java - 从 android 中的另一个 Activity 调用函数

Question

大家好，我是 Android 开发新手，我正在关注 THIS tutorial制作一个简单的音频管理器。但我希望某些函数位于另一个 Activity 类上，并根据相应的按钮按下来调用这些函数。其功能是:

public void vibrate(View view){
   myAudioManager.setRingerMode(AudioManager.RINGER_MODE_VIBRATE);
}
public void ring(View view){
  myAudioManager.setRingerMode(AudioManager.RINGER_MODE_NORMAL);
}
public void silent(View view){
  myAudioManager.setRingerMode(AudioManager.RINGER_MODE_SILENT);
}
public void mode(View view){
 int mod = myAudioManager.getRingerMode();
 if(mod == AudioManager.RINGER_MODE_NORMAL){
     Status.setText("Current Status: Ring");
}
else if(mod == AudioManager.RINGER_MODE_SILENT){
   Status.setText("Current Status: Silent");
}
else if(mod == AudioManager.RINGER_MODE_VIBRATE){
  Status.setText("Current Status: Vibrate");
}
else{

 }
}

有什么办法可以做到这一点吗？而且我不想使用Intent。您的帮助对我来说将是一种荣幸。交易。

发布后更新

更新了 Logcat 日志:

10-28 20:57:51.381: W/dalvikvm(1232): threadid=1: thread exiting with uncaught exception (group=0x40015560)
10-28 20:57:51.401: E/AndroidRuntime(1232): FATAL EXCEPTION: main
10-28 20:57:51.401: E/AndroidRuntime(1232): java.lang.NullPointerException
10-28 20:57:51.401: E/AndroidRuntime(1232):     at edu.shihank.audiomanager.Listeners.vibrate(Listeners.java:13)
10-28 20:57:51.401: E/AndroidRuntime(1232):     at edu.shihank.audiomanager.MainActivity$1.onClick(MainActivity.java:39)

MainActivity.java

protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    AudioManager am = (AudioManager) getSystemService(Context.AUDIO_SERVICE);

    home = (Button) findViewById(R.id.home);
    pocket = (Button) findViewById(R.id.pocket);
    silent = (Button) findViewById(R.id.silent);
    tv = (TextView) findViewById(R.id.tv);

    myAudManHolder = new Listeners();

    pocket.setOnClickListener(new OnClickListener(){

        @Override
        public void onClick(View v) {
            myAudManHolder.vibrate();
        }

    });
}

Listeners.java

public class Listeners {
AudioManager myAudMan;

public void vibrate() {
    myAudMan.setRingerMode(AudioManager.RINGER_MODE_VIBRATE);
   }
}

Answer 1

创建一个包含 AudioManager 的类

public class MainActivity extends Activity {
    private AudioManagerHolder mAudioManagerHolder;

    public void vibrate() {
        mAudioManagerHolder.vibrate();
    }

    public void mode() {
        int mod= mAudioManagerHolder.getMode();
        if(mod == AudioManager.RINGER_MODE_NORMAL){
            Status.setText("Current Status: Ring");
        }
    }
}

public class AudioManagerHolder {
    private AudioManager mAudioManager; 
    private Context mContext;

    public AudioManagerHolder(Context context) {
       mContext = context;
       mAudioManager = (AudioManager)context.getSystemService(Context.AUDIO_SERVICE);
    }

    public void vibrate(){
        mAudioManager.setRingerMode(AudioManager.RINGER_MODE_VIBRATE);
    }

    public int getMode() {
        return mAudioManager.getRingerMode();
    }
}