<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
 xmlns:tools="http://schemas.android.com/tools"
 android:layout_width="match_parent"
 android:layout_height="match_parent"
 android:orientation="vertical">

 <LinearLayout
 android:layout_width="match_parent"
 android:layout_height="110dp"
 android:layout_marginHorizontal="20dp"
 android:orientation="horizontal">

 <TextView
 android:layout_width="150dp"
 android:layout_height="80dp"
 android:layout_marginTop="15dp"
 android:background="@drawable/shape"
 android:gravity="center_horizontal"
 android:text="鬧鐘"
 android:textAlignment="center"
 android:textSize="50sp"></TextView>

 <EditText
 android:autofillHints="true"
 android:hint="10:10:10"
 android:id="@+id/num"
 android:layout_width="match_parent"
 android:layout_height="80dp"
 android:layout_marginLeft="15dp"
 android:layout_marginTop="5dp"
 android:background="@drawable/shape"
 android:gravity="center"
 android:inputType="time"
 android:textSize="35sp"></EditText>
 </LinearLayout>

 <Button
 android:id="@+id/btnStart"
 android:layout_width="match_parent"
 android:layout_height="80dp"
 android:layout_marginHorizontal="20dp"
 android:layout_marginTop="15dp"
 android:background="@drawable/shape"
 android:text="開始"
 android:textSize="50sp"></Button>

 <TextView
 android:id="@+id/text1"
 android:layout_width="match_parent"
 android:layout_height="300dp"
 android:layout_margin="20dp"
 android:background="@drawable/shape"
 android:gravity="center"
 android:text="倒計時"
 android:textSize="100sp"></TextView>
</LinearLayout>

package com.example.clock;
import android.app.Service;
import android.content.Intent;
import android.os.Binder;
import android.os.Handler;
import android.os.IBinder;
import android.os.Message;
import android.util.Log;
import android.widget.EditText;
public class MyService extends Service {
 public MyService() {
 }
 @Override
 public IBinder onBind(Intent intent) {
 return new MyBinder(); //必須實現(xiàn)的方法，用于活動與服務(wù)之間的綁定
 }
 public class MyBinder extends Binder {
 MyHandler handler;
 public MyService getMyService() {
 return MyService.this;
 }
 public MyHandler getHandler() {
 handler=new MyHandler();//初始化一個消息對象
 return handler; //返回該消息對象
 }
 }
 public class MyHandler extends Handler {
 public String[] nums;
 public String str;
 public String str1;
 public void handleMessage(Message msg) {
 str1= String.valueOf(msg.obj); //獲取MainActivity中傳遞的消息
 Log.d("渣", str1);
 new Thread(new Runnable() {
 @Override
 public void run() { //開啟一個線程
  nums=str1.split(":"); //將獲取到的字符串拆分成數(shù)組
  //將字符串中的時間轉(zhuǎn)換成秒
  int time1=Integer.parseInt(nums[2])+60*60*Integer.parseInt(nums[1])+60*Integer.parseInt(nums[1]);
  for(int time = time1;time>=0;time--){ //通過for循環(huán)對對時間進行循環(huán)
  if(time==0){ //如果時間倒計時到0，則顯示（時間到）字樣
  MainActivity.textView.setText("時間到!");
  }
  try { //將time秒重新轉(zhuǎn)換成時間字符串
  int hour = 0;
  int minutes = 0;
  int sencond = 0;
  int temp = time % 3600;
  if (time > 3600) {
  hour = time / 3600;
  if (temp != 0) {
   if (temp > 60) {
   minutes = temp / 60;
   if (temp % 60 != 0) {
   sencond = temp % 60;
   }
   } else {
   sencond = temp;
   }
  }
  } else {
  minutes = time / 60;
  if (time % 60 != 0) {
   sencond = time % 60;
  }
  }
  str=(hour<10?("0"+hour):hour) + ":" + (minutes<10?("0"+minutes):minutes)
   + ":" + (sencond<10?("0"+sencond):sencond);
  MainActivity.num.setText(str); //及時更新EditText的值
  Thread.sleep(1000); //線程休眠1秒
  } catch (Exception e) {
  e.printStackTrace();
  }
  }
 }
 }).start();
 }
 }

 @Override
 public void onDestroy() {
 super.onDestroy();
 }
}

package com.example.clock;

import androidx.appcompat.app.AppCompatActivity;

import android.content.ComponentName;
import android.content.Intent;
import android.content.ServiceConnection;
import android.os.Binder;
import android.os.Bundle;
import android.os.Handler;
import android.os.IBinder;
import android.os.Message;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;

public class MainActivity extends AppCompatActivity {
 MyService.MyBinder myBinder;
 public static EditText num;
 int flag = 0;
 String str;
 Intent intent;
 public static TextView textView;
 @Override
 protected void onCreate(Bundle savedInstanceState) {
 super.onCreate(savedInstanceState);
 setContentView(R.layout.activity_main);
 textView=findViewById(R.id.text1);
 final Button btnStart = (Button) findViewById(R.id.btnStart);
 num = (EditText) findViewById(R.id.num);
 btnStart.setOnClickListener(new View.OnClickListener() {
 @Override
 public void onClick(View v) {
 if (flag == 0) {
  if (num.getText().length() < 1) { //如果未輸入數(shù)值，則獲取默認(rèn)填充值（Hint）
  str = String.valueOf(num.getHint());
  }else {
  str=num.getText().toString(); //獲取輸入的值
  }
  flag = 1; //用于判斷按鈕狀態(tài)
  btnStart.setText("暫停");
  num.setEnabled(false); //將EditText設(shè)置為不可編輯
  intent = new Intent(MainActivity.this, MyService.class); //創(chuàng)建啟動Service的Intent對象
  bindService(intent, conn, BIND_AUTO_CREATE); //綁定指定Service
  Log.d("time", String.valueOf(str));
 } else {
  flag = 0;
  btnStart.setText("開始");
  myBinder.getMyService().onDestroy();
 }
 }
 });
 }
 ServiceConnection conn = new ServiceConnection() {
 @Override
 public void onServiceConnected(ComponentName name, IBinder service) {//設(shè)置與服務(wù)進行通信
 myBinder = (MyService.MyBinder) service; //獲取服務(wù)中的MyBinder對象
 Message message = new Message(); //創(chuàng)建消息對象
 message.obj = str; //傳遞參數(shù)，str是獲取到的值
 MyService.MyHandler handler = myBinder.getHandler(); //獲取MyService中的Handler對象
 handler.sendMessage(message); //通過Handler對象發(fā)送消息
 }

 @Override
 public void onServiceDisconnected(ComponentName name) {

 }
 };
}