<!--
                 代表在应用程序里，当需要该service时，会自动创建新的进程。
                 android:process=":remote"

                 是否可以被系统实例化
                 android:enabled="true"

                 代表是否能被其他应用隐式调用
                 android:exported="true"
        -->
        <service android:name=".service.MyServie2"
                 android:process=":remote"
                 android:enabled="true"
                 android:exported="true">

            <intent-filter>

                <!-- 激活 MyService2 唯一name，不能重名-->
                <action android:name="liudeli.service2.service.MyService2" />

            </intent-filter>

        </service>

package liudeli.service2.service;

import android.app.Service;

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

import liudeli.service2.MainActivity;

public class MyServie2 extends Service {

    @Override
    public IBinder onBind(Intent intent) {
        serviceStartActivity();
        return null;
    }

    /**
     * 在Service启动Activity，需要配置：.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
     */
    private void serviceStartActivity() {
        Intent intent = new Intent(this, MainActivity.class);
        intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
        startActivity(intent);
    }
}

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.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"
    android:background="#fd00">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Service2 APP"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        android:textSize="30sp"
        android:textColor="@android:color/black"
        />

</android.support.constraint.ConstraintLayout>

package liudeli.service1;

import android.app.Activity;
import android.content.ComponentName;
import android.content.Intent;
import android.content.ServiceConnection;
import android.os.Bundle;
import android.os.IBinder;
import android.view.View;

public class StartRemoteActivity extends Activity {

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

    private boolean startRemoteServiceActivity;

    public void startRemoteServiceActivity(View view) {
        Intent intent = new Intent();
        intent.setAction("liudeli.service2.service.MyService2");
        // 注意：?? 5.0以后的版本，需要设置包名才能绑定远程服务
        intent.setPackage("liudeli.service2");
        bindService(intent, conn, BIND_AUTO_CREATE);

        startRemoteServiceActivity = true;
    }

    /**
     * 服务连接接口
     */
    private ServiceConnection  conn = new ServiceConnection() {
        @Override
        public void onServiceConnected(ComponentName name, IBinder service) {

        }

        @Override
        public void onServiceDisconnected(ComponentName name) {

        }
    };

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

        if (startRemoteServiceActivity) {

            // 解绑服务，一定要记得解绑服务，否则会报异常(服务连接资源异常)
            unbindService(conn);
        }
    }
}