Android 升级版倒数计时器

最近需要一个倒数计时器，要求实现倒数计时，暂停，继续，和快进快退的功能。Android本身提供了一个CountdownTimer的类，采用Handler的方式实现，但是只提供了倒数计时的功能，对于暂停，继续，快进快退功能未提供支持，于是在CounterDownTimer的基础上重写了一个类，最终满足要求。

package com.jason.stopwatch.util;



import android.os.Handler;

import android.os.Message;



public abstract class AdvancedCountdownTimer {



	private final long mCountdownInterval;



	private long mTotalTime;



	private long mRemainTime;



	

	public AdvancedCountdownTimer(long millisInFuture, long countDownInterval) {

		mTotalTime = millisInFuture;

		mCountdownInterval = countDownInterval;



		mRemainTime = millisInFuture;

	}



	public final void seek(int value) {

		synchronized (AdvancedCountdownTimer.this) {

			mRemainTime = ((100 - value) * mTotalTime) / 100;

		}

	}



	

	public final void cancel() {

		mHandler.removeMessages(MSG_RUN);

		mHandler.removeMessages(MSG_PAUSE);

	}



	public final void resume() {

		mHandler.removeMessages(MSG_PAUSE);

		mHandler.sendMessageAtFrontOfQueue(mHandler.obtainMessage(MSG_RUN));

	}



	public final void pause() {

		mHandler.removeMessages(MSG_RUN);

		mHandler.sendMessageAtFrontOfQueue(mHandler.obtainMessage(MSG_PAUSE));

	}



	

	public synchronized final AdvancedCountdownTimer start() {

		if (mRemainTime <= 0) {

			onFinish();

			return this;

		}

		mHandler.sendMessageDelayed(mHandler.obtainMessage(MSG_RUN),

				mCountdownInterval);

		return this;

	}



	public abstract void onTick(long millisUntilFinished, int percent);



	

	public abstract void onFinish();



	private static final int MSG_RUN = 1;

	private static final int MSG_PAUSE = 2;



	private Handler mHandler = new Handler() {



		@Override

		public void handleMessage(Message msg) {



			synchronized (AdvancedCountdownTimer.this) {

				if (msg.what == MSG_RUN) {

					mRemainTime = mRemainTime - mCountdownInterval;



					if (mRemainTime <= 0) {

						onFinish();

					} else if (mRemainTime < mCountdownInterval) {

						sendMessageDelayed(obtainMessage(MSG_RUN), mRemainTime);

					} else {



						onTick(mRemainTime, new Long(100

								* (mTotalTime - mRemainTime) / mTotalTime)

								.intValue());



					

						sendMessageDelayed(obtainMessage(MSG_RUN),

								mCountdownInterval);

					}

				} else if (msg.what == MSG_PAUSE) {



				}

			}

		}

	};

}