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

I think you need the control event UIControlEventTouchUpInside.

Answer 2

Connect Touch Up Inside and Value Changed

Answer 3

I use the "Touch Up Inside" and "Touch up outside" notifications.

Interface Builder:

Connect both notifications in the Interface Builder to your receiving method. The method could look like this:

- (IBAction)lengthSliderDidEndSliding:(id)sender {
    NSLog(@"Slider did end sliding... Do your stuff here");
}

In code:

If you want to wire it programatically you would have something like this in your viewWillAppear (or wherever it fits you) call:

[_mySlider addTarget:self
              action:@selector(sliderDidEndSliding:) 
    forControlEvents:(UIControlEventTouchUpInside | UIControlEventTouchUpOutside)];

The receiving method would look like this:

- (void)sliderDidEndSliding:(NSNotification *)notification {
     NSLog(@"Slider did end sliding... Do your stuff here");
}

Answer 4

Swift 3.1

Sometimes you will want the slider's drag events to fire continuously, but have the option of executing different code depending on whether the slider is still being dragged or has just finished being dragged.

To do this, I've expanded on Andy's answer above that makes use of the slider's isTracking property. I needed to record two states: sliderHasFinishedTracking and sliderLastStoredValue.

My code correctly:

• doesn't fire an action upon starting drag

• fires the action if the user only nudges the slider with a single tap (meaning that isTracking remains false)

---

class SliderExample: UIViewController {
  var slider: UISlider = UISlider()
  var sliderHasFinishedTracking: Bool = true
  var sliderLastStoredValue: Float!

  override func loadView() {
    super.loadView()

    slider.minimumValue = 100.0
    slider.maximumValue = 200.0
    slider.isContinuous = true
    slider.value = 100.0
    self.sliderLastStoredValue = slider.value
    slider.addTarget(self, action: #selector(respondToSlideEvents), for: .valueChanged)
    // add your slider to the view however you like
  }

  func respondToSlideEvents(sender: UISlider) {
    let currentValue: Float = Float(sender.value)
    print("Event fired. Current value for slider: \(currentValue)%.")

    if(slider.isTracking) {
      self.sliderHasFinishedTracking = false
      print("Action while the slider is being dragged ⏳")
    } else {
      if(self.sliderHasFinishedTracking && currentValue == self.sliderLastStoredValue){
        print("Slider has finished tracking and its value hasn't changed, " +
              "yet event was fired anyway.                                                                     

                                                        
            

查看更多

0人赞 添加讨论(0) 举报

Answer 5

Try like this

customSlider.minimumValue = 0.0;
    customSlider.maximumValue = 10.0;
[customSlider addTarget:self action:@selector(changeSlider:) forControlEvents:UIControlEventValueChanged];


-(void)changeSlider:(id)sender{
    UISlider *slider=(UISlider *)sender;
    float sliderValue=(float)(slider.value );
NSLog(@"sliderValue = %f",sliderValue);
}

Answer 6

Maybe you should add target for UIControlEventTouchUpInside、UIControlEventTouchUpOutside、UIControlEventTouchCancel events.

I met the same problem before , because i don't add target for UIControlEventTouchCancel event.