Modify the example to work properly

[yyy33]

I almost gave up after half a day of debugging, the action listener has to be defined before it can be used, and it can't have the same name as UIGestureRecognizerDelegate.

    class MainActivity :AppCompatActivity(){

// gesture recognizer actionlistener
private val mActionListener={recognizer:UIGestureRecognizer->
        // gesture recognized
        }

        override fun onCreate(savedInstanceState:Bundle?){
        ...

        val delegate=UIGestureRecognizerDelegate();

        // single tap gesture
        val recognizer1=new UITapGestureRecognizer(this)
        recognizer1.tapsRequired=1
        recognizer1.touchesRequired=1
        recognizer1.tag="single-tap";
        recognizer1.actionListener=mActionListener

        // double tap gesture
        val recognizer2=UITapGestureRecognizer(this)
        recognizer2.tag="double-tap"
        recognizer2.tapsRequired=2
        recognizer2.touchesRequired=1
        recognizer2.actionListener=mActionListener

        // We want to recognize a single tap and a double tap separately. Normally, when the user
        // performs a double tap, the single tap would be triggered twice.
        // In this way, however, the single tap will wait until the double tap will fail. So a single tap
        // and a double tap will be triggered separately.
        recognizer1.requireFailureOf=recognizer2

        // add both gestures to the delegate
        delegate.addGestureRecognizer(recognizer)
        delegate.addGestureRecognizer(recognizer2)

        // forward the touch events to the delegate
        val rootView=findViewById(R.id.root)
        rootView.setGestureDelegate(delegate)

        // optional delegate methods
        delegate.shouldReceiveTouch={recognizer->true}
        delegate.shouldBegin={recognizer->true}
        delegate.shouldRecognizeSimultaneouslyWithGestureRecognizer={recognizer,other->true}
        }
    }