0 Replies Latest reply on Nov 1, 2013 4:49 AM by Jonathan Scherrer

    Problems getting FileProvider and ContentProviders working in Flex Native Extensions.

    Jonathan Scherrer

      As part of an Adobe Flex application, I am writing an android native extension to allow me to send emails with file attachments using files generated from flex code. However I don't want the file to be world readable as it might contain sensitive data. Therefore I want to send the file from within my app's internal storage area / cache. I am using Intents to communicate with other apps (such as Gmail) to send the email.

       

      After doing some research, I discovered that the functionality of FileProviders should do exactly what I want. However the static method **FileProvider.getUriForFile()** is silently failing / crashing the native extension. The native extension stops and returns null with no errors or output from LogCat.

       

      If I manually create the Uri by parsing a string, Gmail complains that it can't attach the file to the email, and the email is sent with no attachment.

       

      Code in FREObject call():

       

          //... (Deal with params from flex app) ...

         

          //Setup Intent, and attach email data send from flex application:

          Intent intent = new Intent(Intent.ACTION_SEND);

          intent.setType("message/rfc822");

          intent.putExtra(Intent.EXTRA_EMAIL, toArray);

          intent.putExtra(Intent.EXTRA_CC, ccArray);

          intent.putExtra(Intent.EXTRA_BCC, bccArray);

          intent.putExtra(Intent.EXTRA_SUBJECT, subject);

          intent.putExtra(Intent.EXTRA_TEXT, message);

         

          Log.d("emaildebug", filePath);

          //Check we can read our email attachment from flex app

          //filePath is a temporary cache location.

          File appFile = new File(filePath);

          if (appFile.exists() && appFile.canRead()) {

              Log.d("emaildebug", "file successfully read");

          } else {

              return null;

          }

       

          //Get a handle on the android Context instead of FREContext.

          Context androidContext = (Context) context.getActivity();

         

          //Get the location of the root files directory.

          File attachPath = androidContext.getFilesDir();

          File attachFile = new File(attachPath, "attachment.pdf");

         

          //Copy file to root of files directory, so that our FileProvider can access it.

          try {

              copyFileUsingChannel(appFile, attachFile);

          } catch (Exception e) {

              Log.d("emaildebug", e.getMessage());

          }

         

          Log.d("emaildebug", "attachFile exists: " + attachFile.exists() );

          Log.d("emaildebug", "attachFile path: " + attachFile.getAbsolutePath());

         

          //This line will silently crash the native extension, instantly returning null, even in try catch.

          //Uri contentUri = FileProvider.getUriForFile(androidContext, "com.example.androidextensiontest.provider", attachFile);

         

          //Therefore manually create the Uri from a string.

          Uri contentUri = Uri.parse("content://com.example.androidextensiontest.provider/files/attachment.pdf");

       

          Log.d("emaildebug", "uri created");

          Log.d("emaildebug", contentUri.toString());

         

          //Grant permisions for all apps that can handle given intent

          //Courtesy of: http://stackoverflow.com/questions/18249007/how-to-use-support-fileprovider-for-sharing-co ntent-to-other-apps

          List<ResolveInfo> resInfoList = androidContext.getPackageManager().queryIntentActivities(intent, PackageManager.MATCH_DEFAULT_ONLY);

          for (ResolveInfo resolveInfo : resInfoList) {

              String packageName = resolveInfo.activityInfo.packageName;

              Log.d("emaildebug", "package: " + packageName);

              androidContext.grantUriPermission(packageName, contentUri, Intent.FLAG_GRANT_WRITE_URI_PERMISSION | Intent.FLAG_GRANT_READ_URI_PERMISSION);

          }

         

          intent.setFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION | Intent.FLAG_GRANT_READ_URI_PERMISSION);

          intent.putExtra(Intent.EXTRA_STREAM, contentUri);

       

          context.getActivity().startActivity(Intent.createChooser(intent, "Send mail using..."));

       

      In Manifest File:

       

          <provider

              android:name="android.support.v4.content.FileProvider"

              android:authorities="com.example.androidextensiontest.provider"

              android:exported="false"

              android:grantUriPermissions="true" >

              <meta-data

                  android:name="android.support.FILE_PROVIDER_PATHS"

                  android:resource="@xml/my_paths" />

          </provider>

       

      **In my_paths.xml:**

       

          <paths xmlns:android="http://schemas.android.com/apk/res/android">

              <files-path name="files" path="." />

          </paths>

       

      LogCat output:

       

          11-01 10:58:09.971: D/emaildebug(17013): /data/data/air.com.example.MyAppName.debug/cache/FlashTmp.V17013/attachment.pdf

          11-01 10:58:09.971: D/emaildebug(17013): file successfully read

          11-01 10:58:09.991: D/emaildebug(17013): attachFile exists: true

          11-01 10:58:09.991: D/emaildebug(17013): attachFile path: /data/data/air.com.example.MyAppName.debug/files/attachment.pdf

          11-01 10:58:09.991: D/emaildebug(17013): uri created

          11-01 10:58:09.991: D/emaildebug(17013): content://com.example.androidextensiontest.provider/files/attachment.pdf

          11-01 10:58:09.991: D/emaildebug(17013): package: com.android.email

          11-01 10:58:09.991: D/emaildebug(17013): package: com.google.android.gm

       

      If I attempt to send the file from external storage using a file:// Uri, the file attachment works perfectly. However as previously mentioned the file attachment potentially contains sensitive data, therefore I wish to avoid using external storage.

       

      What I believe I'm seeing is that FileProviders do not work within native extensions. I tried also using a ContentProvider, however neither the Constructor nor onCreate methods were called.

       

      ContentProvider Manifest:

       

          <provider

              android:name="com.example.androidextensiontest.provider.MyContentProvider"

              android:authorities="com.example.androidextensiontest.provider">

          </provider>

       

      MyContentProvider:

       

          public class MyContentProvider extends ContentProvider implements PipeDataWriter<InputStream> {

       

          public MyContentProvider() {

              // Never Output

              Log.d("emaildebug", "Constructor");

          }

         

          @Override

          public boolean onCreate() {

              // Never Output

              Log.d("emaildebug", "OnCreate");

              return false;

          }

       

          //.. Rest of class

          }

       

      Am I doing something wrong or are ContentProviders / FileProviders just not supported within flex native extensions? Alternatively, are there any other solutions for attaching a file located in internal storage to an email. My searching on Stack Overflow and google has not encountered anyone else having similar experiences, especially regarding FileProvider.getUriForFile(). Any help / comments appreciated.

       

      Sorry for the wall of text, I wanted to record everything I've tried so far, and what works and what doesn't.

       

      tldr; Do ContentProviders / File Providers work in flex native extensions? Are there any other methods of sending internal files as email attachments?