How to access Activity from a React Native Android module?

Question

I\'m attempting to bridge over the Android functionality of keeping the screen on to React Native. I figured I could do this with a simple module, however I don\'t know how

Answer 1

For 0.28 and before, you can get activity from ReactInstanceManagerImpl 's private @Nullable Activity mCurrentActivity;, 0.29+ 's ReactContextBaseJavaModule using the same field.

Answer 2

Editted:

The issue is that getReactApplicationContext() returns the context of the Application and not the Activity. You cannot typecast an Application context to an Activity.

This is a simple workaround

Since usually, there is only one activity (Main Activity) in react-native, We can write a static function in MainActivity to return the activity

private static Activity mCurrentActivity = null;

protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    mCurrentActivity = this;
    ...
}
...
public static Activity getActivity(){
    Activity activity = new Activity();
    activity = mCurrentActivity;
    return activity;
}

then call MainActivity.getActivity() from the bridge modules

Answer 3

For custom UI component, you can get the context in the constructor, and later you can get the activity by context.getCurrentActivity()