Android相机应用程序 - 暂停/退出时出错

Question

每次我退出/暂停我的相机活动时，我的应用程序都会崩溃。我认为这可能与在暂停/退出时释放相机有关，但我不确定在何处执行此操作。一个解释将不胜感激。谢谢！

---

CameraActivity.java

---

public class CameraActivity extends Activity { 
Preview preview; 
Button buttonClick; 

public void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.main); 

    preview = new Preview(this); 

    ((FrameLayout) findViewById(R.id.preview)).addView(preview); 

    buttonClick = (Button) findViewById(R.id.buttonClick); 

    buttonClick.setOnClickListener(new OnClickListener() { 
     @Override 
     public void onClick(View v) { 
      preview.camera.takePicture(shutterCallback, rawCallback, 
        jpegCallback); 
     } 
    }); 
} 

ShutterCallback shutterCallback = new ShutterCallback() { 
    @Override 
    public void onShutter() { 
    } 
}; 

PictureCallback rawCallback = new PictureCallback() { 
    @Override 
    public void onPictureTaken(byte[] data, Camera camera) { 
    } 
}; 

PictureCallback jpegCallback = new PictureCallback() { // <8> 
    @Override 
    public void onPictureTaken(byte[] data, Camera camera) { 
        doSomeStuff();       
     } catch (FileNotFoundException e) { 
      e.printStackTrace(); 
     } catch (IOException e) { 
      e.printStackTrace(); 
     } finally { 
      camera.stopPreview(); 
      camera.startPreview(); 
     } 
    } 
}; 
} 

---

Preview.java

---

public class Preview extends SurfaceView implements SurfaceHolder.Callback { 
SurfaceHolder mHolder; 
public Camera camera; 

Preview(Context context) { 
    super(context); 

    mHolder = getHolder(); 
    mHolder.addCallback(this); 
    mHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS); 
} 

public void surfaceCreated(SurfaceHolder holder) { 
    camera = Camera.open(); 
    camera.setDisplayOrientation(90); 

    try { 

     camera.setPreviewDisplay(holder); 
     camera.setPreviewCallback(new PreviewCallback() { 
      public void onPreviewFrame(byte[] data, Camera camera) { 
       Preview.this.invalidate(); 
      } 
     }); 
    } catch (IOException e) { 
     e.printStackTrace(); 
    } 
} 

public void surfaceDestroyed(SurfaceHolder holder) { 
    camera.stopPreview(); 
    camera.release(); 
    camera = null; 
} 

public void surfaceChanged(SurfaceHolder holder, int format, int w, int h) { 
    camera.startPreview(); 
} 

} 

编辑：这里的例外

08-18 01:18:50.242: ERROR/AndroidRuntime(10222): FATAL EXCEPTION: main 
08-18 01:18:50.242: ERROR/AndroidRuntime(10222): java.lang.RuntimeException: Method called after release() 
08-18 01:18:50.242: ERROR/AndroidRuntime(10222):  at android.hardware.Camera.setHasPreviewCallback(Native Method) 
08-18 01:18:50.242: ERROR/AndroidRuntime(10222):  at android.hardware.Camera.access$600(Camera.java:114) 
08-18 01:18:50.242: ERROR/AndroidRuntime(10222):  at android.hardware.Camera$EventHandler.handleMessage(Camera.java:545) 
08-18 01:18:50.242: ERROR/AndroidRuntime(10222):  at android.os.Handler.dispatchMessage(Handler.java:99) 
08-18 01:18:50.242: ERROR/AndroidRuntime(10222):  at android.os.Looper.loop(Looper.java:143) 
08-18 01:18:50.242: ERROR/AndroidRuntime(10222):  at android.app.ActivityThread.main(ActivityThread.java:4196) 
08-18 01:18:50.242: ERROR/AndroidRuntime(10222):  at java.lang.reflect.Method.invokeNative(Native Method) 
08-18 01:18:50.242: ERROR/AndroidRuntime(10222):  at java.lang.reflect.Method.invoke(Method.java:507) 
08-18 01:18:50.242: ERROR/AndroidRuntime(10222):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839) 
08-18 01:18:50.242: ERROR/AndroidRuntime(10222):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597) 
08-18 01:18:50.242: ERROR/AndroidRuntime(10222):  at dalvik.system.NativeStart.main(Native Method) 

Answer 1

编辑：对不起，我收回了以前的解决方案。 问题是onPreviewFrame回调，你为什么需要它？设置预览显示后，您无需使视图无效，而是由相机自动完成。