iPhone : How to detect the end of slider drag?

Question

How to detect the event when the user has ended the drag of a slider pointer?

Answer 1

Since UISlider is a subclass of UIControl, you can set a target and action for its UIControlEventTouchUpInside.

If you want to do it in code, it looks like this:

[self.slider addTarget:self action:@selector(dragEndedForSlider:)
    forControlEvents:UIControlEventTouchUpInside];

That will send you a dragEndedForSlider: message when the touch ends.

If you want to do it in your nib, you can control-click your slider to get its connections menu, and then drag from the “Touch Up Inside” socket to the target object.

You should also add a target and action for UIControlEventTouchUpOutside and for UIControlEventTouchCancel.

Answer 2

If you don't need any data inbetween drag, than you should simply set:

[mySlider setContinuous: NO];

This way you will receive valueChanged event only when the user stops moving the slider.

Answer 3

Swift 4 and Swift 3

1. Add target for touchUpInside and touchUpOutside events. You can do it either programatically or from storyboard. This is how you do it programatically

   slider.addTarget(self, action: #selector(sliderDidEndSliding), for: [.touchUpInside, .touchUpOutside])
   

2. Write your function to handle the end of slider drag

   func sliderDidEndSliding() {
       print("end sliding")
   }
   

Answer 4

You can add an action that takes two parameters, sender and an event, for UIControlEventValueChanged:

[slider addTarget:self action:@selector(onSliderValChanged:forEvent:) forControlEvents:UIControlEventValueChanged]

Then check the phase of the touch object in your handler:

- (void)onSliderValChanged:(UISlider*)slider forEvent:(UIEvent*)event {     
    UITouch *touchEvent = [[event allTouches] anyObject];
    switch (touchEvent.phase) {     
        case UITouchPhaseBegan:
            // handle drag began
            break;
        case UITouchPhaseMoved:
            // handle drag moved
            break;
        case UITouchPhaseEnded:
            // handle drag ended
            break;
        default:
            break;
    }
}

Swift 4

slider.addTarget(self, action: #selector(onSliderValChanged(slider:event:)), for: .valueChanged)

@objc func onSliderValChanged(slider: UISlider, event: UIEvent) {
    if let touchEvent = event.allTouches?.first {
        switch touchEvent.phase {
        case .began:
            // handle drag began
        case .moved:
            // handle drag moved
        case .ended:
            // handle drag ended
        default:
            break
        }
    }
}

Note in Interface Builder when adding an action you also have the option to add both sender and event parameters to the action.

Answer 5

In Swift 4 you can use this function

1 Frist step:- Adding the target in slider

self.distanceSlider.addTarget(self, action: #selector(self.sliderDidEndSliding(notification:)), for: ([.touchUpInside,.touchUpOutside]))

2 Second step:- Create a function

@objc func sliderDidEndSliding(notification: NSNotification)
{
   print("Hello-->\(distanceSlider.value)")
}

Answer 6

I had similar issue recently. Here is what I did in Swift:

    theSlider.continuous = false;

The code that holds this continuous value reads:

public var continuous: Bool // if set, value change events are generated
    // any time the value changes due to dragging. default = YES

The default seems to be YES (true). Setting it it to false does the thing you want.