onSensorChanged() is not called

Question

I'm having a lot of trouble tonight with sensors, but it appear it is because of onSensorChanged() is not called. Sorry for the eventual duplicate question, but I didn't see any solutions. Here's my code :

public SensorManager manager;
public Sensor rotation_vector;
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    manager = (SensorManager)getSystemService(SENSOR_SERVICE);
    rotation_vector = manager.getDefaultSensor(Sensor.TYPE_ROTATION_VECTOR);
}

@Override
public void onSensorChanged(SensorEvent event) {
    int xValue = (int) event.values[0];
    int yValue = (int) event.values[1];
    int zValue = (int) event.values[2];
   Toast.makeText(getApplicationContext(),"this doesn't appear...",Toast.LENGTH_LONG);


@Override
public void onAccuracyChanged(Sensor sensor, int accuracy) {
    //TODO: we'll see later about it
}
public void onPause() {
        /*Et on le dés-enregistre quand on sort de l'activité, pour économiser de la batterie*/
        super.onPause();
        manager.unregisterListener(this);
}
@Override
    protected void onResume() {
        /*On enregistre le sensor quand l'utilisateur revient sur l'activité*/
        super.onResume();
        manager.registerListener(this, rotation_vector, SensorManager.SENSOR_DELAY_NORMAL);
        if (null != rotation_vector) {
        } else {
            Toast.makeText(getApplicationContext(),
                    "There is no gyroscope on your device",
                Toast.LENGTH_LONG).show();
        }
    }

I have seen a lot of similar code on different forums, but appart from there and some others topic without solutions, I haven't seen such a problem yet... Do I have to add something in AndroidManifest ? Is it a common problem ? It there a solution ?

Thanks, Thomas (sorry for my bad english, I'm French^^)

VizGhar · Accepted Answer · 2015-01-27T17:05:09.277

10

I was not working with Sensors so far, but it looks like you have obtained SensorManager but did not register any listener for changes that should occur. Just ask yourself how could be onSensorChanged called?

Have a look at the sample on official android tutorial site about sensors and you could see this in onResume() method:

@Override
protected void onResume() {
    super.onResume();
    mSensorManager.registerListener(this, mLight, SensorManager.SENSOR_DELAY_NORMAL);
}

Also don't forget to study whole page it can help you a lot.

Edit:

I had to copy paste your sources because I haven't seen any problem. There are 2 basicaly:

Toast is not appearing because you haven't told him to... Toast.show() will display it. But you rather use Log to output changes into console. It's up to you
Do not retype float into int in onSensorChanged() method because all values are 0 or (1/-1 if you are lucky)

So result is following:

@Override
public void onSensorChanged(SensorEvent event) {
    float xValue = event.values[0];
    float yValue = event.values[1];
    float zValue = event.values[2];
    Log.d(LOG_TAG, "x:"+xValue +";y:"+yValue+";z:"+zValue);
}

other methods are correct

edited Jan 27 '15 at 17:05

answered Jan 26 '15 at 22:31

VizGhar

3,036
1
25
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Well, I forgot that part of my code, it was at the bottom... It doesn't solve the problem – Thomas Jan 27 '15 at 08:37
Please update your question then, I'm pretty sure it have to work... Also try non null checks. If it is not working I'll take a deeper look later – VizGhar Jan 27 '15 at 09:59
Done ! What do you call by "non null checks " ? – Thomas Jan 27 '15 at 15:46
I meant exactly those which mentioned @hoan-nguyen in other answer – VizGhar Jan 27 '15 at 17:06
How do I do that ? Sorry I'm new :x – Thomas Jan 29 '15 at 13:21
Click on grey Checkmark next to my answer right below number indicating "likes" – VizGhar Jan 29 '15 at 16:23

score 0 · Answer 2 · answered Jan 27 '15 at 15:39

0

Your device probably does not have Sensor.TYPE_ROTATION_VECTOR. You should check rotation_vector for null.

answered Jan 27 '15 at 15:39

Hoan Nguyen

18,033
3
50
54

I used an app listing every sensor on the device and displaying their data. And the rotation vector sensor worked well – Thomas Jan 27 '15 at 15:47
Register for TYPE_GYROSCOPE also and see if TYPE_ROTATION_VECTOR is now called. – Hoan Nguyen Jan 27 '15 at 16:00

onSensorChanged() is not called

2 Answers2