UISegmentedControl 寄存器点击选定的段

Question

我有一个分段控件，用户可以在其中选择如何对列表进行排序。工作正常。

但是，我希望当点击已选择的片段时，顺序会颠倒。我有所有的代码，但我不知道如何在这些段上注册水龙头。您可以使用的唯一控制事件似乎是 UIControlEventValueChanged，但这不起作用（因为选定的段实际上并没有改变）。

有解决办法吗？如果是这样，它是什么？

提前致谢！

Answer 1

你可以继承UISegmentedControl，然后是override setSelectedSegmentIndex:

- (void) setSelectedSegmentIndex:(NSInteger)toValue {
    if (self.selectedSegmentIndex == toValue) {
        [super setSelectedSegmentIndex:UISegmentedControlNoSegment];
    } else {
        [super setSelectedSegmentIndex:toValue];        
    }
}

如果使用 IB，请确保将 UISegmentedControl 的类设置为您的子类。

现在您可以像往常一样收听相同的UIControlEventValueChanged，除非用户取消选择该段，您将看到selectedSegmentIndex 等于UISegmentedControlNoSegment：

-(IBAction) valueChanged: (id) sender {
    UISegmentedControl *segmentedControl = (UISegmentedControl*) sender;
    switch ([segmentedControl selectedSegmentIndex]) {
        case 0:
            // do something
            break;
        case 1:
            // do something
            break;
        case UISegmentedControlNoSegment:
            // do something
            break;
        default:
            NSLog(@"No option for: %d", [segmentedControl selectedSegmentIndex]);
    }
}

Answer 2

我认为如果你使用-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event 会更好一点——因为这是 UISegmentedControl 的行为。此外，您似乎不需要重载-(void)setSelectedSegmentIndex:(NSInteger)toValue

-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {    
    NSInteger current = self.selectedSegmentIndex;
    [super touchesBegan:touches withEvent:event];
    if (current == self.selectedSegmentIndex) 
        [self sendActionsForControlEvents:UIControlEventValueChanged];
}

Answer 3

我自己想要这个。采用 Julian 的解决方案（谢谢！）并稍作修改。

即使值没有改变，下面的 UISegmentedControl 子类也会简单地触发 UIControlEventValueChanged 事件，这显然读起来有点奇怪，但在我的情况下可以正常工作并且保持简单。

AKSegmentedControl.h

#import <UIKit/UIKit.h>

@interface AKSegmentedControl : UISegmentedControl {
}

@end

AKSegmentedControl.m

#import "AKSegmentedControl.h"

@implementation AKSegmentedControl

- (void)setSelectedSegmentIndex:(NSInteger)toValue {
  // Trigger UIControlEventValueChanged even when re-tapping the selected segment.
  if (toValue==self.selectedSegmentIndex) {
    [self sendActionsForControlEvents:UIControlEventValueChanged];
  }
  [super setSelectedSegmentIndex:toValue];        
}

@end

Answer 4

这适用于 iOS 4 和 5：

-(void) touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
  int oldValue = self.selectedSegmentIndex;
  [super touchesBegan:touches withEvent:event];
  if ( oldValue == self.selectedSegmentIndex )
    [self sendActionsForControlEvents:UIControlEventValueChanged];
}

Answer 5

目前提出的解决方案仍然不起作用，因为除非真的点击了一个新段，否则永远不会调用 setSelectedSegmentIndex。至少在我的情况下这从未奏效，但我确实使用 iOS5，也许这个解决方案在 iOS4 中确实有效。无论如何，这是我的解决方案。 它需要一个额外的子类方法，如下：

-(void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event
{    
    [self setSelectedSegmentIndex:self.selectedSegmentIndex];
    [super touchesEnded:touches withEvent:event];
}

祝你好运！

Answer 6

这是一个相当老的问题，所以我想添加我在 iOS 5+ 应用程序中遇到此问题时使用的相当简单的解决方案。

我所做的只是将一个 Tap Gesture Recognizer 拖到我的 .xib 文件中的 UISegmentedControl 上。检查新手势识别器的连接，确保分段控件是唯一的手势识别器出口，然后将其操作连接到您要在控制器中触发的方法。

此方法应在您触摸分段控件时触发，因此只需使用实例变量检查选定的索引，以查看用户是否触摸了已选定的分段。

@implementation MyViewController

@synthesize selectedSegment;
@synthesize segmentedControl;

// connected to Tap Gesture Recognizer's action
- (IBAction)segmentedControlTouched:(id)sender
{
    NSLog(@"Segmented Control Touched");
    if (selectedSegment == [segmentedControl selectedSegmentIndex]) {
        // Do some cool stuff
    }

    selectedSegment = [segmentedControl selectedSegmentIndex];

