BlackBerry Playbook Tablet for Android porting

Houston, we got it in the mail: a free RIM Blackberry Playbook Tablet because I submitted on time an Android app to the BlackBerry App World. The Android app runs within the Playbook Android emulator (yes so the app is native Android! Pretty cool I'd say!

Booting
Below a few bootup screenshots:

The bootup time for the device is quite long, definitely longer than the Samsung Galaxy Tab 10.1 for example.

Home-screen and taskmanager
This is what the home-screen looks like:

This is what the taskmanager looks like:

The way to go back to the home-screen or switch to another app is by swiping from the button of the screen up.

The simpel app running
And the app runs fine on the real device too :) Those Android figures are also checking it out as you can see...

Those four buddies are called: Don Pablo Calaveroid, Longevity, Fortune and Blessing. The last three were released because of the chinese Year of the Dragon. Too bad they sent one with still the USA power plug attached to it. Luckily I had a converter (as the globetrotter I am ;)...

This is how the tablet 7" screen compares to the Samsung 10.1 (note both screens are very clear, the picture is only trying to show the difference in size of 10" vs 7"):

Tetris just runs fine on it (but that's a native app), the screen is very clear:

Some generic feedback:

• The tablet smells rubbery because it has rubber on the back. Probably done as anti-slip, but even your fingers start to smell like it.
• A bit annoying was that you have to watch the Basics tutorials when doing the setup.
• Like the virtual keyboard, feels like lot less typos than similar sized touch screens

Porting
During converting the app to the PlayBook Android 2.3.3 or higher runtime, I ran into a few issues:

• For emailIntent.putExtra(android.content.Intent.EXTRA_TEXT, emailBody) statements needed to add .toString() to emailBody because otherwise you get an exception telling that EXTRA_TEXT is not a String.
• After each re-install of the app on the emulator, nothing seems to be remembered of the preferences. E.g had to accept the EULA each time after a new deploy, while this does not happen on the "regular" Android emulator. Also works fine on the real Playbook device.
• In my app the user can swipe left to right and vice versa to browse through tips. On the Playbook emulator the text on bottom of the screen was not always correctly updated. It was lagging behind.
• When trying to open the browser with an Intent and URL in the simulator, it says 'No network connection'. Strange, the pre-installed browser on the home screen works just fine... Seems similar to this reported issue.

Android Tablet project lessons learned

A little while ago I had the opportunity to work on a tablet-only app, running Android 3.1 or higher.
The app consists of only one screen, on which everything can be done.Therefore the app basically consists of one Activity and several Fragments (about 4 to be precise).
The Activity controls the Fragments for potential re-use of the Fragments, as recommended. As a basis the official Honeycomb Gallery project was used. Quite unique to this app was though that it has to have 3 columns instead of the usual 2...

To get a feeling for the app, here are some screenshots:


The very first time the user has to log in, after which a sync with the server is done. Note the progress bars showing in the background.


Synchronisation in progress... Notice that the title is indented for some reason. Needs some investigation why it shows here, and not in the Login DialogFragment...


After the data has been loaded, the user can filter all data by selecting from the dropdowns, and selecting items in the lists. The rightmost column then shows a list of questions, dependent on the selected filters. Many types of questions and actions had to be supported; beside the ones you see, also built were dropdowns, multiple radiobuttons, view images and PDFs, etc.

Lessons learned

• Prevent EditText in a ListView from losing focus/text disappearing:
  

  android:windowSoftInputMode="adjustPan"

  
  


• Sometimes Eclipse/DDMS loses the connection with the emulator, it just can't "see it" anymore. For example when you want to run an app in the emulator, the start dialog does not show your running emulator. To fix that run 'adb kill-server', that restarts the server. After this the emulator should be detected again.
  


• You can't disable a RadioGroup such that it disables it contained radiobuttons. You have to disable each radiobutton within that radiogroup seperately.
  


• Note that all Activities in your app might have had onDestroy() called, but the Application instance might still be around! So watch this when you have static variables, like a reference to the database... it might still be open when your Activity's onCreate() is called again!
  


• The 4.0 emulator was taking ages to start up (gave up after about 30mins). Then I compared the settings of my 3.1 AVD with the new 4.0 AVD. It turns out that the hardware property 'Abstract LCD density' setting of the 4.0 AVD is set by default to 240, which means high density. That implies a lot of pixels to draw. Read somewhere that that's one of the issues of a slow starting AVD. So I changed that property to be the same as of the 3.1 AVD, so made it 160. After that, the 4.0 AVD started about as fast as the 3.1 AVD (several minutes).
  I also reduced the 'Device ram size' setting from 512 to 256, but don't think that was the one that fixed it. See also here.
  


• The monkeyrunner recorder script records really slow on a 160 density Android 3.1 AVD. Playback is a lot faster. Here's a bunch of instructions, including 2 scripts for recording/playback which you can also find here and here.
  


• Had a problem trying to show the progress indicator in a ListFragment with the correct top margin. Tried adding addHeaderView() on the fragment to show some text above a fragment list. That works fine, except: when showing the progress indicator, it does not take into account any (top margin) LayoutParams being set! The app needs to set that to stay below the Action Bar which is in "overlay" mode. As soon as the adapter is set, the margin is taken into account correctly. I found the following here: in onCreateView() there is also a similar problem, they set the layoutparams explicitly again:
  
  

  // For some reason, if we omit this, NoSaveStateFrameLayout thinks we are // FILL_PARENT / WRAP_CONTENT, making the progress bar stick to the top of the activity. ... code where LayoutParams are set ...

  Tried several combinations of setting the LayoutParams, but those didn't work either. As a workaround now I have added a FrameLayout above the <fragment> in the main Activity xml. It is a <fragment> with a FrameLayout with a LinearLayout with some TextViews in it. For that one the top margin is set, and since the ListFragment is below it, it is pushed down correctly, even when the progress indicator is shown. Maybe the FrameLayout is causing the problems? Maybe a custom list fragment element would fix it.
  


• How to open a PDF from an app's local private storage:
  
  

  // Assuming you have stored a file like this (note the mode): FileOutputStream f = context.openFileOutput("theFilenameYouStoredThePdfAs", Context.MODE_WORLD_READABLE); ... write bytes to f, do other stuff... // Then you can get a reference for it for an external app via: File file = activity.getFileStreamPath("theFilenameYouStoredThePdfAs"); if (file.exists()) { Toast.makeText(activity, activity.getString(R.string.openingFile), Toast.LENGTH_SHORT).show(); Uri path = Uri.fromFile(file); Intent intent = new Intent(Intent.ACTION_VIEW); intent.setDataAndType(path, "application/pdf"); intent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP); activity.startActivity(intent); }

  
  
• Definitely take a look at the latest Google I/O app, that's always a good reference for figuring out how to do specific things; I consider it a best-practices app (I've also seen it being referred to in blog posts/presentations from the Android team, can't find them now :).