Is it possible to inject code in an android application?

Question

I would like to inject code in an android application at runtime. I have tried to use dx tool to generate a dexfile in the sdcard but when i want to instantiate, it fails. Are there any tools to inject code generating new dalvik bytecode? I am studing some libraries, aspecjt or guice for android. Is it better to work with a script language?

Thanks people :)

Answer 1

Dexmaker is new and designed just for this. Here's part of the example from the project website:

    DexMaker dexMaker = new DexMaker();

    // Generate a HelloWorld class.
    TypeId<?> helloWorld = TypeId.get("LHelloWorld;");
    dexMaker.declare(helloWorld, "HelloWorld.generated", Modifier.PUBLIC, TypeId.OBJECT);
    generateHelloMethod(dexMaker, helloWorld);

    // Create the dex file and load it.
    File outputDir = new File(".");
    ClassLoader loader = dexMaker.generateAndLoad(HelloWorldMaker.class.getClassLoader(),
            outputDir, outputDir);
    Class<?> helloWorldClass = loader.loadClass("HelloWorld");

    // Execute our newly-generated code in-process.
    helloWorldClass.getMethod("hello").invoke(null);