How to intercept Button press on Android

Hello, I am currently trying to invoke callback methods when the Volume Keys or a Hardware Key (Back, Home, Overview ) is pressed. Therefore, I started to implement a custom android module but atm, I am wondering how I can override these methods as they are part of the Activity class and not of GodotSingleton.

Is there a way to intercept presses of the Volume/SystemUI Buttons and execute my own code? I want something like this:

    public class GodotInputHandling extends Godot.SingletonBase {
        private static final String TAG = "inputHandling_Activity";
    
        private Activity activity;
        private int instanceId = 0;
    
        static public Godot.SingletonBase initialize(Activity p_activity)
        {
            return new GodotInputHandling(p_activity);
        }
    
        public GodotInputHandling(Activity p_activity)
        {
            registerClass("GodotInputHandling", new String[]
                {
                    "initModule",
                });
            activity = p_activity;
        }
    
        public void initModule(int _instanceId) {
            //some init code here if needed
        }
    
        //I want something like this, but it should override the metod in the activity
        @Override
        public boolean dispatchKeyEvent(KeyEvent event) {
            //check which key it was and call method in gdscript like:
            // if(event == .... ){
            //     GodotLib.calldeferred(instance_id, "_on_volume_down_pressed", new Object[] { });
            // } else {
            //      GodotLib.calldeferred(instance_id, "_on_foo_pressed", new Object[] { });
            // }
    
        }
    
        //Or something like this, but this method is also part of the activity
        @Override
        public boolean onKeyDown(int keyCode) {
            //...
        }
    
    }