Example code for handling sensor data on Android
In this Android example we'll try to cover sensor management and all things we believe you need to know to do so properly. Think of opening sensors for reading but also closing them when done. Once opened how to handle the data, like smoothing with moving average, triggering stuff on tresholds and more. And sure we'll have to do some of these tasks in de background so we'll also have to make sure we don't drain the battery too much.
I'll try to make it usefull also. This will probably turn into a highly configurable app that can trigger stuff (like wake your device) one certain tresholds. That "wake your device" goal is something I personally need and didn't find a good working alternative for. If possible I'll see if the app can do more than waking up.
Some of the fragments in this example app with information on what they do.
This fragment gives you a list for all sensors that were found on this device. See code for details on how to retrieve this list. This is where to start, use the sensorManager to get a listing and go from there.
For a given sensor display data by listening on data changes. This shows how to open a sensor for listening for data changes but also how to close it properly when done.
A background service using the command pattern (not the binder) to run in the background checking for sensor values. To safe battery the service reads only one sensor value and then unregisters itself. The Alarmmanager is used for scheduling the sensor reading interval.
If the sensor value is below a given treshold it will wake up the screen.
To wake up the screen:
PowerManager pm = (PowerManager) getApplicationContext().getSystemService(Context.POWER_SERVICE);
WakeLock wakeLock = pm.newWakeLock((PowerManager.SCREEN_BRIGHT_WAKE_LOCK | PowerManager.FULL_WAKE_LOCK | PowerManager.ACQUIRE_CAUSES_WAKEUP), "TAG");
wakeLock.acquire();To release the screen lock:
KeyguardManager keyguardManager = (KeyguardManager) getApplicationContext().getSystemService(Context.KEYGUARD_SERVICE);
KeyguardLock keyguardLock = keyguardManager.newKeyguardLock("TAG");
keyguardLock.disableKeyguard();And the manifest needs to contain:
< uses-permission android:name="android.permission.WAKE_LOCK" />
< uses-permission android:name="android.permission.DISABLE_KEYGUARD" />