效果如图所示：
自定义UISwitch
iOS7.0之后无法自定义UISwitch的图片，而在日常的开发需求中，又不可能只有一种开关样式，UI所设计的开关样式千奇百怪，那么系统所提供的开关样式已经不足以满足我们的开发需求了。所以这时候我们就需要自定义开关了。
自定义开关，我们剖析下开关的结构，在系统的UISwitch中，我们可以看出，通过调用 onImage 或者 offImage 属性来设置开关的图片，但是这两个方法在 iOS 6 之后已经被弃用掉了。
NS_CLASS_AVAILABLE_IOS(2_0) __TVOS_PROHIBITED @interface UISwitch : UIControl <NSCoding>
@property(nullable, nonatomic, strong) UIColor *onTintColor NS_AVAILABLE_IOS(5_0) UI_APPEARANCE_SELECTOR;
@property(null_resettable, nonatomic, strong) UIColor *tintColor NS_AVAILABLE_IOS(6_0);
@property(nullable, nonatomic, strong) UIColor *thumbTintColor NS_AVAILABLE_IOS(6_0) UI_APPEARANCE_SELECTOR;
@property(nullable, nonatomic, strong) UIImage *onImage NS_AVAILABLE_IOS(6_0) UI_APPEARANCE_SELECTOR;
@property(nullable, nonatomic, strong) UIImage *offImage NS_AVAILABLE_IOS(6_0) UI_APPEARANCE_SELECTOR;
@property(nonatomic,getter=isOn) BOOL on;
- (instancetype)initWithFrame:(CGRect)frame NS_DESIGNATED_INITIALIZER; // This class enforces a size appropriate for the control, and so the frame size is ignored.
- (nullable instancetype)initWithCoder:(NSCoder *)aDecoder NS_DESIGNATED_INITIALIZER;
- (void)setOn:(BOOL)on animated:(BOOL)animated; // does not send action
@end
那么，我们自定义开关所要暴露出来的属性就要有
- 开关开着时的图片
- 开关关着时的图片
- 开关的背景色
-
开关的状态
在这里，我们可以将开关分为如图所示两部分结构：
自定义开关结构
其中，B为开关提供底部背景色值，A为开关提供开关状态色值，点击开关，A可以左右滑动，并改变状态。
思路：
- 添加点击事件，改变自身状态
- 添加观察者观察自身状态的改变
- 通过判断自身状态，显示自身样式
主要代码如下所示：
@interface BKSwitch : UIControl
@property (nonatomic, assign) BOOL on;
@property (nonatomic, strong) UIView *roundView;//滑块view
@end
@implementation BKSwitch
- (instancetype)initWithFrame:(CGRect)frame{
if (self = [super initWithFrame:frame]) {
[self addObserver:self forKeyPath:@"isOn" options:NSKeyValueObservingOptionOld | NSKeyValueObservingOptionNew context:nil];
[self addTarget:self action:@selector(translateAni) forControlEvents:UIControlEventTouchUpInside];
[self creatView];
}
return self;
}
-(void)creatView{
self.backgroundColor = [UIColor whiteColor];
self.clipsToBounds = YES;
self.layer.cornerRadius = self.bounds.size.height/2;
self.layer.borderColor = [UIColor grayColor].CGColor;
self.layer.borderWidth = .5;
self.roundView = [[UIView alloc]initWithFrame:CGRectMake(0, 1, self.bounds.size.height-2, self.bounds.size.height-2)];
self.roundView.layer.cornerRadius = self.bounds.size.height/2;
// self.roundView.backgroundColor = [UIColor whiteColor];
self.roundView.userInteractionEnabled = NO;
[self addSubview:self.roundView];
// self.roundView.layer.shadowColor = [UIColor blackColor].CGColor;//shadowColor阴影颜色
// self.roundView.layer.shadowOffset = CGSizeMake(0,0);//shadowOffset阴影偏移,x向右偏移4，y向下偏移4，默认(0, -3),这个跟shadowRadius配合使用
// self.roundView.layer.shadowOpacity = 0.5;//阴影透明度，默认0
// self.roundView.layer.shadowRadius = 2;//阴影半径，默认3
}
-(void)setOn:(BOOL)on{
if (on) {
self.roundView.frame = CGRectMake(self.bounds.size.width-self.roundView.bounds.size.width-1, 1, self.bounds.size.height-2, self.bounds.size.height-2);
self.roundView.roundView.backgroundColor = [UIColor colorWithPatternImage:[UIImage imageNamed:@"switchOn"]];
self.roundView.backgroundColor = OCTColorFromRGB(0xffe100);
self.roundView.layer.borderColor = OCTColorFromRGB(0xffe100).CGColor;
}else{
self.roundView.frame = CGRectMake(0, 1, self.bounds.size.height-2, self.bounds.size.height-2);
self.roundView.roundView.backgroundColor = [UIColor colorWithPatternImage:[UIImage imageNamed:@"switchOff"]];
self.roundView.backgroundColor = OCTColorFromRGB(0xc9c9c9);
self.roundView.layer.borderColor = OCTColorFromRGB(0xc9c9c9).CGColor;
}
self.isOn = on;
}
-(BOOL)on{
return self.isOn;
}
- (void)translateAni{
CGRect rect = self.roundView.frame;
[UIView animateWithDuration:0.3 animations:^{
self.roundView.frame = rect;
}];
if (!self.isOn){
rect.origin.x = self.bounds.size.width - self.roundView.bounds.size.width - 1;
}else{
rect.origin.x = 0;
}
[UIView animateWithDuration:0.3 animations:^{
self.roundView.frame = rect;
}completion:^(BOOL finished) {
}];
self.isOn = !self.isOn;
}
//监听isON
//keyPath:属性名称
//object:被观察的对象
//change:变化前后的值都存储在change字典中
//context:注册观察者时，context传过来的值
-(void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary<NSString *,id> *)change context:(void *)context
{
[self sendActionsForControlEvents:UIControlEventValueChanged];
}
-(void)dealloc
{
[self removeObserver:self forKeyPath:@"isOn"];
}
@end
