Question

我想将手机更改为振动模式，但每当我点击振动按钮时，应用程序就会停止工作。

      import android.app.Activity;
      import android.media.AudioManager;
      import android.os.Bundle;
      import android.view.Menu;
      import android.view.MenuItem;
      import android.view.View;
      import android.view.View.OnClickListener;
      import android.widget.Button;

      public class MainActivity extends Activity implements View.OnClickListener {

Button vibration;
AudioManager audioControl;

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

private void initiatlize() {
    // TODO Auto-generated method stub
    Button vibration = (Button) findViewById(R.id.vibration);
    vibration.setOnClickListener(this);
    AudioManager audioControl = (AudioManager) getSystemService(Context.AUDIO_SERVICE);

}
public void onClick(View v){
    switch(v.getId()){
    case R.id.vibration: audioControl.setRingerMode(AudioManager.RINGER_MODE_VIBRATE);
        break;
    }
}

我的Manifest.xml具有以下权限：

<uses-permission android:name="android.permission.WRITE_SETTINGS"/>
<uses-permission android:name="android.permission.MODIFY_AUDIO_SETTINGS"/>
<uses-permission android:name="android.permission.CHANGE_CONFIGURATION"/>

请帮我找出错误。提前谢谢。

修改：在logCat中输出：

02-08 13:31:48.976: D/gralloc_goldfish(865): Emulator without GPU emulation detected.
02-08 13:31:56.026: D/AndroidRuntime(865): Shutting down VM
02-08 13:31:56.026: W/dalvikvm(865): threadid=1: thread exiting with uncaught exception (group=0x409961f8)
02-08 13:31:56.066: E/AndroidRuntime(865): FATAL EXCEPTION: main
02-08 13:31:56.066: E/AndroidRuntime(865): java.lang.NullPointerException
02-08 13:31:56.066: E/AndroidRuntime(865):  at com.example.collegehack.MainActivity.onClick(MainActivity.java:43)
02-08 13:31:56.066: E/AndroidRuntime(865):  at android.view.View.performClick(View.java:3480)
02-08 13:31:56.066: E/AndroidRuntime(865):  at android.view.View$PerformClick.run(View.java:13983)
02-08 13:31:56.066: E/AndroidRuntime(865):  at android.os.Handler.handleCallback(Handler.java:605)
02-08 13:31:56.066: E/AndroidRuntime(865):  at android.os.Handler.dispatchMessage(Handler.java:92)
02-08 13:31:56.066: E/AndroidRuntime(865):  at android.os.Looper.loop(Looper.java:137)
02-08 13:31:56.066: E/AndroidRuntime(865):  at android.app.ActivityThread.main(ActivityThread.java:4340)
02-08 13:31:56.066: E/AndroidRuntime(865):  at java.lang.reflect.Method.invokeNative(Native Method)
02-08 13:31:56.066: E/AndroidRuntime(865):  at java.lang.reflect.Method.invoke(Method.java:511)
02-08 13:31:56.066: E/AndroidRuntime(865):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)
02-08 13:31:56.066: E/AndroidRuntime(865):  at     com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)
02-08 13:31:56.066: E/AndroidRuntime(865):  at dalvik.system.NativeStart.main(Native Method)
02-08 13:31:58.656: I/Process(865): Sending signal. PID: 865 SIG: 9

Answer 1

不要忘记在Manifest.xml文件中包含权限：

<uses-permission android:name="android.permission.VIBRATE"/>

似乎audioControl在

处导致nullpointer

 case R.id.vibration: audioControl.setRingerMode(AudioManager.RINGER_MODE_VIBRATE);

所以将initiatlize()方法重写为

private void initiatlize() {
    // TODO Auto-generated method stub
    vibration = (Button) findViewById(R.id.vibration);
    vibration.setOnClickListener(this);
    audioControl = (AudioManager) getSystemService(Context.AUDIO_SERVICE);
}

Answer 2

尝试将此添加到权限：

uses-permission android:name="android.permission.VIBRATE"

Android手机设置更改崩溃

2 个答案: