blocks|key|1786384|text|记录上一个状态，这样你就可以知道它的状态是否改变了，或者已经用相同的状态触发了。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1786385|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

Log the last state so you can tell if its changed state or has been triggered with the same state.

blocks|key|1786407|text|获取处理程序中开关的状态：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1786408|-+(void)valueChanged:(UISwitch+*)theSwitch+{
+++BOOL+flag+=+theSwitch.on;
}|code-block|syntax|javascript|1786409|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

Get state of switch in handler:

<pre><code>- (void)valueChanged:(UISwitch *)theSwitch {
 BOOL flag = theSwitch.on;
}
</code></pre>

blocks|key|2000212|text|每次按下都不会立即打开/关闭开关。如果开关处于off位置，您可以在它动画到on位置之前按下几次。这些按下的每一个都被解释为“打开开关”，因为在动画完成之前它不会被认为是“打开”。每次按下都会得到一个"valueChanged“回调，尽管这个值实际上还没有改变。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2000213|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

Each press you make doesn't immediately toggle the switch on/off. If the switch is in the off position, you can get a couple of presses in before it animates to the on position. Each of these presses are interpreted as "turn the switch on", since it is not considered "on" until the animation has completed. You get a "valueChanged" callback for each press despite the fact that the value hasn't actually changed yet.

blocks|key|1786464|text|当您将开关关闭/打开时，"value+called.So“已被更改，您可以通过在valueChanged上调用方法来检测开关中的更改。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1786465|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

When you toggle the switch off/On the "value changed" has been called.So you can detecting a change in switch by calling method on valueChanged.

blocks|key|1786475|text|+++-(void)+createSwitch
++++{
++++++++self.searchExistSearchNewSwitch+=+[[UISwitch+alloc]+initWithFrame:CGRectMake(0,0,0,0)];
++++++++[self.searchExistSearchNewSwitch+addTarget:self+action:@selector(switchValueChanged:)+forControlEvents:UIControlEventValueChanged];
++++++++[self.view+addSubview:self.searchExistSearchNewSwitch];
++++}
++++-+(void)switchValueChanged:(UISwitch+*)theSwitch
++++{
++++++++BOOL+flag+=+theSwitch.isOn;
++++}|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|1786476|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

<pre><code> -(void) createSwitch
 {
 self.searchExistSearchNewSwitch = [[UISwitch alloc] initWithFrame:CGRectMake(0,0,0,0)];
 [self.searchExistSearchNewSwitch addTarget:self action:@selector(switchValueChanged:) forControlEvents:UIControlEventValueChanged];
 [self.view addSubview:self.searchExistSearchNewSwitch];
 }
 - (void)switchValueChanged:(UISwitch *)theSwitch
 {
 BOOL flag = theSwitch.isOn;
 }
</code></pre>

blocks|key|1786506|text|这是一个适合我的解决方案。当开关改变时，它还会发送一个属性"will/did+change“通知。该事件也可以正常运行，因为正确地维护了之前和之后的值。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1786507|@interface+MySwitch+:+UISwitch

@end

@implementation+MySwitch
{
++++BOOL+_previousValue;
++++BOOL+_returnPreviousValue;
}

-+(instancetype)+initWithCoder:(NSCoder+*)aDecoder
{
++++self+=+[super+initWithCoder:+aDecoder];
++++if+(!self)+return+nil;

++++_previousValue+=+self.isOn;
++++[self+addTarget:+self+action:+@selector(_didChange)
++++++++++++++++forControlEvents:+UIControlEventValueChanged];

++++return+self;
}

-+(instancetype)+initWithFrame:+(CGRect)+frame
{
++++self+=+[super+initWithFrame:+frame];
++++if+(!self)+return+nil;

++++[self+addTarget:+self+action:+@selector(_didChange)
++++++++++++++++forControlEvents:+UIControlEventValueChanged];

++++return+self;
}

-+(BOOL)+isOn
{
++++return+(_returnPreviousValue)
++++++++++++++++++++++++?+_previousValue
++++++++++++++++++++++++:+[super+isOn];
}

