NSTimer * myTimer = [NSTimer timerWithTimeInterval:1.0 target:self selector:@selector(doSomeThing:) userInfo:nil repeats:YES]; [myTimer fire]
没有将timer加入runloop
doSomeThing缺少参数
忘记传递数据给userInfo
myTimer对象未通过[[myTimer alloc] init]方法初始化
