Easy way to get application context in your Android project

Context is very commonly used parameter in Android development.

We use context for app info, resources, system services, user configurations.

There are two ways to get context:

• Add context as parameter

when we want context in low level library to get resources, we pass context as parameter and pass it one by one, that's too boring.

If you forget pass context from beginning, it's a lot work to do.

Adding a context parameter change the old method signature, this may cause a series of compile error.

• Use Application Singleton

You can simple modify your Application instance become a singleton, so that can be accessed in anywhere.

However, if your project is multiple modules, application singleton is often in App module, which is the top of your multiple modules hierarchy, other low level modules can not depend App module, thus they can not access application singleton anymore.

Thank goodness, the Android Team finally discovery this problem, they developed a androidx library to provider global context, which use a singleton to hold application instance when ContentProvider attach method called.

This work is smart, but still involved a additional ContentProvider component.

We want a simple and light way to get context anywhere

We use the hidden class ActivityThread

    ActivityThread:
    
    public static Application currentApplication() {
        ActivityThread am = currentActivityThread();
        return am != null ? am.mInitialApplication : null;
    }
    

https://cs.android.com/android/platform/superproject/+/master:frameworks/base/core/java/android/app/ActivityThread.java?q=activitythread&ss=android

As you can see, ActivityThread class has method currentApplication from Android 4.x to Android 13,

and it's a public method, used internally by the Android Team, so it's safe to use by us.

Cause the Android Team removed ActivityThread.class when packing Android.jar, so we need a little trick to do.

Good news is the tricky thing has been done for you, you just need add the dependency and joy it!

If you are interested in a little trick , click this

code:

    AppGlobal.getApplication()
    AppGlobal.getPackageName()
    AppGlobal.getProcessName()

gradle:

// add jitpack repo
repositories {
        maven {
            url 'https://jitpack.io'
        }
 }
...

// add dependency
dependencies { 
        implementation "com.github.fatterx:android_global_context:0.0.1"
}

relative links:

• https://github.com/fatterx/android_hidden_api