GCD定时器封装

#import <Foundation/Foundation.h>

NS_ASSUME_NONNULL_BEGIN

@interface LITimer_GCD : NSObject

+(NSString *)execTask:(void(^)(void))task;

+(NSString *)execTask:(void(^)(void))task

          start:(NSTimeInterval)start

       interval:(NSTimeInterval)interval

        repeats:(BOOL)repeatsasync:(BOOL)async;

+(void)cancleTask:(NSString *)taskName;

@end

NS_ASSUME_NONNULL_END

================================================.m文件

#import "LITimer_GCD.h"

@implementation LITimer_GCD

static NSMutableDictionary *timers;

dispatch_semaphore_t semaphore_;

+(void)initialize

{

    staticdispatch_once_tonceToken;

    dispatch_once(&onceToken, ^{

        timers = [[NSMutableDictionary alloc] init];

        semaphore_ = dispatch_semaphore_create(1);

    });

}

+(NSString*)execTask:(void(^)(void))task

{

    return [self execTask:task start:0 interval:1 repeats:YES async:NO];

}

+(NSString*)execTask:(void(^)(void))taskstart:(NSTimeInterval)startinterval:(NSTimeInterval)intervalrepeats:(BOOL)repeatsasync:(BOOL)async

{

    if(!task || start <0|| (interval <=0&& repeats)) {

        returnnil;

    }

    //创建队列

    dispatch_queue_t queue = async ? dispatch_queue_create("timer", DISPATCH_QUEUE_SERIAL) : dispatch_get_main_queue();

    //创建定时器

    dispatch_source_t timer = dispatch_source_create(DISPATCH_SOURCE_TYPE_TIMER, 0, 0, queue);

    //设置时间

    dispatch_source_set_timer(timer,dispatch_time(DISPATCH_TIME_NOW, start *NSEC_PER_SEC), interval *NSEC_PER_SEC,0);

    //加锁-防止多线程操作字典

    dispatch_semaphore_wait(semaphore_, DISPATCH_TIME_FOREVER);

    //设置名字

    NSString *name = [NSString stringWithFormat:@"%lu",(unsigned long)timers.count];

    timers[name] = timer;

    //解锁

    dispatch_semaphore_signal(semaphore_);

    //设置回调

    dispatch_source_set_event_handler(timer, ^{

        task();

        if(!repeats){

            [selfcancleTask:name];

        }

    });

    //启动定时器

    dispatch_resume(timer);

    returnname;

}

+(void)cancleTask:(NSString*)taskName

{

    if(taskName.length<=0) {

        return;

    }

    dispatch_source_ttimer =timers[taskName];

    if(!timer){

        return;

    }

    //加锁

    dispatch_semaphore_wait(semaphore_, DISPATCH_TIME_FOREVER);

    dispatch_source_cancel(timer);

    [timers removeObjectForKey:taskName];

    dispatch_semaphore_signal(semaphore_);

}

@end