[移动开发]Android Service的简单使用与生命周期说明

一、Service的启动分为startService和BindService

1.startService启动服务，Activity与Service是生命周期互不影响，如果通信可以使用广播

2.BindService启动服务，Activity与Service中间有一个连接，要使连接成功，onBind（）必须返回一个IBinder对象。

3.创建一个Service，

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


public class ScorsService extends Service {

    /**
     * 在整个生命周期中只调用一次
     */
    @Override
    public void onCreate() {
        super.onCreate();
        Log.e("ScorsService", "onCreate");
    }

    /**
     * 每一次startService都会调用
     */
    @Override
    public int onStartCommand(Intent intent, int flags, int startId) {
        Log.e("ScorsService", "onStartCommand");
        return super.onStartCommand(intent, flags, startId);
    }

    /**
     * bindService启动时调用，在整个生命周期中只调用一次
     * 要是Activity与Service连接成功，必须返回一个IBinder对象
     */
    @Override
    public IBinder onBind(Intent intent) {
        Log.e("ScorsService", "onBind");
        return new MyIBinder();
    }

    class MyIBinder extends Binder {
        public double scoreNums(double... scores) {
            int count = scores.length;
            if (count == 0) {
                return 0;
            }
            double sum = 0;
            for (double score : scores) {
                sum += score;
            }
            return sum/count;
        }
    }

    /**
     * 在整个生命周期中只调用一次
     */
    @Override
    public boolean onUnbind(Intent intent) {
        Log.e("ScorsService", "onUnbind");
        return super.onUnbind(intent);
    }

    /**
     * 在整个生命周期中只调用一次
     */
    @Override
    public void onDestroy() {
        super.onDestroy();
        Log.e("ScorsService", "onDestroy");
    }

}

需要在Mainfest中注册

4. 在activity中使用startService启动与关闭服务

Intent intent_service;

switch (v.getId()) {
    case R.id.button_startService: //start启动服务
        //隐士启动服务
        /**
         * 安卓5.0时候，采用隐式启动时要给Intent设置一下具体的包名，指明具体是哪个包启动的Service
         * 否则会出现java.lang.IllegalArgumentException: Service Intent must be explicit异常
         * */
        intent_service = new Intent();
        intent_service.setPackage("com.example.broadcastreceiverdemo");
        intent_service.setAction("scorsService.ruidee");
        startService(intent_service);
        break;
    case R.id.button_stopService: //start关闭服务
        intent_service = new Intent();
        intent_service.setPackage("com.example.broadcastreceiverdemo");
        intent_service.setAction("scorsService.ruidee");
        stopService(intent_service);
        break;

????????}

生命周期：oncreate() --> onStartCommand() -- >?onDestroy()

onStartCommand（）在每次调用startService都会调用，其它整个生命周期中只调用一次

4. 在activity中使用bindService启动与关闭服务

首选创建一个ServiceConnection

private ServiceConnection coon = new ServiceConnection() {
    @Override
    public void onServiceConnected(ComponentName name, IBinder service) {
        //连接成功回调,在service中的onBind不能返回bnull
        Log.e("ScorsService", "Activity onServiceConnected 连接成功回调");
        myIBinder = (ScorsService.MyIBinder) service;
        double endScores = myIBinder.scoreNums(60, 70, 80);
        tvStartServiceCont.setText("语数外综合平均成绩是：" + endScores);
    }

    @Override
    public void onServiceDisconnected(ComponentName name) {
        //连接异常回调
        Log.e("ScorsService", "Activity onServiceDisconnected 连接异常回调");
    }
};

事件：

Intent intent_bindservice;
switch (v.getId()) {
    case R.id.button_bindService: //bind启动服务
        /**
         * 第一个参数Intent，表明启动的Service
         * 第二个参数是ServiceConnection 连接
         * 第三个参数flags: BIND_AUTO_CREATE绑定没有创建
         * */
        intent_bindservice = new Intent();
        intent_bindservice.setPackage("com.example.broadcastreceiverdemo");
        intent_bindservice.setAction("scorsService.ruidee");

        bindService(intent_bindservice, coon, BIND_AUTO_CREATE);
        break;
    case R.id.button_unBindService: //unbind关闭服务
        unbindService(coon);
        break;
}

生命周期是：oncreate() --> onBind() --> onUnbind() -->onDestroy()

这些整个生命周期中只调用一次

6.Activity的整体代码

package com.example.broadcastreceiverdemo.service;

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

import androidx.appcompat.app.AppCompatActivity;

import com.example.broadcastreceiverdemo.R;

public class OneStartServiceActivity extends AppCompatActivity implements View.OnClickListener {

    private TextView tvStartServiceCont;
    private Button button_startService, button_stopService, button_bindService, button_unBindService;
    private ScorsService.MyIBinder myIBinder = null;

    private ServiceConnection coon = new ServiceConnection() {
        @Override
        public void onServiceConnected(ComponentName name, IBinder service) {
            //连接成功回调,在service中的onBind不能返回bnull
            Log.e("ScorsService", "Activity onServiceConnected 连接成功回调");
            myIBinder = (ScorsService.MyIBinder) service;
            double endScores = myIBinder.scoreNums(60, 70, 80);
            tvStartServiceCont.setText("语数外综合平均成绩是：" + endScores);
        }

        @Override
        public void onServiceDisconnected(ComponentName name) {
            //连接异常回调
            Log.e("ScorsService", "Activity onServiceDisconnected 连接异常回调");
        }
    };

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.one_startservice_activity);

        initView();
        initDate();
    }

    private void initDate() {
        /**
         * 启动服务
         * */
        button_startService.setOnClickListener(this);
        button_stopService.setOnClickListener(this);
        button_bindService.setOnClickListener(this);
        button_unBindService.setOnClickListener(this);
    }

    private void initView() {
        tvStartServiceCont = findViewById(R.id.tvStartServiceCont);
        button_startService = findViewById(R.id.button_startService);
        button_stopService = findViewById(R.id.button_stopService);
        button_bindService = findViewById(R.id.button_bindService);
        button_unBindService = findViewById(R.id.button_unBindService);

    }

    @Override
    public void onClick(View v) {
        Intent intent_service;
        Intent intent_bindservice;
        switch (v.getId()) {
            case R.id.button_startService: //start启动服务
                //隐士启动服务
                /**
                 * 安卓5.0时候，采用隐式启动时要给Intent设置一下具体的包名，指明具体是哪个包启动的Service
                 * 否则会出现java.lang.IllegalArgumentException: Service Intent must be explicit异常
                 * */
                intent_service = new Intent();
                intent_service.setPackage("com.example.broadcastreceiverdemo");
                intent_service.setAction("scorsService.ruidee");
                startService(intent_service);
                break;
            case R.id.button_stopService: //start关闭服务
                intent_service = new Intent();
                intent_service.setPackage("com.example.broadcastreceiverdemo");
                intent_service.setAction("scorsService.ruidee");
                stopService(intent_service);
                break;
            case R.id.button_bindService: //bind启动服务
                /**
                 * 第一个参数Intent，表明启动的Service
                 * 第二个参数是ServiceConnection 连接
                 * 第三个参数flags: BIND_AUTO_CREATE绑定没有创建
                 * */
                intent_bindservice = new Intent();
                intent_bindservice.setPackage("com.example.broadcastreceiverdemo");
                intent_bindservice.setAction("scorsService.ruidee");

                bindService(intent_bindservice, coon, BIND_AUTO_CREATE);
                break;
            case R.id.button_unBindService: //unbind关闭服务
                unbindService(coon);
                break;
        }
    }
}

布局效果：

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