import com.google.android.gms.drive.DriveApi.DriveContentsResult; //导入依赖的package包/类
@Override
public void onResult(DriveContentsResult result) {
    if (!result.getStatus().isSuccess()) {
        Log.i(TAG, "Error creating new file contents");
        return;
    }
    final DriveContents driveContents = result.getDriveContents();
    new Thread() {
        @Override
        public void run() {
            OutputStream outputStream = driveContents.getOutputStream();
            addTextfileToOutputStream(outputStream);
            MetadataChangeSet changeSet = new MetadataChangeSet.Builder()
                    .setTitle("testFile")
                    .setMimeType("text/plain")
                    .setDescription("This is a text file uploaded from device")
                    .setStarred(true).build();
            Drive.DriveApi.getRootFolder(googleApiClient)
                    .createFile(googleApiClient, changeSet, driveContents)
                    .setResultCallback(fileCallback);
        }
    }.start();
}
 

import com.google.android.gms.drive.DriveApi.DriveContentsResult; //导入依赖的package包/类
/**
 * Gets the file contents, see {@link DriveContents}
 * 
 * @param driveFile	The Drive file.
 * @param openMode	The open mode. See {@link DriveFile}
 * @param downloadProgressListener	If set, opening progress
 * 									information can be show.
 * @returns The Drive file contents, see {@link DriveContents}
 */
public DriveContents sync_getFileContents(DriveFile driveFile, int openMode, 
		DownloadProgressListener downloadProgressListener) throws TBDriveException {
	
	DriveContentsResult result = null;
	if(downloadProgressListener!=null) {
		result = driveFile.open(getGoogleApiClient(), openMode, downloadProgressListener).await();
	}else{
		result = driveFile.open(getGoogleApiClient(), openMode, null).await();	        
	}
	
	if (!result.getStatus().isSuccess()) {
           //Display an error saying file can't be opened
       	Log.e(TAG, "Problem opening the file [" + result.getStatus().getStatusMessage() + "].");
       	throw new TBDriveException("Problem opening the file [" + result.getStatus().getStatusMessage() + "].");
           
       }
	
       //DriveContents object contains pointers to the byte stream
       return result.getDriveContents();
}
 

import com.google.android.gms.drive.DriveApi.DriveContentsResult; //导入依赖的package包/类
/**
 * Gets the file contents, see {@link DriveContents}
 * 
 * @param driveFile	The Drive file.
 * @param openMode	The open mode. See {@link DriveFile}
 * @param downloadProgressListener	If set, opening progress
 * 									information can be show.
 * @param callback See {@link TBDriveFileOpenCallback}
 */
public void async_getFileContents(DriveFile driveFile, int openMode, 
		DownloadProgressListener downloadProgressListener,
		final TBDriveFileOpenCallback callback) {
	
	ResultCallback<DriveContentsResult> contentsOpenedCallback =
	        new ResultCallback<DriveContentsResult>() {
	    @Override
	    public void onResult(DriveContentsResult result) {
	        if (!result.getStatus().isSuccess()) {
	            // display an error saying file can't be opened
	        	Log.e(TAG, "Problem opening the file [" + result.getStatus().getStatusMessage() + "].");
               	if(callback!=null) {
   					callback.setErrorCode(ERROR_FILE_OPEN);
   					callback.setErrorMessage(ERROR_FILE_OPEN_STRING);
   					callback.setErrorDetails(result.getStatus().getStatusMessage());
   					callback.run();
   				}		        	
	            return;
	        }
	        // DriveContents object contains pointers
	        // to the actual byte stream
	        DriveContents contents = result.getDriveContents();
	        if(callback!=null) {
	        	callback.setDriveContents(contents);
				callback.run();
			}
	    }
	};
	
	if(downloadProgressListener!=null) {
		driveFile.open(getGoogleApiClient(), openMode, downloadProgressListener)
		.setResultCallback(contentsOpenedCallback);
	}else{
		driveFile.open(getGoogleApiClient(), openMode, null)
        .setResultCallback(contentsOpenedCallback);
	}
}
 

import com.google.android.gms.drive.DriveApi.DriveContentsResult; //导入依赖的package包/类
@Override
public int uploadFile(File tempFile) {
    DriveFile driveFile;
    MetadataResult metadataResult;
    Metadata metadata;
    DriveContents driveContents = null;
    DriveContentsResult driveContentsResult;
    OutputStream outputStream;
    ExecutionOptions executionOptions;
    int complentionStatus;

