Android中的Touch事件

 

Android中的Touch事件处理

 

主要内容

　　Activity或View类的onTouchEvent()回调函数会接收到touch事件。

　　一个完整的手势是从ACTION_DOWN开始，到ACTION_UP结束。

　　简单的情况下，我们只需要在onTouchEvent()中写个switch case语句，处理各种事件（Touch Down、 Touch Move、 Touch Up等），但是比较复杂的动作就需要更多的处理了。

　　ViewGroup作为一个parent是可以截获传向它的child的touch事件的。

　　如果一个ViewGroup的onInterceptTouchEvent()方法返回true，说明Touch事件被截获，子View不再接收到Touch事件，而是转向本ViewGroup的 onTouchEvent()方法处理。从Down开始，之后的Move，Up都会直接在onTouchEvent()方法中处理。

　　先前还在处理touch event的child view将会接收到一个 ACTION_CANCEL。

　　如果onInterceptTouchEvent()返回false，则事件会交给child view处理。

　　Android中提供了ViewGroup、View、Activity三个层次的Touch事件处理。

　　处理过程是按照Touch事件从上到下传递，再按照是否消费的返回值，从下到上返回，即如果View的onTouchEvent返回false，将会向上传给它的parent的ViewGroup，如果ViewGroup不处理，将会一直向上返回到Activity。

　　即隧道式向下分发，然后冒泡式向上处理。

Activity的Touch事件分发

　　Activity的dispatchTouchEvent (MotionEvent ev)：

    /**
     * Called to process touch screen events.  You can override this to
     * intercept all touch screen events before they are dispatched to the
     * window.  Be sure to call this implementation for touch screen events
     * that should be handled normally.
     *
     * @param ev The touch screen event.
     *
     * @return boolean Return true if this event was consumed.
     */
    public boolean dispatchTouchEvent(MotionEvent ev) {
        if (ev.getAction() == MotionEvent.ACTION_DOWN) {
            onUserInteraction();
        }
        if (getWindow().superDispatchTouchEvent(ev)) {
            return true;
        }
        return onTouchEvent(ev);
    }

　　处理屏幕触摸事件，你可以覆写这个方法来截获所有的触摸屏幕事件，是在它们分发到窗口之前截获。

　　对于要正常处理的触摸屏幕事件，要确认调用这个实现。

　　返回值为true的时候，表明这个事件被消费。

 

　　Activity的onTouchEvent (MotionEvent event)：

　　

　　

    /**
     * Called when a touch screen event was not handled by any of the views
     * under it.  This is most useful to process touch events that happen
     * outside of your window bounds, where there is no view to receive it.
     *
     * @param event The touch screen event being processed.
     *
     * @return Return true if you have consumed the event, false if you haven't.
     * The default implementation always returns false.
     */
    public boolean onTouchEvent(MotionEvent event) {
        if (mWindow.shouldCloseOnTouch(this, event)) {
            finish();
            return true;
        }

        return false;
    }

　　如果一个屏幕触摸事件没有被这个Activity下的任何View所处理，Activity的onTouchEvent将会调用。

　　这对于处理window边界之外的Touch事件非常有用，因为通常是没有View会接收到它们的。

　　返回值为true表明你已经消费了这个事件，false则表示没有消费，默认实现中返回false。

View的Touch事件

　　View的dispatchTouchEvent (MotionEvent event)：

    /**
     * Pass the touch screen motion event down to the target view, or this
     * view if it is the target.
     *
     * @param event The motion event to be dispatched.
     * @return True if the event was handled by the view, false otherwise.
     */
    public boolean dispatchTouchEvent(MotionEvent event) {
        if (mInputEventConsistencyVerifier != null) {
            mInputEventConsistencyVerifier.onTouchEvent(event, 0);
        }

        if (onFilterTouchEventForSecurity(event)) {
            //noinspection SimplifiableIfStatement
            ListenerInfo li = mListenerInfo;
            if (li != null && li.mOnTouchListener != null && (mViewFlags & ENABLED_MASK) == ENABLED
                    && li.mOnTouchListener.onTouch(this, event)) {
                return true;
            }

            if (onTouchEvent(event)) {
                return true;
            }
        }

        if (mInputEventConsistencyVerifier != null) {
            mInputEventConsistencyVerifier.onUnhandledEvent(event, 0);
        }
        return false;
    }

