简单介绍
1、单例类管理GCD计时器；
2、类方法调用计时器API，方便快捷；
3、提供三组API，快速实现计时、倒计时、取消计时；
4、目前仅提供同时存在1组计时器；
5、计时结束后，自动取消，也可手动取消计时器；
注意事项
1、在页面加载和退出时，注意定时器的销毁。
2、及时调用销毁方法，避免释放不掉的问题。
例如：
+ (void)cancelSingleTimer;
.h
构建回调block
/*
每秒频单频计时器回调
current 每秒回调一次 回调当前的时间
end 当为TRUE时 定时器结束
*/
typedef void (^DKTimerSingleTimerBlock)(NSInteger current, BOOL end);
/*
DKTimer
*/
@interface DKTimer : NSObject
/*
倒计时
time：从xx秒开始倒计时
block: 回调
*/
+ (void)countdown:(NSInteger)time block:(DKTimerSingleTimerBlock)block;
/*
计时
max：计时xx时间
block: 回调
*/
+ (void)singleTimer:(NSInteger)max block:(DKTimerSingleTimerBlock)block;
/*
取消计时
*/
+ (void)cancelSingleTimer;
.m
声明属性
/*
每秒频单频计时器；
每次调用前，会销毁之前的定时器；
支持计时和倒计时。倒计时到0时，停止计时；
回调的block均为主线程；
*/
@property (strong, nonatomic) dispatch_source_t singleTimer;
@property (assign, nonatomic) NSInteger current;
@property (assign, nonatomic) NSInteger max;
@property (assign, nonatomic) BOOL sequence;
@property (copy, nonatomic) DKTimerSingleTimerBlock singleTimerBlock;
构建单例类
/*
单例类的创建
使用单例类创建定时器，在一定的环境下，可以高效的控制定时器。
*/
+ (DKTimer *)timer {
static dispatch_once_t onceToken;
static DKTimer *timer = nil;
dispatch_once(&onceToken, ^{
timer = [[DKTimer alloc] init];
});
return timer;
}
公有API
/*
倒计时 最小从1开始倒计时
time：从xx秒开始倒计时
block: 回调
*/
+ (void)countdown:(NSInteger)time block:(DKTimerSingleTimerBlock)block {
if (time <= 0) {
return;
}
[DKTimer timer].singleTimerBlock = block;
[DKTimer timer].sequence = NO;
[DKTimer timer].current = time;
[[DKTimer timer] startSingleTime];
}
/*
计时
max：计时xx时间
block: 回调
*/
+ (void)singleTimer:(NSInteger)max block:(DKTimerSingleTimerBlock)block {
[DKTimer timer].singleTimerBlock = block;
[DKTimer timer].sequence = YES;
[DKTimer timer].max = max;
[DKTimer timer].current = 0;
[[DKTimer timer] startSingleTime];
}
/*
取消计时
*/
+ (void)cancelSingleTimer {
[[DKTimer timer] stopSingleTimer];
}
私有API
/*
计时器的回调方法 主线程
*/
- (void)singleTimerMethod {
if ([DKTimer timer].sequence) {
// 计时
[DKTimer timer].current = [DKTimer timer].current + 1;
BOOL end;
if ([DKTimer timer].current > [DKTimer timer].max) {
// 结束
end = YES;
[self stopSingleTimer];
}else {
// 继续
end = NO;
}
if ([DKTimer timer].singleTimerBlock) {
[DKTimer timer].singleTimerBlock([DKTimer timer].current, end);
}
}else {
// 倒计时
[DKTimer timer].current = [DKTimer timer].current - 1;
BOOL end;
if ([DKTimer timer].current < 0) {
// 结束
end = YES;
[self stopSingleTimer];
}else {
// 继续
end = NO;
}
if ([DKTimer timer].singleTimerBlock) {
[DKTimer timer].singleTimerBlock([DKTimer timer].current, end);
}
}
}
计时器创建 开始 销毁
- (void)stopSingleTimer {
if (_singleTimer) {
dispatch_cancel(_singleTimer);
_singleTimer = nil;
}
}
- (void)startSingleTime {
[self stopSingleTimer];
__weak DKTimer *weakself = self;
NSInteger timeSpace = 1;
dispatch_queue_t queue = dispatch_get_main_queue();
self.singleTimer = dispatch_source_create(DISPATCH_SOURCE_TYPE_TIMER, 0, 0, queue);
dispatch_time_t start = dispatch_time(DISPATCH_TIME_NOW, (int64_t)(1.0 * NSEC_PER_SEC));
uint64_t interval = (uint64_t)(timeSpace * NSEC_PER_SEC);
dispatch_source_set_timer(self.singleTimer, start, interval, 0);
dispatch_source_set_event_handler(self.singleTimer, ^{
dispatch_async(dispatch_get_main_queue(), ^{
[weakself singleTimerMethod];
});
});
dispatch_resume(self.singleTimer);
}
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