fix inconsistencies when user switches camera mode fast

- debounce switching by 500ms when toggling between video/photo capture
- ensure there is only one source of truth for the current camera mode - this is the CameraXPreview
- refactor the MainActivity to depend on the CameraXPreview for the camera mode
- remove unused code in CameraXPreviewListener, MyPreview and in MainActivity

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

@@ -6,11 +6,8 @@ import android.content.Intent
 import android.content.res.ColorStateList
 import android.graphics.Bitmap
 import android.hardware.SensorManager
-import android.hardware.camera2.CameraCharacteristics
 import android.net.Uri
 import android.os.Bundle
-import android.os.Handler
-import android.os.Looper
 import android.provider.MediaStore
 import android.view.*
 import android.widget.LinearLayout
@@ -52,10 +49,8 @@ class MainActivity : SimpleActivity(), PhotoProcessor.MediaSavedListener, Camera
         const val PHOTO_MODE_INDEX = 1
         const val VIDEO_MODE_INDEX = 0
         private const val MIN_SWIPE_DISTANCE_X = 100
-        private const val DELAY_BETWEEN_MODE_SWITCH = 300L
     }
 
-    lateinit var mTimerHandler: Handler
     private lateinit var defaultScene: Scene
     private lateinit var flashModeScene: Scene
     private lateinit var mOrientationEventListener: OrientationEventListener
@@ -63,19 +58,26 @@ class MainActivity : SimpleActivity(), PhotoProcessor.MediaSavedListener, Camera
     private var mPreview: MyPreview? = null
     private var mediaSizeToggleGroup: MaterialButtonToggleGroup? = null
     private var mPreviewUri: Uri? = null
-    private var mIsInPhotoMode = true
-    private var mIsCameraAvailable = false
     private var mIsHardwareShutterHandled = false
-    private var mCurrVideoRecTimer = 0
-    var mLastHandledOrientation = 0
-    private val togglePhotoVideoRunnable = Runnable {
-        handleTogglePhotoVideo()
-    }
+    private var mLastHandledOrientation = 0
 
     private val tabSelectedListener = object : TabSelectedListener {
         override fun onTabSelected(tab: TabLayout.Tab) {
-            camera_mode_tab.removeCallbacks(togglePhotoVideoRunnable)
-            camera_mode_tab.postDelayed(togglePhotoVideoRunnable, DELAY_BETWEEN_MODE_SWITCH)
+            handlePermission(PERMISSION_RECORD_AUDIO) {
+                if (it) {
+                    when (tab.position) {
+                        VIDEO_MODE_INDEX -> mPreview?.initVideoMode()
+                        PHOTO_MODE_INDEX -> mPreview?.initPhotoMode()
+                        else -> throw IllegalStateException("Unsupported  tab position ${tab.position}")
+                    }
+                } else {
+                    toast(R.string.no_audio_permissions)
+                    selectPhotoTab()
+                    if (isVideoCaptureIntent()) {
+                        finish()
+                    }
+                }
+            }
         }
     }
 
@@ -84,7 +86,6 @@ class MainActivity : SimpleActivity(), PhotoProcessor.MediaSavedListener, Camera
         super.onCreate(savedInstanceState)
         appLaunched(BuildConfig.APPLICATION_ID)
         requestWindowFeature(Window.FEATURE_NO_TITLE)
-
         initVariables()
         tryInitCamera()
         supportActionBar?.hide()
@@ -135,14 +136,9 @@ class MainActivity : SimpleActivity(), PhotoProcessor.MediaSavedListener, Camera
     override fun onResume() {
         super.onResume()
         if (hasStorageAndCameraPermissions()) {
-            resumeCameraItems()
-            setupPreviewImage(mIsInPhotoMode)
+            val isInPhotoMode = isInPhotoMode()
+            setupPreviewImage(isInPhotoMode)
             mFocusCircleView.setStrokeColor(getProperPrimaryColor())
-
-            if (isVideoCaptureIntent() && mIsInPhotoMode) {
-                handleTogglePhotoVideo()
-                checkButtons()
-            }
             toggleBottomButtons(enabled = true)
             mOrientationEventListener.enable()
         }
@@ -160,8 +156,6 @@ class MainActivity : SimpleActivity(), PhotoProcessor.MediaSavedListener, Camera
         if (!hasStorageAndCameraPermissions() || isAskingPermissions) {
             return
         }
-
-        hideTimer()
         mOrientationEventListener.disable()
     }
 
@@ -177,18 +171,7 @@ class MainActivity : SimpleActivity(), PhotoProcessor.MediaSavedListener, Camera
     }
 
     private fun initVariables() {
-        mIsInPhotoMode = if (isVideoCaptureIntent()) {
-            false
-        } else if (isImageCaptureIntent()) {
-            true
-        } else {
-            config.initPhotoMode
-        }
-        mIsCameraAvailable = false
         mIsHardwareShutterHandled = false
-        mCurrVideoRecTimer = 0
-        mLastHandledOrientation = 0
-        config.lastUsedCamera = CameraCharacteristics.LENS_FACING_BACK.toString()
     }
 
     override fun onKeyDown(keyCode: Int, event: KeyEvent): Boolean {
@@ -223,16 +206,22 @@ class MainActivity : SimpleActivity(), PhotoProcessor.MediaSavedListener, Camera
             if (grantedCameraPermission) {
                 handleStoragePermission { grantedStoragePermission ->
                     if (grantedStoragePermission) {
-                        if (mIsInPhotoMode) {
-                            initializeCamera()
+                        val isInPhotoMode = isInPhotoMode()
+                        if (isInPhotoMode) {
+                            initializeCamera(true)
                         } else {
                             handlePermission(PERMISSION_RECORD_AUDIO) { grantedRecordAudioPermission ->
                                 if (grantedRecordAudioPermission) {
-                                    initializeCamera()
+                                    initializeCamera(false)
                                 } else {
                                     toast(R.string.no_audio_permissions)
-                                    togglePhotoVideoMode()
-                                    tryInitCamera()
+                                    if (isThirdPartyIntent()) {
+                                        finish()
+                                    } else {
+                                        // re-initialize in photo mode
+                                        config.initPhotoMode = true
+                                        tryInitCamera()
+                                    }
                                 }
                             }
                         }
@@ -248,6 +237,17 @@ class MainActivity : SimpleActivity(), PhotoProcessor.MediaSavedListener, Camera
         }
     }
 
+    private fun isInPhotoMode(): Boolean {
+        return mPreview?.isInPhotoMode()
+            ?: if (isVideoCaptureIntent()) {
+                false
+            } else if (isImageCaptureIntent()) {
+                true
+            } else {
+                config.initPhotoMode
+            }
+    }
+
     private fun handleStoragePermission(callback: (granted: Boolean) -> Unit) {
         if (isTiramisuPlus()) {
             handlePermission(PERMISSION_READ_MEDIA_IMAGES) { grantedReadImages ->
@@ -268,24 +268,6 @@ class MainActivity : SimpleActivity(), PhotoProcessor.MediaSavedListener, Camera
 
     private fun isVideoCaptureIntent(): Boolean = intent?.action == MediaStore.ACTION_VIDEO_CAPTURE
 
-    private fun checkImageCaptureIntent() {
-        if (isImageCaptureIntent()) {
-            hideIntentButtons()
-            val output = intent.extras?.get(MediaStore.EXTRA_OUTPUT)
-            if (output != null && output is Uri) {
-                mPreview?.setTargetUri(output)
-            }
-        }
-    }
-
-    private fun checkVideoCaptureIntent() {
-        if (isVideoCaptureIntent()) {
-            mIsInPhotoMode = false
-            hideIntentButtons()
-            shutter.setImageResource(R.drawable.ic_video_rec_vector)
-        }
-    }
-
     private fun createToggleGroup(): MaterialButtonToggleGroup {
         return MaterialButtonToggleGroup(this).apply {
             isSingleSelection = true
@@ -293,7 +275,7 @@ class MainActivity : SimpleActivity(), PhotoProcessor.MediaSavedListener, Camera
         }
     }
 
-    private fun initializeCamera() {
+    private fun initializeCamera(isInPhotoMode: Boolean) {
         setContentView(R.layout.activity_main)
         initButtons()
         initModeSwitcher()
@@ -318,8 +300,7 @@ class MainActivity : SimpleActivity(), PhotoProcessor.MediaSavedListener, Camera
             WindowInsetsCompat.CONSUMED
         }
 
-        checkVideoCaptureIntent()
-        if (mIsInPhotoMode) {
+        if (isInPhotoMode) {
             selectPhotoTab()
         } else {
             selectVideoTab()
@@ -332,25 +313,18 @@ class MainActivity : SimpleActivity(), PhotoProcessor.MediaSavedListener, Camera
             listener = this,
             outputUri = outputUri,
             isThirdPartyIntent = isThirdPartyIntent,
-            initInPhotoMode = mIsInPhotoMode,
+            initInPhotoMode = isInPhotoMode,
         )
-        checkImageCaptureIntent()
-        mPreview?.setIsImageCaptureIntent(isImageCaptureIntent())
 
-        val imageDrawable = if (config.lastUsedCamera == CameraCharacteristics.LENS_FACING_BACK.toString()) {
-            R.drawable.ic_camera_front_vector
-        } else {
-            R.drawable.ic_camera_rear_vector
-        }
-
-        toggle_camera.setImageResource(imageDrawable)
-
-        mFocusCircleView = FocusCircleView(applicationContext)
+        mFocusCircleView = FocusCircleView(this)
         view_holder.addView(mFocusCircleView)
 
-        mTimerHandler = Handler(Looper.getMainLooper())
         setupPreviewImage(true)
         initFlashModeTransitionNames()
+
+        if (isThirdPartyIntent) {
+            hideIntentButtons()
+        }
     }
 
     private fun initFlashModeTransitionNames() {
@@ -362,9 +336,9 @@ class MainActivity : SimpleActivity(), PhotoProcessor.MediaSavedListener, Camera
     }
 
     private fun initButtons() {
-        toggle_camera.setOnClickListener { toggleCamera() }
+        toggle_camera.setOnClickListener { mPreview!!.toggleFrontBackCamera() }
         last_photo_video_preview.setOnClickListener { showLastMediaPreview() }
-        toggle_flash.setOnClickListener { toggleFlash() }
+        toggle_flash.setOnClickListener { mPreview!!.handleFlashlightClick() }
         shutter.setOnClickListener { shutterPressed() }
 
         settings.setShadowIcon(R.drawable.ic_settings_vector)
@@ -437,11 +411,6 @@ class MainActivity : SimpleActivity(), PhotoProcessor.MediaSavedListener, Camera
         mPreview?.setFlashlightState(flashMode)
     }
 
-    private fun toggleCamera() {
-        if (checkCameraAvailable()) {
-            mPreview!!.toggleFrontBackCamera()
-        }
-    }
 
     private fun showLastMediaPreview() {
         if (mPreviewUri != null) {
@@ -450,24 +419,8 @@ class MainActivity : SimpleActivity(), PhotoProcessor.MediaSavedListener, Camera
         }
     }
 
-    private fun toggleFlash() {
-        if (checkCameraAvailable()) {
-            if (mIsInPhotoMode) {
-                showFlashOptions(true)
-            } else {
-                mPreview?.toggleFlashlight()
-            }
-        }
-    }
-
     private fun shutterPressed() {
-        if (checkCameraAvailable()) {
-            handleShutter()
-        }
-    }
-
-    private fun handleShutter() {
-        if (mIsInPhotoMode) {
+        if (isInPhotoMode()) {
             toggleBottomButtons(enabled = false)
             change_resolution.isEnabled = true
             mPreview?.tryTakePicture()
@@ -481,71 +434,15 @@ class MainActivity : SimpleActivity(), PhotoProcessor.MediaSavedListener, Camera
         startActivity(intent)
     }
 
-    private fun handleTogglePhotoVideo() {
-        handlePermission(PERMISSION_RECORD_AUDIO) {
-            if (it) {
-                togglePhotoVideo()
-            } else {
-                toast(R.string.no_audio_permissions)
-                selectPhotoTab()
-                if (isVideoCaptureIntent()) {
-                    finish()
-                }
-            }
-        }
-    }
-
-    private fun togglePhotoVideo() {
-        if (!checkCameraAvailable()) {
-            return
-        }
-
-        if (isVideoCaptureIntent()) {
-            mPreview?.initVideoMode()
-        }
-
-        mPreview?.setFlashlightState(FLASH_OFF)
-        hideTimer()
-        togglePhotoVideoMode()
-        checkButtons()
-        toggleBottomButtons(enabled = true)
-    }
-
-    private fun togglePhotoVideoMode() {
-        mIsInPhotoMode = !mIsInPhotoMode
-        config.initPhotoMode = mIsInPhotoMode
-    }
-
-    private fun checkButtons() {
-        if (mIsInPhotoMode) {
-            initPhotoMode()
-        } else {
-            tryInitVideoMode()
-        }
-    }
-
-    private fun initPhotoMode() {
+    override fun onInitPhotoMode() {
         shutter.setImageResource(R.drawable.ic_shutter_animated)
-        mPreview?.initPhotoMode()
         setupPreviewImage(true)
         selectPhotoTab()
     }
 
-    private fun tryInitVideoMode() {
-        try {
-            mPreview?.initVideoMode()
-            initVideoButtons()
-        } catch (e: Exception) {
-            if (!isVideoCaptureIntent()) {
-                toast(R.string.video_mode_error)
-            }
-        }
-    }
-
-    private fun initVideoButtons() {
+    override fun onInitVideoMode() {
         shutter.setImageResource(R.drawable.ic_video_rec_animated)
         setupPreviewImage(false)
-        mPreview?.checkFlashlight()
         selectVideoTab()
     }
 
@@ -578,21 +475,9 @@ class MainActivity : SimpleActivity(), PhotoProcessor.MediaSavedListener, Camera
         }
     }
 
-    private fun hideTimer() {
-        video_rec_curr_timer.text = 0.getFormattedDuration()
-        video_rec_curr_timer.beGone()
-        mCurrVideoRecTimer = 0
-        mTimerHandler.removeCallbacksAndMessages(null)
-    }
-
-    private fun resumeCameraItems() {
-        if (!mIsInPhotoMode) {
-            initVideoButtons()
-        }
-    }
 
     private fun hasStorageAndCameraPermissions(): Boolean {
-        return if (mIsInPhotoMode) hasPhotoModePermissions() else hasVideoModePermissions()
+        return if (isInPhotoMode()) hasPhotoModePermissions() else hasVideoModePermissions()
     }
 
     private fun hasPhotoModePermissions(): Boolean {
@@ -648,17 +533,6 @@ class MainActivity : SimpleActivity(), PhotoProcessor.MediaSavedListener, Camera
 
     private fun rotate(view: View, degrees: Int) = view.animate().rotation(degrees.toFloat()).start()
 
-    private fun checkCameraAvailable(): Boolean {
-        if (!mIsCameraAvailable) {
-            toast(R.string.camera_unavailable)
-        }
-        return mIsCameraAvailable
-    }
-
-    override fun setCameraAvailable(available: Boolean) {
-        mIsCameraAvailable = available
-    }
-
     override fun setHasFrontAndBackCamera(hasFrontAndBack: Boolean) {
         toggle_camera?.beVisibleIf(hasFrontAndBack)
     }

app/src/main/kotlin/com/simplemobiletools/camera/helpers/Config.kt

@@ -35,10 +35,6 @@ class Config(context: Context) : BaseConfig(context) {
         get() = prefs.getBoolean(FLIP_PHOTOS, true)
         set(flipPhotos) = prefs.edit().putBoolean(FLIP_PHOTOS, flipPhotos).apply()
 
-    var lastUsedCamera: String
-        get() = prefs.getString(LAST_USED_CAMERA, "0")!!
-        set(cameraId) = prefs.edit().putString(LAST_USED_CAMERA, cameraId).apply()
-
     var lastUsedCameraLens: Int
         get() = prefs.getInt(LAST_USED_CAMERA_LENS, CameraSelector.LENS_FACING_BACK)
         set(lens) = prefs.edit().putInt(LAST_USED_CAMERA_LENS, lens).apply()

app/src/main/kotlin/com/simplemobiletools/camera/implementations/CameraXInitializer.kt

@@ -23,7 +23,8 @@ class CameraXInitializer(private val activity: BaseSimpleActivity) {
             mediaOutputHelper,
             cameraErrorHandler,
             listener,
-            initInPhotoMode,
+            isThirdPartyIntent = isThirdPartyIntent,
+            initInPhotoMode = initInPhotoMode,
         )
     }
 

app/src/main/kotlin/com/simplemobiletools/camera/implementations/CameraXPreview.kt

@@ -4,6 +4,8 @@ import android.annotation.SuppressLint
 import android.content.Context
 import android.hardware.SensorManager
 import android.hardware.display.DisplayManager
+import android.os.Handler
+import android.os.Looper
 import android.util.Rational
 import android.util.Size
 import android.view.*
@@ -19,6 +21,7 @@ import androidx.camera.view.PreviewView.ScaleType
 import androidx.core.content.ContextCompat
 import androidx.core.view.doOnLayout
 import androidx.lifecycle.DefaultLifecycleObserver
+import androidx.lifecycle.Lifecycle
 import androidx.lifecycle.LifecycleOwner
 import androidx.window.layout.WindowMetricsCalculator
 import com.bumptech.glide.load.ImageHeaderParser.UNKNOWN_ORIENTATION
@@ -39,6 +42,7 @@ class CameraXPreview(
     private val mediaOutputHelper: MediaOutputHelper,
     private val cameraErrorHandler: CameraErrorHandler,
     private val listener: CameraXPreviewListener,
+    private val isThirdPartyIntent: Boolean,
     initInPhotoMode: Boolean,
 ) : MyPreview, DefaultLifecycleObserver {
 
@@ -46,6 +50,7 @@ class CameraXPreview(
         // Auto focus is 1/6 of the area.
         private const val AF_SIZE = 1.0f / 6.0f
         private const val AE_SIZE = AF_SIZE * 1.5f
+        private const val CAMERA_MODE_SWITCH_WAIT_TIME = 500L
     }
 
     private val config = activity.config
@@ -80,6 +85,29 @@ class CameraXPreview(
             }
         }
     }
+    private val startCameraHandler = Handler(Looper.getMainLooper())
+    private val photoModeRunnable = Runnable {
+        if (imageCapture == null) {
+            isPhotoCapture = true
+            if (!isThirdPartyIntent) { // we don't want to store the state for 3rd party intents
+                config.initPhotoMode = true
+            }
+            startCamera()
+        } else {
+            listener.onInitPhotoMode()
+        }
+    }
+    private val videoModeRunnable = Runnable {
+        if (videoCapture == null) {
+            isPhotoCapture = false
+            if (!isThirdPartyIntent) { // we don't want to store the state for 3rd party intents
+                config.initPhotoMode = false
+            }
+            startCamera()
+        } else {
+            listener.onInitVideoMode()
+        }
+    }
 
     private var preview: Preview? = null
     private var cameraProvider: ProcessCameraProvider? = null
@@ -92,13 +120,11 @@ class CameraXPreview(
     private var flashMode = FLASH_MODE_OFF
     private var isPhotoCapture = initInPhotoMode
     private var lastRotation = 0
+    private var lastCameraStartTime = 0L
 
     init {
         bindToLifeCycle()
         mediaSoundHelper.loadSounds()
-        previewView.doOnLayout {
-            startCamera()
-        }
     }
 
     private fun bindToLifeCycle() {
@@ -106,13 +132,12 @@ class CameraXPreview(
     }
 
     private fun startCamera(switching: Boolean = false) {
-        imageQualityManager.initSupportedQualities()
-
-        val cameraProviderFuture = ProcessCameraProvider.getInstance(activity)
+        val cameraProviderFuture = ProcessCameraProvider.getInstance(activity.applicationContext)
         cameraProviderFuture.addListener({
             try {
                 val provider = cameraProviderFuture.get()
                 cameraProvider = provider
+                imageQualityManager.initSupportedQualities()
                 videoQualityManager.initSupportedQualities(provider)
                 bindCameraUseCases()
                 setupCameraObservers()
@@ -128,11 +153,11 @@ class CameraXPreview(
 
         val resolution = if (isPhotoCapture) {
             imageQualityManager.getUserSelectedResolution(cameraSelector).also {
-                displaySelectedResolution(it.toResolutionOption())
+                listener.displaySelectedResolution(it.toResolutionOption())
             }
         } else {
             val selectedQuality = videoQualityManager.getUserSelectedQuality(cameraSelector).also {
-                displaySelectedResolution(it.toResolutionOption())
+                listener.displaySelectedResolution(it.toResolutionOption())
             }
             MySize(selectedQuality.width, selectedQuality.height)
         }
@@ -178,10 +203,6 @@ class CameraXPreview(
         setFlashlightState(config.flashlightState)
     }
 
-    private fun displaySelectedResolution(resolutionOption: ResolutionOption) {
-        listener.displaySelectedResolution(resolutionOption)
-    }
-
     private fun getRotatedResolution(resolution: MySize, rotationDegrees: Int): Size {
         return if (rotationDegrees == Surface.ROTATION_0 || rotationDegrees == Surface.ROTATION_180) {
             Size(resolution.height, resolution.width)
@@ -201,10 +222,12 @@ class CameraXPreview(
         return if (isPhotoCapture) {
             buildImageCapture(resolution, rotation).also {
                 imageCapture = it
+                videoCapture = null
             }
         } else {
             buildVideoCapture().also {
                 videoCapture = it
+                imageCapture = null
             }
         }
     }
@@ -242,15 +265,19 @@ class CameraXPreview(
     private fun setupCameraObservers() {
         listener.setFlashAvailable(camera?.cameraInfo?.hasFlashUnit() ?: false)
         listener.onChangeCamera(isFrontCameraInUse())
-
+        if (isPhotoCapture) {
+            listener.onInitPhotoMode()
+        } else {
+            listener.onInitVideoMode()
+        }
         camera?.cameraInfo?.cameraState?.observe(activity) { cameraState ->
             if (cameraState.error == null) {
                 when (cameraState.type) {
-                    CameraState.Type.OPEN-> {
+                    CameraState.Type.OPENING,
+                    CameraState.Type.OPEN -> {
                         listener.setHasFrontAndBackCamera(hasFrontCamera() && hasBackCamera())
                         listener.setCameraAvailable(true)
                     }
-                    CameraState.Type.OPENING,
                     CameraState.Type.PENDING_OPEN,
                     CameraState.Type.CLOSING,
                     CameraState.Type.CLOSED -> {
@@ -315,12 +342,21 @@ class CameraXPreview(
 
     override fun onStart(owner: LifecycleOwner) {
         orientationEventListener.enable()
+        previewView.doOnLayout {
+            if (owner.lifecycle.currentState.isAtLeast(Lifecycle.State.STARTED)) {
+                startCamera()
+            }
+        }
     }
 
     override fun onStop(owner: LifecycleOwner) {
         orientationEventListener.disable()
     }
 
+    override fun isInPhotoMode(): Boolean {
+        return isPhotoCapture
+    }
+
     override fun showChangeResolution() {
         val selectedResolution = if (isPhotoCapture) {
             imageQualityManager.getUserSelectedResolution(cameraSelector).toResolutionOption()
@@ -380,7 +416,15 @@ class CameraXPreview(
         startCamera(switching = true)
     }
 
-    override fun toggleFlashlight() {
+    override fun handleFlashlightClick() {
+        if (isPhotoCapture) {
+            listener.showFlashOptions(true)
+        } else {
+            toggleFlashlight()
+        }
+    }
+
+    private fun toggleFlashlight() {
         val newFlashMode = if (isPhotoCapture) {
             when (flashMode) {
                 FLASH_MODE_OFF -> FLASH_MODE_ON
@@ -399,17 +443,22 @@ class CameraXPreview(
     }
 
     override fun setFlashlightState(state: Int) {
+        var flashState = state
         if (isPhotoCapture) {
-            camera?.cameraControl?.enableTorch(state == FLASH_ALWAYS_ON)
+            camera?.cameraControl?.enableTorch(flashState == FLASH_ALWAYS_ON)
         } else {
-            camera?.cameraControl?.enableTorch(state == FLASH_ON || state == FLASH_ALWAYS_ON)
+            camera?.cameraControl?.enableTorch(flashState == FLASH_ON || flashState == FLASH_ALWAYS_ON)
+            // reset to the FLASH_ON for video capture
+            if (flashState == FLASH_ALWAYS_ON) {
+                flashState = FLASH_ON
+            }
         }
-        val newFlashMode = state.toCameraXFlashMode()
+        val newFlashMode = flashState.toCameraXFlashMode()
         flashMode = newFlashMode
         imageCapture?.flashMode = newFlashMode
 
