如何使用NotificationListenerService android获取Whatsapp的联系方式？

public class MyNotificationListenerService extends NotificationListenerService {
    // 实现相关方法
}

@Override
public void onNotificationPosted(StatusBarNotification sbn) {
    if (sbn.getPackageName().equals("com.whatsapp")) {
        // 获取WhatsApp通知的联系方式
        String contact = sbn.getNotification().extras.getString(Notification.EXTRA_TITLE);
        // 处理联系方式
        // ...
    }
}

<service
    android:name=".MyNotificationListenerService"
    android:label="Notification Listener"
    android:permission="android.permission.BIND_NOTIFICATION_LISTENER_SERVICE">
    <intent-filter>
        <action android:name="android.service.notification.NotificationListenerService" />
    </intent-filter>
</service>

public class MainActivity extends AppCompatActivity {
    private static final int REQUEST_CODE = 123;

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

        // 请求用户授权
        if (!isNotificationServiceEnabled()) {
            Intent intent = new Intent("android.settings.ACTION_NOTIFICATION_LISTENER_SETTINGS");
            startActivityForResult(intent, REQUEST_CODE);
        }
    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        if (requestCode == REQUEST_CODE) {
            if (isNotificationServiceEnabled()) {
                // 用户已授权
                // 启动NotificationListenerService
                startService(new Intent(this, MyNotificationListenerService.class));
            } else {
                // 用户未授权
                // 提示用户授权
            }
        }
    }

    private boolean isNotificationServiceEnabled() {
        String packageName = getPackageName();
        String flat = Settings.Secure.getString(getContentResolver(), "enabled_notification_listeners");
        if (flat != null) {
            return flat.contains(packageName);
        }
        return false;
    }
}