定时器,计时器底层实现,每个方法都很简单
#import <Foundation/Foundation.h>
typedef void (^taskBlock)(void);
@interface XMTimer : NSObject
+ (void) startTimerTask:(NSTimeInterval) startTime interval :(NSTimeInterval) interval taskBlock :(taskBlock) block ;
+ (void) startTimerTask:(NSTimeInterval) startTime interval :(NSTimeInterval) interval durationTime :(NSTimeInterval) durationTime taskBlock :(taskBlock) block taskEndBlock :(taskBlock) taskEndBlock ;
+ (void) startTimerTask:(NSTimeInterval) startTime durationTime :(NSTimeInterval) durationTime taskBlock :(taskBlock