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在触摸时更改GridView中项目的背景颜色

androidgridviewontouchlistener
4

我有一个gridView布局，其中填充了textView元素。我为gridView实现了onTouch()，当触摸到的单元格需要更改背景颜色时。以下是我的代码，但它无法正常工作，并且在触摸时VM关闭。

gridView.setOnTouchListener(new OnTouchListener() {
        public boolean onTouch(View v, MotionEvent me) {

            int action = me.getActionMasked();
            float currentXPosition = me.getX();
            float currentYPosition = me.getY();
            int position = gridView.pointToPosition((int) currentXPosition, (int) currentYPosition);

            // Change the color of the key pressed
            ((TextView) gridView.getItemAtPosition(position)).setBackgroundColor(Color.RED);
            return true;
    }
}

编辑：Logcat跟踪

12-10 15:34:28.081: E/InputEventReceiver(829): Exception dispatching input event.
12-10 15:34:28.081: E/MessageQueue-JNI(829): Exception in MessageQueue callback: handleReceiveCallback
12-10 15:34:28.221: E/MessageQueue-JNI(829): java.lang.ClassCastException: java.lang.String cannot be cast to android.widget.TextView
12-10 15:34:28.221: E/MessageQueue-JNI(829):    at com.example.helloworld.GridViewActivity$1.onTouch(GridViewActivity.java:62)
12-10 15:34:28.221: E/MessageQueue-JNI(829):    at android.view.View.dispatchTouchEvent(View.java:7122)
12-10 15:34:28.221: E/MessageQueue-JNI(829):    at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2170)
12-10 15:34:28.221: E/MessageQueue-JNI(829):    at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1905)
12-10 15:34:28.221: E/MessageQueue-JNI(829):    at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2176)
12-10 15:34:28.221: E/MessageQueue-JNI(829):    at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1877)
12-10 15:34:28.221: E/MessageQueue-JNI(829):    at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2176)
12-10 15:34:28.221: E/MessageQueue-JNI(829):    at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1877)
12-10 15:34:28.221: E/MessageQueue-JNI(829):    at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2176)
12-10 15:34:28.221: E/MessageQueue-JNI(829):    at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1877)
12-10 15:34:28.221: E/MessageQueue-JNI(829):    at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2176)
12-10 15:34:28.221: E/MessageQueue-JNI(829):    at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1877)
12-10 15:34:28.221: E/MessageQueue-JNI(829):    at com.android.internal.policy.impl.PhoneWindow$DecorView.superDispatchTouchEvent(PhoneWindow.java:1925)
12-10 15:34:28.221: E/MessageQueue-JNI(829):    at com.android.internal.policy.impl.PhoneWindow.superDispatchTouchEvent(PhoneWindow.java:1379)
12-10 15:34:28.221: E/MessageQueue-JNI(829):    at android.app.Activity.dispatchTouchEvent(Activity.java:2396)
12-10 15:34:28.221: E/MessageQueue-JNI(829):    at com.android.internal.policy.impl.PhoneWindow$DecorView.dispatchTouchEvent(PhoneWindow.java:1873)
12-10 15:34:28.221: E/MessageQueue-JNI(829):    at android.view.View.dispatchPointerEvent(View.java:7307)
12-10 15:34:28.221: E/MessageQueue-JNI(829):    at android.view.ViewRootImpl.deliverPointerEvent(ViewRootImpl.java:3174)
12-10 15:34:28.221: E/MessageQueue-JNI(829):    at android.view.ViewRootImpl.deliverInputEvent(ViewRootImpl.java:3119)
12-10 15:34:28.221: E/MessageQueue-JNI(829):    at android.view.ViewRootImpl.doProcessInputEvents(ViewRootImpl.java:4155)
12-10 15:34:28.221: E/MessageQueue-JNI(829):    at android.view.ViewRootImpl.enqueueInputEvent(ViewRootImpl.java:4134)
12-10 15:34:28.221: E/MessageQueue-JNI(829):    at android.view.ViewRootImpl$WindowInputEventReceiver.onInputEvent(ViewRootImpl.java:4226)
12-10 15:34:28.221: E/MessageQueue-JNI(829):    at android.view.InputEventReceiver.dispatchInputEvent(InputEventReceiver.java:171)
12-10 15:34:28.221: E/MessageQueue-JNI(829):    at android.os.MessageQueue.nativePollOnce(Native Method)
12-10 15:34:28.221: E/MessageQueue-JNI(829):    at android.os.MessageQueue.next(MessageQueue.java:125)
12-10 15:34:28.221: E/MessageQueue-JNI(829):    at android.os.Looper.loop(Looper.java:124)
12-10 15:34:28.221: E/MessageQueue-JNI(829):    at android.app.ActivityThread.main(ActivityThread.java:4745)
12-10 15:34:28.221: E/MessageQueue-JNI(829):    at java.lang.reflect.Method.invokeNative(Native Method)
12-10 15:34:28.221: E/MessageQueue-JNI(829):    at java.lang.reflect.Method.invoke(Method.java:511)
12-10 15:34:28.221: E/MessageQueue-JNI(829):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)
12-10 15:34:28.221: E/MessageQueue-JNI(829):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
12-10 15:34:28.221: E/MessageQueue-JNI(829):    at dalvik.system.NativeStart.main(Native Method)
12-10 15:34:28.263: D/AndroidRuntime(829): Shutting down VM
12-10 15:34:28.263: W/dalvikvm(829): threadid=1: thread exiting with uncaught exception (group=0x40a13300)
12-10 15:34:28.362: E/AndroidRuntime(829): FATAL EXCEPTION: main
12-10 15:34:28.362: E/AndroidRuntime(829): java.lang.ClassCastException: java.lang.String cannot be cast to android.widget.TextView
12-10 15:34:28.362: E/AndroidRuntime(829):  at com.example.helloworld.GridViewActivity$1.onTouch(GridViewActivity.java:62)
12-10 15:34:28.362: E/AndroidRuntime(829):  at android.view.View.dispatchTouchEvent(View.java:7122)
12-10 15:34:28.362: E/AndroidRuntime(829):  at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2170)
12-10 15:34:28.362: E/AndroidRuntime(829):  at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1905)
12-10 15:34:28.362: E/AndroidRuntime(829):  at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2176)
12-10 15:34:28.362: E/AndroidRuntime(829):  at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1877)
12-10 15:34:28.362: E/AndroidRuntime(829):  at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2176)
12-10 15:34:28.362: E/AndroidRuntime(829):  at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1877)
12-10 15:34:28.362: E/AndroidRuntime(829):  at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2176)
12-10 15:34:28.362: E/AndroidRuntime(829):  at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1877)
12-10 15:34:28.362: E/AndroidRuntime(829):  at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2176)
12-10 15:34:28.362: E/AndroidRuntime(829):  at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1877)
12-10 15:34:28.362: E/AndroidRuntime(829):  at com.android.internal.policy.impl.PhoneWindow$DecorView.superDispatchTouchEvent(PhoneWindow.java:1925)
12-10 15:34:28.362: E/AndroidRuntime(829):  at com.android.internal.policy.impl.PhoneWindow.superDispatchTouchEvent(PhoneWindow.java:1379)
12-10 15:34:28.362: E/AndroidRuntime(829):  at android.app.Activity.dispatchTouchEvent(Activity.java:2396)
12-10 15:34:28.362: E/AndroidRuntime(829):  at com.android.internal.policy.impl.PhoneWindow$DecorView.dispatchTouchEvent(PhoneWindow.java:1873)
12-10 15:34:28.362: E/AndroidRuntime(829):  at android.view.View.dispatchPointerEvent(View.java:7307)
12-10 15:34:28.362: E/AndroidRuntime(829):  at android.view.ViewRootImpl.deliverPointerEvent(ViewRootImpl.java:3174)
12-10 15:34:28.362: E/AndroidRuntime(829):  at android.view.ViewRootImpl.deliverInputEvent(ViewRootImpl.java:3119)
12-10 15:34:28.362: E/AndroidRuntime(829):  at android.view.ViewRootImpl.doProcessInputEvents(ViewRootImpl.java:4155)
12-10 15:34:28.362: E/AndroidRuntime(829):  at android.view.ViewRootImpl.enqueueInputEvent(ViewRootImpl.java:4134)
12-10 15:34:28.362: E/AndroidRuntime(829):  at android.view.ViewRootImpl$WindowInputEventReceiver.onInputEvent(ViewRootImpl.java:4226)
12-10 15:34:28.362: E/AndroidRuntime(829):  at android.view.InputEventReceiver.dispatchInputEvent(InputEventReceiver.java:171)
12-10 15:34:28.362: E/AndroidRuntime(829):  at android.os.MessageQueue.nativePollOnce(Native Method)
12-10 15:34:28.362: E/AndroidRuntime(829):  at android.os.MessageQueue.next(MessageQueue.java:125)
12-10 15:34:28.362: E/AndroidRuntime(829):  at android.os.Looper.loop(Looper.java:124)
12-10 15:34:28.362: E/AndroidRuntime(829):  at android.app.ActivityThread.main(ActivityThread.java:4745)
12-10 15:34:28.362: E/AndroidRuntime(829):  at java.lang.reflect.Method.invokeNative(Native Method)
12-10 15:34:28.362: E/AndroidRuntime(829):  at java.lang.reflect.Method.invoke(Method.java:511)
12-10 15:34:28.362: E/AndroidRuntime(829):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)
12-10 15:34:28.362: E/AndroidRuntime(829):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
12-10 15:34:28.362: E/AndroidRuntime(829):  at dalvik.system.NativeStart.main(Native Method)
你能提供一个logcat跟踪吗？ - Jeremy D
2个回答
2

