Android——CountDownTimer

最新推荐文章于 2024-05-15 02:13:53 发布

chumin19890524

最新推荐文章于 2024-05-15 02:13:53 发布

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本文介绍了一个简单的倒计时定时器实现方法，通过Google API中的CountDownTimer类，可以轻松设置从当前到未来某一时刻的倒计时，并在指定的时间间隔内触发回调更新剩余时间。

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通过Google API，很清楚的知道是用于倒计时。

Class Overview

Schedule a countdown until a time in the future, with regular notifications on intervals along the way. Example of showing a 30 second countdown in a text field:

 new CountdownTimer(30000, 1000) {

     public void onTick(long millisUntilFinished) {
         mTextField.setText("seconds remaining: " + millisUntilFinished / 1000);
     }

     public void onFinish() {
         mTextField.setText("done!");
     }
  }.start();

The calls to onTick(long) are synchronized to this object so that one call to onTick(long) won't ever occur before the previous callback is complete. This is only relevant when the implementation of onTick(long) takes an amount of time to execute that is significant compared to the countdown interval.
onTick(long)针对这个计时器对象是synchronized。

Summary

Public Constructors
	CountDownTimer(long millisInFuture, long countDownInterval)

Public Methods
final void	cancel() Cancel the countdown.
abstract void	onFinish() Callback fired when the time is up.
abstract void	onTick(long millisUntilFinished) Callback fired on regular interval.
synchronized final CountDownTimer	start() Start the countdown.

Public Constructors

public CountDownTimer (long millisInFuture, long countDownInterval)

Since: API Level 1

Parameters

millisInFuture	The number of millis in the future from the call to `start()` until the countdown is done and `onFinish()` is called.
countDownInterval	The interval along the way to receive `onTick(long)` callbacks.

第一个参数是倒计时的总时间，第二个参数是每隔多长时间调用一次onTick(long)。