NSTimer 的初始化
初始化方法:有五种初始化方法
- (NSTimer *)timerWithTimeInterval:(NSTimeInterval)ti invocation:(NSInvocation *)invocation repeats:(BOOL)yesOrNo;
//例如:
//初始化一个Invocation对象
NSInvocation * invo = [NSInvocation invocationWithMethodSignature:[[self class] instanceMethodSignatureForSelector:@selector(init)]];
[invo setTarget:self];
[invo setSelector:@selector(timerAction)];
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;
//例如:
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;
//例如:
NSTimer * timer = [NSTimer timerWithTimeInterval:1 target:self selector:@selector(timerAction) userInfo:nil repeats:NO];
- (NSTimer *)scheduledTimerWithTimeInterval:(NSTimeInterval)ti target:(id)aTarget selector:(SEL)aSelector userInfo:(id)userInfo repeats:(BOOL)yesOrNo;
//例如:
NSTimer * timer = [NSTimer scheduledTimerWithTimeInterval:1 target:self selector:@selector(timerAction:) userInfo:@"123" repeats:YES];
- (instancetype)initWithFireDate:(NSDate *)date interval:(NSTimeInterval)ti target:(id)t selector:(SEL)s userInfo:(id)ui repeats:(BOOL)repeats:(BOOL)yesOrNo;
//例如:
NSTimer * timer = [[NSTimer alloc]initWithFireDate:[NSDate distantPast] interval:1 target:self selector:@selector(timerAction:) userInfo:nil repeats:YES];
[[NSRunLoop mainRunLoop]addTimer:timer forMode:NSDefaultRunLoopMode];
它的属性
@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) NSTimeInterval timeInterval;//这个是一个只读属性,获取定时器调用间隔时间
@property NSTimeInterval tolerance;//这是7.0之后新增的一个属性,因为NSTimer并不完全精准,通过这个值设置误差范围
@property (readonly, getter=isValid) BOOL valid;//获取定时器是否有效
@property (readonly, retain) id userInfo;//获取参数信息
释放,销毁定时器
[timer invalidate];//是唯一的方法将定时器从循环池中移除
timer=nil;//同时置空