Nstimer not invalidating

Posted by / 21-Jan-2018 18:44

However, for a repeating timer, you must invalidate the timer object yourself by calling its [invalidate() ] method.

Calling this method requests the removal of the timer from the current run loop; as a result, you should always call the [invalidate() ] method from the same thread on which the timer was installed.

= Selectable Button.button With Type(UIButton Type Custom)do |button| button.style Id = 'timer_button' Title(' Start Timer', for State: UIControl State Normal) Title("Interrupt!" , for State: UIControl State Selected) Target(next Responder, action: 'timer_button_tapped:', for Control Events: UIControl Event Touch Up Inside) end end and you'll see the button background turn to red like so: Once the timer reaches zero, the button background returns to green.Because of the various input sources a typical run loop manages, the effective resolution of the time interval for a timer is limited to on the order of 50-100 milliseconds.If a timer’s firing time occurs during a long callout or while the run loop is in a mode that is not monitoring the timer, the timer does not fire until the next time the run loop checks the timer.

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Therefore, the actual time at which the timer fires potentially can be a significant period of time after the scheduled firing time. 总结:nstimer可能不会定时触发 定时时间间隔为2秒,t1秒添加成功,那么会在t2、t4、t6、t8、t10秒注册好事件,并在这些时间触发。假设第3秒时,执行了一个超时操作耗费了5.5秒,则触发时间是:t2、t8.5、t10,第4和第6秒就被跳过去了,虽然在t8.5秒触发了一次,但是下一次触发时间是t10,而不是t10.5。 Repeating Versus Non-Repeating Timers You specify whether a timer is repeating or non-repeating at creation time.

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