Android- Using DexClassLoader to load apk file.

Question

Hi guys,

I've hit a bit of a wall. Any help would be appreciated. I have an app that I want to use DexClassLoader to load another apk file.

Here is my code:

DexClassLoader dLoader = new DexClassLoader("/sdcard/download/test.apk","/sdcard/download",null,ClassLoader.getSystemClassLoader().getParent());
Class calledClass = dLoader.loadClass("com.test.classname");
Intent it=new Intent(this, calledClass);
it.setClassName("com.test", "com.test.classname");
startActivity(it);

Now I had already installed test.apk so when I ran the above code it worked fine and launched the application. However I want to be able to run this without test.apk being installed already (as that would defeat the entire point of the application) . So I uninstalled it and when I ran the my app again I get this error:

android.content.ActivityNotFoundException: Unable to find explicit
activity class {com.test/com.test.classname}; have you declared this
activity in your AndroidManifest.xml.

So I'm a bit stumped here. This activity is declared in the Manifest of the apk I am trying to run. I can't declare it in my applications Manifest. Any ideas?

Thanks, Craig

Answer 1

You can't do that. Even if you're able to access classes from external file, Android still does not know them. And you don't run activities directly, but by requesting Android to run them, so they have to be registered/installed into system.

Answer 2

Try using Android's PathClassLoader:

    String packagePath = "com.mypackage";
    String classPath = "com.mypackage.ExternalClass";

    String apkName = null;
    try {
        apkName = getPackageManager().getApplicationInfo(packagePath,0).sourceDir;
    } catch (PackageManager.NameNotFoundException e) {
        // catch this
    }

    // add path to apk that contains classes you wish to load
    String extraApkPath = apkName + ":/path/to/extraLib.apk" 

    PathClassLoader pathClassLoader = new dalvik.system.PathClassLoader(
            apkName,
            ClassLoader.getSystemClassLoader());

    try {
        Class<?> handler = Class.forName(classPath, true, pathClassLoader);
    } catch (ClassNotFoundException e) {
        // catch this
    }