Android使用CountDownTimer类实现倒计时闹钟

下面使用CountDownTimer类实现倒计时小闹钟，CountDownTimer类其实很简单，一般只需重写其onFinish和onTick方法就可以实现倒计时小闹钟，代码如下：

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：

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
  android:layout_width="match_parent"
  android:layout_height="match_parent" >

  <Button
    android:id="@+id/main_btn_close_music"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:text="关闭音乐"
    android:visibility="gone" />

  <LinearLayout
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_centerInParent="true"
    android:gravity="center"
    android:orientation="horizontal" >

    <Button
      android:id="@+id/main_btn_down"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:text="-"
      android:textSize="40dp" />

    <TextView
      android:id="@+id/main_tv"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:padding="10dp"
      android:text="0:00"
      android:textSize="40dp" />

    <Button
      android:id="@+id/main_btn_up"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:text="+"
      android:textSize="40dp" />
  </LinearLayout>

  <Button
    android:id="@+id/main_start"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_alignParentBottom="true"
    android:text="Start" />

</RelativeLayout>

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持脚本之家。