　　将touch屏幕的事件向下传递到目标View，或者传递到本View，如果它就是目标View。

　　如果事件被这个View处理，则返回true，否则返回false。

　　onTouchEvent (MotionEvent event)：

 /**
     * Implement this method to handle touch screen motion events.
     *
     * @param event The motion event.
     * @return True if the event was handled, false otherwise.
     */
    public boolean onTouchEvent(MotionEvent event) {
        final int viewFlags = mViewFlags;

        if ((viewFlags & ENABLED_MASK) == DISABLED) {
            if (event.getAction() == MotionEvent.ACTION_UP && (mPrivateFlags & PFLAG_PRESSED) != 0) {
                setPressed(false);
            }
            // 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));
        }

        if (mTouchDelegate != null) {
            if (mTouchDelegate.onTouchEvent(event)) {
                return true;
            }
        }

        if (((viewFlags & CLICKABLE) == CLICKABLE ||
                (viewFlags & LONG_CLICKABLE) == LONG_CLICKABLE)) {
            switch (event.getAction()) {
                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);
                       }

                        if (!mHasPerformedLongPress) {
                            // 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)) {
                                    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();
                    }
                    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();
                        }
                        postDelayed(mPendingCheckForTap, ViewConfiguration.getTapTimeout());
                    } else {
                        // Not inside a scrolling container, so show the feedback right away
                        setPressed(true);
                        checkForLongClick(0);
                    }
                    break;

                case MotionEvent.ACTION_CANCEL:
                    setPressed(false);
                    removeTapCallback();
                    removeLongPressCallback();
                    break;

                case MotionEvent.ACTION_MOVE:
                    final int x = (int) event.getX();
                    final int y = (int) event.getY();

                    // Be lenient about moving outside of buttons
                    if (!pointInView(x, y, mTouchSlop)) {
                        // Outside button
                        removeTapCallback();
                        if ((mPrivateFlags & PFLAG_PRESSED) != 0) {
                            // Remove any future long press/tap checks
                            removeLongPressCallback();

                            setPressed(false);
                        }
                    }
                    break;
            }
            return true;
        }

        return false;
    }

　　实现这个方法来处理touch屏幕的事件。

　　返回true如果这个事件被处理了。

ViewGroup的Touch事件

　　因为ViewGroup是View的子类，所以它覆写方法时会加上Override注解，如果没有覆写，则沿用父类实现，如onTouchEvent()。

　　dispatchTouchEvent (MotionEvent ev)：　

/**
     * {@inheritDoc}
     */
    @Override
    public boolean dispatchTouchEvent(MotionEvent ev) {
        if (mInputEventConsistencyVerifier != null) {
            mInputEventConsistencyVerifier.onTouchEvent(ev, 1);
        }

        boolean handled = false;
        if (onFilterTouchEventForSecurity(ev)) {
            final int action = ev.getAction();
            final int actionMasked = action & MotionEvent.ACTION_MASK;

            // Handle an initial down.
            if (actionMasked == MotionEvent.ACTION_DOWN) {
                // Throw away all previous state when starting a new touch gesture.
                // The framework may have dropped the up or cancel event for the previous gesture
                // due to an app switch, ANR, or some other state change.
                cancelAndClearTouchTargets(ev);
                resetTouchState();
            }

            // Check for interception.
            final boolean intercepted;
            if (actionMasked == MotionEvent.ACTION_DOWN
                    || mFirstTouchTarget != null) {
                final boolean disallowIntercept = (mGroupFlags & FLAG_DISALLOW_INTERCEPT) != 0;
                if (!disallowIntercept) {
                    intercepted = onInterceptTouchEvent(ev);
                    ev.setAction(action); // restore action in case it was changed
                } else {
                    intercepted = false;
                }
            } else {
                // There are no touch targets and this action is not an initial down
                // so this view group continues to intercept touches.
                intercepted = true;
            }