}

@end

Answer 7

在 iOS8 上，这里的每个答案似乎都不起作用或触发更改两次。我想出了非常简单的解决方案 - 所以我想分享一下。

在子类中我只有：

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
    [super touchesBegan:touches withEvent:event];
    [self setSelectedSegmentIndex:UISegmentedControlNoSegment];
}

它的作用是在更改分段控制段之前将选定段重置为 -1。它会发生在 touchesEnded 方法中。

Answer 8

斯威夫特 5

class ReselectableSegmentedControl: UISegmentedControl {
    // Captures existing selected segment on touchesBegan.
    var oldValue: Int!

    override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
        self.oldValue = self.selectedSegmentIndex
        super.touchesBegan(touches, with: event)
    }

    override func touchesEnded(_ touches: Set<UITouch>, with event: UIEvent?) {
        super.touchesEnded(touches, with: event)

        if self.oldValue == self.selectedSegmentIndex {
            self.sendActions(for: .valueChanged)
        }
    }
}

来自here

Answer 9

这行得通：

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
    int oldValue = self.selectedSegmentIndex;
    [super touchesBegan:touches withEvent:event];
    if (oldValue == self.selectedSegmentIndex)
    {
        [super setSelectedSegmentIndex:UISegmentedControlNoSegment];
        [self sendActionsForControlEvents:UIControlEventValueChanged];
    }
}

Answer 10

在 Swift 3 中，我至少可以想象以下两种解决方案。对于特殊情况，我还发布了第三种解决方案，其中选定的段用作切换按钮。

解决方案 1：

提示：此解决方案仅适用于瞬时 controlSegments！如果您需要固定控制的解决方案，请选择解决方案 2

这个想法是注册第二个在 touch-up-inside 时触发的事件：

// this solution works only for momentary segment control:
class Solution1ViewController : UIViewController {
    var current:Int = UISegmentedControlNoSegment
    @IBOutlet weak var mySegmentedControl: UISegmentedControl! {
        didSet {
            guard mySegmentedControl != nil else { return }

            self.mySegmentedControl!.addTarget(
                self,
                action:#selector(changeSelection(sender:)),
                for: .valueChanged)

            self.mySegmentedControl!.addTarget(
                self,
                action:#selector(changeSelection(sender:)),
                for: .touchUpInside)
        }
    }

    func changeSelection(sender: UISegmentedControl) {
        if current == sender.selectedSegmentIndex {
            // user hit the same button again!
            print("user hit the same button again!")
        }
        else {
            current = sender.selectedSegmentIndex
            // user selected a new index
             print("user selected a new index")
        }
    }
}

解决方案 2： 另一种方法是覆盖UISegmentedControl 中的触摸功能并触发valueChanged，即使段索引没有更改。因此，您可以按如下方式覆盖UISegmentedControl：

// override UISegmentControl to fire event on second hit:
class Solution2SegmentControl : UISegmentedControl
{
    private var current:Int = UISegmentedControlNoSegment
    override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
        current = self.selectedSegmentIndex
        super.touchesBegan(touches, with: event)
    }
    override func touchesEnded(_ touches: Set<UITouch>, with event: UIEvent?) {
        super.touchesEnded(touches, with: event)
        if current == self.selectedSegmentIndex {
            self.sendActions(for: .valueChanged)
        }
    }
}

// solution2 works with stationary (default) segment controls
class Solution2ViewController : UIViewController {
    var current:Int = UISegmentedControlNoSegment

    @IBOutlet weak var mySegmentedControl: UISegmentedControl! {
        didSet {
            guard mySegmentedControl != nil else { return }

            self.mySegmentedControl!.addTarget(
                self,
                action:#selector(changeSelection(sender:)),
                for: .valueChanged)
        }
    }

    func changeSelection(sender: UISegmentedControl) {
        if current == sender.selectedSegmentIndex {
            // user hit the same button again!
            print("user hit the same button again!")
        }
        else {
            current = sender.selectedSegmentIndex
            // user selected a new index
            print("user selected a new index")
        }
    }
}

解决方案 3： 如果您的方法是将选定的段设置为切换按钮，则可以更改解决方案 2 以清理如下代码：

class MyToggleSegmentControl : UISegmentedControl {
    /// you could enable or disable the toggle behaviour here
    var shouldToggle:Bool = true

    private var current:Int = UISegmentedControlNoSegment
    override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
        current = self.selectedSegmentIndex
        super.touchesBegan(touches, with: event)
    }
    override func touchesEnded(_ touches: Set<UITouch>, with event: UIEvent?) {
        super.touchesEnded(touches, with: event)
        if shouldToggle, current == self.selectedSegmentIndex {
            self.selectedSegmentIndex = UISegmentedControlNoSegment
        }
    }
}

