Android服务的一个最小示例

1. 新建项目，一切默认。
2. 新建一个Service，此处取名为Accelerometer。写入内容如下：

package com.rokid.accelerometerservice;

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


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

    public final String TAG = "fyg";

    @Override
    public void onCreate() {
        super.onCreate();
        Log.d(TAG, "onCreate: Service Created");
    }

    @Override
    public int onStartCommand(Intent intent, int flags, int startId) {
        Log.d(TAG, "onStartCommand: Service Started");
        return super.onStartCommand(intent, flags, startId);
    }

    @Override
    public void onDestroy() {
        Log.d(TAG, "onDestroy: Service Destroyed");
        super.onDestroy();
    }

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

3. MainActivity.java的内容修改如下：

package com.rokid.accelerometerservice;

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

public class MainActivity extends AppCompatActivity implements View.OnClickListener{

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

        Button startService = (Button) findViewById(R.id.btnStartService);
        Button stopService = (Button) findViewById(R.id.btnStopService);

        startService.setOnClickListener(this);
        stopService.setOnClickListener(this);
    }

    @Override
    public void onClick(View view) {
        switch (view.getId()) {
            case R.id.btnStartService:
                Intent startIntent = new Intent(this, Accelerometer.class);
                startService(startIntent);
                break;

            case R.id.btnStopService:
                Intent stopIntent = new Intent(this, Accelerometer.class);
                stopService(stopIntent);
                break;

            default:
                break;

        }
    }
}

4. res/layout/activity_main.xml内容如下：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    tools:context="com.rokid.accelerometerservice.MainActivity">

    <Button
        android:id="@+id/btnStartService"
        android:text="Start Service"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" />

    <Button
        android:id="@+id/btnStopService"
        android:text="Stop Service"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" />

</LinearLayout>

5. 检查一下AndroidManifest.xml的内容：

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.rokid.accelerometerservice">

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>

        <service
            android:name=".Accelerometer"
            android:enabled="true"
            android:exported="true">

        </service>
    </application>

</manifest>

screenshot

6. 运行后，点击按钮，在AS上的日志窗口查看日志输出。

onCreate: Service Created
onStartCommand: Service Started
onDestroy: Service Destroyed

测试通过。