Android 处理MediaFile应用程序中的异常

我正在开发一个媒体文件应用程序，用于播放存储在 我的原始文件夹。总共大约有32种声音。这就是我想要的 单击每个按钮后执行以下操作：

Button btnGrowUp = (Button) this.findViewById(R.id.GrowUp);
btnGrowUp.setOnClickListener(btnGrowUpListener);

private OnClickListener btnGrowUpListener = new OnClickListener()
{
    public void onClick(View v)
    {
        //Toast.makeText(getBaseContext(), "Grow Up audio file is being played", Toast.LENGTH_SHORT).show();

        MediaPlayer mp = MediaPlayer.create(MainScreen.this, R.raw.growup);
        mp.start();
    }
};

我得到一个运行时异常，说应用程序意外地停止了 在我的logcat窗口中查看以下消息：

12-19 12:33:05.420: WARN/dalvikvm(699): threadid=3: thread exiting with uncaught exception (group=0x4000fe70) 12-19 12:33:05.441: ERROR/AndroidRuntime(699): Uncaught handler: thread main exiting due to uncaught exception 12-19 12:33:05.460: ERROR/AndroidRuntime(699): java.lang.NullPointerException 12-19 12:33:05.460: ERROR/AndroidRuntime(699): at com.myapps.media.MainScreen$8.onClick(MainScreen.java:244) 12-19 12:33:05.460: ERROR/AndroidRuntime(699): at android.view.View.performClick(View.java:2179) 12-19 12:33:05.460: ERROR/AndroidRuntime(699): at android.view.View.onTouchEvent(View.java:3828) 12-19 12:33:05.460: ERROR/AndroidRuntime(699): at android.widget.TextView.onTouchEvent(TextView.java:6291) 12-19 12:33:05.460: ERROR/AndroidRuntime(699): at android.view.View.dispatchTouchEvent(View.java:3368) 12-19 12:33:05.460: ERROR/AndroidRuntime(699): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:863) 12-19 12:33:05.460: ERROR/AndroidRuntime(699): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:863) 12-19 12:33:05.460: ERROR/AndroidRuntime(699): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:863) 12-19 12:33:05.460: ERROR/AndroidRuntime(699): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:863) 12-19 12:33:05.460: ERROR/AndroidRuntime(699): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:863) 12-19 12:33:05.460: ERROR/AndroidRuntime(699): at com.android.internal.policy.impl.PhoneWindow $DecorView.superDispatchTouchEvent(PhoneWindow.java:1707) 12-19 12:33:05.460: ERROR/AndroidRuntime(699): at com.android.internal.policy.impl.PhoneWindow.superDispatchTouchEvent (PhoneWindow.java:1197) 12-19 12:33:05.460: ERROR/AndroidRuntime(699): at android.app.Activity.dispatchTouchEvent(Activity.java:1993) 12-19 12:33:05.460: ERROR/AndroidRuntime(699): at com.android.internal.policy.impl.PhoneWindow $DecorView.dispatchTouchEvent(PhoneWindow.java:1691) 12-19 12:33:05.460: ERROR/AndroidRuntime(699): at android.view.ViewRoot.handleMessage(ViewRoot.java:1525) 12-19 12:33:05.460: ERROR/AndroidRuntime(699): at android.os.Handler.dispatchMessage(Handler.java:99) 12-19 12:33:05.460: ERROR/AndroidRuntime(699): at android.os.Looper.loop(Looper.java:123) 12-19 12:33:05.460: ERROR/AndroidRuntime(699): at android.app.ActivityThread.main(ActivityThread.java:3948) 12-19 12:33:05.460: ERROR/AndroidRuntime(699): at java.lang.reflect.Method.invokeNative(Native Method) 12-19 12:33:05.460: ERROR/AndroidRuntime(699): at java.lang.reflect.Method.invoke(Method.java:521) 12-19 12:33:05.460: ERROR/AndroidRuntime(699): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run (ZygoteInit.java:782) 12-19 12:33:05.460: ERROR/AndroidRuntime(699): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:540) 12-19 12:33:05.460: ERROR/AndroidRuntime(699): at dalvik.system.NativeStart.main(Native Method) 12-19 12:33:05.520: INFO/Process(563): Sending signal. PID: 699 SIG: 3 12-19 12:33:05.520: INFO/dalvikvm(699): threadid=7: reacting to signal 3 12-19 12:33:05.601: INFO/dalvikvm(699): Wrote stack trace to '/data/ anr/traces.txt' 12-19 12:33:05.982: INFO/ARMAssembler(563): generated scanline__00000077:03515104_00000000_00000000 [ 27 ipp] (41 ins) at [0x27c718:0x27c7bc] in 982527 ns 12-19 12:33:06.011: INFO/ARMAssembler(563): generated scanline__00000077:03515104_00001001_00000000 [ 64 ipp] (84 ins) at [0x27c7c0:0x27c910] in 1804978 ns 如何解决这个问题？多谢各位

Maqsood

您正在使用的Javadoc表示，如果创建播放器失败，它将返回null

---

在调用start方法之前，您没有检查创建是否成功，因此根据上面的堆栈跟踪，这是您看到的异常最可能的原因。

因为代码列表中没有行号，如果您让我们知道哪一行失败，那将非常有帮助！或者使用pasty，我想上下文很重要。正在定义的匿名侦听器btnGrowUpListener被封装在一个名为MainScreen的类中，因此为了提供所需的Android上下文，需要使用MainScreen。使用这个符号。非常感谢！我已经解决了。