Programming and general geekiness.

Posts tagged ‘android development’

Update to Keep Calm

I updated Keep Calm on Google Play today to version 2.2.5. This new update fixes a couple of bugs and makes poster generation a lot more efficient which should, in theory, mean that the app is a lot less likely to crash – an error reported due to a memory error.

The reason that the app had been crashing for some users (especially those with older phones with less RAM and older versions of Android) was because the background of the poster was being regenerated every time something was changed on the poster. This was a necessary because Keep Calm Pro allows for a greater variety in the backgrounds (solid color, linear gradient, radial gradient and an image) however was completely unnecessary for Keep Calm and therefore lead to an unnecessary Bitmap object hogging up memory.

The two apps share the same class to generate the poster (its called Dunkirk and the majority of variables, functions and classes in the app get their namesake from various WWII battles to keep me entertained whilst coding) so an extra function has been added to this that generates higher quality posters. I also adjusted the resolution the preview as rendered at – by default it is 600 by 900 (this is the export resolution) however if the screen resolution is lower than that it will be rendered at the lower resolution.

Hopefully this update has fixed any bugs that were in Keep Calm which is now within in three/four days of 50,000 downloads :).

Keep Calm on Google Play

Things I’d like from Android

Android is a good platform – not a great platform, but a good one. I’ve been doing a lot of Android development recently and it certainly has many good features and it is easy (and cheap) to make an app for the system. There are, however, a great number of problems with Android from a developer’s point of view. This is a rough list of things I would like to see from the Android project. I don’t think that it necessarily needs them, but I think it would be a good thing for the platform if it had a few of them:

  • SVG support everywhere: A major problem with Android at the moment is that you have to create at least three different copies of the same icon for use in app because Android apps can run on many different devices at different resolutions. If all icons were changed to SVG it would be possible to just include one copy of the icon and know that it would be shown at maximum quality on all screens. This would also be useful when Android displays eventually get to a higher pixel density (as in the iPhone and iPad) as icons would never appear pixelated. SVG font support would also be handy but not a requirement.
  • Better font support: Android currently comes with three fonts whereas Windows Phone and iOS come with over fifty. You can include fonts in your app however if you wish to do this you have to change the font of each View pragmatically rather than via styling or XML which can increase the size of the app and also make it slower. Again, SVG font support would be useful.
  • Higher PPI displays: When the iPhone got a Retina Display the only way that Android devices could get a similar resolution was to get bigger screens because Android wouldn’t run as well on higher density displays. There should be some big system changes to get this support.
  • One Android: It amazes me how phone manufacturers have fragmented Android by adding new UIs and alternative apps. Whilst some of these are really great it often means that some devices won’t receive a major update for months after it has been released because the UI is being developed. If Android could go back to being pure Android it would make it a lot easier for developers and require less testing of apps.
  • Google Play gift cards: This seems like a painfully simple thing to do but it is one of many reasons why iOS developers make a lot more than Android developers. It is a well known fact Android users ‘don’t like buying apps’ however the problem is that most of them can’t. When you set up an iTunes account you either have to type in your bank details or set it so that you will use gift cards however this is not required for Google Play registration. As most Android users have not created a Google Wallet account they can’t buy Android apps. By selling gift cards everywhere (as iTunes does) more people are likely to start buying apps.
  • Better integration between Eclipse and Google Play: Currently you can create an app in Eclipse, export it and then upload it to Google Play. It makes a lot more sense, however, to integrate the two so that developers sign into Eclipse and then press one button to upload an app to Google Play. This would also simplify the process of creating in-app purchases.
  • OTA updates: Most iOS devices are now running iOS 5.x and many are already running iOS 5.1, which came out in the last month. On Android most devices are still stuck with a two year old version of Android because phone manufacturers (who are responsible for updates) have not chosen to update to Ice Cream Sandwich. If Google were to take over the updating of Android devices it would probably mean that more people were using the latest version of the software.
  • Better emulator: The Android emulator is very good however it can be incredibly slow when trying to emulate Android 3.x and Android 4.x devices.

Sharing and saving Bitmaps in Android

If you’ve ever worked with Android development before you’ll probably know that once you get it right it can be incredibly rewarding however if you get it wrong it can be a real pain to fix. Sometimes the development also demonstrates the fragmentation of Android and how it can be a great challenge to do something relatively simple because it works differently on different devices.

I recently developed the Keep Calm app for Android that allows users to create Keep Calm and Carry On style posters. The app has been a reasonable success (20,000 downloads in a month) however there has been one major issue: not everyone could save properly. At first I didn’t really understand why this was because all of the testing I had done indicated that the Bitmap object that the image was stored in was being correctly saved to the SD card and it would then appear in the Gallery app. However, this was not the case for everyone.

