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android – 如何在Google云端硬盘中替换文件?

作者:互联网

使用以下代码(取自android-quickstart),如果您拍摄多张照片,此代码可以生成多个具有相同名称的文件.如何修改以确保替换具有相同名称的文件?

public class MainActivity extends Activity implements ConnectionCallbacks,
        OnConnectionFailedListener {

    private static final String TAG = "android-drive-quickstart";
    private static final int REQUEST_CODE_CAPTURE_IMAGE = 1;
    private static final int REQUEST_CODE_CREATOR = 2;
    private static final int REQUEST_CODE_RESOLUTION = 3;

    private GoogleApiClient mGoogleApiClient;
    private Bitmap mBitmapToSave;

    /**
     * Create a new file and save it to Drive.
     */
    private void saveFileToDrive() {
        // Start by creating a new contents, and setting a callback.
        Log.i(TAG, "Creating new contents.");
        final Bitmap image = mBitmapToSave;
        Drive.DriveApi.newContents(mGoogleApiClient).setResultCallback(new ResultCallback<ContentsResult>() {

            @Override
            public void onResult(ContentsResult result) {
                // If the operation was not successful, we cannot do anything
                // and must
                // fail.
                if (!result.getStatus().isSuccess()) {
                    Log.i(TAG, "Failed to create new contents.");
                    return;
                }
                // Otherwise, we can write our data to the new contents.
                Log.i(TAG, "New contents created.");
                // Get an output stream for the contents.
                OutputStream outputStream = result.getContents().getOutputStream();
                // Write the bitmap data from it.
                ByteArrayOutputStream bitmapStream = new ByteArrayOutputStream();
                image.compress(Bitmap.CompressFormat.PNG, 100, bitmapStream);
                try {
                    outputStream.write(bitmapStream.toByteArray());
                } catch (IOException e1) {
                    Log.i(TAG, "Unable to write file contents.");
                }
                // Create the initial metadata - MIME type and title.
                // Note that the user will be able to change the title later.
                MetadataChangeSet metadataChangeSet = new MetadataChangeSet.Builder()
                        .setMimeType("image/jpeg")
                        .setTitle("Android Photo.png")
                        .build();
                // Create an intent for the file chooser, and start it.
                IntentSender intentSender = Drive.DriveApi
                        .newCreateFileActivityBuilder()
                        .setInitialMetadata(metadataChangeSet)
                        .setInitialContents(result.getContents())
                        .build(mGoogleApiClient);
                try {
                    startIntentSenderForResult(
                            intentSender, REQUEST_CODE_CREATOR, null, 0, 0, 0);
                } catch (SendIntentException e) {
                    Log.i(TAG, "Failed to launch file chooser.");
                }
            }
        });
    }

    @Override
    protected void onResume() {
        super.onResume();
        if (mGoogleApiClient == null) {
            // Create the API client and bind it to an instance variable.
            // We use this instance as the callback for connection and connection
            // failures.
            // Since no account name is passed, the user is prompted to choose.
            mGoogleApiClient = new GoogleApiClient.Builder(this)
                    .addApi(Drive.API)
                    .addScope(Drive.SCOPE_FILE)
                    .addConnectionCallbacks(this)
                    .addOnConnectionFailedListener(this)
                    .build();
        }
        // Connect the client. Once connected, the camera is launched.
        mGoogleApiClient.connect();
    }
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        mGoogleApiClient = new GoogleApiClient.Builder(this)
                .addApi(Drive.API)
                .addScope(Drive.SCOPE_FILE)
                .addConnectionCallbacks(this)
                .addOnConnectionFailedListener(this)
                .build();
    }
    @Override
    protected void onStart() {
        super.onStart();
        mGoogleApiClient.connect();
    }
    @Override
    protected void onPause() {
        if (mGoogleApiClient != null) {
            mGoogleApiClient.disconnect();
        }
        super.onPause();
    }

    @Override
    protected void onActivityResult(final int requestCode, final int resultCode, final Intent data) {
        switch (requestCode) {
            case REQUEST_CODE_CAPTURE_IMAGE:
                // Called after a photo has been taken.
                if (resultCode == Activity.RESULT_OK) {
                    // Store the image data as a bitmap for writing later.
                    mBitmapToSave = (Bitmap) data.getExtras().get("data");
                }
                break;
            case REQUEST_CODE_CREATOR:
                // Called after a file is saved to Drive.
                if (resultCode == RESULT_OK) {
                    Log.i(TAG, "Image successfully saved.");
                    mBitmapToSave = null;
                    // Just start the camera again for another photo.
                    startActivityForResult(new Intent(MediaStore.ACTION_IMAGE_CAPTURE),
                            REQUEST_CODE_CAPTURE_IMAGE);
                }
                break;
        }
    }

