Prevent re-attempting video preview playback on error

Previously if a media file was selected but the VideoView
could not play it, the VideoView would popup an error dialog
and at the end of a timeout the video preview was started again.
The result was an endless stream of error dialogs.

This error case is now detected, and if a file fails to
play a Toast is shown and the video playback is stopped.

app/src/main/java/protect/videotranscoder/activity/MainActivity.java

@@ -1398,6 +1398,17 @@ public void onClick(View v)
             }
         });
 
+        videoView.setOnErrorListener(new MediaPlayer.OnErrorListener()
+        {
+            @Override
+            public boolean onError(MediaPlayer mp, int what, int extra)
+            {
+                Toast.makeText(MainActivity.this, R.string.mediaPlaybackFailed, Toast.LENGTH_LONG).show();
+                stopVideoPlayback();
+                return true;
+            }
+        });
+
         FFmpegUtil.getMediaDetails(new File(path), new ResultCallbackHandler<MediaInfo>()
         {
             @Override

app/src/main/res/values/strings.xml

@@ -39,6 +39,7 @@
     <string name="fieldMissingError"><xliff:g id="field_name">%s</xliff:g> missing</string>
     <string name="fieldMissingOrInvalidError"><xliff:g id="field_name">%s</xliff:g> missing or invalid</string>
     <string name="invalidMediaFile">The selected media file is invalid or not supported</string>
+    <string name="mediaPlaybackFailed">The selected media file could not be previewed</string>
 
     <string name="writePermissionExplanation">This application needs access to storage in order to read and write media files. Without this access, the application cannot transcode.</string>
     <string name="permissionRequestAgain">Request again</string>