            // Check for cancelation.
            final boolean canceled = resetCancelNextUpFlag(this)
                    || actionMasked == MotionEvent.ACTION_CANCEL;

            // Update list of touch targets for pointer down, if needed.
            final boolean split = (mGroupFlags & FLAG_SPLIT_MOTION_EVENTS) != 0;
            TouchTarget newTouchTarget = null;
            boolean alreadyDispatchedToNewTouchTarget = false;
            if (!canceled && !intercepted) {
                if (actionMasked == MotionEvent.ACTION_DOWN
                        || (split && actionMasked == MotionEvent.ACTION_POINTER_DOWN)
                        || actionMasked == MotionEvent.ACTION_HOVER_MOVE) {
                    final int actionIndex = ev.getActionIndex(); // always 0 for down
                    final int idBitsToAssign = split ? 1 << ev.getPointerId(actionIndex)
                            : TouchTarget.ALL_POINTER_IDS;

                    // Clean up earlier touch targets for this pointer id in case they
                    // have become out of sync.
                    removePointersFromTouchTargets(idBitsToAssign);

                    final int childrenCount = mChildrenCount;
                    if (newTouchTarget == null && childrenCount != 0) {
                        final float x = ev.getX(actionIndex);
                        final float y = ev.getY(actionIndex);
                        // Find a child that can receive the event.
                        // Scan children from front to back.
                        final View[] children = mChildren;

                        final boolean customOrder = isChildrenDrawingOrderEnabled();
                        for (int i = childrenCount - 1; i >= 0; i--) {
                            final int childIndex = customOrder ?
                                    getChildDrawingOrder(childrenCount, i) : i;
                            final View child = children[childIndex];
                            if (!canViewReceivePointerEvents(child)
                                    || !isTransformedTouchPointInView(x, y, child, null)) {
                                continue;
                            }

                            newTouchTarget = getTouchTarget(child);
                            if (newTouchTarget != null) {
                                // Child is already receiving touch within its bounds.
                                // Give it the new pointer in addition to the ones it is handling.
                                newTouchTarget.pointerIdBits |= idBitsToAssign;
                                break;
                            }

                            resetCancelNextUpFlag(child);
                            if (dispatchTransformedTouchEvent(ev, false, child, idBitsToAssign)) {
                                // Child wants to receive touch within its bounds.
                                mLastTouchDownTime = ev.getDownTime();
                                mLastTouchDownIndex = childIndex;
                                mLastTouchDownX = ev.getX();
                                mLastTouchDownY = ev.getY();
                                newTouchTarget = addTouchTarget(child, idBitsToAssign);
                                alreadyDispatchedToNewTouchTarget = true;
                                break;
                            }
                        }
                    }

                    if (newTouchTarget == null && mFirstTouchTarget != null) {
                        // Did not find a child to receive the event.
                        // Assign the pointer to the least recently added target.
                        newTouchTarget = mFirstTouchTarget;
                        while (newTouchTarget.next != null) {
                            newTouchTarget = newTouchTarget.next;
                        }
                        newTouchTarget.pointerIdBits |= idBitsToAssign;
                    }
                }
            }

            // Dispatch to touch targets.
            if (mFirstTouchTarget == null) {
                // No touch targets so treat this as an ordinary view.
                handled = dispatchTransformedTouchEvent(ev, canceled, null,
                        TouchTarget.ALL_POINTER_IDS);
            } else {
                // Dispatch to touch targets, excluding the new touch target if we already
                // dispatched to it.  Cancel touch targets if necessary.
                TouchTarget predecessor = null;
                TouchTarget target = mFirstTouchTarget;
                while (target != null) {
                    final TouchTarget next = target.next;
                    if (alreadyDispatchedToNewTouchTarget && target == newTouchTarget) {
                        handled = true;
                    } else {
                        final boolean cancelChild = resetCancelNextUpFlag(target.child)
                                || intercepted;
                        if (dispatchTransformedTouchEvent(ev, cancelChild,
                                target.child, target.pointerIdBits)) {
                            handled = true;
                        }
                        if (cancelChild) {
                            if (predecessor == null) {
                                mFirstTouchTarget = next;
                            } else {
                                predecessor.next = next;
                            }
                            target.recycle();
                            target = next;
                            continue;
                        }
                    }
                    predecessor = target;
                    target = next;
                }
            }

