照相机拍照后返回空白图像

Question

我用下面的代码来实现拍照功能。但是它总是返回一个空白图像.错误出现在哪呢？

Camera.Parameters p = camera.getParameters();
            List<Size> sizes = p.getSupportedPictureSizes();
            // Choose any one you want among sizes
            Size size = sizes.get(0);
            p.setPictureSize(size.width, size.height);

            p.set("flash-mode","off");
            p.set("focus-mode","auto");
            p.setExposureCompensation(100);
            p.setFocusMode("auto");
            camera.setParameters(p);
            camera.startPreview();
            camera.takePicture(shutterCallback, rawCallback,
                    jpegCallback);

ShutterCallback shutterCallback = new ShutterCallback() {
        public void onShutter() {
            Log.d(TAG, "onShutter'd");
        }
    };

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

    /** Handles data for jpeg picture */
    PictureCallback jpegCallback = new PictureCallback() {
        public void onPictureTaken(byte[] data, Camera camera) {
            FileOutputStream outStream = null;
            try {
                // write to local sandbox file system
                // outStream =
                // CameraDemo.this.openFileOutput(String.format("%d.jpg",
                // System.currentTimeMillis()), 0);
                // Or write to sdcard
                outStream = new FileOutputStream(String.format(
                        "/sdcard/%d.jpg", System.currentTimeMillis()));
                outStream.write(data);
                outStream.close();
                Log.d(TAG, "onPictureTaken - wrote bytes: " + data.length);
            } catch (FileNotFoundException e) {
                e.printStackTrace();
            } catch (IOException e) {
                e.printStackTrace();
            } finally {
            }
            Log.d(TAG, "onPictureTaken - jpeg");
        }
    };
    @Override
    public void draw(Canvas canvas) {
        super.draw(canvas);
        Paint p = new Paint(Color.RED);
        Log.d(TAG, "draw");
        canvas.drawText("PREVIEW", canvas.getWidth() / 2,
                canvas.getHeight() / 2, p);
    }

我看了一些设置flash的问题。在程序中设置了曝光和集中模式，但
是照相机拍照后仍然返回空白图像。

Answer 1

Camera.java

public class Camera extends Activity 
  {
 private static final int CAMERA_REQUEST = 1888;
 private String selectedImagePath;

@Override
public void onCreate(Bundle savedInstanceState)
{
    super.onCreate(savedInstanceState);
    Intent cameraIntent = new Intent(ACTION_IMAGE_CAPTURE);
    startActivityForResult(cameraIntent, CAMERA_REQUEST);
}

@Override
public void onActivityResult(int requestCode, int resultCode, Intent data)
{
    if (resultCode == RESULT_OK) {
        if (requestCode == CAMERA_REQUEST) 
        { 
            Bitmap photo = (Bitmap) data.getExtras().get("data"); 
            ByteArrayOutputStream bytes = new ByteArrayOutputStream();
            photo.compress(Bitmap.CompressFormat.JPEG, 40, bytes);
            Random randomGenerator = new Random();randomGenerator.nextInt();
            String newimagename=randomGenerator.toString()+".jpg";
            File f = new File(Environment.getExternalStorageDirectory()
                                    + File.separator + newimagename);
            try {
                f.createNewFile();
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
            //write the bytes in file

            try {
                fo = new FileOutputStream(f.getAbsoluteFile());
            } catch (FileNotFoundException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
            try {
                fo.write(bytes.toByteArray());
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
                uri=f.getAbsolutePath(); 
    //this is the url that where you are saved the image
      }

  }