Added custom predictive back gesture layer (#329)

app/build.gradle

@@ -203,6 +203,8 @@ dependencies {
     implementation 'androidx.dynamicanimation:dynamicanimation-ktx:1.0.0-alpha03'
     implementation 'androidx.security:security-crypto:1.1.0-alpha06'
     implementation 'androidx.work:work-runtime-ktx:2.9.0'
+    implementation 'androidx.transition:transition-ktx:1.5.1'
+    implementation("androidx.navigation:navigation-fragment-ktx:2.7.7")
 
     // Google
     implementation 'com.google.android.material:material:1.12.0'

app/src/main/java/app/simple/inure/decorations/transitions/CustomTransition.kt

@@ -0,0 +1,29 @@
+package app.simple.inure.decorations.transitions
+
+import android.animation.Animator
+import android.animation.ObjectAnimator
+import android.view.View
+import android.view.ViewGroup
+import androidx.transition.Transition
+import androidx.transition.TransitionValues
+
+class CustomTransition : Transition() {
+    override fun captureStartValues(transitionValues: TransitionValues) {
+        transitionValues.values["custom:transition:alpha"] = transitionValues.view.alpha
+    }
+
+    override fun captureEndValues(transitionValues: TransitionValues) {
+        transitionValues.values["custom:transition:alpha"] = 1f
+    }
+
+    override fun createAnimator(
+            sceneRoot: ViewGroup,
+            startValues: TransitionValues?,
+            endValues: TransitionValues?
+    ): Animator? {
+        val view = endValues?.view ?: return null
+        val startAlpha = startValues?.values?.get("custom:transition:alpha") as? Float ?: 0f
+        val endAlpha = endValues.values["custom:transition:alpha"] as Float
+        return ObjectAnimator.ofFloat(view, View.ALPHA, startAlpha, endAlpha)
+    }
+}

app/src/main/java/app/simple/inure/decorations/views/XMLWebView.kt → app/src/main/java/app/simple/inure/decorations/views/WebViewXMLViewer.kt

@@ -19,7 +19,7 @@ import java.io.IOException
 import java.io.InputStream
 
 @SuppressLint("SetJavaScriptEnabled")
-class XMLWebView(context: Context, attributeSet: AttributeSet) : WebView(context, attributeSet) {
+class WebViewXMLViewer(context: Context, attributeSet: AttributeSet) : WebView(context, attributeSet) {
     init {
         settings.apply {
             useWideViewPort = false

app/src/main/java/app/simple/inure/dialogs/app/HtmlViewer.kt

@@ -5,12 +5,12 @@ import android.view.LayoutInflater
 import android.view.View
 import android.view.ViewGroup
 import app.simple.inure.R
-import app.simple.inure.decorations.views.XMLWebView
+import app.simple.inure.decorations.views.WebViewXMLViewer
 import app.simple.inure.extensions.fragments.ScopedBottomSheetFragment
 
 class HtmlViewer : ScopedBottomSheetFragment() {
 
-    private lateinit var webView: XMLWebView
+    private lateinit var webView: WebViewXMLViewer
 
     override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? {
         return inflater.inflate(R.layout.dialog_html, container, false)

app/src/main/java/app/simple/inure/extensions/fragments/ScopedFragment.kt

@@ -15,9 +15,13 @@ import android.os.Handler
 import android.os.Looper
 import android.util.Log
 import android.view.View
+import android.view.ViewGroup
 import android.view.WindowInsets
 import android.view.WindowInsetsAnimation
+import android.view.animation.PathInterpolator
 import android.widget.ImageView
+import androidx.activity.BackEventCompat
+import androidx.activity.OnBackPressedCallback
 import androidx.activity.addCallback
 import androidx.annotation.IntegerRes
 import androidx.annotation.RequiresApi
@@ -28,7 +32,11 @@ import androidx.lifecycle.Lifecycle
 import androidx.lifecycle.lifecycleScope
 import androidx.lifecycle.repeatOnLifecycle
 import androidx.transition.ArcMotion
+import androidx.transition.ChangeBounds
 import androidx.transition.Fade
+import androidx.transition.TransitionManager
+import androidx.transition.TransitionSeekController
+import androidx.transition.TransitionSet
 import app.simple.inure.R
 import app.simple.inure.apk.utils.PackageUtils
 import app.simple.inure.constants.BundleConstants
@@ -40,6 +48,10 @@ import app.simple.inure.dialogs.miscellaneous.Error.Companion.showError
 import app.simple.inure.dialogs.miscellaneous.Loader
 import app.simple.inure.dialogs.miscellaneous.Warning.Companion.showWarning
 import app.simple.inure.interfaces.fragments.SureCallbacks
+import app.simple.inure.math.Extensions.half
+import app.simple.inure.math.Extensions.negate
+import app.simple.inure.math.Extensions.zero
+import app.simple.inure.math.Range.mapRange
 import app.simple.inure.popups.behavior.PopupArcType
 import app.simple.inure.popups.behavior.PopupTransitionType
 import app.simple.inure.preferences.BehaviourPreferences
@@ -75,6 +87,12 @@ abstract class ScopedFragment : Fragment(), SharedPreferences.OnSharedPreference
     protected var minimumHorizontalAngle = 80
     protected var minimumVerticalAngle = 15
 
