altBeacon: didEnterRegion

I'm writing an Android App custom Class that utilises AltBeacon's Android-Beacon-Library. But when first start, If I'm in the beacon region, the didEnterRegion() won't work. I want to create an event right away. I can't find any other solution. Plz, Any help appreciated! This is my code ▼

beaconManager.addMonitorNotifier(new MonitorNotifier() {
            @Override
            public void didEnterRegion(Region region) {
                //Log.i(TAG, "I just saw an beacon for the first time!");
                sendData(dataStart);
                mHandler.post(new Runnable() {
                    @Override
                    public void run() {
                        tv_beacon_.setText("work");
                    }
                });
            }

            @Override
            public void didExitRegion(Region region) {
                //Log.i(TAG, "I no longer see an beacon");
                sendData(dataEnd);
                mHandler.post(new Runnable() {
                    @Override
                    public void run() {
                        tv_beacon_.setText("not work");
                    }
                });
            }

            @Override
            public void didDetermineStateForRegion(int state, Region region) {
                Log.i(TAG, "I have just switched from seeing/not seeing beacons: "+state);

            }