Android实验：启动式service

实验目的

充分理解Service的作用，与Activity之间的区别，掌握Service的生命周期以及对应函数，了解Service的主线程性质；掌握主线程的界面刷新的设计原则，掌握启动service的方式，及其工作原理

实验内容

任务1：在service中实现随机数产生；
任务2：在Activity界面实现随机数的显示，并采用启动式完成service的启动；

实验要求

1、在service中实现随机数产生；
2、实现Service中的各个生命周期函数，并理解其功能；
2、在Activity界面实现随机数的显示，每2秒更新一次；
3、采用启动式完成service的启动；

项目结构

在这里插入图片描述

代码实现

mainActivity

import android.app.Service;
import android.content.Intent;
import android.util.Log;
import android.os.IBinder;import java.util.Random;public class RandomNumberService extends Service {private static final String TAG="RandomNumberService";//日志标签private static final Random random=new Random();//随机数生成器private static int randomNumber;//随机数的变量@Overridepublic void onCreate(){super.onCreate();Log.d(TAG,"onCreate:Service is Created");//打印日志}@Overridepublic int onStartCommand(Intent intent,int flags,int startID){Log.d(TAG,"onStartCommand:Service activity");randomNumber=random.nextInt(1000);//打印随机数return super.onStartCommand(intent,flags,startID);}@Overridepublic void onDestroy(){super.onDestroy();Log.d(TAG,"drop Service");}@Overridepublic IBinder onBind(Intent intent){return null;//不支持绑定服务}public static int getRandomNumber(){return randomNumber;}}

RandomNumberService

import android.app.Service;
import android.content.Intent;
import android.util.Log;
import android.os.IBinder;import java.util.Random;public class RandomNumberService extends Service {private static final String TAG="RandomNumberService";//日志标签private static final Random random=new Random();//随机数生成器private static int randomNumber;//随机数的变量@Overridepublic void onCreate(){super.onCreate();Log.d(TAG,"onCreate:Service is Created");//打印日志}@Overridepublic int onStartCommand(Intent intent,int flags,int startID){Log.d(TAG,"onStartCommand:Service activity");randomNumber=random.nextInt(1000);//打印随机数return super.onStartCommand(intent,flags,startID);}@Overridepublic void onDestroy(){super.onDestroy();Log.d(TAG,"drop Service");}@Overridepublic IBinder onBind(Intent intent){return null;//不支持绑定服务}public static int getRandomNumber(){return randomNumber;}}

activity_main

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"xmlns:app="http://schemas.android.com/apk/res-auto"xmlns:tools="http://schemas.android.com/tools"android:layout_width="match_parent"android:layout_height="match_parent"tools:context=".mainActivity"><TextViewandroid:id="@+id/textView"android:layout_width="wrap_content"android:layout_height="wrap_content"android:text="0"android:textSize="36sp"app:layout_constraintBottom_toBottomOf="parent"app:layout_constraintLeft_toLeftOf="parent"app:layout_constraintRight_toRightOf="parent"app:layout_constraintTop_toTopOf="parent" /></androidx.constraintlayout.widget.ConstraintLayout>

AndroidManifest

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"xmlns:tools="http://schemas.android.com/tools"><applicationandroid:allowBackup="true"android:dataExtractionRules="@xml/data_extraction_rules"android:fullBackupContent="@xml/backup_rules"android:icon="@mipmap/ic_launcher"android:label="@string/app_name"android:roundIcon="@mipmap/ic_launcher_round"android:supportsRtl="true"android:theme="@style/Theme.Exp3"tools:targetApi="31"><activityandroid:name=".mainActivity"android:exported="true"android:label="@string/app_name"android:theme="@style/Theme.Exp3"><intent-filter><action android:name="android.intent.action.MAIN" /><category android:name="android.intent.category.LAUNCHER" /></intent-filter></activity><service android:name=".RandomNumberService" /></application></manifest>