Question

这是我录制视频并将其保存到驱动器的代码。但我的日志显示如下：

03-09 08:43:55.005 12760-12760/classroom.shivani.upload I/drive-quickstart: API client connected.
03-09 08:43:55.005 12760-12760/classroom.shivani.upload I/drive-quickstart: Starting camera Intent
03-09 08:43:55.014 12760-12760/classroom.shivani.upload I/drive-quickstart: file uri is :file:///storage/emulated/0/DCIM/VID_20170309_084355.mp4
03-09 08:43:55.052 12760-12760/classroom.shivani.upload I/drive-quickstart: calling rccv
03-09 08:43:55.053 12760-12760/classroom.shivani.upload I/drive-quickstart: In pre execute
03-09 08:43:55.057 12760-13801/classroom.shivani.upload I/drive-quickstart: In background
03-09 08:43:55.058 12760-13801/classroom.shivani.upload I/drive-quickstart: file path is :/storage/emulated/0/DCIM/VID_20170309_084355.mp4
03-09 08:43:55.058 12760-13801/classroom.shivani.upload I/drive-quickstart: file name is :VID_20170309_084355.mp4
03-09 08:43:55.175 12760-12760/classroom.shivani.upload I/drive-quickstart: In post execute

如何将视频保存到驱动器？

private class Async extends AsyncTask<File,Void,Void>{

        @Override
        protected void onPreExecute()
        {
            super.onPreExecute();
            Log.i(TAG, "In pre execute");
        }
    protected Void doInBackground(File... params)
            {
                Log.i(TAG, "In background");
                final File file1=params[0];

                Log.i(TAG, "file path is :"+file1.getPath());
                Log.i(TAG, "file name is :"+file1.getName());

                Drive.DriveApi.newDriveContents(mGoogleApiClient).setResultCallback(new ResultCallback<DriveApi.DriveContentsResult>() {
                    @Override
                    public void onResult(DriveApi.DriveContentsResult result) {
                        if (!result.getStatus().isSuccess()) {
                            Log.i(TAG, "Failed to create new contents.");
                            return;
                        }
                        Log.i(TAG, "New contents created.");
                        OutputStream outputStream =
                                result.getDriveContents()
                                        .getOutputStream();
                        FileInputStream fis;
                        try {

                            Log.i(TAG, "Within try catch");

                            fis = new FileInputStream(file1.getPath
                                    ());
                            Log.i(TAG, "file name is :"+file1.getName());
                            ByteArrayOutputStream baos = new
                                    ByteArrayOutputStream();
                            byte[] buf = new byte[102400];
                            int n;
                            while (-1 != (n = fis.read(buf)))
                                baos.write(buf, 0, n);
                            byte[] photoBytes = baos.toByteArray();
                            outputStream.write(photoBytes);

                            outputStream.close();

                            fis.close();
                            Log.i(TAG, "successfully created video file");
                            Log.i(TAG, "Setting Metadata");
                            String title = file1.getName();
                            MetadataChangeSet metadataChangeSet =
                                    new MetadataChangeSet.Builder()
                                            .setMimeType("video/mp4").setTitle
                                            (title).build();

                            Log.i(TAG, "Creating new video on Drive (" + title
                                    + ")");
                            IntentSender intentSender = Drive.DriveApi
                                    .newCreateFileActivityBuilder()
                                    .setInitialMetadata(metadataChangeSet)
                                    .setInitialDriveContents(result.getDriveContents())
                                    .build(mGoogleApiClient);
                            try {
                                startIntentSenderForResult(
                                        intentSender, REQUEST_CODE_CREATOR, null, 0, 0, 0);
                            } catch (IntentSender.SendIntentException e) {
                                Log.i(TAG, "Failed to launch file chooser.");
                            }


                            Log.i(TAG, "congrats new video created with name (" + title + ")");

                        } catch (FileNotFoundException e) {
                            Log.w(TAG, "FileNotFoundException: "
                                    + e.getMessage());
                        } catch (IOException e1) {
                            Log.w(TAG, "Unable to write file contents." + e1.getMessage());
                        }
                        // Create an intent for the file chooser, and start it.


                    }
                });
            return null;
            }

 protected void onPostExecute(Void result)
        {
            super.onPostExecute(result);
            Log.i(TAG, "In post execute");


        }

我正在创建Async类的实例：

@Override
    public void onConnected(Bundle connectionHint) {
        Log.i(TAG, "API client connected.");
        Log.i(TAG, "Starting camera Intent");
        String mediaStorageDir= Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DCIM).getPath();
        String timeStamp=new SimpleDateFormat("yyyyMMdd_HHmmss", Locale.getDefault()).format(new Date());
        fileUri = Uri.fromFile(new java.io.File(mediaStorageDir + java.io.File.separator +"VID_"+timeStamp + ".mp4"));
        file=new File(fileUri.getPath());
        Log.i(TAG, "file uri is :"+fileUri);
        Intent cameraIntent = new Intent(android.provider.MediaStore.ACTION_VIDEO_CAPTURE);
        cameraIntent.putExtra(MediaStore.EXTRA_DURATION_LIMIT,15);
        cameraIntent.putExtra(MediaStore.EXTRA_OUTPUT,fileUri);
        startActivity(cameraIntent);
        Log.i(TAG, "calling rccv");
        new Async().execute(file);

    }

Answer 1

问题是这个

protected Void doInBackground(File... params) {

    Log.i(TAG, "In background");
    final File file1=params[0];

    Log.i(TAG, "file path is :"+file1.getPath());
    Log.i(TAG, "file name is :"+file1.getName());

    Drive.DriveApi.newDriveContents(mGoogleApiClient).setResultCallback(new ResultCallback<DriveApi.DriveContentsResult>() {
        // all the other stuff
    });

    return null;
}

你基本上直接穿过doInBackground()并立即返回null，因为该方法不会等待DriveApi做任何事情。这不是应该如何使用异步任务。

只是尝试在主线程上调用它，它很可能已经是异步任务或类似的东西

Drive.DriveApi.newDriveContents(mGoogleApiClient).setResultCallback(new ResultCallback<DriveApi.DriveContentsResult>() {
    // all the other stuff
});

Answer 2

我通过声明doInBackground和onPostExecute同步来解决一个非常类似的问题（...）
protected synchronized void doInBackground（Void ... params） {...}
protected synchronized void onPostExecute（布尔结果）{...}
（...）
在我的例子中，doInBackground（）首先进入（因为它应该），但在doInBackground（）＆＃34;技术上＆＃34;之前调用onPostExecute（）。完成（我无法弄清楚为什么 - 也许我的解压缩库对象有自己的线程并且没有阻止doInBackground（）方法）。同步方法解决了问题（当然，并非没有性能影响）

调用onPostExecute（）而不在doInBackground（）中完成任务

2 个答案: