do not store mCurrCameraId in the activity

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

@@ -44,7 +44,6 @@ class MainActivity : SimpleActivity(), PreviewListener, PhotoProcessor.MediaSave
     private var mIsVideoCaptureIntent = false
     private var mIsHardwareShutterHandled = false
     private var mCurrVideoRecTimer = 0
-    private var mCurrCameraId = 0
     var mLastHandledOrientation = 0
 
     override fun onCreate(savedInstanceState: Bundle?) {
@@ -115,7 +114,6 @@ class MainActivity : SimpleActivity(), PreviewListener, PhotoProcessor.MediaSave
         mIsVideoCaptureIntent = false
         mIsHardwareShutterHandled = false
         mCurrVideoRecTimer = 0
-        mCurrCameraId = 0
         mLastHandledOrientation = 0
         mCameraImpl = getMyCamera()
 
@@ -191,10 +189,9 @@ class MainActivity : SimpleActivity(), PreviewListener, PhotoProcessor.MediaSave
 
         (btn_holder.layoutParams as RelativeLayout.LayoutParams).setMargins(0, 0, 0, (navBarHeight + resources.getDimension(R.dimen.activity_margin)).toInt())
 
-        mCurrCameraId = config.lastUsedCamera
         mPreview = PreviewCameraOne(this, camera_surface_view, this)
         view_holder.addView(mPreview)
-        toggle_camera.setImageResource(if (mCurrCameraId == mCameraImpl.getBackCameraId()) R.drawable.ic_camera_front else R.drawable.ic_camera_rear)
+        toggle_camera.setImageResource(if (config.lastUsedCamera == mCameraImpl.getBackCameraId()) R.drawable.ic_camera_front else R.drawable.ic_camera_rear)
 
         mFocusCircleView = FocusCircleView(applicationContext)
         view_holder.addView(mFocusCircleView)
@@ -221,25 +218,7 @@ class MainActivity : SimpleActivity(), PreviewListener, PhotoProcessor.MediaSave
             return
         }
 
-        mCurrCameraId = if (mCurrCameraId == mCameraImpl.getBackCameraId()) {
+        mPreview!!.toggleCamera()
-            mCameraImpl.getFrontCameraId()
-        } else {
-            mCameraImpl.getBackCameraId()
-        }
-
-        config.lastUsedCamera = mCurrCameraId
-        var newIconId = R.drawable.ic_camera_front
-        mPreview?.releaseCamera()
-        if (mPreview?.setCamera(mCurrCameraId) == true) {
-            if (mCurrCameraId == mCameraImpl.getFrontCameraId()) {
-                newIconId = R.drawable.ic_camera_rear
-            }
-            toggle_camera.setImageResource(newIconId)
-            mPreview?.setFlashlightState(FLASH_OFF)
-            hideTimer()
-        } else {
-            toast(R.string.camera_switch_error)
-        }
     }
 
     private fun showLastMediaPreview() {
@@ -259,7 +238,7 @@ class MainActivity : SimpleActivity(), PreviewListener, PhotoProcessor.MediaSave
 
     fun updateFlashlightState(state: Int) {
         config.flashlightState = state
-        val flashDrawable =  when (state) {
+        val flashDrawable = when (state) {
             FLASH_OFF -> R.drawable.ic_flash_off
             FLASH_ON -> R.drawable.ic_flash_on
             else -> R.drawable.ic_flash_auto
@@ -267,6 +246,10 @@ class MainActivity : SimpleActivity(), PreviewListener, PhotoProcessor.MediaSave
         toggle_flash.setImageResource(flashDrawable)
     }
 
+    fun updateCameraIcon(showFront: Boolean) {
+        toggle_camera.setImageResource(if (showFront) R.drawable.ic_camera_front else R.drawable.ic_camera_rear)
+    }
+
     private fun shutterPressed() {
         if (checkCameraAvailable()) {
             handleShutter()
@@ -428,7 +411,7 @@ class MainActivity : SimpleActivity(), PreviewListener, PhotoProcessor.MediaSave
         window.decorView.systemUiVisibility = View.SYSTEM_UI_FLAG_LOW_PROFILE
     }
 
-    private fun hideTimer() {
+    fun hideTimer() {
         video_rec_curr_timer.text = 0.getFormattedDuration()
         video_rec_curr_timer.beGone()
         mCurrVideoRecTimer = 0
@@ -451,7 +434,7 @@ class MainActivity : SimpleActivity(), PreviewListener, PhotoProcessor.MediaSave
 
     private fun resumeCameraItems() {
         showToggleCameraIfNeeded()
-        if (mPreview?.setCamera(mCurrCameraId) == true) {
+        if (mPreview?.setCamera() == true) {
             hideNavigationBarIcons()
             mPreview?.checkFlashlight()
 

app/src/main/kotlin/com/simplemobiletools/camera/views/PreviewCameraOne.kt

@@ -1,6 +1,7 @@
 package com.simplemobiletools.camera.views
 
 import android.annotation.SuppressLint
+import android.annotation.TargetApi
 import android.app.Activity
 import android.content.Context
 import android.graphics.Point
@@ -20,7 +21,9 @@ import com.simplemobiletools.camera.activities.MainActivity
 import com.simplemobiletools.camera.dialogs.ChangeResolutionDialog
 import com.simplemobiletools.camera.extensions.*
 import com.simplemobiletools.camera.helpers.*
+import com.simplemobiletools.camera.implementations.MyCameraOneImpl
 import com.simplemobiletools.commons.extensions.*
+import com.simplemobiletools.commons.helpers.isJellyBean1Plus
 import java.io.File
 import java.io.IOException
 import java.util.*
@@ -43,6 +46,7 @@ class PreviewCameraOne : ViewGroup, SurfaceHolder.Callback, MediaScannerConnecti
     private var mScaleGestureDetector: ScaleGestureDetector? = null
     private var mZoomRatios = ArrayList<Int>()
     private var mFlashlightState = FLASH_OFF
+    private var mCameraImpl: MyCameraOneImpl? = null
 
     private var mCurrVideoPath = ""
     private var mCanTakePicture = false
@@ -62,8 +66,8 @@ class PreviewCameraOne : ViewGroup, SurfaceHolder.Callback, MediaScannerConnecti
     private var mRotationAtCapture = 0
     private var mIsFocusingBeforeCapture = false
     private var autoFocusHandler = Handler()
+    private var mActivity: MainActivity? = null
 
-    var mActivity: MainActivity? = null
     var isWaitingForTakePictureCallback = false
     var mTargetUri: Uri? = null
     var isImageCaptureIntent = false
@@ -78,6 +82,7 @@ class PreviewCameraOne : ViewGroup, SurfaceHolder.Callback, MediaScannerConnecti
         mSurfaceHolder = mSurfaceView.holder
         mSurfaceHolder.addCallback(this)
         mSurfaceHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS)
+        mCameraImpl = MyCameraOneImpl(activity.applicationContext)
         mCanTakePicture = false
         mIsInVideoMode = false
         mIsSurfaceCreated = false
@@ -118,7 +123,7 @@ class PreviewCameraOne : ViewGroup, SurfaceHolder.Callback, MediaScannerConnecti
         }
     }
 
-    fun setCamera(cameraId: Int): Boolean {
+    fun setCamera(cameraId: Int = mCurrCameraId): Boolean {
         mCurrCameraId = cameraId
         val newCamera: Camera
         try {
@@ -187,6 +192,24 @@ class PreviewCameraOne : ViewGroup, SurfaceHolder.Callback, MediaScannerConnecti
         return true
     }
 
+    fun toggleCamera() {
+        mCurrCameraId = if (mCurrCameraId == mCameraImpl!!.getBackCameraId()) {
+            mCameraImpl!!.getFrontCameraId()
+        } else {
+            mCameraImpl!!.getBackCameraId()
+        }
+
+        mConfig.lastUsedCamera = mCurrCameraId
+        releaseCamera()
+        if (setCamera(mCurrCameraId)) {
+            setFlashlightState(FLASH_OFF)
+            mActivity?.updateCameraIcon(mCurrCameraId == mCameraImpl!!.getFrontCameraId())
+            mActivity?.hideTimer()
+        } else {
+            mActivity?.toast(R.string.camera_switch_error)
+        }
+    }
+
     private fun refreshPreview() {
         mIsSixteenToNine = getSelectedResolution().isSixteenToNine()
         mSetupPreviewAfterMeasure = true
@@ -290,6 +313,7 @@ class PreviewCameraOne : ViewGroup, SurfaceHolder.Callback, MediaScannerConnecti
         }
     }
 
+    @TargetApi(Build.VERSION_CODES.JELLY_BEAN_MR1)
     private fun takePicture() {
         if (mCanTakePicture) {
             val selectedResolution = getSelectedResolution()
@@ -299,7 +323,7 @@ class PreviewCameraOne : ViewGroup, SurfaceHolder.Callback, MediaScannerConnecti
                 mActivity!!.toast(R.string.setting_resolution_failed)
             }
 
-            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN_MR1) {
+            if (isJellyBean1Plus()) {
                 mCamera!!.enableShutterSound(false)
             }