java - 从 sleep 中返回时相机强制关闭。安卓

Question

在我的应用程序中，我正在捕捉图像。除非手机在预览运行时进入休眠状态，否则一切正常。不太确定如何处理它，我认为最好只是防止手机在此过程中自动进入休眠状态。我不知道该怎么做。如果我这样做会阻止手机在我按下电源按钮时进入 hibernate 状态吗？也许这里有更深层次的问题。

日志:

08-28 16:17:10.879: WARN/dalvikvm(9652): threadid=3: thread exiting with uncaught exception (group=0x4001b390)
08-28 16:17:10.879: ERROR/AndroidRuntime(9652): Uncaught handler: thread main exiting due to uncaught exception
08-28 16:17:10.879: ERROR/AndroidRuntime(9652): java.lang.RuntimeException: Method called after release()
08-28 16:17:10.879: ERROR/AndroidRuntime(9652):     at android.hardware.Camera.setHasPreviewCallback(Native Method)
08-28 16:17:10.879: ERROR/AndroidRuntime(9652):     at android.hardware.Camera.access$600(Camera.java:58)
08-28 16:17:10.879: ERROR/AndroidRuntime(9652):     at android.hardware.Camera$EventHandler.handleMessage(Camera.java:339)
08-28 16:17:10.879: ERROR/AndroidRuntime(9652):     at android.os.Handler.dispatchMessage(Handler.java:99)
08-28 16:17:10.879: ERROR/AndroidRuntime(9652):     at android.os.Looper.loop(Looper.java:123)
08-28 16:17:10.879: ERROR/AndroidRuntime(9652):     at android.app.ActivityThread.main(ActivityThread.java:4595)
08-28 16:17:10.879: ERROR/AndroidRuntime(9652):     at java.lang.reflect.Method.invokeNative(Native Method)
08-28 16:17:10.879: ERROR/AndroidRuntime(9652):     at java.lang.reflect.Method.invoke(Method.java:521)
08-28 16:17:10.879: ERROR/AndroidRuntime(9652):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:860)
08-28 16:17:10.879: ERROR/AndroidRuntime(9652):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:618)
08-28 16:17:10.879: ERROR/AndroidRuntime(9652):     at dalvik.system.NativeStart.main(Native Method)

takephoto activity:

public class takephoto extends Activity {
     private static final String TAG = "GrowJournalDemo";
      Preview preview; // <1>
      Button buttonClick; // <2>
      String journ_id;
      String plant_id;
    // private String plantid = ((resource) this.getApplication()).getplantId();
      /** Called when the activity is first created. */
      @Override
      public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        setContentView(R.layout.photo);

        preview = new Preview(this); // <3>
        ((FrameLayout) findViewById(R.id.preview)).addView(preview); // <4>
        String journalid = ((resource) this.getApplication()).getjournalName();
        plant_id = ((resource) this.getApplication()).getplantId();
        journ_id = journalid;
        buttonClick = (Button) findViewById(R.id.buttonClick);
        buttonClick.setOnClickListener(new OnClickListener() {
          public void onClick(View v) { // <5>

             // preview.camera.takePicture(shutterCallback, rawCallback, jpegCallback);
              preview.camera.autoFocus(new Camera.AutoFocusCallback() {
                  Camera.ShutterCallback shutterCallback = new Camera.ShutterCallback() {
                    public void onShutter() {
                      // Play your sound here.
                    }
                  };
                  public void onAutoFocus(boolean success, Camera camera) {
                    preview.camera.takePicture(null, null, jpegCallback);
                  }
                });

          }
        });

        Log.d(TAG, "onCreate'd");
      }

      // Called when shutter is opened
      ShutterCallback shutterCallback = new ShutterCallback() { // <6>
        public void onShutter() {
          Log.d(TAG, "onShutter'd");
        }
      };

      // Handles data for raw picture
      PictureCallback rawCallback = new PictureCallback() { // <7>
        public void onPictureTaken(byte[] data, Camera camera) {
          Log.d(TAG, "onPictureTaken - raw");
        }
      };

      // Handles data for jpeg picture
      PictureCallback jpegCallback = new PictureCallback() { // <8>
        public void onPictureTaken(byte[] data, Camera camera) {
          FileOutputStream outStream = null;
          try {
              android.os.Environment.getExternalStorageState();
            // create a File object for the parent directory
              File PhotoDirectory = new File(
                      android.os.Environment.getExternalStorageDirectory()+
                      "/GrowJournalPhotos/"+journ_id+"/"+plant_id+"/");
              // have the object build the directory structure, if needed.
              PhotoDirectory.mkdirs();
              // create a File object for the output file
              File outputFile = new File(PhotoDirectory, "photo.jpg");
              // now attach the OutputStream to the file object, instead of a String representation
              outStream = new FileOutputStream(outputFile);

            outStream.write(data);
            outStream.close();
            Log.d(TAG, "onPictureTaken - wrote bytes: " + data.length);
            setResult(RESULT_OK);
            finish();

          } catch (FileNotFoundException e) { // <10>
            e.printStackTrace();
          } catch (IOException e) {
            e.printStackTrace();
          } finally {
          }
          Log.d(TAG, "onPictureTaken - jpeg");
        }
      };

    }

预览表面 View :

public class Preview extends SurfaceView implements SurfaceHolder.Callback {
    private static final String TAG = "Preview";

      SurfaceHolder mHolder;  // <2>
      public Camera camera; // <3>

      Preview(Context context) {
        super(context);

        // Install a SurfaceHolder.Callback so we get notified when the
        // underlying surface is created and destroyed.
        mHolder = getHolder();  // <4>
        mHolder.addCallback(this);  // <5>
        mHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS); // <6>
      }

      // Called once the holder is ready
      public void surfaceCreated(SurfaceHolder holder) {  // <7>
        // The Surface has been created, acquire the camera and tell it where
        // to draw.
        camera = Camera.open(); // <8>
        try {
          camera.setPreviewDisplay(holder);  // <9>

          camera.setPreviewCallback(new PreviewCallback() { // <10>
            // Called for each frame previewed
            public void onPreviewFrame(byte[] data, Camera camera) {  // <11>
              Log.d(TAG, "onPreviewFrame called at: " + System.currentTimeMillis());
              Preview.this.invalidate();  // <12>
            }
          });
        } catch (IOException e) { // <13>
          e.printStackTrace();
        }
      }

      // Called when the holder is destroyed
      public void surfaceDestroyed(SurfaceHolder holder) {  // <14>
        camera.stopPreview();
        camera.release();
        camera = null;
      }

      // Called when holder has changed
      public void surfaceChanged(SurfaceHolder holder, int format, int w, int h) { // <15>
        camera.startPreview();
      }


    }

我添加了一个唤醒锁来防止手机变暗，我觉得这是一个临时解决方案，因为当通过电源按钮强制设备进入休眠状态时仍然存在强制关闭。

Answer 1

为什么要为每个预览帧调用 invalidate()？相机显示应该在没有它的情况下更新。

要么完全删除预览回调(因为你似乎没有做任何其他事情)，要么在你释放之前尝试在 onResume() 中设置 camera.setPreviewCallback(null) 以便它释放相机资源后不会尝试调用它。您遇到异常是因为您在释放相机后试图在某处访问它。