现在我们可以如下清理changeSelection函数：

func changeSelection(sender: UISegmentedControl) {
    switch sender.selectedSegmentIndex {
    case UISegmentedControlNoSegment:
        print("none")
    default:
        print("selected: \(sender.selectedSegmentIndex)")
    }
}

Answer 11

我的第一个想法是将Touch Up Inside 或Touch Down 操作连接到您的排序方法，但这似乎不起作用。

第二个想法更多的是变通，在分段控件上设置Momentary 属性。然后，每次点击它都会触发Value Did Change 动作。

Answer 12

帮助很大！我想要做的是选择一个或不设置按钮 - 当设置一个按钮时，第二次点击会取消它。这是我的修改：

- (void)setSelectedSegmentIndex:(NSInteger)toValue
{
  // Trigger UIControlEventValueChanged even when re-tapping the selected segment.
  if (toValue==self.selectedSegmentIndex) {
    [super setSelectedSegmentIndex:UISegmentedControlNoSegment]; // notify first
    [self sendActionsForControlEvents:UIControlEventValueChanged]; // then unset
  } else {
    [super setSelectedSegmentIndex:toValue]; 
  }
}

Notify first 让您在重置之前读取控件以找到当前设置。

Answer 13

这是我的解决方案。如果您希望在每次触摸时触发 ValueChanged 事件，我认为最优雅...

.h

@interface UISegmentedControlAllChanges : UISegmentedControl
@end

.m

@implementation UISegmentedControlAllChanges

-(void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event
{    
    [self sendActionsForControlEvents:UIControlEventValueChanged];
    [super touchesEnded:touches withEvent:event];
}

@end

Answer 14

根据 Bob de Graaf 的回答：

-(void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event
{
    [self sendActionsForControlEvents:UIControlEventAllTouchEvents];
    [super touchesEnded:touches withEvent:event];
}

注意使用UIControlEventAllTouchEvents 而不是UIControlEventValueChanged。

也无需致电-(void)setSelectedSegmentIndex:。

Answer 15

在对我有用的代码段下方。重复点击同一段将取消选择它。

@implementation WUUnselectableSegmentedControl
{
    NSUInteger _selectedIndexBeforeTouches;
}

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
    _selectedIndexBeforeTouches = self.selectedSegmentIndex;
    [super touchesBegan:touches withEvent:event];
}

-(void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event
{
    [super touchesEnded:touches withEvent:event];

    if (_selectedIndexBeforeTouches == self.selectedSegmentIndex)
    {
        // Selection didn't change after touch - deselect
        self.selectedSegmentIndex = UISegmentedControlNoSegment;
        [self sendActionsForControlEvents:UIControlEventValueChanged];
    }
}

@end

Answer 16

iOS 9 解决方案。用这样的类覆盖 UISegmentedControl：

@interface SegmentedControl()

@property (nonatomic) NSInteger previousCurrent;

@end

@implementation SegmentedControl

- (void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event {
    self.previousCurrent = self.selectedSegmentIndex;
    [super touchesBegan:touches withEvent:event];
}

- (void)touchesEnded:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event {
    [super touchesEnded:touches withEvent:event];

    if (self.selectedSegmentIndex == self.previousCurrent) {
        [self sendActionsForControlEvents:UIControlEventValueChanged];
    }

    self.previousCurrent = NSNotFound;
}

@end

Answer 17

似乎是一个有趣的问题。该方案扩展了 Steve E 和 yershuachu 的解决方案。此版本使用 UITapGestureRecognizer 来捕获所有触摸并将 selectedSegmentIndex 设置为 -1；但它也会将所有触摸传递给 UISegmentedControl，因此它可以处理任何正常的触摸。不需要子类化。

UISegmentedControl *mySegControl;

- (void)viewDidLoad
{
    [super viewDidLoad];

    [mySegControl addTarget:self action:@selector(segmentAction:)
           forControlEvents:UIControlEventValueChanged];
    // allow the a seg button tap to be seen even if already selected
    UITapGestureRecognizer *tapGesture = [[UITapGestureRecognizer alloc]
                                          initWithTarget:self action:@selector(unitsSegTap:)];
    tapGesture.cancelsTouchesInView = NO; // pass touches through for normal taps
    [mySegControl addGestureRecognizer:tapGesture];

    // continue setup ...
}

- (void)segTap:(UITapGestureRecognizer *)sender
{
    mySegControl.selectedSegmentIndex = -1;
}

// called for UIControlEventValueChanged
- (void)segmentAction:(UISegmentedControl *)sender
{
    NSInteger index = sender.selectedSegmentIndex;
    NSLog(@"unitsSegmentAction %d",(int)index);
    // process the segment
}

Answer 18

我正在使用 KVO 为 iOS8 反转已选择的段。

#import "QCSegmentedControl.h"

static void *QCSegmentedControlContext = &QCSegmentedControlContext;

@implementation QCSegmentedControl

- (id)initWithCoder:(NSCoder *)aDecoder {
    self = [super initWithCoder:aDecoder];
    if (self) {
        [self registerKVO];
    }

    return self;
}

- (void)dealloc {
    [self removeObserver:self forKeyPath:@"selectedSegmentIndex"];
}

#pragma mark -

- (void)registerKVO {
    [self addObserver:self
           forKeyPath:@"selectedSegmentIndex"
              options:(NSKeyValueObservingOptionNew | NSKeyValueObservingOptionOld)
              context:QCSegmentedControlContext];
}

- (void)observeValueForKeyPath:(NSString *)keyPath
                      ofObject:(id)object
                        change:(NSDictionary *)change
                       context:(void *)context {
    if (context == QCSegmentedControlContext) {
        NSNumber *new = change[NSKeyValueChangeNewKey];
        NSNumber *old = change[NSKeyValueChangeOldKey];
        if (new.integerValue == old.integerValue) {
            self.selectedSegmentIndex = UISegmentedControlNoSegment;
        }
    }
}

@end

Answer 19

从当前的 iOS v8.x 开始，所选答案的解决方案对我不起作用。但是@Andy 提供了一个解决方案，我会完成：

子类化UISegmentedControl，并覆盖子类中的touchesEnded方法：

-(void) touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event
{
    [self sendActionsForControlEvents:UIControlEventAllTouchEvents];
    [super touchesEnded:touches withEvent:event];
}

在您打算使用 UISegmentedControl 的类中，创建一个 iVar currentSelectedSegIndex。在您的 UIControlEventValueChanged 操作方法旁边添加 UIControlEventAllTouchEvents：

NSInteger currentSelectedSegIndex;

[aSegmentedController addTarget:self action:@selector(aSegmentedControllerSelection:) forControlEvents:UIControlEventValueChanged];
[aSegmentedController addTarget:self action:@selector(aSegmentedControllerAllTouchEvent:) forControlEvents:UIControlEventAllTouchEvents];

实现两个动作方法：

-(void)aSegmentedControllerAllTouchEvent:(MyUISegmentedControl *)seg
{
    seg.selectedSegmentIndex = UISegmentedControlNoSegment;
}
-(void)aSegmentedControllerSelection:(MyUISegmentedControl *)seg
{
    if (currentSelectedSegIndex == seg.selectedSegmentIndex)
    {
        seg.selectedSegmentIndex = UISegmentedControlNoSegment;
        currentSelectedSegIndex = NSIntegerMax;
        NSLog(@"%s Deselected.", __PRETTY_FUNCTION__);
        // do your stuff if deselected
        return;
    }
    NSLog(@"%s Selected index:%u", __PRETTY_FUNCTION__, seg.selectedSegmentIndex);
    currentSelectedSegIndex = seg.selectedSegmentIndex;
    //do your stuff if selected index
}

Answer 20

因为 UISegmentedControl 负责设置段，所以它应该只重置状态。我稍微修改了其他人对 swift 5 的建议：

//MARK: Custom segmentedControl
///  Every element works like a flipflop  [see](http://stackoverflow.com/questions/17652773/how-to-deselect-a-segment-in-segmented-control-button-permanently-till-its-click)
@IBDesignable class GRSegmentedControl: UISegmentedControl {
  private let url = Bundle.main.url(forResource: "PlopChoiceCntrl", withExtension: "aiff")!
  private var soundID:SystemSoundID = 0

  override init(items: [Any]?) {
    AudioServicesCreateSystemSoundID(url as CFURL, &soundID)
    super.init(items: items)
  }

  required init?(coder: NSCoder) {
    AudioServicesCreateSystemSoundID(url as CFURL, &soundID)
    super.init(coder: coder)
  }

  override func touchesEnded(_ touches: Set<UITouch>, with event: UIEvent?) {
    AudioServicesPlaySystemSound(soundID)
    let previousSelectedSegmentIndex = self.selectedSegmentIndex
    super.touchesEnded(touches, with: event)
    if previousSelectedSegmentIndex == self.selectedSegmentIndex {
      if let touch = touches.first{
        let touchLocation = touch.location(in: self)
        if bounds.contains(touchLocation) {
          self.selectedSegmentIndex = UISegmentedControl.noSegment
        }
      }
    }
  }
}