如何在 Android 中创建未绑定服务？

Question

Android 上的许多服务示例和教程都是针对 bound services 的，但是如果我想创建一个未绑定的服务并且根本不必处理绑定怎么办？

潜在反对者请注意

请在投反对票前仔细阅读 answering your own questions is a good thing 的原因。

Answer 1

首先要做的是将服务添加到您的清单中，在 <application> 标签内：

<application ...>

    ...        

    <service
        android:name=".RecordingService"
        android:exported="false">

</application>

然后我们创建实际的服务class:

public class RecordingService extends Service {
    private int NOTIFICATION = 1; // Unique identifier for our notification

    public static boolean isRunning = false;
    public static RecordingService instance = null;


    private NotificationManager notificationManager = null;


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

    @Override
    public void onCreate(){
        instance = this;
        isRunning = true;

        notificationManager = (NotificationManager) getSystemService(NOTIFICATION_SERVICE);

        super.onCreate();
    }

    @Override
    public int onStartCommand(Intent intent, int flags, int startId){
        // The PendingIntent to launch our activity if the user selects this notification
        PendingIntent contentIntent = PendingIntent.getActivity(this, 0, new Intent(this, MainActivity.class), 0);

        // Set the info for the views that show in the notification panel.
        Notification notification = new NotificationCompat.Builder(this)
                .setSmallIcon(R.mipmap.ic_launcher)        // the status icon
                .setTicker("Service running...")           // the status text
                .setWhen(System.currentTimeMillis())       // the time stamp
                .setContentTitle("My App")                 // the label of the entry
                .setContentText("Service running...")      // the content of the entry
                .setContentIntent(contentIntent)           // the intent to send when the entry is clicked
                .setOngoing(true)                          // make persistent (disable swipe-away)
                .build();

        // Start service in foreground mode
        startForeground(NOTIFICATION, notification);

        return START_STICKY;
    }


    @Override
    public void onDestroy(){
        isRunning = false;
        instance = null;

        notificationManager.cancel(NOTIFICATION); // Remove notification

        super.onDestroy();
    }


    public void doSomething(){
        Toast.makeText(getApplicationContext(), "Doing stuff from service...", Toast.LENGTH_SHORT).show();
    }

}

此服务所做的只是在运行时显示通知，并且在调用其 doSomething() 方法时可以显示 toasts。

如您所见，它是作为 singleton 实现的，跟踪它自己的实例 - 但没有通常的静态单例工厂方法，因为服务自然是单例并且是由意图创建的。当它是运行.

时，该实例对于外部获取服务的 "handle" 很有用

最后，我们需要从 activity:

启动和停止服务

public void startOrStopService(){
    if( RecordingService.isRunning ){
        // Stop service
        Intent intent = new Intent(this, RecordingService.class);
        stopService(intent);
    }
    else {
        // Start service
        Intent intent = new Intent(this, RecordingService.class);
        startService(intent);
    }
}

在此示例中，服务根据其当前状态通过相同的方法启动和停止。

我们还可以从 activity:

中调用 doSomething() 方法

public void makeServiceDoSomething(){
    if( RecordingService.isRunning )
        RecordingService.instance.doSomething();
}

如何在 Android 中创建未绑定服务？

How do I create an unbound service in Android?

android

android-service

android-service-binding