交给代理者处理
if (mTouchDelegate.onTouchEvent(event)) {
return true;
}
}
//如果view可以点击并且长按则一定返回true
if (clickable || (viewFlags & TOOLTIP) == TOOLTIP) {
switch (action) {
//抬起事件
case MotionEvent.ACTION_UP:
mPrivateFlags3 &= ~PFLAG3_FINGER_DOWN;
//判断是否是长按事件
if ((viewFlags & TOOLTIP) == TOOLTIP) {
handleTooltipUp();
}
//没有设置长按事件点击
if (!clickable) {
removeTapCallback();
//移除长按点击runnable
removeLongPressCallback();
mInContextButtonPress = false;
//设置长按点击false
mHasPerformedLongPress = false;
mIgnoreNextUpEvent = false;
break;
}
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);
}
if (!mHasPerformedLongPress && !mIgnoreNextUpEvent) {
// This is a tap, so remove the longpress check
removeLongPressCallback();
// 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)) {
//在ACTION_UP中调用了onClick监听
performClick();
}
}
}
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:
if (event.getSource() == InputDevice.SOURCE_TOUCHSCREEN) {
mPrivateFlags3 |= PFLAG3_FINGER_DOWN;
}
//表示长按事件还未触发
mHasPerformedLongPress = false;
//clickable为false,或者没有设置长按事件
if (!clickable) {
//检查长按事件监听
checkForLongClick(0, x, y);
break;
}
//返回true,表示actiondowm事件被消费
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();
//发送延迟消息,时间为100毫秒,mPendingCheckForTap是CheckForTap实现了runnable接口
postDelayed(mPendingCheckForTap, ViewConfiguration.getTapTimeout());
} else {
// Not inside a scrolling container, so show the feedback right away
//设置当前控件按下状态并提供触摸坐标动画提示
setPressed(true, x, y);
//检查长按事件
checkForLongClick(0, x, y);
}
break;
case MotionEvent.ACTION_CANCEL:
//判断控件是否设置clickable或者是否是长按事件
if (clickable) {
setPressed(false);
}
removeTapCallback();
removeLongPressCallback();
mInContextButtonPress = false;
mHasPerformedLongPress = false;
mIgnoreNextUpEvent = false;
mPrivateFlags3 &= ~PFLAG3_FINGER_DOWN;
break;
case MotionEvent.ACTION_MOVE:
if (clickable) {
//当前view视图中的点发生改变时,才有必要传入到被视图管理的drawable与子视图中
drawableHotspotChanged(x, y);
}
//如果用户手指移出控件,就移除所有的监听,移除Action_down设置的检测与长按
// Be lenient about moving outside of buttons
if (!pointInView(x, y, mTouchSlop)) {
// Outside button
// Remove any future long press/tap checks
removeTapCallback();
//去除标示,刷新背景
removeLongPressCallback();
if ((mPrivateFlags & PFLAG_PRESSED) != 0) {
setPressed(false);
}
mPrivateFlags3 &= ~PFLAG3_FINGER_DOWN;
}
break;
}
return true;
}
return false;
}
private void checkForLongClick(int delayOffset, float x, float y) {
//判断是否是长按事件监听
if ((mViewFlags & LONG_CLICKABLE) == LONG_CLICKABLE || (mViewFlags & TOOLTIP) == TOOLTIP) {
mHasPerformedLongPress = false;
if (mPendingCheckForLongPress == null) {
mPendingCheckForLongPress = new CheckForLongPress();
}
mPendingCheckForLongPress.setAnchor(x, y);
mPendingCheckForLongPress.rememberWindowAttachCount();
mPendingCheckForLongPress.rememberPressedState();
//发送一个延迟消息
postDelayed(mPendingCheckForLongPress,
ViewConfiguration.getLongPressTimeout() - delayOffset);
}
}
private void handleTooltipUp() {
if (mTooltipInfo == null || mTooltipInfo.mTooltipPopup == null) {
return;
}
//移除消息队列中特殊的runnable
removeCallbacks(mTooltipInfo.mHideTooltipRunnable);
//发送延迟消息,延迟1500毫秒
postDelayed(mTooltipInfo.mHideTooltipRunnable,
ViewConfiguration.getLongPressTooltipHideTimeout());
}
//在ACTION_UP中调用
public boolean performClick() {
final boolean result;
final ListenerInfo li = mListenerInfo;
//控件只要onclickListener不为空,也就是该控件调用了setOnClickListener监听,result就返回true否则返回false
if (li != null && li.mOnClickListener != null) {
playSoundEffect(SoundEffectConstants.CLICK);
li.mOnClickListener.onClick(this);
result = true;
} else {
result = false;
}
sendAccessibilityEvent(AccessibilityEvent.TYPE_VIEW_CLICKED);
notifyEnterOrExitForAutoFillIfNeeded(true);
return result;
}
//控件调用了setOnClickLisener监听,如果控件是disclickable就设置clickable为true
public void setOnClickListener(@Nullable OnClickListener l) {
if (!isClickable()) {
setClickable(true);
}
getListenerInfo().mOnClickListener = l;
}
public boolean onTouchEvent(MotionEvent event) {
int x = (int)event.getX();
int y = (int)event.getY();
boolean sendToDelegate = false;
boolean hit = true;
boolean handled = false;
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
Rect bounds = mBounds;
//只有点击的在该控件区域时,才会触发action_down事件
if (bounds.contains(x, y)) {
mDelegateTargeted = true;
sendToDelegate = true;
}
break;
case MotionEvent.ACTION_UP:
case MotionEvent.ACTION_MOVE:
sendToDelegate = mDelegateTargeted;
if (sendToDelegate) {
Rect slopBounds = mSlopBounds;
if (!slopBounds.contains(x, y)) {
hit = false;
}
}
break;
case MotionEvent.ACTION_CANCEL:
sendToDelegate = mDelegateTargeted;
mDelegateTargeted = false;
break;
}
if (sendToDelegate) {
final View delegateView = mDelegateView;
if (hit) {
// Offset event coordinates to be inside the target view
event.setLocation(delegateView.getWidth() / 2, delegateView.getHeight() / 2);
} else {
// Offset event coordinates to be outside the target view (in case it does
// something like tracking pressed state)
int slop = mSlop;
event.setLocation(-(slop * 2), -(slop * 2));
}
//只有view的dispatchEvent返回为true,handled才返回true
handled = delegateView.dispatchTouchEvent(event);
}
return handled;
}
onTouchEvent
源码分析总结:这两个方法都是在 View 的 dispatchTouchEvent
中调用的,onTouch
优先于 onTouchEvent
执行。如果在 onTouch
方法中通过返回 true 将事件消费掉,onTouchEvent
将不会再执行。
onTouch 执行需要满足两个条件:
mOnTouchListener
的值不能为空
if (onFilterTouchEventForSecurity(event)) {
//noinspection SimplifiableIfStatement
ListenerInfo li = mListenerInfo;
if (li != null && li.mOnTouchListener != null
&& (mViewFlags & ENABLED_MASK) == ENABLED
&& li.mOnTouchListener.onTouch(this, event)) {
result = true;
}
if (!result && onTouchEvent(event)) {
result = true;
}
}
onTouch
事件要先于onClick
事件执行,onTouch在事件分发方法dispatchTouchEvent中调用,而onClick
在事件处理方法onTouchEvent
中被调用,onTouchEvent
要后于dispatchTouchEvent
方法的调用。