Question

我在Android中使用以下Drive API代码从Google云端硬盘下载文件。

MetadataChangeSet changeSet = new MetadataChangeSet.Builder()
            .setMimeType(Constants.MIME_TYPE_DOCX)
            .build();

Task<Metadata> updateMetadataTask =
            mDriveResourceClient.updateMetadata(file, changeSet);

通过使用此代码，我可以下载所有文件，即Docx，Doc，Image，xls，xlsx，txt，pdf等。

但是它给出了以下文件的问题。

Google Doc（application / vnd.google-apps.document），

SpreadSheet（application / vnd.google-apps.spreadsheet），

演示文稿文件（application / vnd.google-apps.presentation）

即使我尝试使用此代码更改所选文件的元数据，但仍然显示文件大小为0（零）并且扩展名为null。

{{1}}

因此，如果有人实施，请建议解决方案。

Answer 1

我尝试使用Google云端硬盘Android API下载Google文档，电子表格和演示文稿文件，但未使用Drive API获得任何正确的解决方案。

但我在很多地方都读过你可以使用REST下载这些文件。最后，当我将这两个代码组合起来时，我得到了正确的解决方案，即Drive API Code和REST code

以下是代码。

首先，您需要在App模块的build.gradle文件中添加这两行。

compile('com.google.api-client:google-api-client-android:1.23.0') {
   exclude group: 'org.apache.httpcomponents'
}
compile('com.google.apis:google-api-services-drive:v3-rev107-1.23.0') {
  exclude group: 'org.apache.httpcomponents'
}

其次，按所选帐户初始化GoogleAccountCredential和Drive。

private com.google.api.services.drive.Drive driveService = null;
private GoogleAccountCredential signInCredential;
private long timeStamp;
private String fileName;


// Initialize credentials and service object.
signInCredential = GoogleAccountCredential.usingOAuth2(
   getApplicationContext(), Arrays.asList(SCOPES))
   .setBackOff(new ExponentialBackOff());


 if (!TextUtils.isEmpty(signInAccount.getAccount().name)) {  
  signInCredential.setSelectedAccountName(signInAccount.getAccount().name);
  signInCredential.setSelectedAccount(new Account(signInAccount.getAccount().name, getPackageName()));
}

if (!TextUtils.isEmpty(signInCredential.getSelectedAccountName())) {
   HttpTransport transport = AndroidHttp.newCompatibleTransport();
   JsonFactory jsonFactory = JacksonFactory.getDefaultInstance();
   driveService = new com.google.api.services.drive.Drive.Builder(transport, jsonFactory, signInCredential)
           .setApplicationName(appName)
           .build();
}

//传递两个参数，即fileId和mimeType，选择文件名时得到的参数。

public void retrieveGoogleDocContents(String fileId, String mimeType) throws IOException {
   try {        

   File storageDir =createStorageDir();

   timeStamp = System.currentTimeMillis();
//selectedFileName which one you get when you select any file from the drive, or you can use any name.
   fileName = selectedFileName + "." +getFileExtension(mimeType);

   File localFile = new File(storageDir, timeStamp + "_" + fileName);
   if (!localFile.exists()) {
       if (localFile.createNewFile())
           Log.d(TAG, fileCreated);
   }


   AsyncTask<Void, Void, Boolean> task = new AsyncTask<Void, Void, Boolean>() {

       @Override
       protected void onPreExecute() {
           super.onPreExecute();
       }

       @Override
       protected Boolean doInBackground(Void... params) {

           boolean isSuccess = false;
           OutputStream outputStream = null;

           try {
               outputStream = new FileOutputStream(localFile);

               com.google.api.services.drive.Drive.Files.Export request = driveService.files().export(fileId,getFileMimeType(mimeType));
               request.getMediaHttpDownloader().setProgressListener(new GoogleDriveActivity.CustomProgressListener());
               request.getMediaHttpDownloader().setDirectDownloadEnabled(false);
               request.executeMediaAndDownloadTo(outputStream);

               isSuccess = true;

           } catch (UserRecoverableAuthIOException e) {
               Log.d(TAG, "REQUEST_AUTHORIZATION Called");
               startActivityForResult(e.getIntent(), REQUEST_AUTHORIZATION);
           } catch (IOException transientEx) {
               // Network or server error, try later
               Log.e(TAG, transientEx.toString());
           } finally {
              close(outputStream);
           }

           return isSuccess;
       }

       @Override
       protected void onPostExecute(Boolean isSuccess) {
           Log.i(TAG, "Download Successfully :" + isSuccess);           
                    }

   };
   task.execute();
   } catch (IOException e){
   Log.e(TAG, e.toString()); 
   }
 }

public static void close(Closeable c) {
   if (c == null) return;
   try {
       c.close();
   } catch (IOException e) {
       log.log(Level.SEVERE, e.getMessage(), e);
   }
}


public static File createStorageDir() {
   String path = Environment.getExternalStorageDirectory() + "/" + Constants.IMAGE_DIRECTORY;
   File storageDir = new File(path);
   if (!storageDir.exists()) {
       if (storageDir.mkdir())
           Log.d(TAG, "Directory created.");
       else
           Log.d(TAG, "Directory is not created.");
   } else
       Log.d(TAG, "Directory exist.");

   return storageDir;
}

这是文件mime类型和扩展名。

public final static String ICON_DOCX = "docx";
public final static String ICON_PPTX = "pptx";
public final static String ICON_XLSX = "xlsx";

public final static String MIME_TYPE_GOOGLE_DOC = "application/vnd.google-apps.document";
public final static String MIME_TYPE_GOOGLE_SPREADSHEET = "application/vnd.google-apps.spreadsheet";
public final static String MIME_TYPE_GOOGLE_PRESENTATION = "application/vnd.google-apps.presentation";
public final static String MIME_TYPE_DOCX = "application/vnd.openxmlformats-officedocument.wordprocessingml.document";
public final static String MIME_TYPE_XLSX = "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet";
public final static String MIME_TYPE_PPTX = "application/vnd.openxmlformats-officedocument.presentationml.presentation";


public static String getFileExtension(String fileMimeType) {
   String fileExtension = Constants.ICON_PDF;

   if (fileMimeType.equals(Constants.MIME_TYPE_GOOGLE_DOC))
       fileExtension = Constants.ICON_DOCX;
   else if (fileMimeType.equals(Constants.MIME_TYPE_GOOGLE_SPREADSHEET))
       fileExtension = Constants.ICON_XLSX;
   else if (fileMimeType.equals(Constants.MIME_TYPE_GOOGLE_PRESENTATION))
       fileExtension = Constants.ICON_PPTX;

   return fileExtension;
}

public static String getFileMimeType(String fileMimeType) {
   String newMimeType = Constants.MIME_TYPE_PDF;

   if (fileMimeType.equals(Constants.MIME_TYPE_GOOGLE_DOC))
       newMimeType = Constants.MIME_TYPE_DOCX;
   else if (fileMimeType.equals(Constants.MIME_TYPE_GOOGLE_SPREADSHEET))
       newMimeType = Constants.MIME_TYPE_XLSX;
   else if (fileMimeType.equals(Constants.MIME_TYPE_GOOGLE_PRESENTATION))
       newMimeType = Constants.MIME_TYPE_PPTX;

   return newMimeType;
}

如何使用Drive API下载Google Doc，电子表格和演示文稿文件？

1 个答案: