16. July 2017

Android Studio: Failure INSTALL_FAILED_TEST_ONLY

Starting application from Android Studio may fail with the mysterious message: Installation failed with message INSTALL_FAILED_TEST_ONLY.

The IDE will prompt you whether you want to uninstall the existing application.

Even this uninstallation may fail. When you open Run console, you can see something like this:

$ adb shell pm uninstall rocks.georgik.sdlapp
$ adb shell pm install -r "/data/local/tmp/rocks.georgik.sdlapp"
	pkg: /data/local/tmp/rocks.georgik.sdlapp
Failure [INSTALL_FAILED_TEST_ONLY]

$ adb shell pm uninstall rocks.georgik.sdlapp
DELETE_FAILED_INTERNAL_ERROR
Error while Installing APK

There is a relatively simple fix to this issue. Click drop-down menu with your configuration and choose Edit Configurations…

Select tab General and add -t to Install Flags field. Click Ok.

Now start the application again and it should work.

5. July 2017

SDL2 application for Android built by Gradle 4

SDL2 is a well known library for making games or interactive application for Linux, Windows or macOS. The library has also support for mobile devices. Building application for Android requires a little bit more effort than build for desktops.

Let’s go step-by-step.

First of all download Gradle 4 and add bin directory with gradle to your PATH environment variable.

Download and install Android Studio.

Clone sdl2-android-example project from GitHub.

Open the repo in Android Studio and open SDK Manager. Go to Tools, select menu Android, and select item SDK Manager.

In the lower right corner check option Show Package Details. Install Android SDK Build Tool e.g. version 25.0.3 and NDK.

When you open the sdl2-android-example you will see following structure. There are two gradle files in the top level directory. The first is build.gradle. The file contains a dependency on gradle-experimental plugin which is recommended for NDK builds for Android.

buildscript {
    repositories {
       jcenter()
    }
    dependencies {
        // Android native build plugin compatible with Gradle 4
        classpath 'com.android.tools.build:gradle-experimental:0.11.0-alpha-preview-02'
    }
}

allprojects {
    repositories {
        jcenter()
    }
}

The second Gradle file is settings.gradle. The file contains a list of modules which are in the project. One module is SDL2 library. Then there are two further modules app and main. The app module is the bridge between Java and SDL2. The main module contains C code for the application.

gradle.ext.sdkVersion = 21

include ':app'
include ':SDL2'
include ':main'

These two files provide a skeleton for the build of the application. Each module SDL2, app and main are stored in the directory that matches the name a of module. Each module contains its own build.gradle which describes how to build the module.

The module file SDL2/build.gradle is interesting because it contains many excludes. It does not make sense to build all C files from SDL2 for Android.

The module file main/build.gradle contains information for linking the C application with SDL2 library.

The module file app/build.gradle contains information how to wrap all the C source code into final application.

First of all, it is necessary to build the library:

gradle SDL2:distributeLib

Gradle will build all flavors. If you’re experiencing problems with Android Studio, just sync the project after executing this command from command line.

Now you can deploy the application to a device or an emulator. Go to Gradle projects, expand :app module, expand Tasks, expand install and double click installDebug target.

We will discuss how to use further SDL2 libraries in next articles. You can find more under topic SDL2.

31. May 2017

How to debug C/C++ code in Android Studio

Android Studio has support for debugging Java and also C/C++ code. The problem is that in default configuration the debugger might not work. There is a quick way how to fix the issue.

Go to your application and select Edit Configurations…

Select tab Debugger and change Debug type to value Dual. Press Ok.

Android Studio will check installed packages and in the case of missing debugger it will prompt you to confirm the fix. Just click Yes.

After installation of necessary packages, the debugger will start and you’ll be able to debug even C/C++ code.