<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    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"
    android:orientation="vertical"
    tools:context=".MainActivity">


    <EditText
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:id="@+id/etData"
        android:text="默认信息"
        />

    <Button
        android:id="@+id/btnStartService"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="启动服务" />

    <Button
        android:id="@+id/btnStopService"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="停止服务" />

</LinearLayout>

package com.imooc.connectservice;

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

public class MyService extends Service {
    private boolean running = false;
    private String data = "这是默认信息";

    public MyService() {
    }

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

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

        data = intent.getStringExtra("data");
        return super.onStartCommand(intent, flags, startId);


    }

    @Override
    public void onCreate() {
        super.onCreate();
        running = true;
        new Thread(){
            @Override
            public void run(){
                super.run();

                while (running){
                    System.out.println(data);
                    try {
                        sleep(1000);
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }

                }

            }
        }.start();
    }

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

        running = false;
    }
}

package com.imooc.connectservice;

import androidx.appcompat.app.AppCompatActivity;

import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.EditText;

public class MainActivity extends AppCompatActivity implements View.OnClickListener {

    private EditText etData;


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

        etData = (EditText) findViewById(R.id.etData);

        findViewById(R.id.btnStartService).setOnClickListener(this);
        findViewById(R.id.btnStopService).setOnClickListener(this);

    }

    @Override
    public void onClick(View v) {
        switch (v.getId()){
            case R.id.btnStartService:
                Intent i = new Intent(this,MyService.class);
                i.putExtra("data",etData.getText().toString());
                startService(i);
                break;
            case R.id.btnStopService:
                stopService(new Intent(this,MyService.class));

        }
    }
}