实际上，我搞清楚了！

我在这里将TextView强制转换为错误的返回类型。

((TextView) gridView.getItemAtPosition(position)).setBackgroundColor(Color.RED);

我真正需要的是getChildAt方法而不是getItemAtPosition方法（该方法返回一个字符串）。
String s = (String) gridView.getItemAtPosition(position);
TextView tv = (TextView) gridView.getChildAt(position);
tv.setBackgroundColor(Color.RED);
getChildAt 的位置与项目的位置不同。这会导致错误和错误的视图。 - xmen
0

使用gridView.setOnItemClickListener代替。您还将在onItemClick方法中获得位置，而不必像现在一样计算它。

编辑 我刚意识到您想在项目仍被按下时更改颜色。在这种情况下，我建议将适配器中的项目背景设置为选择器可绘制对象。

实际上，颜色应该保持“选中”状态，直到我用另一个按钮取消选择。所以，选择器不起作用。此外，我想实际触摸拖动多个项目，而不是单击一个。因此，如果我在3个单元格上进行滑动，则这3个单元格的颜色应该变为红色。 - PS376
一个选择器对你来说将是完美的！当按下或选定时，您将需要将背景设置为红色。在onItemClick函数中，将当前项目设置为已选。 - Rotem
实际上，更改所选颜色只是初始阶段。我需要执行更多与颜色无关的操作。因此，当触摸TextView项目时，我只需要一种访问它的方式。 - PS376
在这种情况下，我会通过网格适配器为网格中的每个项目添加一个触摸监听器。 - Rotem
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