            // Update list of touch targets for pointer up or cancel, if needed.
            if (canceled
                    || actionMasked == MotionEvent.ACTION_UP
                    || actionMasked == MotionEvent.ACTION_HOVER_MOVE) {
                resetTouchState();
            } else if (split && actionMasked == MotionEvent.ACTION_POINTER_UP) {
                final int actionIndex = ev.getActionIndex();
                final int idBitsToRemove = 1 << ev.getPointerId(actionIndex);
                removePointersFromTouchTargets(idBitsToRemove);
            }
        }

        if (!handled && mInputEventConsistencyVerifier != null) {
            mInputEventConsistencyVerifier.onUnhandledEvent(ev, 1);
        }
        return handled;
    }

　　将Touch事件向下传递到目标View，因为自身也是View，所以目标View如果是自己，则传递给自己。

　　返回true，如果这个事件是被本View所处理。

　　onInterceptTouchEvent (MotionEvent ev)

　　ViewGroup中比较特殊的一个方法。默认实现如下：

    public boolean onInterceptTouchEvent(MotionEvent ev) {
        return false;
    }

　　这个方法注释很长：

    /**
     * Implement this method to intercept all touch screen motion events.  This
     * allows you to watch events as they are dispatched to your children, and
     * take ownership of the current gesture at any point.
     *
     * <p>Using this function takes some care, as it has a fairly complicated
     * interaction with {@link View#onTouchEvent(MotionEvent)
     * View.onTouchEvent(MotionEvent)}, and using it requires implementing
     * that method as well as this one in the correct way.  Events will be
     * received in the following order:
     *
     * <ol>
     * <li> You will receive the down event here.
     * <li> The down event will be handled either by a child of this view
     * group, or given to your own onTouchEvent() method to handle; this means
     * you should implement onTouchEvent() to return true, so you will
     * continue to see the rest of the gesture (instead of looking for
     * a parent view to handle it).  Also, by returning true from
     * onTouchEvent(), you will not receive any following
     * events in onInterceptTouchEvent() and all touch processing must
     * happen in onTouchEvent() like normal.
     * <li> For as long as you return false from this function, each following
     * event (up to and including the final up) will be delivered first here
     * and then to the target's onTouchEvent().
     * <li> If you return true from here, you will not receive any
     * following events: the target view will receive the same event but
     * with the action {@link MotionEvent#ACTION_CANCEL}, and all further
     * events will be delivered to your onTouchEvent() method and no longer
     * appear here.
     * </ol>
     *
     * @param ev The motion event being dispatched down the hierarchy.
     * @return Return true to steal motion events from the children and have
     * them dispatched to this ViewGroup through onTouchEvent().
     * The current target will receive an ACTION_CANCEL event, and no further
     * messages will be delivered here.
     */

　　实现这个方法可以截获所有的Touch事件。这样你就可以控制向child分发的Touch事件。

　　一般实现这个方法，需要同时实现View.onTouchEvent(MotionEvent)方法。

　　事件是按照如下的顺序被接收的：

　　1.首先在onInterceptTouchEvent()中接收到Down事件。

　　2.Down事件将会：要么给这个ViewGroup的一个child view处理，要么是这个ViewGroup自己的onTouchEvent()处理。

　　处理意味着你应该在onTouchEvent()的实现中返回true，这样你就可以继续看到这个gesture的其他部分，如果返回false，将会返回寻找一个parent view去处理它。

　　如果在onTouchEvent()中返回true，你将不会再在onInterceptTouchEvent()再收到接下来的事件，所有的Touch处理必须放在onTouchEvent()中正常处理。

　　3.如果你在onInterceptTouchEvent()中返回false，接下来的每一个事件都会先传到onInterceptTouchEvent()，之后传递到目标view的onTouchEvent()中。

　　4.如果你在onInterceptTouchEvent()中返回true，将不会再接收到手势中的其他事件，当前的目标view将会接收到同一个事件，但是动作是 ACTION_CANCEL。其他所有的事件将会被直接传递到onTouchEvent()中，并且不再在onInterceptTouchEvent()中出现。