-        config.flashlightState = state
-        listener.onChangeFlashMode(state)
+        config.flashlightState = flashState
+        listener.onChangeFlashMode(flashState)
     }
 
     override fun tryTakePicture() {
@@ -470,13 +519,23 @@ class CameraXPreview(
     }
 
     override fun initPhotoMode() {
-        isPhotoCapture = true
-        startCamera()
+        debounceChangeCameraMode(photoModeRunnable)
     }
 
     override fun initVideoMode() {
-        isPhotoCapture = false
-        startCamera()
+        debounceChangeCameraMode(videoModeRunnable)
+    }
+
+    private fun debounceChangeCameraMode(cameraModeRunnable: Runnable) {
+        val currentTime = System.currentTimeMillis()
+        if (currentTime - lastCameraStartTime > CAMERA_MODE_SWITCH_WAIT_TIME) {
+            cameraModeRunnable.run()
+        } else {
+            startCameraHandler.removeCallbacks(photoModeRunnable)
+            startCameraHandler.removeCallbacks(videoModeRunnable)
+            startCameraHandler.postDelayed(cameraModeRunnable, CAMERA_MODE_SWITCH_WAIT_TIME)
+        }
+        lastCameraStartTime = currentTime
     }
 
     override fun toggleRecording() {
@@ -492,8 +551,7 @@ class CameraXPreview(
     private fun startRecording() {
         val videoCapture = videoCapture ?: throw IllegalStateException("Camera initialization failed.")
 
-        val mediaOutput = mediaOutputHelper.getVideoMediaOutput()
-        val recording = when (mediaOutput) {
+        val recording = when (val mediaOutput = mediaOutputHelper.getVideoMediaOutput()) {
             is MediaOutput.FileDescriptorMediaOutput -> {
                 FileDescriptorOutputOptions.Builder(mediaOutput.fileDescriptor).build()
                     .let { videoCapture.output.prepareRecording(activity, it) }

app/src/main/kotlin/com/simplemobiletools/camera/implementations/CameraXPreviewListener.kt

@@ -5,7 +5,9 @@ import android.net.Uri
 import com.simplemobiletools.camera.models.ResolutionOption
 
 interface CameraXPreviewListener {
-    fun setCameraAvailable(available: Boolean)
+    fun onInitPhotoMode()
+    fun onInitVideoMode()
+    fun setCameraAvailable(available: Boolean) {}
     fun setHasFrontAndBackCamera(hasFrontAndBack: Boolean)
     fun setFlashAvailable(available: Boolean)
     fun onChangeCamera(frontCamera: Boolean)

app/src/main/kotlin/com/simplemobiletools/camera/interfaces/MyPreview.kt

@@ -1,18 +1,14 @@
 package com.simplemobiletools.camera.interfaces
 
-import android.net.Uri
-
 interface MyPreview {
 
-    fun setTargetUri(uri: Uri) = Unit
+    fun isInPhotoMode(): Boolean
 
-    fun setIsImageCaptureIntent(isImageCaptureIntent: Boolean) = Unit
-
-    fun setFlashlightState(state: Int) = Unit
+    fun setFlashlightState(state: Int)
 
     fun toggleFrontBackCamera()
 
-    fun toggleFlashlight() = Unit
+    fun handleFlashlightClick()
 
     fun tryTakePicture()
 
@@ -22,7 +18,5 @@ interface MyPreview {
 
     fun initVideoMode()
 
-    fun checkFlashlight() = Unit
-
-    fun showChangeResolution() = Unit
+    fun showChangeResolution()
 }