ioscocoa-touchios4uitouchcustom-draw

How to draw on screen using hand gestures in iPhone SDK?

I want to draw on screen by moving my fingers across the screen.

How can we achieve this in iPhone SDK?

Solution

  • You first need to implement the touch sensing methods from UIResponder chain. The methods you need to implement are

    - (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event
- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event

    Inside this methods you can use Core Graphics drawing methods to draw custom drawing. This tutorial will walk you through the steps.