在4.0上使用onTouchListener和onClickListener的Android TextView NullPointerException
我有一个TextView，我已经分配了onTouchListener和onClickListener：
myTextView.setOnTouchListener(new OnTouchListener() { public boolean onTouch(View v, MotionEvent event) { _gestureDetector.onTouchEvent(event); return false; } }); myTextView.setOnClickListener(new OnClickListener() { public void onClick(View v) { // Show Toast Notification } }); onTouchListener将检测手势检测器的onFling（）。 这个代码没有任何问题，除了Android 4.0（冰淇淋三明治）。 使用4.0，我在“_gestureDetector.onTouchEvent（event）;”上收到NullPointerException。 （当我试图逃跑时）。
但是，如果我注释掉onClickListener，则fling将起作用，我将不会收到NullPointerException。
我假设如果触摸侦听器都返回false，则不会消耗该事件，从而允许两者都工作。
有没有人有任何想法？ 谢谢！
这是我的更多代码：
/** Called when the activity is first created. */ @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.calendar); _gestureDetector = new GestureDetector(new GestureListener()); } private class GestureListener extends SimpleOnGestureListener { @Override public boolean onDown(MotionEvent e) { return false; } @Override public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY) { if (e1.getY() - e2.getY() > SWIPE_MIN_DISTANCE && Math.abs(velocityY) > SWIPE_THRESHOLD_VELOCITY) { // Bottom to top _calendarTableLayout.removeAllViews(); int month = _calendar.get(Calendar.MONTH); _calendar.set(Calendar.MONTH, month + 1); _calendar.set(Calendar.DATE, 1); // important drawCalendar(); return true; } else if (e2.getY() - e1.getY() > SWIPE_MIN_DISTANCE && Math.abs(velocityY) > SWIPE_THRESHOLD_VELOCITY) { // Top to bottom _calendarTableLayout.removeAllViews(); int month = _calendar.get(Calendar.MONTH); _calendar.set(Calendar.MONTH, month - 1); _calendar.set(Calendar.DATE, 1); // important redrawCalendar(); return true; } return false; } @Override public void onLongPress(MotionEvent e) { // Do nothing } @Override public boolean onScroll(MotionEvent e1, MotionEvent e2, float distanceX, float distanceY) { // Do nothing return false; } @Override public void onShowPress(MotionEvent e) { // Do nothing } @Override public boolean onSingleTapUp(MotionEvent e) { // Do nothing return false; } }
堆栈跟踪：
01-27 11:12:16.406: E/AndroidRuntime(1448): FATAL EXCEPTION: main 01-27 11:12:16.406: E/AndroidRuntime(1448): java.lang.NullPointerException 01-27 11:12:16.406: E/AndroidRuntime(1448): at android.view.GestureDetector.onTouchEvent(GestureDetector.java:587) 01-27 11:12:16.406: E/AndroidRuntime(1448): at com.my.package.MyActivity$9.onTouch(MyActivity.java:287) 01-27 11:12:16.406: E/AndroidRuntime(1448): at android.view.View.dispatchTouchEvent(View.java:5481) 01-27 11:12:16.406: E/AndroidRuntime(1448): at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:1959) 01-27 11:12:16.406: E/AndroidRuntime(1448): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1728) 01-27 11:12:16.406: E/AndroidRuntime(1448): at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:1959) 01-27 11:12:16.406: E/AndroidRuntime(1448): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1728) 01-27 11:12:16.406: E/AndroidRuntime(1448): at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:1959) 01-27 11:12:16.406: E/AndroidRuntime(1448): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1728) 01-27 11:12:16.406: E/AndroidRuntime(1448): at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:1959) 01-27 11:12:16.406: E/AndroidRuntime(1448): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1728) 01-27 11:12:16.406: E/AndroidRuntime(1448): at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:1959) 01-27 11:12:16.406: E/AndroidRuntime(1448): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1728) 01-27 11:12:16.406: E/AndroidRuntime(1448): at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:1959) 01-27 11:12:16.406: E/AndroidRuntime(1448): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1728) 01-27 11:12:16.406: E/AndroidRuntime(1448): at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:1959) 01-27 11:12:16.406: E/AndroidRuntime(1448): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1728) 01-27 11:12:16.406: E/AndroidRuntime(1448): at com.android.internal.policy.impl.PhoneWindow$DecorView.superDispatchTouchEvent(PhoneWindow.java:1892) 01-27 11:12:16.406: E/AndroidRuntime(1448): at com.android.internal.policy.impl.PhoneWindow.superDispatchTouchEvent(PhoneWindow.java:1371) 01-27 11:12:16.406: E/AndroidRuntime(1448): at android.app.Activity.dispatchTouchEvent(Activity.java:2364) 01-27 11:12:16.406: E/AndroidRuntime(1448): at com.android.internal.policy.impl.PhoneWindow$DecorView.dispatchTouchEvent(PhoneWindow.java: 1840) 01-27 11:12:16.406: E/AndroidRuntime(1448): at android.view.View.dispatchPointerEvent(View.java:5662) 01-27 11:12:16.406: E/AndroidRuntime(1448): at android.view.ViewRootImpl.deliverPointerEvent(ViewRootImpl.java:2863) 01-27 11:12:16.406: E/AndroidRuntime(1448): at android.view.ViewRootImpl.handleMessage(ViewRootImpl.java:2442) 01-27 11:12:16.406: E/AndroidRuntime(1448): at android.os.Handler.dispatchMessage(Handler.java:99) 01-27 11:12:16.406: E/AndroidRuntime(1448): at android.os.Looper.loop(Looper.java:137) 01-27 11:12:16.406: E/AndroidRuntime(1448): at android.app.ActivityThread.main(ActivityThread.java:4340) 01-27 11:12:16.406: E/AndroidRuntime(1448): at java.lang.reflect.Method.invokeNative(Native Method) 01-27 11:12:16.406: E/AndroidRuntime(1448): at java.lang.reflect.Method.invoke(Method.java:511) 01-27 11:12:16.406: E/AndroidRuntime(1448): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784) 01-27 11:12:16.406: E/AndroidRuntime(1448): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551) 01-27 11:12:16.406: E/AndroidRuntime(1448): at dalvik.system.NativeStart.main(Native Method)
我的朋友，当你从_gestureDetector获得你想要处理的事件时，尝试返回true：
public boolean onTouch(View v, MotionEvent event) { if (_gestureDetector.onTouchEvent(event)) { return true; } return false; }
否则，返回false。
我看了一下GestureDetector的Android源代码（4.0.1 r1）： http ：//grepcode.com/file/repository.grepcode.com/java/ext/com.google.android/android/4.0.1_r1/android /view/GestureDetector.java?av=f
第587行似乎不是问题的根源，因为mVelocityTracker总是被该点初始化。 你知道你有4.0的哪个版本？
这可能是4.0中的一个错误，我会在这里向他们提交一个错误报告：
http://code.google.com/p/android/issues/list
同时，您是否可以将OnClickListener中的代码移动到SimpleGestureListener的OnSingleTapConfirmed方法中？ 这样，它应该仍然做正确的事情，就像你的点击监听器被注释掉，但你得到相同的行为。