写在前面
封装，是因为下次懒得再写！一生只爱一个。
分析
倒计时，肯定是要用到计时器了。我们会想到这个NSTimer和dispatch_source_set_timer。二者的区别点这里。
关于定时器
1、首先声明一个本地对象：
dispatch_source_t verifyTimer;//验证码定时器
2、创建一个队列，用来装载这个定时器
dispatch_queue_t queue = dispatch_queue_create(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0);
3、创建这个定时器对象
verifyTimer = dispatch_source_create(DISPATCH_SOURCE_TYPE_TIMER, 0, 0, queue);
4、设置定时器从现在起执行，执行的频率为每秒执行一次。
dispatch_source_set_timer(verifyTimer, dispatch_walltime(NULL, 0), 1.0*NSEC_PER_SEC, 0);//每秒执行
5、监听每次执行
__weak typeof(self)weakSelf = self;
dispatch_source_set_event_handler(verifyTimer, ^{
if (timeout <= 0) {
//倒计时结束
dispatch_async(dispatch_get_main_queue(), ^{
//执行一些UI上的代码
//并释放定时器
[weakSelf stopCountDown];
});
}else{
//倒计时中
dispatch_async(dispatch_get_main_queue(), ^{
if (_countDownChanging) {
//设置按钮文字，外部返回title
[weakSelf setTitle:_countDownChanging(weakSelf,timeout) forState:UIControlStateNormal];
[weakSelf setTitle:_countDownChanging(weakSelf,timeout) forState:UIControlStateDisabled];
}else{
//设置按钮文字，外部不放回，设置默认的
NSString *title = [NSString stringWithFormat:@"%zd秒",timeout];
[weakSelf setTitle:title forState:UIControlStateNormal];
[weakSelf setTitle:title forState:UIControlStateDisabled];
}
});
//每次执行减1秒
timeout--;
}
});
6、开启定时器
dispatch_resume(verifyTimer);
7、结束定时器
dispatch_source_cancel(verifyTimer);
以上是关于整个定时器的创建、开启和结束。
全部代码
.h文件
#import
@class WxxCountDownButton;
typedef void (^TouchedCountDownButtonHandler)(WxxCountDownButton *countDownButton,NSInteger tag);
typedef NSString* (^CountDownChanging)(WxxCountDownButton *countDownButton,NSUInteger second);
typedef NSString* (^CountDownFinished)(WxxCountDownButton *countDownButton,NSUInteger second);
@interface WxxCountDownButton : UIButton
///带圆角边框的按钮
-(instancetype)initHasBorderWithNormalColor:(UIColor*)normalColor
changeColor:(UIColor*)changeColor;
///监听按钮事件
-(void)countButtonHandler:(TouchedCountDownButtonHandler)touchedCountDownButtonHandler;
///开始倒计时
- (void)startCountDownWithSecond:(NSUInteger)totalSecond;
///停止倒计时
- (void)stopCountDown;
///倒计时中
- (void)countDownChanging:(CountDownChanging)countDownChanging;
///倒计时结束(需要在切换页面的时候调用，以便释放定时对象)
- (void)countDownFinished:(CountDownFinished)countDownFinished;
@end
.m文件
#import "WxxCountDownButton.h"
@interface WxxCountDownButton(){
NSInteger _second;
NSUInteger _totalSecond;
UIColor *_normalColor;
UIColor *_changeColor;
CountDownChanging _countDownChanging;
CountDownFinished _countDownFinished;
TouchedCountDownButtonHandler _touchedCountDownButtonHandler;
dispatch_source_t verifyTimer;//定时器
BOOL isHasBorder;//是否带边框
}
@end
@implementation WxxCountDownButton
-(instancetype)initHasBorderWithNormalColor:(UIColor*)normalColor
changeColor:(UIColor*)changeColor{
self = [super init];
if (self) {
_normalColor = normalColor;
_changeColor = changeColor;
isHasBorder = YES;
//边框
self.layer.borderWidth = 1;
self.layer.masksToBounds = YES;
self.layer.cornerRadius = 4;
self.layer.borderColor = normalColor.CGColor;
//字体颜色
[self setTitleColor:normalColor forState:UIControlStateNormal];
[self setTitleColor:changeColor forState:UIControlStateDisabled];
}
return self;
}
-(void)countButtonHandler:(TouchedCountDownButtonHandler)touchedCountDownButtonHandler{
_touchedCountDownButtonHandler = [touchedCountDownButtonHandler copy];
[self addTarget:self action:@selector(touched:) forControlEvents:UIControlEventTouchUpInside];
}
- (void)touched:(WxxCountDownButton *)sender{
if (_touchedCountDownButtonHandler) {
