Question

我正在开发一个媒体文件应用程序，用于播放存储的声音我的原始文件夹。总共有大约32个声音。这就是我的意思点击每个按钮：

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“app意外停止” 按照我的logcat窗口中的消息：

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

如何解决此问题？谢谢

Maqsood

Answer 1

您正在使用的MediaPlayer constructor的Javadoc表示如果播放器的创建失败，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，这是您看到的异常的最可能原因。

在MediaFile应用程序中处理异常

1 个答案: