turn off the Dialer screen if device is put to the ear

app/src/main/AndroidManifest.xml

@@ -14,6 +14,7 @@
     <uses-permission android:name="android.permission.READ_SYNC_SETTINGS"/>
     <uses-permission android:name="android.permission.READ_CALL_LOG"/>
     <uses-permission android:name="android.permission.WRITE_CALL_LOG"/>
+    <uses-permission android:name="android.permission.WAKE_LOCK"/>
 
     <uses-feature
         android:name="android.hardware.telephony"

app/src/main/kotlin/com/simplemobiletools/contacts/pro/activities/DialerActivity.kt

@@ -1,8 +1,14 @@
 package com.simplemobiletools.contacts.pro.activities
 
+import android.content.Context
 import android.content.Intent
+import android.hardware.Sensor
+import android.hardware.SensorEvent
+import android.hardware.SensorEventListener
+import android.hardware.SensorManager
 import android.net.Uri
 import android.os.Bundle
+import android.os.PowerManager
 import com.simplemobiletools.commons.extensions.beGone
 import com.simplemobiletools.commons.extensions.updateTextColors
 import com.simplemobiletools.contacts.pro.R
@@ -10,12 +16,18 @@ import com.simplemobiletools.contacts.pro.helpers.ContactsHelper
 import com.simplemobiletools.contacts.pro.models.Contact
 import kotlinx.android.synthetic.main.activity_dialer.*
 
-class DialerActivity : SimpleActivity() {
+class DialerActivity : SimpleActivity(), SensorEventListener {
+    private val SENSOR_SENSITIVITY = 4
     private var number = ""
+    private var sensorManager: SensorManager? = null
+    private var proximity: Sensor? = null
+    private var proximityWakeLock: PowerManager.WakeLock? = null
 
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
         setContentView(R.layout.activity_dialer)
+        dialer_hangup_button.setOnClickListener { finish() }
+        initProximityWakeLock()
 
         if (intent.action == Intent.ACTION_CALL && intent.data != null && intent.dataString?.contains("tel:") == true) {
             number = Uri.decode(intent.dataString).substringAfter("tel:")
@@ -25,13 +37,28 @@ class DialerActivity : SimpleActivity() {
                 }
             }
         }
-
-        dialer_hangup_button.setOnClickListener { finish() }
     }
 
     override fun onResume() {
         super.onResume()
         updateTextColors(dialer_holder)
+        sensorManager!!.registerListener(this, proximity!!, SensorManager.SENSOR_DELAY_NORMAL)
+    }
+
+    override fun onPause() {
+        super.onPause()
+        sensorManager!!.unregisterListener(this)
+    }
+
+    private fun initProximityWakeLock() {
+        sensorManager = getSystemService(Context.SENSOR_SERVICE) as SensorManager
+        proximity = sensorManager!!.getDefaultSensor(Sensor.TYPE_PROXIMITY)
+        val powerManager = getSystemService(Context.POWER_SERVICE) as PowerManager
+        proximityWakeLock = if (powerManager.isWakeLockLevelSupported(PowerManager.PROXIMITY_SCREEN_OFF_WAKE_LOCK)) {
+            powerManager.newWakeLock(PowerManager.PROXIMITY_SCREEN_OFF_WAKE_LOCK, "SimpleContacts:ProximityWakeLock")
+        } else {
+            null
+        }
     }
 
     private fun updateCallee(contact: Contact?) {
@@ -43,4 +70,28 @@ class DialerActivity : SimpleActivity() {
             callee_number.beGone()
         }
     }
+
+    override fun onAccuracyChanged(sensor: Sensor?, accuracy: Int) {}
+
+    override fun onSensorChanged(event: SensorEvent) {
+        if (event.sensor.type == Sensor.TYPE_PROXIMITY) {
+            if (event.values[0] >= -SENSOR_SENSITIVITY && event.values[0] <= SENSOR_SENSITIVITY) {
+                turnOffScreen()
+            } else {
+                turnOnScreen()
+            }
+        }
+    }
+
+    private fun turnOffScreen() {
+        if (proximityWakeLock?.isHeld == false) {
+            proximityWakeLock!!.acquire()
+        }
+    }
+
+    private fun turnOnScreen() {
+        if (proximityWakeLock?.isHeld == true) {
+            proximityWakeLock!!.release(PowerManager.RELEASE_FLAG_WAIT_FOR_NO_PROXIMITY)
+        }
+    }
 }