    @Override
    public void onConnectionFailed(ConnectionResult result) {
        // Called whenever the API client fails to connect.
        Log.i(TAG, "GoogleApiClient connection failed: " + result.toString());
        if (!result.hasResolution()) {
            // show the localized error dialog.
            GooglePlayServicesUtil.getErrorDialog(result.getErrorCode(), this, 0).show();
            return;
        }
        // The failure has a resolution. Resolve it.
        // Called typically when the app is not yet authorized, and an
        // authorization
        // dialog is displayed to the user.
        try {
            result.startResolutionForResult(this, REQUEST_CODE_RESOLUTION);
        } catch (SendIntentException e) {
            Log.e(TAG, "Exception while starting resolution activity", e);
        }
    }

    @Override
    public void onConnected(Bundle connectionHint) {
        Log.i(TAG, "API client connected.");
        if (mBitmapToSave == null) {
            // This activity has no UI of its own. Just start the camera.
            startActivityForResult(new Intent(MediaStore.ACTION_IMAGE_CAPTURE),
                    REQUEST_CODE_CAPTURE_IMAGE);
            return;
        }
        saveFileToDrive();
    }

    @Override
    public void onConnectionSuspended(int cause) {
        Log.i(TAG, "GoogleApiClient connection suspended");
    }
}

解决方法:

我按如下方式打开驱动文件进行写入:

writeDriveFile(DriveFile file, Handler handler){
    //see query task below to get a drive file by its name. Be careful you can get multiple data elements in the MetadataBuffer below if you have uploaded multiple files with the same name.
    Task<DriveContents> openFileTask = myDriveResourceClient.openFile(file, DriveFile.MODE_WRITE_ONLY);

然后用该任务将一些对象字节写入流someObject.getBytes(),这里没有魔法.然后提交结果.

openFileTask
            .continueWithTask(task -> {
                DriveContents contents = task.getResult();

                // Process contents...
                try (OutputStream writer = contents.getOutputStream()) {
                    writer.write(someObject.getBytes());
                    writer.close();
                }

                //Add whatever metadata you want here
                MetadataChangeSet changeSet = new MetadataChangeSet.Builder()
                        .setLastViewedByMeDate(new Date())
                        .build();

                //commit the file to Google Drive
                Task<Void> commitTask = myDriveResourceClient.commitContents(contents, changeSet);
                handler.onWriteResults();
                return commitTask;
            })
            .addOnFailureListener(e -> {
                // Handle failure
                Log.e(TAG, "Unable to read contents", e);
                handler.onDriveError(e);
            });

处理程序只是我为Drive API执行后要处理的错误或结果定义的接口.您还可以添加addOnCompleteListener()以在写入完成后处理某些内容.

file是DriveFile的一个实例,可以通过查询任务获取.在任务代码块中找到的元数据有一个getDriveId()方法,它有一个asDrivefFile()方法来获取上面需要的Drive文件.

Query query = new Query.Builder()
            .addFilter(Filters.eq(SearchableField.TITLE, "file name"))
            .build();
Task<MetadataBuffer> queryTask = mDriveResourceClient.query(query);

然后处理MetadataBuffer

queryTask.continueWithTask(
                    task -> {
                        MetadataBuffer metadataBuffer = task.getResult() ;
                        //I have this loop because I wanted to know if there were other versions of the file on the drive
                        for(Metadata data : metadataBuffer) {
                            Log.d(TAG, "******************* metadataBuffer title is " + data.getTitle());

                            if(data.getTitle().equals("file name")){
                                //this is just a method I defined that encapsulates the drive writing code above.
                                writeDriveFile(data.getDriveId().asDriveFile(), jsonContent, handler);
                            }
                        }
                        return task;
                    })
            .addOnCompleteListener(task -> {
                //some complete tasks
                }
            })
            .addOnFailureListener(e -> {
                Log.e(TAG, "************************** Error searching for " + fileName, e);
                handler.onDriveError(e);
            });

此代码全部用于写入App文件夹,但您只需在创建资源客户端时设置正确的范围.

删除驱动器文件可以按如下方式完成.

 public void deleteDriveFile(DriveResource file){
    Task<Void> deleteTask = mDriveResourceClient.delete(file);
    deleteTask
            .continueWith(task -> {
                Log.d(TAG, "************* Deleted drive file: " + file.getDriveId().toInvariantString());
                return task;
            })
            .addOnFailureListener(e -> {
                //log some sort of error for yourself
            });
}

标签:android,google-drive-sdk
来源: https://codeday.me/bug/20190728/1562802.html