Question

我想实现一个BroadcastReceiver来监听联系人是否已被删除/更新。我读到了ContantObserver，但我不知道如何在应用程序背景中运行它，例如BroadcastReceiver。

我该如何实现？有没有办法在应用程序的后台运行ContantObserver。

我关注this FAQ.

Answer 1

实施广播接收器并使用onChange ContentObserver方法发送广播以定位此接收器..请参阅this以了解使用自定义意图和广播IP>

Answer 2

启动服务并将ContentObserver注册到此服务器

以下是我所做的示例代码，它将侦听Contacts.CONTENT_URI中的任何更改并通知用户

这是服务

public class ContactObserverService extends Service implements ContactObserver.OnUpdate {
private ContactObserver contactObserver ;

public ContactObserverService() {
}

@Override
public void onCreate(){
    super.onCreate();
    contactObserver = new ContactObserver(this);
    Toast.makeText(this,"Service Started",Toast.LENGTH_SHORT).show();
    this.getContentResolver().registerContentObserver(ContactsContract.Contacts.CONTENT_URI,false,contactObserver);
}

@Override
public void onDestroy() {
    if( contactObserver !=null  )
    {
        this.getContentResolver().unregisterContentObserver(contactObserver);
    }
    super.onDestroy();
}

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

@Override
public int onStartCommand(Intent intent, int flags, int startId) {
    // The service is starting, due to a call to startService()
    return START_STICKY;
}

@Override
public void onUpdate(Uri uri) {
    NotificationCompat.Builder builder = (NotificationCompat.Builder) new NotificationCompat.Builder(this)
            .setContentTitle("Contact Update Notifier")
            .setContentText(uri.getQuery())
            .setSmallIcon(R.drawable.images);
    NotificationManager manager = (NotificationManager)getSystemService(NOTIFICATION_SERVICE);
    manager.notify(1,builder.build());
}
}

ContentObserver类是

public class ContactObserver extends ContentObserver {
private OnUpdate onUpdate;

public interface OnUpdate{
    void onUpdate(Uri uri);
}
public ContactObserver(OnUpdate onUpdate) {
    super(new Handler());
    this.onUpdate = onUpdate;
}

@Override
public void onChange(boolean selfChange) {
    this.onChange(selfChange, null);
}
@Override
public void onChange(boolean selfChange, Uri uri) {
    // this is NOT UI thread, this is a BACKGROUND thread
    uri.getQueryParameterNames();
    onUpdate.onUpdate(uri);
}
}

如何接收联系人更改：Android

2 个答案: