cleanup flash implementation

- fix issues with brightness control
- add separate classes for Android 5 and Android 6+ for simplicity
- properly cleanup camera in onDestory and also when stroboscope/flashlight mode are disabled

Author: KryptKode

app/src/main/kotlin/com/simplemobiletools/flashlight/activities/MainActivity.kt

@@ -9,7 +9,6 @@ import android.graphics.drawable.LayerDrawable
 import android.os.Bundle
 import android.view.WindowManager
 import android.widget.ImageView
-import androidx.core.view.isVisible
 import com.simplemobiletools.commons.extensions.*
 import com.simplemobiletools.commons.helpers.LICENSE_EVENT_BUS
 import com.simplemobiletools.commons.helpers.PERMISSION_CAMERA
@@ -183,7 +182,7 @@ class MainActivity : SimpleActivity() {
     private fun setupCameraImpl() {
         mCameraImpl = MyCameraImpl.newInstance(this, object : CameraTorchListener {
             override fun onTorchEnabled(isEnabled: Boolean) {
-                if (mCameraImpl?.supportsBrightnessControl() == true) {
+                if (mCameraImpl!!.supportsBrightnessControl()) {
                     brightness_bar.beVisibleIf(isEnabled)
                 }
             }

app/src/main/kotlin/com/simplemobiletools/flashlight/helpers/CameraFlash.kt

@@ -0,0 +1,12 @@
+package com.simplemobiletools.flashlight.helpers
+
+interface CameraFlash {
+    fun initialize()
+    fun toggleFlashlight(enable: Boolean)
+    fun changeTorchBrightness(level: Int) {}
+    fun getMaximumBrightnessLevel(): Int = DEFAULT_BRIGHTNESS_LEVEL
+    fun supportsBrightnessControl(): Boolean = false
+    fun getCurrentBrightnessLevel(): Int = DEFAULT_BRIGHTNESS_LEVEL
+    fun unregisterListeners(){}
+    fun release(){}
+}

app/src/main/kotlin/com/simplemobiletools/flashlight/helpers/LollipopCameraFlash.kt

@@ -0,0 +1,37 @@
+@file:Suppress("DEPRECATION")
+
+package com.simplemobiletools.flashlight.helpers
+
+import android.graphics.SurfaceTexture
+import android.hardware.Camera
+
+class LollipopCameraFlash : CameraFlash {
+    private var camera: Camera? = null
+    private var params: Camera.Parameters? = null
+
+    override fun toggleFlashlight(enable: Boolean) {
+        if (camera == null || params == null || camera!!.parameters == null) {
+            return
+        }
+        val flashMode = if (enable) Camera.Parameters.FLASH_MODE_ON else Camera.Parameters.FLASH_MODE_OFF
+        params!!.flashMode = flashMode
+        camera!!.parameters = params
+        if (enable) {
+            val dummy = SurfaceTexture(1)
+            camera!!.setPreviewTexture(dummy)
+            camera!!.startPreview()
+        }
+    }
+
+    override fun initialize() {
+        camera = Camera.open()
+        params = camera!!.parameters
+        params!!.flashMode = Camera.Parameters.FLASH_MODE_OFF
+        camera!!.parameters = params
+    }
+
+    override fun release() {
+        camera!!.release()
+        camera = null
+    }
+}

app/src/main/kotlin/com/simplemobiletools/flashlight/helpers/PostMarshmallowCamera.kt renamed to app/src/main/kotlin/com/simplemobiletools/flashlight/helpers/MarshmallowPlusCameraFlash.kt

@@ -13,10 +13,10 @@ import com.simplemobiletools.flashlight.models.Events
 import org.greenrobot.eventbus.EventBus
 
 @RequiresApi(Build.VERSION_CODES.M)
-internal class PostMarshmallowCamera(
+internal class MarshmallowPlusCameraFlash(
     private val context: Context,
-    private val cameraTorchListener: CameraTorchListener? = null,
-) {
+    private var cameraTorchListener: CameraTorchListener? = null,
+) : CameraFlash {
 
     private val manager = context.getSystemService(Context.CAMERA_SERVICE) as CameraManager
     private var cameraId: String? = null
@@ -35,12 +35,13 @@ internal class PostMarshmallowCamera(
         }
     }
 
-    fun toggleMarshmallowFlashlight(enable: Boolean) {
+    override fun toggleFlashlight(enable: Boolean) {
         try {
-            manager.setTorchMode(cameraId!!, enable)
-            if (enable) {
+            if (supportsBrightnessControl() && enable) {
                 val brightnessLevel = getCurrentBrightnessLevel()
                 changeTorchBrightness(brightnessLevel)
+            } else {
+                manager.setTorchMode(cameraId!!, enable)
             }
         } catch (e: Exception) {
             context.showErrorToast(e)
@@ -51,13 +52,13 @@ internal class PostMarshmallowCamera(
         }
     }
 
-    fun changeTorchBrightness(level: Int) {
+    override fun changeTorchBrightness(level: Int) {
         if (isTiramisuPlus()) {
             manager.turnOnTorchWithStrengthLevel(cameraId!!, level)
         }
     }
 
-    fun getMaximumBrightnessLevel(): Int {
+    override fun getMaximumBrightnessLevel(): Int {
         return if (isTiramisuPlus()) {
             val characteristics = manager.getCameraCharacteristics(cameraId!!)
             characteristics.get(CameraCharacteristics.FLASH_INFO_STRENGTH_MAXIMUM_LEVEL) ?: MIN_BRIGHTNESS_LEVEL
@@ -66,24 +67,28 @@ internal class PostMarshmallowCamera(
         }
     }
 
-    fun supportsBrightnessControl(): Boolean {
+    override fun supportsBrightnessControl(): Boolean {
         val maxBrightnessLevel = getMaximumBrightnessLevel()
         return maxBrightnessLevel > MIN_BRIGHTNESS_LEVEL
     }
 
-    fun getCurrentBrightnessLevel(): Int {
+    override fun getCurrentBrightnessLevel(): Int {
         var brightnessLevel = context.config.brightnessLevel
         if (brightnessLevel == DEFAULT_BRIGHTNESS_LEVEL) {
             brightnessLevel = getMaximumBrightnessLevel()
         }
         return brightnessLevel
     }
 
-    fun initialize() {
+    override fun initialize() {
         manager.registerTorchCallback(torchCallback, Handler(context.mainLooper))
     }
 
-    fun cleanUp() {
+    override fun unregisterListeners() {
         manager.unregisterTorchCallback(torchCallback)
     }
+
+    override fun release() {
+        cameraTorchListener = null
+    }
 }