怎么在Android中利用CountDownTimer类实现一个倒计时闹钟？很多新手对此不是很清楚，为了帮助大家解决这个难题，下面小编将为大家详细讲解，有这方面需求的人可以来学习下，希望你能有所收获。
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MainActivity：
package com.home.brewclock;
import android.app.Activity;
import android.media.MediaPlayer;
import android.os.Bundle;
import android.os.CountDownTimer;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.TextView;
public class MainActivity extends Activity implements OnClickListener {
private Button addTimeBtn;
private Button decreaseTimeBtn;
private Button startBtn;
private Button closeMusicBtn;
private TextView timeText;
private int brewTime = 3;
private CountDownTimer countDownTimer;
private boolean isBrewing = false;
private MediaPlayer alarmMusic;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
addTimeBtn = (Button) findViewById(R.id.main_btn_up);
decreaseTimeBtn = (Button) findViewById(R.id.main_btn_down);
startBtn = (Button) findViewById(R.id.main_start);
closeMusicBtn = (Button) findViewById(R.id.main_btn_close_music);
timeText = (TextView) findViewById(R.id.main_tv);
addTimeBtn.setOnClickListener(this);
decreaseTimeBtn.setOnClickListener(this);
startBtn.setOnClickListener(this);
closeMusicBtn.setOnClickListener(this);
setBrewTime(3);
}
/**
* 设置闹钟倒计时初始值
*
* @param minutes
*/
public void setBrewTime(int minutes) {
if (isBrewing)
return;
brewTime = minutes;
if (brewTime < 1) {
brewTime = 1;
}
timeText.setText(String.valueOf(brewTime) + "m");
}
/**
* 开启闹钟
*/
public void startBrew() {
// 创建一个CountDownTimer对象记录闹钟时间
countDownTimer = new CountDownTimer(brewTime * 60 * 1000, 1000) {
@Override
public void onTick(long millisUntilFinished) {
timeText.setText(String.valueOf(millisUntilFinished / 1000)
+ "s");
}
@Override
public void onFinish() {
isBrewing = false;
timeText.setText(brewTime + "m");
startBtn.setText("Start");
// 加载指定音乐，并为之创建MediaPlayer对象
alarmMusic = MediaPlayer.create(MainActivity.this, R.raw.music);
// 设置为循环播放
alarmMusic.setLooping(true);
// 播放音乐
alarmMusic.start();
closeMusicBtn.setVisibility(0);
}
};
countDownTimer.start();
startBtn.setText("Stop");
isBrewing = true;
}
/**
* 停止计时
*/
public void stopBrew() {
if (countDownTimer != null) {
countDownTimer.cancel();
}
isBrewing = false;
startBtn.setText("Start");
}
@Override
public void onClick(View v) {
if (v == addTimeBtn) {
setBrewTime(brewTime + 1);
} else if (v == decreaseTimeBtn) {
setBrewTime(brewTime - 1);
} else if (v == startBtn) {
if (isBrewing) {
stopBrew();
} else {
startBrew();
}
} else if (v == closeMusicBtn) {
if (alarmMusic != null) {
alarmMusic.stop();
closeMusicBtn.setVisibility(8);
}
}
}
}布局文件：