    Log.i(TAG, "start upload of DB file temp:" + tempFile.getName());

    try {
        driveFile = mDriveId.asDriveFile();

        // Get metadata
        metadataResult = driveFile.getMetadata(mGoogleApiClient).await();
        checkStatus(metadataResult);

        metadata = metadataResult.getMetadata();

        Log.i(TAG, "try to upload of DB file:" + metadata.getOriginalFilename());

        if (!metadata.isPinned()) {
            pinFile(driveFile);
        }

        // Writing file
        driveContentsResult = mDriveContent.reopenForWrite(mGoogleApiClient).await();
        checkStatus(driveContentsResult);

        driveContents = driveContentsResult.getDriveContents();

        outputStream  = driveContents.getOutputStream();

        // Copio il file
        FileUtils.copyFile(tempFile, outputStream);
        Log.i(TAG, "try to commit file copy done");

        // Commit del file
        executionOptions = new ExecutionOptions.Builder()
                .setNotifyOnCompletion(true)
                .setConflictStrategy(ExecutionOptions.CONFLICT_STRATEGY_KEEP_REMOTE)
                .build();

        driveContents.commit(mGoogleApiClient, null, executionOptions);

        Log.i(TAG, "file committed - wait for complention");

        // Wait for complention
        complentionStatus = mGDriveCompletionRecevier.waitCompletion();

        Log.i(TAG, "received complention status:" + complentionStatus);

        if (complentionStatus == CompletionEvent.STATUS_CONFLICT) {
            return UPLOAD_CONFLICT;
        } else if (complentionStatus == CompletionEvent.STATUS_FAILURE) {
            throw new SyncException(SyncStatus.Code.ERROR_UPLOAD_CLOUD, "Error writing file to GDrive (FAILURE of commit)");
        }

        return UPLOAD_OK;
    } catch (IOException e) {
        if (driveContents != null) {
            driveContents.discard(mGoogleApiClient);
        }
        throw new SyncException(SyncStatus.Code.ERROR_UPLOAD_CLOUD, "Error writing file to GDrive message:" + e.getMessage());
    }
}
 

import com.google.android.gms.drive.DriveApi.DriveContentsResult; //导入依赖的package包/类
@Override
public InputStream downloadFile() {
    DriveFile driveFile;
    MetadataResult metadataResult;
    Metadata metadata;
    DriveContentsResult driveContentsResult;
    InputStream inputStream = null;

    Log.i(TAG, "start download of DB file");

    try {
        mDriveContent = null;
        driveFile = mDriveId.asDriveFile();

        // Get metadata
        metadataResult = driveFile.getMetadata(mGoogleApiClient).await();
        checkStatus(metadataResult);

        // Writing file
        driveContentsResult = driveFile.open(mGoogleApiClient, DriveFile.MODE_READ_ONLY, null).await();
        checkStatus(driveContentsResult);

        metadata = metadataResult.getMetadata();

        Log.i(TAG, "downloaded DB file:" + metadata.getOriginalFilename() + " modified on: " + metadata.getModifiedDate() + " size:" + metadata.getFileSize() + " bytes");

        mDriveContent = driveContentsResult.getDriveContents();

        inputStream  = mDriveContent.getInputStream();

        if (metadata.getFileSize() < 3) {
            inputStream.close();
            return null;
        }

        return inputStream;
    } catch (Exception e) {
        if (mDriveContent != null) {
            mDriveContent.discard(mGoogleApiClient);
        }
        throw new SyncException(SyncStatus.Code.ERROR_DOWNLOAD_CLOUD, "Error reading file from GDrive message:" + e.getMessage());
    }
}