Android Camera takePicture函数不调用Callback函数

Question

我正在为我的应用程序开发自定义相机活动。 我在这里按照 Android 开发者网站的说明进行操作： http://developer.android.com/guide/topics/media/camera.html 一切似乎都很好，除了没有调用回调函数并且没有保存图片。这是我的代码：

public class CameraActivity extends Activity {
private Camera mCamera;
private CameraPreview mPreview;
private static final String TAG = "CameraActivity";

/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.camera);

    // Create an instance of Camera
    mCamera = getCameraInstance();

    // Create our Preview view and set it as the content of our activity.
    mPreview = new CameraPreview(this, mCamera);
    FrameLayout preview = (FrameLayout) findViewById(R.id.camera_preview);
    preview.addView(mPreview);

    Button captureButton = (Button) findViewById(R.id.button_capture);
    captureButton.setOnClickListener(new OnClickListener() {
        @Override
        public void onClick(View v) {
            Log.v(TAG, "will now take picture");
            mCamera.takePicture(null, null, mPicture);
            Log.v(TAG, "will now release camera");
            mCamera.release();
            Log.v(TAG, "will now call finish()");
            finish();
        }
    });        
}

private PictureCallback mPicture = new PictureCallback() {

    @Override
    public void onPictureTaken(byte[] data, Camera camera) {
        Log.v(TAG, "Getting output media file");
        File pictureFile = getOutputMediaFile();
        if (pictureFile == null) {
            Log.v(TAG, "Error creating output file");
            return;
        }
        try {
            FileOutputStream fos = new FileOutputStream(pictureFile);
            fos.write(data);
            fos.close();
        } catch (FileNotFoundException e) {
            Log.v(TAG, e.getMessage());
        } catch (IOException e) {
            Log.v(TAG, e.getMessage());
        }
    }
};

private static File getOutputMediaFile() {
    String state = Environment.getExternalStorageState();
    if (!state.equals(Environment.MEDIA_MOUNTED)) {
        return null;
    }
    else {
        File folder_gui = new File(Environment.getExternalStorageDirectory() + File.separator + "GUI");
        if (!folder_gui.exists()) {
            Log.v(TAG, "Creating folder: " + folder_gui.getAbsolutePath());
            folder_gui.mkdirs();
        }
        File outFile = new File(folder_gui, "temp.jpg");
        Log.v(TAG, "Returnng file: " + outFile.getAbsolutePath());
        return outFile;
    }
}

点击按钮后，我得到日志：“现在将拍照”，“现在将释放相机”和“现在将调用完成”。活动成功结束，但在活动期间未调用回调函数

mCamera.takePicture(null, null, mPicture);

函数（没有来自 mPicture 回调或 getMediaOutputFile 函数的日志）并且在指定的位置没有文件。

有什么想法吗？ :) 非常感谢！

Answer 1

对mCamera.takePicture() 的调用是异步的。这意味着调用立即完成，但实际的图片拍摄和处理发生在稍后的某个时间。但是，您在调用 mCamera.takePicture() 后立即执行此操作：

Log.v(TAG, "will now release camera");
mCamera.release();
Log.v(TAG, "will now call finish()");
finish();

这意味着你已经释放了相机资源并在相机有机会真正拍照并给你回电之前完成了Activity。

您需要将该代码移入回调方法onPictureTaken()，以便在回调发生后释放资源并完成Activity。

Answer 2

像这样使用 SurfaceView 自定义相机一次单击拍摄多张图像

clickbtn.setOnClickListener(new OnClickListener() {

        @SuppressWarnings("deprecation")
        @Override
        public void onClick(View v) {

            for (int i = 0; i < 5; i++) {
                mcamera = mPreview.getCamera();

                getimage(mcamera);

                Toast.makeText(getApplicationContext(),
                        "multiple image count=" + i, 1000).show();

            }

            if (mPreview == null) {
                mPreview = new CamLayer(MainActivity.this);
            }


        }
    });

和

    public static void getimage(Camera mcamera) {


    PictureCallback mPicture = new PictureCallback() {

        @Override
        public void onPictureTaken(byte[] data, Camera camera) {
            pictureFile = getOutputMediaFile();
            Log.e("path file 11111111", ""+pictureFile);
            if (pictureFile == null) {
                return;
            }
            try {
                FileOutputStream fos = new FileOutputStream(pictureFile);
                fos.write(data);
                fos.close();

            } catch (FileNotFoundException e) {

            } catch (Exception e) {

            }
        }
    };
    try {

        mcamera.startPreview();
        mcamera.takePicture(null, null, mPicture);
        Thread.sleep(2000);

    } catch (Exception exception) {
        exception.printStackTrace();
    }

}

private static File getOutputMediaFile() {
    File mediaStorageDir = new File(
            Environment
                    .getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES),
            "Sunil3");
    if (!mediaStorageDir.exists()) {
        if (!mediaStorageDir.mkdirs()) {

            return null;
        }
    }


    File mediaFile = new File(String.format(mediaStorageDir+File.separator+"%d.jpg", System.currentTimeMillis()));

    return mediaFile;
}