　　

　　onInterceptTouchEvent()的返回值：true将会从子view中偷取运动事件，把它们分配到这个ViewGroup的onTouchEvent()中，当前目标view将会接收到取消动作，并且接下来的动作都不会再经过onInterceptTouchEvent()。

　　ViewGroup的onTouchEvent()是采用父类View的默认实现，有需要的话可以覆写。

 

代码示例

 　　写了一个Demo观察输出和调用关系，代码如下：

package com.mengdd.hellotouch;

import android.util.Log;
import android.view.MotionEvent;

public class Utils {

    public static void showMotionEventType(MotionEvent event, String logTag,
            String methodName) {

        final int action = event.getActionMasked();
        switch (action) {
            case MotionEvent.ACTION_DOWN:
                Log.i(logTag, methodName + ": " + action + ": ACTION_DOWN");
                break;
            case MotionEvent.ACTION_MOVE:
                Log.i(logTag, methodName + ": " + action + ": ACTION_MOVE");
                break;
            case MotionEvent.ACTION_UP:
                Log.i(logTag, methodName + ": " + action + ": ACTION_UP");
                break;
            case MotionEvent.ACTION_CANCEL:
                Log.i(logTag, methodName + ": " + action + ": ACTION_CANCEL");
                break;

            default:
                break;
        }

    }

    public static void showReturnValue(boolean returnValue, String logTag,
            String methodName) {
        Log.w(logTag, methodName + " return: " + returnValue);
    }

    public static void showInfo(String info, String logTag, String methodName) {
        Log.e(logTag, methodName + " info: " + info);
    }
}

package com.mengdd.hellotouch;

import com.example.helloscroller.R;

import android.app.Activity;
import android.os.Bundle;
import android.view.MotionEvent;

public class HelloTouchActivity extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_hello_scroller);
    }

    @Override
    public boolean dispatchTouchEvent(MotionEvent ev) {
        Utils.showMotionEventType(ev, "Activity", "dispatchTouchEvent");
        boolean result = super.dispatchTouchEvent(ev);

        Utils.showReturnValue(result, "Activity", "dispatchTouchEvent");
        return result;
    }

    @Override
    public boolean onTouchEvent(MotionEvent event) {

        Utils.showMotionEventType(event, "Activity", "onTouchEvent");
        boolean result = super.onTouchEvent(event);
        Utils.showReturnValue(result, "Activity", "onTouchEvent");
        return result;
    }

}

package com.mengdd.hellotouch;

import android.content.Context;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;
import android.widget.LinearLayout;

public class MyViewGroup extends LinearLayout {

    public MyViewGroup(Context context, AttributeSet attrs) {
        super(context, attrs);
        init();
    }

    public MyViewGroup(Context context) {
        super(context);
        init();
    }

    private void init() {

        setOnClickListener(mOnClickListener);
        setOnLongClickListener(mOnLongClickListener);
    }

    @Override
    public boolean onInterceptTouchEvent(MotionEvent event) {
        Utils.showMotionEventType(event, "ViewGroup", "onInterceptTouchEvent");
        boolean returnValue = super.onInterceptTouchEvent(event);

        // This method JUST determines whether we want to intercept the motion.
        // If we return true, onTouchEvent will be called

        Utils.showReturnValue(returnValue, "ViewGroup", "onInterceptTouchEvent");
        return returnValue;

    }

    @Override
    public boolean dispatchTouchEvent(MotionEvent event) {
        Utils.showMotionEventType(event, "ViewGroup", "dispatchTouchEvent");
        boolean returnValue = super.dispatchTouchEvent(event);
        Utils.showReturnValue(returnValue, "ViewGroup", "dispatchTouchEvent");
        return returnValue;
    }

