Question

当我按下CameraActivity

上的快门按钮时，我遇到了两件奇怪的事

在设备2.3和4.0（Galaxy Ace II，Nexus One和Galaxy Nexus）上，它将冻结约2秒钟，然后继续nextActivity。
只有Galaxy Ace 2.3.6，它会给我一个像pic这样的乱码像素在冻结期间下面，但它可以在nextActivity稍后给我正确的图像。

garbled pixels

起初我认为我的PicutureCallback方法可能有些错误或耗费时间，但似乎没问题？我无法理解为什么这个乱码像素只会出现在Galaxy Ace上。

那么是否有更好的方法来处理PictureCallback以使其更快？

没有错误日志，所以我只需输入相关代码：

// I call the takePicture in my button listener.
camera.takePicture(null, null, mPicture);

// here's the picture callback
private PictureCallback mPicture = new PictureCallback() {

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


        new ShutterHandler(data).execute();
    }

    class ShutterHandler extends AsyncTask<Void, Void, Void> {

        Bitmap bm;
        String timeStamp;
        String filename;
        Intent nextIntent = new Intent(CameraActivity.this, nextActivity.class);

        // a tricky way to pass data into the AsyncTask
        public ShutterHandler(byte[] data) {
            bm = BitmapFactory.decodeByteArray(data, 0, data.length);

        }


        @Override
        protected Void doInBackground(Void... params) {
            // simply generate a time stamp as filename
            timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss").format(new Date());
            filename = timeStamp + ".jpg";
            Uri path;
            try {

                // save file to app's private folder
                FileOutputStream fos = openFileOutput(filename, Context.MODE_PRIVATE);

                bm.compress(Bitmap.CompressFormat.JPEG, 100, fos);              
                // retrieve Uri from the file
                path = Uri.fromFile(getFileStreamPath(filename));

                Log.d("CameraActivity", "file saved to: " + path);
                fos.flush();
                fos.close();

                // launch ShowMarkersActivity
                String pathString = path.getPath();
                nextIntent.putExtra("IMG", pathString);
                nextIntent.putExtra("FileName", filename);
                nextIntent.putExtra("FLAG", true);

            } catch (FileNotFoundException e) {
                Log.d("CameraActivity", "File not found: " + e.getMessage());
            } catch (IOException e) {
                Log.d("CameraActivity", "Error accessing file: " + e.getMessage());
            }
            return null;                        
        }
        protected void onPostExecute(Void v) {
            CameraActivity.this.startActivity(nextIntent);
            finish();
        }

    }
};

Answer 1

如果你要求相机图片回调返回jpeg格式，它将显着更快。在大多数可用设备上，图片回调仍然很慢。

takePicture（）总是冻结几秒钟

1 个答案: