How to deselect a segment in Segmented control button permanently till its clicked again

Question

I have a UISegmentedControl with 4 segments. When it is selected, it should maintain the selected state. When the same segment is clicked again, it should deselect itself. How to achieve this?

Solution 1

Since UISegmentedControl only sends an action if a not selected segment is selected, you have to subclass UISegmentedControl to make a tiny change in its touch handling. I use this class:

@implementation MBSegmentedControl

// this sends a value changed event even if we reselect the currently selected segment
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
    NSInteger current = self.selectedSegmentIndex;
    [super touchesBegan:touches withEvent:event];
    if (current == self.selectedSegmentIndex) {
        [self sendActionsForControlEvents:UIControlEventValueChanged];
    }
}

@end

Now you will get UIControlEventValueChanged events even if the segment is already selected. Simply save the current index in a variable and compare it in the action. If the two indexes match you have to unselect the touched segment.

// _selectedSegmentIndex is an instance variable of the view controller

- (void)viewWillAppear:(BOOL)animated {
    [super viewWillAppear:animated];
    _selectedSegmentIndex = self.segment.selectedSegmentIndex;
}

- (IBAction)segmentChanged:(UISegmentedControl *)sender {
    if (sender.selectedSegmentIndex == _selectedSegmentIndex) {
        NSLog(@"Segment %d deselected", sender.selectedSegmentIndex);
        sender.selectedSegmentIndex =  UISegmentedControlNoSegment;
        _selectedSegmentIndex = UISegmentedControlNoSegment;
    }
    else {
        NSLog(@"Segment %d selected", sender.selectedSegmentIndex);
        _selectedSegmentIndex = sender.selectedSegmentIndex;
    }
}

---

iOS 7 changed how touches are handled for UISegmentedControl. The selectedSegmentIndex is now changed during touchesEnded:.

So the updated Subclass should look like this:

@implementation MBSegmentedControl

+ (BOOL)isIOS7 {
    static BOOL isIOS7 = NO;
    static dispatch_once_t onceToken;
    dispatch_once(&onceToken, ^{
        NSInteger deviceSystemMajorVersion = [[[[[UIDevice currentDevice] systemVersion] componentsSeparatedByString:@"."] objectAtIndex:0] integerValue];
        if (deviceSystemMajorVersion >= 7) {
            isIOS7 = YES;
        }
        else {
            isIOS7 = NO;
        }
    });
    return isIOS7;
}

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
    NSInteger previousSelectedSegmentIndex = self.selectedSegmentIndex;
    [super touchesBegan:touches withEvent:event];
    if (![[self class] isIOS7]) {
        // before iOS7 the segment is selected in touchesBegan
        if (previousSelectedSegmentIndex == self.selectedSegmentIndex) {
            // if the selectedSegmentIndex before the selection process is equal to the selectedSegmentIndex
            // after the selection process the superclass won't send a UIControlEventValueChanged event.
            // So we have to do this ourselves.
            [self sendActionsForControlEvents:UIControlEventValueChanged];
        }
    }
}

- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {
    NSInteger previousSelectedSegmentIndex = self.selectedSegmentIndex;
    [super touchesEnded:touches withEvent:event];
    if ([[self class] isIOS7]) {
        // on iOS7 the segment is selected in touchesEnded
        if (previousSelectedSegmentIndex == self.selectedSegmentIndex) {
            [self sendActionsForControlEvents:UIControlEventValueChanged];
        }
    }
}

@end

---

Swift 2.2 version, fixed the problem Grzegorz noticed.

class ReselectableSegmentedControl: UISegmentedControl {
    @IBInspectable var allowReselection: Bool = true

    override func touchesEnded(touches: Set<UITouch>, withEvent event: UIEvent?) {
        let previousSelectedSegmentIndex = self.selectedSegmentIndex
        super.touchesEnded(touches, withEvent: event)
        if allowReselection && previousSelectedSegmentIndex == self.selectedSegmentIndex {
            if let touch = touches.first {
                let touchLocation = touch.locationInView(self)
                if CGRectContainsPoint(bounds, touchLocation) {
                    self.sendActionsForControlEvents(.ValueChanged)
                }
            }
        }
    }
}

---

Swift 3.0 changes the fix for this to look like the following:

class MyDeselectableSegmentedControl: UISegmentedControl {
    override func touchesEnded(_ touches: Set<UITouch>, with event: UIEvent?) {
        let previousIndex = selectedSegmentIndex

        super.touchesEnded(touches, with: event)

        if previousIndex == selectedSegmentIndex {
            let touchLocation = touches.first!.location(in: self)

            if bounds.contains(touchLocation) {
                sendActions(for: .valueChanged)
            }
        }
    }
}

Solution 2

Here is a fix for a problem that when you try to cancel selection by starting tap on UISegmentControl and later you finish touch outside - it still does deselection.

- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event
{
CGPoint locationPoint = [[touches anyObject] locationInView:self];
CGPoint viewPoint = [self convertPoint:locationPoint fromView:self];
if ([self pointInside:viewPoint withEvent:event]) {
    int oldValue = self.selectedSegmentIndex;
    [super touchesEnded:touches withEvent:event];
    if (oldValue == self.selectedSegmentIndex)
    {
        [super setSelectedSegmentIndex:UISegmentedControlNoSegment];
        [self sendActionsForControlEvents:UIControlEventValueChanged];
    }
}
}

Solution 3

You can do it with the following (thank you Grzegorz's answer and Matthias's answer):

- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {
    NSInteger previousSelectedSegmentIndex = self.selectedSegmentIndex;

    [super touchesEnded:touches withEvent:event];

    CGPoint locationPoint = [[touches anyObject] locationInView:self];
    CGPoint viewPoint = [self convertPoint:locationPoint fromView:self];
    if ([self pointInside:viewPoint withEvent:event] && previousSelectedSegmentIndex == self.selectedSegmentIndex) {
        self.selectedSegmentIndex = UISegmentedControlNoSegment;
        [self sendActionsForControlEvents:UIControlEventValueChanged];
    }
}

I have made an open-source (MIT Licensed) class STASegmentedControl (supports iOS 7+), that has this functionality baked in (and more).

Solution 4

In reference to the answer posted by @Matthias Bauch. I had to make little changes as per Swift 2.2 in Xcode 7.3:

class ReselectableSegmentedControl: UISegmentedControl {
    @IBInspectable var allowReselection: Bool = true
    override func touchesEnded(touches: Set<UITouch>, withEvent event: UIEvent?) {
        let previousSelectedSegmentIndex = self.selectedSegmentIndex
        super.touchesEnded(touches, withEvent: event)
        if allowReselection && previousSelectedSegmentIndex == self.selectedSegmentIndex {
            if let touch = touches.first {
                let touchLocation = touch.locationInView(self)
                if CGRectContainsPoint(bounds, touchLocation) {
                    self.sendActionsForControlEvents(.ValueChanged)
                }
            }
        }
    }
}

Solution 5

swift 3.1 version posted by @Kushal Ashok

class ReselectableSegmentedControl: UISegmentedControl {
    @IBInspectable var allowReselection: Bool = true

    override func touchesEnded(_ touches: Set<UITouch>, with event: UIEvent?) {
        let previousSelectedSegmentIndex = self.selectedSegmentIndex
        super.touchesEnded(touches, with: event)
        if allowReselection && previousSelectedSegmentIndex == self.selectedSegmentIndex {
            if let touch = touches.first {
                let touchLocation = touch.location(in: self)
                if bounds.contains(touchLocation) {
                    self.sendActions(for: .valueChanged)
                }
            }
        }
    }
}

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Comments

[Alyoshak]

This answer aided me a 2nd time when iOS7 was released. I should be able to upvote it again.

[Mike Pollard]

You can also encapsulate the deselecting code within this subclass by adding self.selectedSegmentIndex = UISegmentedControlNoSegment; before [self sendActionsForControlEvents:UIControlEventValueChanged];

[Grzegorz Krukowski]

Problem with that solution is when you start touch on component and drag it outside component to cancel touch - it still deselects the item

[LavaSlider]

[self pointInside:withEvent] uses the visible dimensions of the segmented control. If I use this and touch inside, then drag just a little outside before releasing, it leaves the segment light blue, like my finger is still down, and does not send the event. Is there a way to know the hitTest region for the control to see if the point is within it?

[Raheel Sadiq]

Thats a really nice solution! Thank you