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How to download a file from Google Drive using Drive.API?

I use Google Drive.Api to sync user application data with a user account.

The user database is in sqlite database format. I successfully downloaded the binary file to disk, but could not load the file from the application.

How to get the url file:

final GoogleAccountCredential credential = GoogleAccountCredential.usingOAuth2(this, Arrays.asList(DriveScopes.DRIVE_FILE)); credential.setSelectedAccountName(accountName); service = new com.google.api.services.drive.Drive.Builder(AndroidHttp.newCompatibleTransport(), new GsonFactory(), credential).build(); Query query = new Query.Builder() .addFilter(Filters.eq(SearchableField.TITLE, "BackupFile")) .build(); final DriveFolder folder = Drive.DriveApi.getRootFolder(mGoogleApiClient); folder.queryChildren(mGoogleApiClient, query).setResultCallback(new ResultCallback<DriveApi.MetadataBufferResult>() { @Override public void onResult(DriveApi.MetadataBufferResult metadataBufferResult) { final MetadataBuffer metadataBuffer = metadataBufferResult.getMetadataBuffer(); int iCount = metadataBuffer.getCount(); if (iCount == 1) { Log.i("Tag", "file was found"); final DriveId myFileId = metadataBuffer.get(0).getDriveId(); final DriveFile file = Drive.DriveApi.getFile(mGoogleApiClient, myFileId); new Thread(new Runnable() { @Override public void run() { DriveResource.MetadataResult mdRslt = file.getMetadata(mGoogleApiClient).await(); if (mdRslt != null && mdRslt.getStatus().isSuccess()) { String link = mdRslt.getMetadata().getWebContentLink(); Log.d("TAG", "Link to File:" + link); DownloadBackup(link); } } }).start(); } metadataBuffer.release(); } });

Attempting to upload a file via:

 public void DownloadBackup(String url){ InputStream mInput=null; FileOutputStream mOutput=null; if(url != null && url.length() > 0 ){ try { GoogleAccountCredential crd = GoogleAccountCredential.usingOAuth2(this, Arrays.asList(DriveScopes.DRIVE_FILE)); crd.setSelectedAccountName(accountName); com.google.api.services.drive.Drive srv = new com.google.api.services.drive.Drive.Builder(AndroidHttp.newCompatibleTransport(), new GsonFactory(), crd).build(); mInput = srv.getRequestFactory().buildGetRequest(new GenericUrl(url)).execute().getContent(); String outFileName = getApplicationContext().getDatabasePath(DatabaseHandler.DATABASE_NAME).getPath(); mOutput = new FileOutputStream(outFileName); byte[] mBuffer = new byte[1024]; int mLength; while ((mLength = mInput.read(mBuffer)) > 0) { mOutput.write(mBuffer, 0, mLength); } mOutput.flush(); Log.d("TAG", "Successfully Downloaded contents"); } catch (IOException e) { e.printStackTrace(); }finally { try { //Close the streams if(mOutput != null){ mOutput.close(); } if(mInput != null){ mInput.close(); } } catch (IOException e) { Log.e("Tag", "failed to close databases"); } } } else { // The file doesn't have any content stored on Drive. // return null; Log.e("Tag", "No content on Drive"); } }

Error Log:

 W/System.err﹕ com.google.api.client.http.HttpResponseException: 401 Unauthorized W/System.err﹕ <HTML> W/System.err﹕ <HEAD> W/System.err﹕ <TITLE>Unauthorized</TITLE> W/System.err﹕ </HEAD> W/System.err﹕ <BODY BGCOLOR="#FFFFFF" TEXT="#000000"> W/System.err﹕ <H1>Unauthorized</H1> W/System.err﹕ <H2>Error 401</H2> W/System.err﹕ </BODY> W/System.err﹕ </HTML> W/System.err﹕ [ 06-12 11:01:05.447 26208:26236 W/System.err ] at com.google.api.client.http.HttpRequest.execute(HttpRequest.java:1061) W/System.err﹕ at com.example.app.activities.Main.DownloadBackup(Main.java:487) W/System.err﹕ at com.example.app.activities.Main$15$1.run(Main.java:332) W/System.err﹕ at java.lang.Thread.run(Thread.java:841)
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android sqlite google-drive-sdk google-drive-android-api
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1 answer

Here is how I do it successfully. Instead of saving the result "getWebContentLink" I save the identifier of the file / folder (this is a string). And pass this identifier to a method like this:

  /************************************************************************* * get file contents * @param resId file driveId * @return file content / null on fail */ static InputStream read(String resId) { if (mGOOSvc != null && mConnected && resId != null) try { File gFl = mGOOSvc.files().get(resId).setFields("downloadUrl").execute(); if (gFl != null){ String strUrl = gFl.getDownloadUrl(); return mGOOSvc.getRequestFactory() .buildGetRequest(new GenericUrl(strUrl)).execute().getContent(); } } catch (Exception e) { /* error handling */ } return null; }

get "downloadURL" and get content. The full context of this method can be seen here .

Luck

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