_touchedCountDownButtonHandler(sender,sender.tag);
}
}
#pragma -mark count down method
- (void)startCountDownWithSecond:(NSUInteger)totalSecond
{
self.enabled = NO;
_totalSecond = totalSecond;
_second = totalSecond;
__block NSInteger timeout = totalSecond;
dispatch_queue_t queue = dispatch_queue_create(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0);
verifyTimer = dispatch_source_create(DISPATCH_SOURCE_TYPE_TIMER, 0, 0, queue);
dispatch_source_set_timer(verifyTimer, dispatch_walltime(NULL, 0), 1.0*NSEC_PER_SEC, 0);//每秒执行
__weak typeof(self)weakSelf = self;
dispatch_source_set_event_handler(verifyTimer, ^{
if (timeout <= 0) {
//倒计时结束
dispatch_async(dispatch_get_main_queue(), ^{
// [weakSelf setBackgroundColor:_normalColor];
if (isHasBorder) {
self.layer.borderColor = _normalColor.CGColor;
}
[weakSelf stopCountDown];
});
}else{
//倒计时中
dispatch_async(dispatch_get_main_queue(), ^{
// [weakSelf setBackgroundColor:_changeColor];
if (isHasBorder) {
self.layer.borderColor = _changeColor.CGColor;
}
if (_countDownChanging) {
[weakSelf setTitle:_countDownChanging(weakSelf,timeout) forState:UIControlStateNormal];
[weakSelf setTitle:_countDownChanging(weakSelf,timeout) forState:UIControlStateDisabled];
}else{
NSString *title = [NSString stringWithFormat:@"%zd秒",timeout];
[weakSelf setTitle:title forState:UIControlStateNormal];
[weakSelf setTitle:title forState:UIControlStateDisabled];
}
});
timeout--;
}
});
dispatch_resume(verifyTimer);
}
- (void)stopCountDown{
//停止计时线程
if (verifyTimer) {
dispatch_source_cancel(verifyTimer);
verifyTimer = nil;
}
//按钮可用
self.enabled = YES;
//设置正常颜色
if (isHasBorder) {
self.layer.borderColor = _normalColor.CGColor;
}
_second = _totalSecond;
if (_countDownFinished) {
[self setTitle:_countDownFinished(self,_totalSecond)forState:UIControlStateNormal];
[self setTitle:_countDownFinished(self,_totalSecond)forState:UIControlStateDisabled];
}else{
[self setTitle:@"重新获取" forState:UIControlStateNormal];
[self setTitle:@"重新获取" forState:UIControlStateDisabled];
}
}
- (void)countDownChanging:(CountDownChanging)countDownChanging{
_countDownChanging = [countDownChanging copy];
}
- (void)countDownFinished:(CountDownFinished)countDownFinished{
_countDownFinished = [countDownFinished copy];
}
@end
具体的按钮样式，可以自己根据需要去做修改。本demo的按钮样式是：带圆角边框，文字颜色同边框，无背景颜色
具体的使用方式如下：
button = [[WxxCountDownButton alloc]initHasBorderWithNormalColor:[UIColor blueColor] changeColor:[UIColor lightGrayColor]];
[self.view addSubview:button];
button.frame = CGRectMake(120, 150, 80, 30);
button.titleLabel.font = [UIFont systemFontOfSize:12];
[button setTitle:@"发送验证码" forState:UIControlStateNormal];
[button countButtonHandler:^(WxxCountDownButton *countDownButton, NSInteger tag) {
[countDownButton startCountDownWithSecond:59];
[countDownButton countDownChanging:^NSString *(WxxCountDownButton *countDownButton, NSUInteger second) {
NSString *title = [NSString stringWithFormat:@"(%lu)正在发送",(unsigned long)second];
return title;
}];
[countDownButton countDownFinished:^NSString *(WxxCountDownButton *countDownButton, NSUInteger second) {
return @"发送验证码";
}];
}];
切换页面的时候，记得停止和释放：
-(void)viewWillDisappear:(BOOL)animated{
[button stopCountDown];
}
小结
- NSTimer的话，如果是主线程的RunLoop，需要设置NSRunLoopCommonModes模式，以防止UI等操作对计时器的影响。如果是开启新的线程的话，虽然不受UI影响，但是需要手动开启RunLoop。
- 如果是dispatch_source_set_timer，计时准确，写起来也是挺方便的。
- 计时过程和计时结束对外暴露方法，可以由用户自定义显示文字，做相关UI修改。
- 自定义UIButton对外暴露的方法，用block来写，外部调用可以写到一起，简洁！