在通话过程中无法打开相机闪光灯

Question

我正在尝试构建一个应用程序，其中相机闪光灯将在通话和短信传入活动中发生。但相机闪光灯在通话过程中没有打开...我写了简单的程序。

public class MainActivity extends Activity { 
    ..... 
    .... 

    public static class AlertHandler extends BroadcastReceiver { 
      @Override 
      public void onReceive(Context context, Intent intent) { 
      System.out.println("===inside oneceive"); 
      boolean incomingCall = false; 
      Parameters alertParams; 
       Camera alertCamera; 
       String callState = intent.getStringExtra(TelephonyManager.EXTRA_STATE); 
       if (null != callState && callState.equals(TelephonyManager.EXTRA_STATE_RINGING)) { 
        incomingCall = true; 
       } 
       System.out.println("===incomingCall =="+incomingCall); 

       if(incomingCall){ 
        System.out.println("OPENING CAMERA..."); 
        alertCamera = Camera.open(); 
        alertParams = alertCamera.getParameters(); 
        alertParams.setFlashMode(Parameters.FLASH_MODE_TORCH); 
        alertCamera.setParameters(alertParams); 
        alertCamera.startPreview(); 
       }     

       } 
      } 
     } 

我得到了sysout开放相机好，但现在闪光。 请帮助一些代码修复。 logcat没有错误。

在这个应用程序玩的存储区很多，它们是如何工作的？

Answer 1

使用此其工作

public class MainActivity extends ActionBarActivity { 

private static Camera camera; 
// flag to detect flash is on or off 
private static boolean isLighOn = false; 

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

    camera = Camera.open(); 

} 

public static void toggle() { 

    if (isLighOn) { 

     Log.i("info", "torch is turn off!"); 
     final Parameters p = camera.getParameters(); 
     p.setFlashMode(Parameters.FLASH_MODE_OFF); 
     camera.setParameters(p); 
     camera.stopPreview(); 
     isLighOn = false; 

    } else { 

     Log.i("info", "torch is turn on!"); 
     final Parameters p = camera.getParameters(); 
     p.setFlashMode(Parameters.FLASH_MODE_TORCH); 

     camera.setParameters(p); 
     camera.startPreview(); 
     isLighOn = true; 

    } 

} 

} 

public class AlertHandler extends BroadcastReceiver { 

boolean incomingCall = false; 

@Override 
public void onReceive(Context context, Intent intent) { 

    String callState = intent.getStringExtra(TelephonyManager.EXTRA_STATE); 

    if (null != callState 
      && callState.equals(TelephonyManager.EXTRA_STATE_RINGING)) { 
     incomingCall = true; 

    } 

    if (incomingCall) { 
     MainActivity.toggle(); 
    } else { 
     MainActivity.toggle(); 
    } 

} 
}