大气压变低时是否可以向用户发送通知？

Question

在我的应用中，我想在大气压力低于某个特定数字时向用户发送通知。

我知道我必须使用if语句，所以我已经尝试了几天。我尝试将if语句与TextView一起使用，这会获得大气压力，但是这种方法没有用……

public class MainActivity extends AppCompatActivity {


    private TextView txt;
    private SensorManager sensorManager;
    private Sensor pressureSensor;
    private SensorEventListener sensorEventListener = new SensorEventListener() {

        @Override
        public void onSensorChanged(SensorEvent sensorEvent) {
            float[] values = sensorEvent.values;
            txt.setText(String.format("%.3f mbar", values[0]));
        }

        @Override
        public void onAccuracyChanged(Sensor sensor, int i) {
        }
    };

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        txt = findViewById(R.id.barometric);

        //Here is the code I tried... But it is already underlined in red...
        if(barometric < 90.5){

        }

        sensorManager = (SensorManager) getSystemService(SENSOR_SERVICE);
        pressureSensor = sensorManager.getDefaultSensor(Sensor.TYPE_PRESSURE);

        FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.settings);
        fab.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                startActivity(new Intent(MainActivity.this, Main2Activity.class));
            }
        });
    }

    @Override
    protected void onResume() {
        super.onResume();
        sensorManager.registerListener(sensorEventListener, pressureSensor, SensorManager.SENSOR_DELAY_UI);
    }

    @Override
    protected void onPause() {
        super.onPause();
        sensorManager.unregisterListener(sensorEventListener);
    }
}