Android SensorManager registerListener - not possible to set custom interval of sensor events - android-sensors

Question

I wanted to set an individual interval of sensor events beside:
the given delays: "SENSOR_DELAY_NORMAL, SENSOR_DELAY_U, SENSOR_DELAY_GAME, ENSOR_DELAY_FASTEST".
But non of the "registerListener" methodes seems to support an individual value:
Looking into the implementation of the SensorManager class shows:
public boolean registerListener(SensorEventListener listener, Sensor sensor, int rateUs,
int maxBatchReportLatencyUs) {
int delay = getDelay(rateUs);
return registerListenerImpl(listener, sensor, delay, null,maxBatchReportLatencyUs, 0);
}
private static int getDelay(int rate) {
int delay = -1;
switch (rate) {
case SENSOR_DELAY_FASTEST:
delay = 0;
break;
case SENSOR_DELAY_GAME:
delay = 20000;
break;
case SENSOR_DELAY_UI:
delay = 66667;
break;
case SENSOR_DELAY_NORMAL:
delay = 200000;
break;
default:
delay = rate;
break;
}
return delay;
}
Is there realy no way to set an individual value for the sensor event interval?

Answer 1

SENSOR_DELAY_NORMAL, SENSOR_DELAY_UI, etc are all simply integers, as shown in your code. Saying you want SENSOR_DELAY_UI is the same as telling the sensor manager to use an interval of 66667 microseconds. However, per the docs, you can simply input your own interval in that field:
The desired delay between two consecutive events in microseconds. This is only a hint to the system. Events may be received faster or slower than the specified rate. Usually events are received faster. Can be one of SENSOR_DELAY_NORMAL, SENSOR_DELAY_UI, SENSOR_DELAY_GAME, SENSOR_DELAY_FASTEST or the delay in microseconds.
However, it's important to note the other part of that quote:
...The desired delay between two consecutive events in microseconds. This is only a hint to the system....
At the end of the day, it's just a suggestion and the Android system doesn't seem to be too good about respecting your request. If you really care about the interval I would suggest adding a method in your callback that checks the time delta between now and the last time you recorded a sensor value and then only recording it if its been sufficiently long.
Source: Android Link

Answer 2

You can simply use a Timer and a boolean flag to handle this problem:
imagine you want to check sensor event values every 1 seconds(for example):
boolean mustReadSensor;
Timer timer = new Timer();
timer.scheduleAtFixedRate(new TimerTask() {
#Override
public void run() {
mustReadSensor = true;
}
}, 0, 1000); // 1000 ms delay
and here is onSensorChanged:
#Override
public void onSensorChanged(SensorEvent event) {
if (!mustReadSensor) {
return;
}
mustReadSensor = false;
//handle sensor values here
}