Question

Android上的服务的许多示例和教程都适用于bound services，但是如果我想创建一个未绑定的服务而不必处理绑定呢？

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Answer 1

要做的第一件事是将服务添加到<application>标记内的清单中：

<application ...>

    ...        

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

</application>

然后我们创建实际的服务类：

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();
    }

}

所有这些服务都会在运行时显示通知，并且可以在调用doSomething()方法时显示toasts。

正如您所注意到的那样，它被实现为singleton，跟踪自己的实例 - 但没有通常的静态单件工厂方法，因为服务是天生的单例并且是由意图创建的。该实例对外部有用，可以获得一个＆＃34;句柄＆＃34;在服务运行时服务。

最后，我们需要从活动开始和停止服务：

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，服务以相同的方法启动和停止，具体取决于它的当前状态。

我们也可以从我们的活动中调用doSomething()方法：

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

如何在Android中创建未绑定的服务？

1 个答案: