一、初始化方法:有五种初始化方法,分别是
+ (NSTimer *)timerWithTimeInterval:(NSTimeInterval)ti invocation:(NSInvocation *)invocation repeats:(BOOL)yesOrNo;
使用方法:
- (void)viewDidLoad {
[super viewDidLoad];
//初始化一个Invocation对象
NSInvocation * invo = [NSInvocation invocationWithMethodSignature:[[self class] instanceMethodSignatureForSelector:@selector(init)]];
[invo setTarget:self];
[invo setSelector:@selector(myLog)];
NSTimer * timer = [NSTimer timerWithTimeInterval:1 invocation:invo repeats:YES];
//加入主循环池中
[[NSRunLoop mainRunLoop]addTimer:timer forMode:NSDefaultRunLoopMode];
//开始循环
[timer fire];
}
+ (NSTimer *)scheduledTimerWithTimeInterval:(NSTimeInterval)ti invocation:(NSInvocation *)invocation repeats:(BOOL)yesOrNo;
使用方法:
NSTimer * timer = [NSTimer scheduledTimerWithTimeInterval:1 invocation:invo repeats:YES];
+ (NSTimer *)timerWithTimeInterval:(NSTimeInterval)ti target:(id)aTarget selector:(SEL)aSelector userInfo:(id)userInfo repeats:(BOOL)yesOrNo;
使用方法:
NSTimer * timer = [NSTimer timerWithTimeInterval:1 target:self selector:@selector(myLog) userInfo:nil repeats:NO]
+ (NSTimer *)scheduledTimerWithTimeInterval:(NSTimeInterval)ti target:(id)aTarget selector:(SEL)aSelector userInfo:(id)userInfo repeats:(BOOL)yesOrNo;
使用方法:
NSTimer * timer = [NSTimer scheduledTimerWithTimeInterval:1 target:self selector:@selector(myLog:) userInfo:@"123" repeats:YES]
- (instancetype)initWithFireDate:(NSDate *)date interval:(NSTimeInterval)ti target:(id)t selector:(SEL)s userInfo:(id)ui repeats:(BOOL)rep
使用方法:
NSTimer * timer = [[NSTimer alloc]initWithFireDate:[NSDate distantPast] interval:1 target:self selector:@selector(myLog:) userInfo:nil repeats:YES];
[[NSRunLoop mainRunLoop]addTimer:timer forMode:NSDefaultRunLoopMode];
注意:这五种初始化方法的异同:
1、参数repeats是指定是否循环执行,YES将循环,NO将只执行一次。
2、timerWithTimeInterval这两个类方法创建出来的对象如果不用 addTimer: forMode方法手动加入主循环池中,将不会循环执行。并且如果不手动调用fair,则定时器不会启动。
3、scheduledTimerWithTimeInterval这两个方法不需要手动调用fair,会自动执行,并且自动加入主循环池。
4、init方法需要手动加入循环池,它会在设定的启动时间启动。
二、成员变量
@property (copy) NSDate *fireDate;
这是设置定时器的启动时间,常用来管理定时器的启动与停止
//启动定时器
timer.fireDate = [NSDate distantPast];
//停止定时器
timer.fireDate = [NSDate distantFuture];
@property (readonly) NSTim