android - 从 Camera Intent 中检索内容 Uri

Question

我正在触发相机拍照的 Intent，如下所示:

Intent cameraIntent = new Intent(android.provider.MediaStore.ACTION_IMAGE_CAPTURE);
Uri myPhoto = Uri.fromFile(new File(Environment.getExternalStorageDirectory(),
    "the_photo.jpg"));

cameraIntent.putExtra(MediaStore.EXTRA_OUTPUT, myPhoto);
startActivityForResult(cameraIntent, INTENT_GET_PICTURE_FROM_CAMERA);

现在我想要显示这张照片的缩略图。如果我存储“myPhoto”Uri，我可以准确地看到文件系统上的文件。但是，要使用 Media Store API，我需要 Content Uri 表单上的 Uri。无论如何可以从相机返回的 Intent 中检索它，如果没有，我如何将我的文件系统 Uri 转换为 android 内容 Uri。

请注意，我知道我可以只获取位图并对其进行解码，同时进行下采样。这不是我想要的。我可以查询所有的缩略图，我看到它存在，所以我想从系统中获取它。

谢谢

Answer 1

我通过对项目执行媒体扫描解决了这个问题。从那里我可以获得内容 Uri(下面代码中处理程序的额外复杂性是因为我需要在操作 View 时在 UI 线程上处理我的结果):

private Uri mCameraFilePath;
private Context mContext;
...

private void handlePictureFromCamera(Intent data) {

    MyMediaScannerClient client = new MyMediaScannerClient(
            mCameraFilePath.getPath(), new Handler(), new OnMediaScanned() {

        @Override
        public void mediaScanned(Uri contentUri) {
            //Here I have the content uri as its now in the media store
        }
    });
    MediaScannerConnection connection = new MediaScannerConnection(mContext, client);
    client.mConnection = connection;
    connection.connect();
}

private interface OnMediaScanned {
    public void mediaScanned(Uri contentUri);
}

/**
 * This is used to scan a given file (image in this case) to ensure it is added
 * to the media store thus making its content uri available. It returns the
 * content form Uri by means of a callback on the supplied handler's thread.
 */
private class MyMediaScannerClient implements MediaScannerConnectionClient {

    private final String mPath;
    private MediaScannerConnection mConnection;
    private final OnMediaScanned mFileScannedCallback;
    private final Handler mHandler;

    public MyMediaScannerClient(String path, Handler handler, OnMediaScanned fileScannedCallback) {
        mPath = path;
        mFileScannedCallback = fileScannedCallback;
        mHandler = handler;
    }

    @Override
    public void onMediaScannerConnected() {
        mConnection.scanFile(mPath, null);
    }

    @Override
    public void onScanCompleted(String path, final Uri uri) {

        mConnection.disconnect();
        mHandler.post(new Runnable() {

            @Override
            public void run() {
                mFileScannedCallback.mediaScanned(uri);
            }
        });
    }
}