adding automatic rotation of the onboarding carousel items

- items change every 5 seconds
- uses fake dragging to control the page transition speed, by default it's too fast

vector/src/main/java/im/vector/app/core/extensions/Integer.kt

@@ -0,0 +1,19 @@
+/*
+ * Copyright (c) 2021 New Vector Ltd
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package im.vector.app.core.extensions
+
+fun Int.incrementAndWrap(max: Int, min: Int = 0, amount: Int = 1) = if (this == max) min else this + amount

vector/src/main/java/im/vector/app/core/extensions/ViewPager2.kt

@@ -0,0 +1,57 @@
+/*
+ * Copyright (c) 2021 New Vector Ltd
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package im.vector.app.core.extensions
+
+import android.animation.Animator
+import android.animation.TimeInterpolator
+import android.animation.ValueAnimator
+import android.view.animation.AccelerateDecelerateInterpolator
+import androidx.viewpager2.widget.ViewPager2
+
+fun ViewPager2.setCurrentItem(
+        item: Int,
+        duration: Long,
+        interpolator: TimeInterpolator = AccelerateDecelerateInterpolator(),
+        pagePxWidth: Int = width // Default value taken from getWidth() from ViewPager2 view
+) {
+    val pxToDrag: Int = pagePxWidth * (item - currentItem)
+    val animator = ValueAnimator.ofInt(0, pxToDrag)
+    var previousValue = 0
+    animator.addUpdateListener { valueAnimator ->
+        val currentValue = valueAnimator.animatedValue as Int
+        val currentPxToDrag = (currentValue - previousValue).toFloat()
+        kotlin.runCatching {
+            fakeDragBy(-currentPxToDrag)
+            previousValue = currentValue
+        }.onFailure { animator.cancel() }
+    }
+    animator.addListener(object : Animator.AnimatorListener {
+        override fun onAnimationStart(animation: Animator?) {
+            beginFakeDrag()
+        }
+
+        override fun onAnimationEnd(animation: Animator?) {
+            endFakeDrag()
+        }
+
+        override fun onAnimationCancel(animation: Animator?) = Unit
+        override fun onAnimationRepeat(animation: Animator?) = Unit
+    })
+    animator.interpolator = interpolator
+    animator.duration = duration
+    animator.start()
+}

vector/src/main/java/im/vector/app/features/onboarding/ftueauth/FtueAuthSplashCarouselFragment.kt

@@ -22,20 +22,29 @@ import android.view.LayoutInflater
 import android.view.View
 import android.view.ViewGroup
 import androidx.core.view.isVisible
+import androidx.lifecycle.lifecycleScope
 import com.airbnb.mvrx.withState
 import com.google.android.material.dialog.MaterialAlertDialogBuilder
 import com.google.android.material.tabs.TabLayoutMediator
 import im.vector.app.BuildConfig
 import im.vector.app.R
+import im.vector.app.core.extensions.incrementAndWrap
+import im.vector.app.core.extensions.setCurrentItem
+import im.vector.app.core.flow.tickerFlow
 import im.vector.app.databinding.FragmentFtueSplashCarouselBinding
 import im.vector.app.features.VectorFeatures
 import im.vector.app.features.onboarding.OnboardingAction
 import im.vector.app.features.onboarding.OnboardingFlow
 import im.vector.app.features.settings.VectorPreferences
+import kotlinx.coroutines.flow.launchIn
+import kotlinx.coroutines.flow.onEach
 import org.matrix.android.sdk.api.failure.Failure
 import java.net.UnknownHostException
 import javax.inject.Inject
 
+private const val CAROUSEL_ROTATION_DELAY_MS = 5000L
+private const val CAROUSEL_TRANSITION_TIME_MS = 500L
+
 class FtueAuthSplashCarouselFragment @Inject constructor(
         private val vectorPreferences: VectorPreferences,
         private val vectorFeatures: VectorFeatures,
@@ -52,7 +61,8 @@ class FtueAuthSplashCarouselFragment @Inject constructor(
     }
 
     private fun setupViews() {
-        views.splashCarousel.adapter = carouselController.adapter
+        val carouselAdapter = carouselController.adapter
+        views.splashCarousel.adapter = carouselAdapter
         TabLayoutMediator(views.carouselIndicator, views.splashCarousel) { _, _ -> }.attach()
         carouselController.setData(SplashCarouselState())
 
@@ -69,6 +79,13 @@ class FtueAuthSplashCarouselFragment @Inject constructor(
                     "Branch: ${BuildConfig.GIT_BRANCH_NAME}"
             views.loginSplashVersion.debouncedClicks { navigator.openDebug(requireContext()) }
         }
+
+        views.splashCarousel.apply {
+            val itemCount = carouselAdapter.itemCount
+            tickerFlow(lifecycleScope, delayMillis = CAROUSEL_ROTATION_DELAY_MS)
+                    .onEach { setCurrentItem(currentItem.incrementAndWrap(max = itemCount - 1), duration = CAROUSEL_TRANSITION_TIME_MS) }
+                    .launchIn(lifecycleScope)
+        }
     }
 
     private fun getStarted() {