Question

I have a canvas.DrawText. I want to use gestures to dynamically change the text color and font. This is all working nice using a popup view class. But I want to make this more direct maybe using Fling scroll.

There are millions of colors and by sliding finger on the screen I thought I could increase/decrease the colorInteger and send it to paint.setColor(colorInteger ); before I draw. I have tried all day using various methods.

I have public boolean onTouchEvent(MotionEvent event) {

I know I must catch the x/y in MotionEvent.ACTION_DOWN

Wanted to use the screen left edge for color change and screen right for Font change. I have 21 ttf fonts.

The thing is, I see there is the OnGestureListener onscroll implementation but that will disable my onTouchEvent right? I have lots of movement going on in there.

public boolean onTouchEvent(MotionEvent event) {

Any idea?

Answer 1

You can use GestureDetector. Implement a GestureDetector.OnGestureListener and catch gestures there.

class MyActivity extends Activity implements GestureDetector.OnGestureListener {

    // ....
    gestureDetector = new GestureDetector(getContext(), this);

Provide GestureDetector with touch events like this:

@Override
public boolean onTouchEvent(MotionEvent event) {
    if (gestureDetector.onTouchEvent(event))
        return true;
    else return super.onTouchEvent(event);
}

In GestureDetector.OnGestureListener‘s onDown you must return true if you want to process this gesture. E.g. then the user puts his finger donw in a specified area return true, and false otherwise. If false is returned here, complicated sequences (like fling or scroll) started with this event will not be detected.