Service入门（一）——startService、stopService

MainActivity.class文件：

package com.example.guocong.service;

import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;

public class MainActivity extends AppCompatActivity {

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

        findViewById(R.id.btnStartService).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                startService(new Intent(MainActivity.this,MyService.class));
            }
        });

        findViewById(R.id.btnStopService).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                stopService(new Intent(MainActivity.this,MyService.class));
            }
        });
    }
}

MyService文件：

package com.example.guocong.service;

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

public class MyService extends Service {
    public MyService() {
    }

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


    //执行onStartService时执行onStartService
    @Override
    public int onStartCommand(Intent intent, int flags, int startId) {



            new Thread() {
                @Override
                public void run() {
                    super.run();

                    while(true) {
                        System.out.println("服务正在运行");

                        try {
                            sleep(1000);
                        } catch (InterruptedException e) {
                            e.printStackTrace();
                        }
                    }
                }
            }.start();

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

Activity.xml文件:

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/activity_main"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.example.guocong.service.MainActivity"
    android:orientation="vertical"
    >

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Hello World!" />

    <Button
        android:text="启动Service服务"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/btnStartService" />
    <Button
        android:text="停止Service服务"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/btnStopService" />
LinearLayout>

可通过模拟器的setting/APP/Running目录查看后台正在运行程序；startActivity用于创建Service,stopService用于销毁Service。

补充一下：MainActivity文件中的Intent也可以这样写：

    private Intent intent;
     //初始化intent
   intent=new Intent(MainActivity.this,MyService.class);

        findViewById(R.id.btnStartService).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                startService(intent);
            }
        });

        findViewById(R.id.btnStopService).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                stopService(intent);
            }
        });