android

Android requires developers to sign their applications with a digital certificate and that each future release be signed with the same certificate.

Sadly, bad things happen when the developer (you) looses access to the certificate : he (you) will not be able to release updates for the application without it. Never. Ever.

Android does not currently support multiple certificates per application so the best you could do would be to release a new app with the same name, in the hope your users will find a way to it by themselves.

As years go on, you will change your computer, wipe USB keys, reinstall OS, ...
So many dangerous operations for your digital certificates, hidden among millions of files !
If, like me, you are anxious at the idea of losing your certificates or passwords, just print a paper copy !
Although it is not invulnerable, paper should be less prone to mass erasing than a simple electronic file.

The idea is simple, not new, and you just need to know two commands to get a printable hard copy of your certificate.

Let's start.

This has been annoying me since the beginning : small screen devices are not taken into account by the vast majority of apps editors.

Worse : despite Google's pleading about size-caring (see http://developer.android.com/design), they recommend patterns that actually don't fit the real small screens for which size-caring IS important.

Here are screenshots of Android Market and Google Reader on an Xperia Mini (HVGA 320x480, 88mm long) :

Today I ran into a small problem that might happen sometimes : trying to benefit from a 2 day-only offer to download for free Duke Nukem 3d (just for fun, I don't think it's going to be the killer app this year), I found out that my phone had not enough free memory to install it (Market told me : 56MB required).

After putting several apps off the memory (to SD card) to free enough space to install it and after a first failed attempt to download the 28MB archive, I was able to download the .apk from the Market (that was "phase 1 : download").

Immediately after the file was downloaded, I started up my Open Advanced Task Killer to free more memory for the installation process.

Of course I got the very bad idea to kill the Android Market process, while it was already installing the app ("phase 2 : installation").

From there, even though Duke Nukem 3d was listed in my installed apps, I only had the option to install it, not to launch nor uninstall it. Even launching the Market again was not triggering the installation anymore.

The first time I read Android developer docs, there was something that was unclear to me : what resource to put in which XML file.

In this article, I will focus on resources in res/values and give some hints about how to name your XML resource files and what kind of resource to put inside.

...

In my case I had only one or two arrays of strings so it was overwhelming to put them in a separate file just because they were of a different type.

Another problem was accessing constant values from both XML layout and Java code. They are constant strings for internal use only, but in order to avoid duplicate declarations I decided to make them available as XML resources. I wanted those resources to be clearly separated from other, 'user visible', resources like GUI labels.

Another thing adding to the fog was the fact that, in derivate files (e.g. strings-fr.xml is derivated from strings.xml), you only want to find values relevant for the given file.
For instance, if you put all values of type 'string' in the same file but only a part of them should be internationalized, you would have a gap between the original and derivated files not only by the translated values but also by the list of values they declare. When coming back to the project after a long time, you might have a hard time remembering why there is this gap.

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For SwitchDataSwitch, I wanted to provide users with a 1-click solution to enable and disable data traffic (2G/3G/...).
I chose the notification bar since it is a very accessible place, visible almost all the time and that can be expanded without stopping the running activity :

 
The notification bar is usually presented in its reduced form (here the dark bar at the top of the screen with the smallest icons) but can be expanded by sliding it downwards.

Unfortunately, Android's Notification API is really made for instant notifications, not persistent ones, and that implies several inconveniences :

• when creating a notification, the developer has to put an icon in the reduced notification bar, taking some precious space
• by default an 'event timestamp' is shown next to the expanded content of the notification, which means nothing for a permanent service
• there is no programmatic way to know if a notification is currently displayed or not

This article describes a way to create a notification that :

• doesn't show up in the reduced notification bar
• doesn't have a timestamp in the expanded notification bar