Iphone – UISlider returns two Touch Up Inside events, why does that happen

cocoa-touchiphoneuislider

I have a slider that I'm using to set a float value somewhere. I connect Value Changed to a method in my viewController. That part works fine.

I need to know when the user starts touching the control but not necessarily every single instant that the slider changes (I receive the Value Changed events for that). So I connected a Touch Up Inside event to another method in the viewController.

The problem it, that method gets called twice when the user touches the UISlider control. WTF? It doesn't work that way with UIButtons or other touch events like Touch Down.

I can work around it, I think, but it seems like a bug in the way the slider control handles touches. Does anybody know why it happens?

BTW: the double touch event happens even when Touch Up Inside is the only connected event.

Best Answer

Just so it doesn't break with future updates 

[customSlider addTarget:self action:@selector(sliderDown:) forControlEvents:UIControlEventTouchDown];

[customSlider addTarget:self action:@selector(sliderAction:) forControlEvents:UIControlEventTouchUpInside];



- (void)sliderDown:(id)sender
{

    sliderused = NO;

}

- (void)sliderAction:(id)sender
{
    if(sliderused){
    return;
}

sliderused = YES;

//Your Code Here
}
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