    // ViewGroup自己的Touch事件处理，如果在onInterceptTouchEvent返回true，则会到这里处理，不传入child
    @Override
    public boolean onTouchEvent(MotionEvent event) {
        Utils.showMotionEventType(event, "ViewGroup", "onTouchEvent");

        boolean returnValue = super.onTouchEvent(event);
        Utils.showReturnValue(returnValue, "ViewGroup", "onTouchEvent");
        return returnValue;
    }

    private OnClickListener mOnClickListener = new OnClickListener() {

        @Override
        public void onClick(View v) {
            Utils.showInfo("onClick", "ViewGroup", "mOnClickListener");
            // onClick是ACTION_UP后调用的

        }
    };

    private OnLongClickListener mOnLongClickListener = new OnLongClickListener() {

        @Override
        public boolean onLongClick(View v) {
            // onLongClick按下到一定的时间就调用了
            Utils.showInfo("onLongClick", "ViewGroup", "mOnLongClickListener");
            // 如果返回false，则长按结束的ACTION_UP调用onClick
            // 如果返回true，onLongClick后不再调用onClick
            return true;
        }
    };

}

package com.mengdd.hellotouch;

import android.content.Context;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;
import android.widget.TextView;

public class MyView extends TextView {

    public MyView(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
        init();
    }

    public MyView(Context context, AttributeSet attrs) {
        super(context, attrs);
        init();
    }

    public MyView(Context context) {
        super(context);
    }

    private void init() {

        setOnClickListener(mOnClickListener);
        setOnLongClickListener(mOnLongClickListener);
    }

    @Override
    public boolean dispatchTouchEvent(MotionEvent event) {
        Utils.showMotionEventType(event, "View", "dispatchTouchEvent");
        boolean returnValue = super.dispatchTouchEvent(event);
        Utils.showReturnValue(returnValue, "View", "dispatchTouchEvent");
        return returnValue;
    }

    @Override
    public boolean onTouchEvent(MotionEvent event) {
        Utils.showMotionEventType(event, "View", "onTouchEvent");
        boolean returnValue = super.onTouchEvent(event);
        Utils.showReturnValue(returnValue, "View", "onTouchEvent");

        return returnValue;
    }

    private OnClickListener mOnClickListener = new OnClickListener() {

        @Override
        public void onClick(View v) {
            Utils.showInfo("onClick", "View", "mOnClickListener");

        }
    };

    private OnLongClickListener mOnLongClickListener = new OnLongClickListener() {

        @Override
        public boolean onLongClick(View v) {
            Utils.showInfo("onLongClick", "View", "mOnLongClickListener");

            // 如果返回false，则长按结束的ACTION_UP调用onClick
            return false;
        }
    };

}

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context=".HelloTouchActivity" >

    <com.mengdd.hellotouch.MyViewGroup
        android:layout_width="match_parent"
        android:layout_height="match_parent" 
        android:orientation="vertical">

        <com.mengdd.hellotouch.MyView
            android:layout_width="100dp"
            android:layout_height="100dp"
            android:layout_gravity="center"
            android:text="Hello"
            android:background="#FFBBFFBB" />
    </com.mengdd.hellotouch.MyViewGroup>

</RelativeLayout>

 

Click事件处理

　　Click事件：View的短按和长按都是注册监听器的（setListener）：

　　onClick是在ACTION_UP之后执行的。

　　onLongClick则是按下到一定时间之后执行的，这个时间是ViewConfiguration中的：

　　private static final int TAP_TIMEOUT = 180; //180毫秒

　　这里需要注意onLongClick的返回值，如果是false，则onLongClick之后，手指抬起，ACTION_UP之后还是回执行到onClick；但是如果onLongClick返回true，则不会再调用onClick。

参考资料

　　本博客中：

　　Android 触摸手势基础 官方文档概览

　　http://www.cnblogs.com/mengdd/p/3335508.html

　　Android的Touch事件处理机制

　　http://www.cnblogs.com/frydsh/archive/2012/11/08/2760408.html 

　　Android FrameWork——Touch事件派发过程详解

　　http://blog.csdn.net/stonecao/article/details/6759189

　　Android事件传递机制【Touch事件】

　　http://orgcent.com/android-touch-event-mechanism/

　　Android 编程下 Touch 事件的分发和消费机制

　　http://www.cnblogs.com/sunzn/archive/2013/05/10/3064129.html