-+(void)+setOn:(BOOL)+on+animated:+(BOOL)+animated
{
++++[super+setOn:+on+animated:+animated];

++++_previousValue+=+on;
}

-+(void)+_didChange
{
++++BOOL+isOn+=+self.isOn;

++++if+(isOn+==+_previousValue)+return;

++++_returnPreviousValue+=+true;
++++[self+willChangeValueForKey:+@"on"];
++++_returnPreviousValue+=+false;

++++_previousValue+=+isOn;
++++[self+didChangeValueForKey:++@"on"];
}

@end|code-block|syntax|javascript|1786508|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

Here's a solution that works for me.
It also sends a property "will/did change" notification when the switch is changed.
The event also functions correctly in that the before and after values are maintained correctly.

<pre><code>@interface MySwitch : UISwitch

@end

@implementation MySwitch
{
 BOOL _previousValue;
 BOOL _returnPreviousValue;
}

- (instancetype) initWithCoder:(NSCoder *)aDecoder
{
 self = [super initWithCoder: aDecoder];
 if (!self) return nil;

 _previousValue = self.isOn;
 [self addTarget: self action: @selector(_didChange)
 forControlEvents: UIControlEventValueChanged];

 return self;
}

- (instancetype) initWithFrame: (CGRect) frame
{
 self = [super initWithFrame: frame];
 if (!self) return nil;

 [self addTarget: self action: @selector(_didChange)
 forControlEvents: UIControlEventValueChanged];

 return self;
}

- (BOOL) isOn
{
 return (_returnPreviousValue)
 ? _previousValue
 : [super isOn];
}

- (void) setOn:(BOOL) on animated: (BOOL) animated
{
 [super setOn: on animated: animated];

 _previousValue = on;
}

- (void) _didChange
{
 BOOL isOn = self.isOn;

 if (isOn == _previousValue) return;

 _returnPreviousValue = true;
 [self willChangeValueForKey: @"on"];
 _returnPreviousValue = false;

 _previousValue = isOn;
 [self didChangeValueForKey: @"on"];
}

@end
</code></pre>

blocks|key|2000368|text|我的问题是个愚蠢的问题。我预期enabled值会发生变化，但显然这不是在切换开关时要检查的正确值，应该使用on或isOn。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|2000369|entityMap^0|F|7|1H|2|1K|4|0^^$0|@$1|2|3|4|5|6|7|H|8|@$9|I|A|J|B|C]|$9|K|A|L|B|C]|$9|M|A|N|B|C]]|D|@]|E|$]]|$1|F|3|-4|5|6|7|O|8|@]|D|@]|E|$]]]|G|$]]

My problem was a stupid one... I was expecting the <code>enabled</code> value to change, but obviously that isn't the correct value to inspect upon the toggle of the switch, the <code>on</code> or <code>isOn</code> is the correct thing to use.

This sounds trivial but I'm noticing some weirdness. I've wired up a handler for the Value Changed event of a UISwitch. What I would expect is that each time the handler is called the value of the switch would change. But that's actually not always the case. If you press the switch rapidly on/off the handler can get called consecutively with the SAME state for the switch (in my specific application this is an issue). So I'm wondering if anyone else has noticed this behavior and has figured out a good solution.

Detecting a change in UISwitch

这听起来微不足道，但我注意到了一些奇怪的地方。我为UISwitch的Value Changed事件连接了一个处理程序。我期望的是，每次调用处理程序时，开关的值都会改变。但事实并非如此。如果您快速地按下开关，处理程序可能会以开关的相同状态被连续调用(在我的特定应用程序中，这是一个问题)。所以我想知道是否有人注意到了这个行...

问检测UISwitch中的更改
EN

社区

活动

资源

关于

腾讯云开发者

热门产品

热门推荐

更多推荐

问检测UISwitch中的更改EN

社区

活动

资源

关于

腾讯云开发者

热门产品

热门推荐

更多推荐

问检测UISwitch中的更改
EN