Android Explorations

A new release of Hanzi Recognizer is now available on Google Play . The new version features various UI improvements, a couple of search enhancements and support for the newest version of the eSpeak TTS  engine. As my other apps , Hanzi Recognizer is now officially free from context menus. All contextual actions are implemented as action modes, in line with the latest Android design guidelines . If you long-press a list items, it will be highlighted, and contextual actions will be shown in the action bar. Here's how selecting a dictionary entry in the search result list looks like: Another Android design pattern implemented in the new version is the split action bar . On devices with narrow screens (mostly handsets), only two action items can be shown in the top action bar. The rest are stashed in the overflow menu, which poses a usability problem when all of the actions are equally used. To solve this, Hanzi Recognizer now uses a split action bar in the favorites and hist...

One of the less known new features introduced in ICS is the ability to backup a device to a file on your computer via USB. All you have to do is enable USB debugging, connect your phone to a computer and type the adb backup command in a shell. That will show a confirmation dialog on the phone prompting you to authorize the backup and optionally specify a backup encryption password. It looks something like this: This doesn't require rooting your phone and lets you backup application data, both user installed and system applications (APK's), as well as shared storage (SD card) contents. There are some limitations though: it won't backup apps that have explicitly forbidden backups in their manifest, it won't backup protected (with DRM) apps and it won't backup some system settings such as APN's and WiFi access points. The transfer speed is limited by ADB channel speed (less than 1MB/s), so full backups can take quite some time. There is also a rather annoying...

This article describes how to talk to the system keystore daemon directly and store app-specific secrets in the system credential storage. It will introduce private API's, not available via the Android SDK and some OS services implementation details. Those may change at any time, and are not guaranteed to work. While the techniques described have been tested on a few different devices and OS versions (2.1 to 4.0), there are no guarantees. Use caution if you decide to implement them in a production app. As described in previous articles , Android has had a system-level credential storage since Donut (1.6). Up until ICS (4.0), it was only used by the VPN and WiFi connection services to store private keys and certificates, and a public API was not available. ICS introduced a public API  and integrated the credential storage with the rest of the OS. However, while the underlying implementation is able to store arbitrary data owned by any app, the ICS API only allows us to store ...

After a long break, a new Kanji Recognizer version is now available on Google Play . This release introduces a new quiz training mode and adds some further UI improvements, courtesy of ActionBarSherlock . One of the most popular features of the app is the kanji writing quiz. In the standard quiz mode, you are presented with the kanji's reading and English meaning (optional) and based on this information you have to recall the corresponding kanji and write it correctly. The quiz evaluates your input and keeps track of which characters you miswrote.This is a helpful tool for testing characters you already know, but it is only effective if you are fairly confident in your knowledge for the  particular level. If you can't remember a kanji, you need to skip it and can see the proper stroke order only after the quiz is over. To help you practice characters you haven't yet mastered, the new version introduces a training mode. If you select the training mode option in the quiz co...