Android 服务的使用示例

MyService.java 的代码如下：

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

public class MyService extends Service {

    private static final String TAG = "MyService";

    private InfoBinder mBinder = new InfoBinder();

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

    class InfoBinder extends Binder {
        public void start() {
            Log.d(TAG, "start entered");
        }

        public int getCurrentInfo() {
            Log.d(TAG, "getCurrentInfo entered");
            return 0;
        }
    }

    @Override
    public void onCreate() {
        super.onCreate();
        Log.d(TAG, "onCreate entered");

        Intent intent = new Intent(this, MainActivity.class);
        PendingIntent pendingIntent = PendingIntent.getActivity(this, 0,
                intent, 0);

        Notification notification = new Notification.Builder(this)
                .setContentTitle("This is title")
                .setContentText("This is content")
                .setAutoCancel(false)
                .setOngoing(true)
                .setTicker("This is content")
                .setContentIntent(pendingIntent)
                .build();

        startForeground(1, notification);
    }

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

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

MyIntentService.java 的代码如下：

import android.app.IntentService;
import android.content.Intent;
import android.util.Log;

public class MyIntentService extends IntentService {

    private static final String TAG = "MyIntentService";

    public MyIntentService() {
        super("MyIntentService");
    }

    @Override
    protected void onHandleIntent(Intent intent) {
        Log.d(TAG, "onHandleIntent entered thread id is " + Thread.currentThread().getId());
    }

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

测试用的文件MainActivity.java的代码如下：

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.util.Log;
import android.view.KeyEvent;
import android.view.View;

public class MainActivity extends Activity {

    private static final String TAG = "MainActivity";

    private MyService.InfoBinder infoBinder;

    private ServiceConnection connection = new ServiceConnection() {
        @Override
        public void onServiceConnected(ComponentName componentName, IBinder iBinder) {
            infoBinder = (MyService.InfoBinder) iBinder;
            infoBinder.start();
            infoBinder.getCurrentInfo();
        }

        @Override
        public void onServiceDisconnected(ComponentName componentName) {

        }
    };

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

    @Override
    public boolean onKeyUp(int keyCode, KeyEvent event) {
        if (keyCode == KeyEvent.KEYCODE_BACK) {
            moveTaskToBack(true);
        }
        return super.onKeyUp(keyCode, event);
    }

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

    public void startService(View view) {
        Intent intent = new Intent(this, MyService.class);
        startService(intent);
    }

    public void stopService(View view) {
        Intent intent = new Intent(this, MyService.class);
        stopService(intent);
    }

    public void bindService(View view) {
        Intent intent = new Intent(this, MyService.class);
        bindService(intent, connection, BIND_AUTO_CREATE);
    }

    public void unbindService(View view) {
        unbindService(connection);
    }

    public void startIntentService(View view) {
        Log.d(TAG, "UI thread id is " + Thread.currentThread().getId());
        Intent intent = new Intent(this, MyIntentService.class);
        startService(intent);
    }
}

主布局文件 activity_main.xml 的代码如下：

<?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"
    tools:context=".MainActivity"
    android:orientation="vertical"
    >

    <Button
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="@string/start_service"
        android:onClick="startService"
        />

    <Button
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="@string/stop_service"
        android:onClick="stopService"
        />

    <Button
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="@string/bind_service"
        android:onClick="bindService"
        />

    <Button
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="@string/unbind_service"
        android:onClick="unbindService"
        />

    <Button
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="@string/start_intent_service"
        android:onClick="startIntentService"
        />

</LinearLayout>

本示例中使用的字符串内容 string.xml 的代码如下：

<resources>
    <string name="start_service">Start Service</string>
    <string name="stop_service">Stop Service</string>
    <string name="bind_service">Bind Service</string>
    <string name="unbind_service">Unbind Service</string>
    <string name="start_intent_service">Start Intent Service</string>
</resources>

另外需要在 AndroidManifest.xml 中加入两个 Service 的相关内容：

        <service android:name=".MyService" />
        <service android:name=".MyIntentService" />

本文参考自 《Android 第一行代码》