Question

我正在制作小型应用，可预览相机，点击屏幕即可保存图像。

我的问题是图像保存后，我想开始不同的活动，它会做预览并有一些工具。但我做什么活动并没有开始。

这是我的代码

public class CameraActivity extends Activity {
    private SurfaceView preview = null;
    private SurfaceHolder previewHolder = null;
    private Camera camera = null;
    private boolean inPreview = false;
    private boolean cameraConfigured = false;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.camera);

        preview = (SurfaceView) findViewById(R.id.preview);

        Button button = (Button) findViewById(R.id.button_capture);

        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if (camera != null) {
                    camera.takePicture(null, null, photoCallback);
                    onPause();
                    Intent intent = new Intent(CameraActivity.this, PreviewAndSaveActivity.class);

                    intent.putExtra("image", "");
                    CameraActivity.this.startActivity(intent);
                }
            }
        });

        previewHolder = preview.getHolder();
        previewHolder.addCallback(surfaceCallback);
        previewHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
    }

    @Override
    public void onResume() {
        super.onResume();

        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.GINGERBREAD) {
            Camera.CameraInfo info = new Camera.CameraInfo();

            for (int i = 0; i < Camera.getNumberOfCameras(); i++) {
                Camera.getCameraInfo(i, info);

                if (info.facing == Camera.CameraInfo.CAMERA_FACING_BACK) {
                    camera = Camera.open(i);
                }
            }
        }

        if (camera == null) {
            camera = Camera.open();
        }

        startPreview();
    }

    @Override
    public void onPause() {
        if (camera != null) {
            if (inPreview) {
                camera.stopPreview();
            }

            camera.release();
            camera = null;
        }
        inPreview = false;

        super.onPause();
    }

    private Camera.Size getBestPreviewSize(int width, int height,
            Camera.Parameters parameters) {
        Camera.Size result = null;

        for (Camera.Size size : parameters.getSupportedPreviewSizes()) {
            if (size.width <= width && size.height <= height) {
                if (result == null) {
                    result = size;
                } else {
                    int resultArea = result.width * result.height;
                    int newArea = size.width * size.height;

                    if (newArea > resultArea) {
                        result = size;
                    }
                }
            }
        }

        return (result);
    }

    private Camera.Size getSmallestPictureSize(Camera.Parameters parameters) {
        Camera.Size result = null;

        for (Camera.Size size : parameters.getSupportedPictureSizes()) {
            if (result == null) {
                result = size;
            } else {
                int resultArea = result.width * result.height;
                int newArea = size.width * size.height;

                if (newArea < resultArea) {
                    result = size;
                }
            }
        }

        return (result);
    }

    private void initPreview(int width, int height) {
        if (camera != null && previewHolder.getSurface() != null) {
            try {
                camera.setPreviewDisplay(previewHolder);
            } catch (Throwable t) {
                Log.e("PreviewDemo-surfaceCallback",
                        "Exception in setPreviewDisplay()", t);
                Toast.makeText(CameraActivity.this, t.getMessage(),
                        Toast.LENGTH_LONG).show();
            }

            if (!cameraConfigured) {
                Camera.Parameters parameters = camera.getParameters();
                Camera.Size size = getBestPreviewSize(width, height, parameters);
                Camera.Size pictureSize = getSmallestPictureSize(parameters);


                if (size != null && pictureSize != null) {
                    parameters.setPreviewSize(size.width, size.height);
                    parameters.setPictureSize(pictureSize.width,
                            pictureSize.height);
                    parameters.setPictureFormat(ImageFormat.JPEG);
                    parameters.setFlashMode(Camera.Parameters.FLASH_MODE_AUTO);
                    camera.setParameters(parameters);

                    cameraConfigured = true;
                }
            }
        }
    }

    private void startPreview() {
        if (cameraConfigured && camera != null) {
            camera.startPreview();
            inPreview = true;
        }
    }

    SurfaceHolder.Callback surfaceCallback = new SurfaceHolder.Callback() {
        public void surfaceCreated(SurfaceHolder holder) {
            // no-op -- wait until surfaceChanged()
        }

        public void surfaceChanged(SurfaceHolder holder, int format, int width,
                int height) {
            initPreview(width, height);
            startPreview();
        }

        public void surfaceDestroyed(SurfaceHolder holder) {


        }
    };

    Camera.PictureCallback photoCallback = new Camera.PictureCallback() {
        public void onPictureTaken(byte[] data, Camera camera) {
            camera.takePicture(null, null, new PhotoHandler(
                    getApplicationContext()));
            camera.startPreview();
            inPreview = true;
        }
    };

}

在解码和保存图像后的PhotoHandler中我想开始活动

public class PhotoHandler implements PictureCallback {

    private final Context context;

    public PhotoHandler(Context context) {
        this.context = context;

    }

    @Override
    public void onPictureTaken(byte[] data, Camera camera) {

        File pictureFileDir = getDir();

        if (!pictureFileDir.exists() && !pictureFileDir.mkdirs()) {

            Log.d("", "Can't create directory to save image.");
            Toast.makeText(context, "Can't create directory to save image.",
                    Toast.LENGTH_LONG).show();
            return;

        }

        SimpleDateFormat dateFormat = new SimpleDateFormat("yyyymmddhhmmss");
        String date = dateFormat.format(new Date());
        String photoFile = "pic_" + date + ".jpg";

        String pictureName = pictureFileDir.getPath() + File.separator
                + photoFile;

        File pictureFile = new File(pictureName);
        FileOutputStream fos = null;
        try {
            fos = new FileOutputStream(pictureFile);
            fos.write(data);

            Intent intent = new Intent(context, PreviewAndSaveActivity.class);

            intent.putExtra("image", pictureName);
            context.startActivity(intent);

        } catch (Exception error) {
            Toast.makeText(context, "Image could not be saved.",
                    Toast.LENGTH_LONG).show();
        } finally {
            if (fos != null) {
                try {
                    fos.flush();
                    fos.close();
                } catch (IOException e) {
                }
            }
        }
    }

    private File getDir() {
        File sdDir = Environment
            .getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES);
        return new File(sdDir, "dir");
    }
    }

有什么建议我做错了吗？

Answer 1

试试这段代码：

（替换按钮单击侦听器）

button.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            if (camera != null) {
                camera.takePicture(null, null, photoCallback);
                onPause();
                Intent intent = new Intent(CameraActivity.this, PreviewAndSaveActivity.class);

                intent.putExtra("image", "");
                CameraActivity.this.startActivityForResult(intent, 100);
            }
        }
    });

在您的CameraActivity中，添加此回调方法以在图像保存后重定向另一个活动：

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    if (requestCode == 100) {
        // start you new activity from here...
    }
    super.onActivityResult(requestCode, resultCode, data);
}

照片拍摄后的Android相机启动活动

1 个答案: