fix deprecated getter use; fix leaking of display listener instances

@@ -26,6 +26,7 @@ import android.util.Size
 import android.hardware.display.DisplayManager
 import android.view.WindowManager
 import android.content.Context
+import android.os.Build
 
 
 class MobileScanner(
@@ -43,6 +44,7 @@ class MobileScanner(
     private var scanner = BarcodeScanning.getClient()
     private var lastScanned: List<String?>? = null
     private var scannerTimeout = false
+    private var displayListener: MobileScannerDisplayListener? = null
 
     /// Configurable variables
     var scanWindow: List<Float>? = null
@@ -171,11 +173,22 @@ class MobileScanner(
     }
 
     // Return the best resolution for the actual device orientation.
-    // By default camera set its resolution to width 480 and height 640 which is too low for ML KIT.
-    // If we return an higher resolution than device can handle, camera package take the most relevant one available.
-    // Resolution set must take care of device orientation to preserve aspect ratio.
-    private fun getResolution(windowManager: WindowManager, cameraResolution: Size): Size {
-        val rotation = windowManager.defaultDisplay.rotation
+    //
+    // By default the resolution is 480x640, which is too low for ML Kit.
+    // If the given resolution is not supported by the display,
+    // the closest available resolution is used.
+    //
+    // The resolution should be adjusted for the display rotation, to preserve the aspect ratio.
+    @Suppress("deprecation")
+    private fun getResolution(cameraResolution: Size): Size {
+        val rotation = if (Build.VERSION.SDK_INT >= 30) {
+            activity.applicationContext.display!!.rotation
+        } else {
+            val windowManager = activity.applicationContext.getSystemService(Context.WINDOW_SERVICE) as WindowManager
+
+            windowManager.defaultDisplay.rotation
+        }
+
         val widthMaxRes = cameraResolution.width
         val heightMaxRes = cameraResolution.height
 
@@ -187,7 +200,6 @@ class MobileScanner(
         return targetResolution
     }
 
-
     /**
      * Start barcode scanning by initializing the camera and barcode scanner.
      */
@@ -253,19 +265,21 @@ class MobileScanner(
             val analysisBuilder = ImageAnalysis.Builder()
                 .setBackpressureStrategy(ImageAnalysis.STRATEGY_KEEP_ONLY_LATEST)
             val displayManager = activity.applicationContext.getSystemService(Context.DISPLAY_SERVICE) as DisplayManager
-            val windowManager = activity.applicationContext.getSystemService(Context.WINDOW_SERVICE) as WindowManager
 
             if (cameraResolution != null) {
+                // TODO: migrate to ResolutionSelector with ResolutionStrategy when upgrading to camera 1.3.0
                 // Override initial resolution
-                analysisBuilder.setTargetResolution(getResolution(windowManager, cameraResolution))
-                // Listen future orientation change to apply the custom resolution
-                displayManager.registerDisplayListener(object : DisplayManager.DisplayListener {
-                    override fun onDisplayAdded(displayId: Int) {}
-                    override fun onDisplayRemoved(displayId: Int) {}
-                    override fun onDisplayChanged(displayId: Int) {
-                        analysisBuilder.setTargetResolution(getResolution(windowManager, cameraResolution))
+                analysisBuilder.setTargetResolution(getResolution(cameraResolution))
+
+                if (displayListener == null) {
+                    displayListener = MobileScannerDisplayListener {
+                        analysisBuilder.setTargetResolution(getResolution(cameraResolution))
                     }
-                }, null)
+
+                    displayManager.registerDisplayListener(
+                        displayListener, null,
+                    )
+                }
             }
 
             val analysis = analysisBuilder.build().apply { setAnalyzer(executor, captureOutput) }
@@ -316,6 +330,13 @@ class MobileScanner(
             throw AlreadyStopped()
         }
 
+        if (displayListener != null) {
+            val displayManager = activity.applicationContext.getSystemService(Context.DISPLAY_SERVICE) as DisplayManager
+
+            displayManager.unregisterDisplayListener(displayListener)
+            displayListener = null
+        }
+
         val owner = activity as LifecycleOwner
         camera?.cameraInfo?.torchState?.removeObservers(owner)
         cameraProvider?.unbindAll()