I soon discovered that it wasn’t a technical issue with my app entirely. The default Gallery app gets a list of files in the various images folders on the SD card each time it loads but the Android system doesn’t always refresh this list of files very often – sometimes only when the device is restarted. Clearly it would have been a major issue for my users to have to restart their phone each time they wanted to view a file so I came up with this solution:

String saved = Images.Media.insertImage(this.getContentResolver(), bitmap, title, description);
Uri sdCardUri = Uri.parse("file://" + Environment.getExternalStorageDirectory());
sendBroadcast(new Intent(Intent.ACTION_MEDIA_MOUNTED, sdCardUri));

The bitmap object is of type Bitmap whereas title and description are both Strings. The sendBroadcast function (your activity inherit it as the class extends Activity, where the function is) then forces the OS to remount the SD card as it would do when the device starts up meaning that your picture will appear in the Gallery app. If you want to prove this to your users you can load up the file in the app:

Intent intent = new Intent();
intent.setDataAndType(Uri.parse(saved), "image/*");

This then loads the image up, using an Intent, in whatever the default Gallery app is. Remember that you’ll need to add the android.permission.WRITE_EXTERNAL_STORAGE to your Android Manifest otherwise the app will fail. The obvious progression of saving is, of course, sharing and Android makes this incredibly easy to do without having to use the APIs of all the various social networks that exist – instead the app can just utilize services provided by other social network apps on the phone. Here is how to do it:

Intent sharingIntent = new Intent(Intent.ACTION_SEND);
sharingIntent.putExtra(Intent.EXTRA_STREAM, Uri.parse(saved));
startActivity(Intent.createChooser(sharingIntent, "Share image"));

This loads up a menu (unless no options are available other than email) headed with the “Share image” text asking the user what service they would like to share it with. The appropriate app will then launch. Another cool thing I’ve done using a Bitmap is to set the wallpaper. You’ll need to ensure that the Bitmap is double the width of the user’s device and the same height (explained in this Lifehacker article) – this could be done using a Canvas. Here is the code you can use:

WallpaperManager wallpaperM = WallpaperManager.getInstance(this);

Like with saving, you’ll need to ensure that you add the android.permission.SET_WALLPAPER t0 your manifest otherwise, again, the app will fail. Hopefully this article has helped you with your projects and if you have any other problems leave me a message in the comments.

Prerequisites for Android Development

I really like doing Android development and over the past few months I’ve done quite a bit of it but I found at the beginning that some things didn’t seem to be entirely logical that were quite important despite the fact that I already had a vast programming knowledge. Here is a list of things I reckon are useful for learning Android development:

  • Java experience: I don’t think that you need to know loads of Java to develop Android apps but I would say it is important that you at least know the syntax and roughly how to do things. Experience in a similar language like C# or C++ would probably get you by, just so long as you know the difference between a package, class and that kind of thing
  • Experience in another object-orientated language: Some experience in another language would also be useful because despite the fact that most Android development is in Java it is useful to understand how other languages do things because a lot of the Android specific Java has had influence from C++
  • An understanding of how apps work: This would probably come with programming experience but you really aren’t going to get anywhere if you don’t get how the most basic apps. Reading a few tutorials can help fix this
  • Experience creating user interfaces via code and and a visual designer: Android uses both XML layouts and pure Java code to create User Interfaces so provided that you have done something in both before you’ll probably be fine. I should imagine that it would probably be OK if you’ve done JavaScript DOM and HTML
  • Basic knowledge of XML and SQLite: You won’t need to know how to do these perfectly but so long as you can create XML documents and edit them. I wouldn’t say SQLite knowledge is vital but it would be good to have some database knowledge
  • A basic understanding of other mobile platforms: I had done a tiny amount of iOS and Windows Phone development before starting Android which probably helped me a tiny bit because it gives you some knowledge of design. Windows Phone development is probably more different to Android than iOS, so even if you’ve just created a calculator in iOS you’ll be in a good position to start Android development
  • Good resources for testing: The emulator is good but I’ve found that it always useful to either have at least one Android device for testing. I also recommend setting up a few different devices in the emulator with different screen sizes and versions of Android because that will give you a chance to test in loads of different environments
  • You’ve read some stuff on Android development: It is worthwhile reading up on Android development before you get started. Android Design and the Android Guide are both good places to start and reading some blogs will probably help develop your ideas. If you get stuck, make sure that you go on Stack Overflow.

Once you are fairly confident with all of this I recommend going over to Lars Vogel’s site which has some great development tutorials.