+    val transitionSet = TransitionSet().apply {
+        addTransition(Fade(Fade.MODE_OUT))
+        addTransition(ChangeBounds())
+        addTransition(Fade(Fade.MODE_IN))
+    }
+
     /**
      * [ScopedFragment]'s own [Handler] instance
      */
@@ -117,6 +135,10 @@ abstract class ScopedFragment : Fragment(), SharedPreferences.OnSharedPreference
         }
 
         animateBlur()
+
+        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.UPSIDE_DOWN_CAKE) {
+            setupBackPressedCallback(view as ViewGroup)
+        }
     }
 
     private fun animateBlur() {
@@ -513,6 +535,86 @@ abstract class ScopedFragment : Fragment(), SharedPreferences.OnSharedPreference
         }
     }
 
+    @RequiresApi(Build.VERSION_CODES.UPSIDE_DOWN_CAKE)
+    open fun setupBackPressedCallback(view: ViewGroup) {
+        val windowWidth = if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.R) {
+            requireActivity().windowManager.currentWindowMetrics.bounds.width()
+        } else {
+            zero()
+        }
+
+        val windowHeight = if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.R) {
+            requireActivity().windowManager.currentWindowMetrics.bounds.height()
+        } else {
+            zero()
+        }
+
+        val maxXShift = windowWidth / MAX_WINDOW_WIDTH
+
+        val callback = object : OnBackPressedCallback(enabled = true) {
+            var controller: TransitionSeekController? = null
+
+            @RequiresApi(Build.VERSION_CODES.UPSIDE_DOWN_CAKE)
+            override fun handleOnBackStarted(backEvent: BackEventCompat) {
+                controller = TransitionManager.controlDelayedTransition(
+                        view,
+                        transitionSet
+                )
+            }
+
+            @RequiresApi(Build.VERSION_CODES.UPSIDE_DOWN_CAKE)
+            override fun handleOnBackProgressed(backEvent: BackEventCompat) {
+                if (controller?.isReady == true) {
+                    controller?.currentFraction = backEvent.progress
+                }
+
+                // Shift the view based on the swipe progress
+                val backProgress = backEvent.progress
+                val interpolatedProgress = EMPHASIZED_DECELERATE.getInterpolation(backProgress)
+                val totalTranslationY = backEvent.touchY
+                    .mapRange(zero(), windowHeight, windowHeight.half().negate(), windowHeight.half())
+                    .div(MAX_WINDOW_HEIGHT)
+
+                when (backEvent.swipeEdge) {
+                    BackEventCompat.EDGE_LEFT -> {
+                        view.translationX = interpolatedProgress * maxXShift
+                        view.translationY = totalTranslationY * interpolatedProgress
+                    }
+                    BackEventCompat.EDGE_RIGHT -> {
+                        view.translationX = -(interpolatedProgress * maxXShift)
+                        view.translationY = totalTranslationY * interpolatedProgress
+                    }
+                }
+
+                view.scaleX = 1F - (0.1F * interpolatedProgress)
+                view.scaleY = 1F - (0.1F * interpolatedProgress)
+                // view.alpha = 1F - (0.5F * interpolatedProgress)
+            }
+
+            @RequiresApi(Build.VERSION_CODES.UPSIDE_DOWN_CAKE)
+            override fun handleOnBackPressed() {
+                Log.d(TAG, "handleOnBackPressed: ")
+                // Finish playing the transition when the user commits back )
+                this.isEnabled = false
+                popBackStack()
+            }
+
+            @RequiresApi(Build.VERSION_CODES.UPSIDE_DOWN_CAKE)
+            override fun handleOnBackCancelled() {
+                Log.d(TAG, "handleOnBackCancelled: ")
+                // If the user cancels the back gesture, reset the state
+                resetCallbackState()
+            }
+
+            private fun resetCallbackState() {
+                // Animate the view back to its original position
+                view.animate().translationX(0F).scaleX(1F).scaleY(1F).start()
+            }
+        }
+
+        requireActivity().onBackPressedDispatcher.addCallback(viewLifecycleOwner, callback)
+    }
+
     /**
      * Return the {@link Application} this fragment is currently associated with.
      */
@@ -608,12 +710,6 @@ abstract class ScopedFragment : Fragment(), SharedPreferences.OnSharedPreference
     protected fun openFragmentArc(fragment: ScopedFragment, icon: View, tag: String? = null, duration: Long? = null) {
         fragment.setArcTransitions(duration ?: resources.getInteger(R.integer.animation_duration).toLong())
 
-        //        try {
-        //            (fragment.exitTransition as TransitionSet?)?.excludeTarget(icon, true)
-        //        } catch (e: java.lang.ClassCastException) {
-        //            (fragment.exitTransition as MaterialContainerTransform?)?.excludeTarget(icon, true)
-        //        }
-
         try {
             val transaction = requireActivity().supportFragmentManager.beginTransaction().apply {
                 setReorderingAllowed(true)
@@ -739,6 +835,14 @@ abstract class ScopedFragment : Fragment(), SharedPreferences.OnSharedPreference
     }
 
     companion object {
+        private val EMPHASIZED_DECELERATE = PathInterpolator(0.05f, 0.7f, 0.1f, 1f)
+
+        /**
+         * Lower values will result in a more emphasized movement
+         */
+        private const val MAX_WINDOW_WIDTH = 20
+        private const val MAX_WINDOW_HEIGHT = 5
+
         private const val TAG = "ScopedFragment"
     }
 }

app/src/main/java/app/simple/inure/math/Extensions.kt

@@ -20,4 +20,22 @@ object Extensions {
     fun Double.percentOf(total: Double): Double = (this * 100.0 / total)
 
     fun Float.getPercentPart(total: Float): Float = (this * total / 100.0).toFloat()
-}
+
+    fun Float.negate(): Float = -this
+
+    fun Double.negate(): Double = -this
+
+    fun Int.negate(): Int = -this
+
+    fun Long.negate(): Long = -this
+
+    fun Int.half(): Int = this / 2
+
+    fun Long.half(): Long = this / 2
+
+    fun Float.half(): Float = this / 2.0f
+
+    fun Double.half(): Double = this / 2.0
+
+    fun zero() = 0
+}

app/src/main/java/app/simple/inure/math/Range.kt

@@ -0,0 +1,27 @@
+package app.simple.inure.math
+
+object Range {
+    fun Float.mapRange(fromMin: Float, fromMax: Float, toMin: Float, toMax: Float): Float {
+        return (this - fromMin) / (fromMax - fromMin) * (toMax - toMin) + toMin
+    }
+
+    fun Float.mapRange(fromMin: Int, fromMax: Int, toMin: Int, toMax: Int): Float {
+        return (this - fromMin) / (fromMax - fromMin) * (toMax - toMin) + toMin
+    }
+
+    fun Double.mapRange(fromMin: Double, fromMax: Double, toMin: Double, toMax: Double): Double {
+        return (this - fromMin) / (fromMax - fromMin) * (toMax - toMin) + toMin
+    }
+
+    fun Int.mapRange(fromMin: Int, fromMax: Int, toMin: Int, toMax: Int): Int {
+        return ((this - fromMin) / (fromMax - fromMin) * (toMax - toMin) + toMin).toInt()
+    }
+
+    fun Long.mapRange(fromMin: Long, fromMax: Long, toMin: Long, toMax: Long): Long {
+        return ((this - fromMin) / (fromMax - fromMin) * (toMax - toMin) + toMin).toLong()
+    }
+
+    fun Float.normalize(min: Float, max: Float): Float {
+        return (this - min) / (max - min)
+    }
+}

app/src/main/java/app/simple/inure/ui/panels/Home.kt

@@ -319,6 +319,10 @@ class Home : ScopedFragment() {
         /* no-op */
     }
 
+    override fun setupBackPressedCallback(view: ViewGroup) {
+        /* no-op */
+    }
+
     companion object {
         fun newInstance(): Home {
             val args = Bundle()

app/src/main/java/app/simple/inure/ui/viewers/XMLWebView.kt

@@ -18,18 +18,18 @@ import app.simple.inure.constants.BundleConstants
 import app.simple.inure.constants.MimeConstants
 import app.simple.inure.decorations.ripple.DynamicRippleImageButton
 import app.simple.inure.decorations.typeface.TypeFaceTextView
+import app.simple.inure.decorations.views.WebViewXMLViewer
 import app.simple.inure.extensions.fragments.ScopedFragment
 import app.simple.inure.factories.panels.XMLViewerViewModelFactory
 import app.simple.inure.popups.viewers.PopupXmlViewer
 import app.simple.inure.util.NullSafety.isNull
 import app.simple.inure.util.ViewUtils.gone
 import app.simple.inure.viewmodels.viewers.XMLViewerViewModel
 import java.io.IOException
-import app.simple.inure.decorations.views.XMLWebView as ViewsXMLWebView
 
 class XMLWebView : ScopedFragment() {
 
-    private lateinit var manifest: ViewsXMLWebView
+    private lateinit var manifest: WebViewXMLViewer
     private lateinit var name: TypeFaceTextView
     private lateinit var options: DynamicRippleImageButton
     private lateinit var progress: ProgressBar

app/src/main/res/layout/dialog_html.xml

@@ -23,7 +23,7 @@
             android:fadingEdgeLength="25dp"
             android:requiresFadingEdge="vertical">
 
-            <app.simple.inure.decorations.views.XMLWebView
+            <app.simple.inure.decorations.views.WebViewXMLViewer
                 android:id="@+id/web_view"
                 android:layout_width="match_parent"
                 android:layout_height="match_parent" />

app/src/main/res/layout/fragment_web_viewer.xml

@@ -11,7 +11,7 @@
         android:layout_width="match_parent"
         android:layout_height="1px" />
 
-    <app.simple.inure.decorations.views.XMLWebView
+    <app.simple.inure.decorations.views.WebViewXMLViewer
         android:id="@+id/source_view"
         android:layout_width="match_parent"
         android:layout_height="match_parent" />