无法从相机解码位图文件

Question

我正在尝试使用本机设备相机拍照。我从发送意图开始：

private void dispatchTakePictureIntent() {
    Intent takePictureIntent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
    // Ensure that there's a camera activity to handle the intent
    if (takePictureIntent.resolveActivity(getMainActivity().getPackageManager()) != null) {
        // Create the File where the photo should go
        File photoFile = null;
        try {
            photoFile = createImageFile();
        } catch (IOException ex) {
            ex.printStackTrace();
        }
        // Continue only if the File was successfully created
        if (photoFile != null) {
            takePictureIntent.putExtra(MediaStore.EXTRA_OUTPUT,
                    Uri.fromFile(photoFile));
            startActivityForResult(takePictureIntent, REQUEST_TAKE_PHOTO);
        }
    }
}

相机启动，文件创建，我正在拍照，然后这张照片被接收并使用以下代码解码：

@Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
    if (requestCode == REQUEST_TAKE_PHOTO && resultCode == Activity.RESULT_OK) {
        Bitmap bitmap = BitmapFactory.decodeFile(mCurrentPhotoPath);

        if (bitmap == null) {
            Crashlytics.log("Bitmap factory returned null");
        }

        mImageCropper.setBitmapPhoto(bitmap);
        expand(mMainImage);
    }
}

这是创建文件并记住它的路径的方法：

private File createImageFile() throws IOException {
    // Create an image file name
    @SuppressLint("SimpleDateFormat") String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss").format(new Date());
    String imageFileName = "JPEG_" + timeStamp + "_";
    File storageDir = getActivity().getExternalFilesDir(Environment.DIRECTORY_PICTURES);
    File image = File.createTempFile(
            imageFileName,  /* prefix */
            ".jpg",         /* suffix */
            storageDir      /* directory */
    );
    if (!image.exists()) {
        Log.e("take photo", "can't create photo file");
        Crashlytics.logException(new NullPointerException("Can't read photo from camera"));
    } else {
        Log.d("take photo", "photo file created " + image.getPath());
    }

    mCurrentPhotoPath = image.getAbsolutePath();
    return image;
}

但有时我在解码此位图时出错：

D/skia: --- SkImageDecoder::Factory returned null

当我重新启动设备（Nexus 5 (6.0 Marshmallow)，但它也发生在其他设备上）时，此过程的第一次运行正常，但随后开始出现错误。我无法在 genymotion 模拟器（Nexus 5、5.0）上重现此错误

更新 - 原因和解决方法

似乎原生安卓相机应用程序在位图完全写入持久存储之前返回它的结果。我并不引以为豪的代码，但它仍然有效：

final Handler handler = new Handler();

@Override
public void onActivityResult(final int requestCode, final int resultCode, Intent data) {
    Runnable decodeRunnable = new Runnable() {
        int counter = 0;

        @Override
        public void run() {
            if (requestCode == REQUEST_TAKE_PHOTO && resultCode == Activity.RESULT_OK) {
                Bitmap bitmap = BitmapFactory.decodeFile(mCurrentPhotoPath);

                if (bitmap == null && counter < 20) {
                    handler.postDelayed(this, 200);
                }
                mImageCropper.setBitmapPhoto(bitmap);
                expand(mMainImage);
            }
        }
    };
    handler.postDelayed(decodeRunnable, 100);
}

如您所见，此方法将尝试解码位图最多 20 次，尝试之间有 200 毫秒的中断。如果您有更好的想法，我们将不胜感激。

Answer 1

我创建了一个 AsyncTask 来处理这个问题，直到我们找到更优雅的方法来处理这个问题我决定使用this one here。