Android中Service的开发和理解

Service
service是一种服务，可以脱离activity运行，就好像网易云音乐的后台播放等等；
分类
具有Stat Services 和Bound Service两种
1.创建services

右键点击创建services即可，如果手动创建需要在xml中配置信息

2.使用services

public class MyService extends Service {
    static boolean isplay;
    MediaPlayer player;
    public MyService() {
    }

    @Override
    public IBinder onBind(Intent intent) {
        // TODO: Return the communication channel to the service.
        throw new UnsupportedOperationException("Not yet implemented");
    }

    @Override
    public void onCreate() {
        super.onCreate();
        player=MediaPlayer.create(this,R.raw.who);
        Log.i("Service","oncreat方法调用");
    }

    @Override
    public int onStartCommand(Intent intent, int flags, int startId) {

        if(!player.isPlaying())
        {
            player.start();
            isplay=player.isPlaying();

        }


        return super.onStartCommand(intent, flags, startId);
    }

    @Override
    public void onDestroy() {
        Log.i("Service","销毁方法调用");
        player.stop();
        isplay=player.isPlaying();
        player.release();
        super.onDestroy();
    }

调用方法播放音乐；
services的生命周期和activity相似
3.启动services就完事了

   Intent intent=new Intent(services.this,MyService.class);
                startService(intent);

Bound Service

boundservice是将services与activity连接起来的一种services。
他可以实现与activity共消失和创建，另外可以调用services里的方法。
不是很懂，待探究

package com.example.demo;

import androidx.appcompat.app.AppCompatActivity;

import android.content.ComponentName;
import android.content.Intent;
import android.content.ServiceConnection;
import android.os.Bundle;
import android.os.IBinder;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;

import java.util.List;

public class caipiao extends AppCompatActivity {
    caipiaoservise caipiaoservise;
   int[] tvid={R.id.h1,R.id.h2,R.id.h3,R.id.h4,R.id.h5};
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_caipiao);
    Button button= findViewById(R.id.xuan);
    button.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {

            List<String> number=caipiaoservise.getnumb();
            for(int i=0;i<number.size();i++)
            {
                TextView tv=(TextView)findViewById(tvid[i]);
                tv.setText(number.get(i).toString());


            }
        }
    });

    }



    //创建servicescon
   private ServiceConnection conn=new ServiceConnection() {
        @Override
        public void onServiceConnected(ComponentName name, IBinder service) {
            caipiaoservise=((caipiaoservise.MyBinder)service).getService();

        }

        @Override
        public void onServiceDisconnected(ComponentName name) {

        }
    };

    @Override
    protected void onStart() {
        super.onStart();
        Intent intent=new Intent(caipiao.this,caipiaoservise.class);
        bindService(intent,conn,BIND_AUTO_CREATE);

    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        unbindService(conn);
    }
}

package com.example.demo;

import android.app.Service;
import android.content.Intent;
import android.os.Binder;
import android.os.IBinder;

import java.util.ArrayList;
import java.util.List;
import java.util.Random;

public class caipiaoservise extends Service {

    public caipiaoservise() {


    }
   public class MyBinder extends Binder{


        public caipiaoservise getService()
        {
            return caipiaoservise.this;
        }
   }
    @Override
    public IBinder onBind(Intent intent) {
        // TODO: Return the communication channel to the service.
     //   throw new UnsupportedOperationException("Not yet implemented");
        return new MyBinder();
    }

    public List<String> getnumb()
    {
        String n;
        ArrayList<String> arrayList=new ArrayList<>();
        for (int i=0;i<5;i++) {
            int numb = new Random().nextInt(32);
            if (numb < 10) {
                n = "0" + numb;

            }
            else
            {
                n=String.valueOf(numb);
            }

            arrayList.add(n);

        }
        return arrayList;
    }

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