Fixed ViewPager bug when rotating device (#2)

README.md

@@ -31,7 +31,7 @@ Download the app showcasing the examples: [demo.apk](./media/demo.apk)
 Add the following dependency to your <b>build.gradle</b>:
 
 ```gradle
-implementation 'nl.joery.animatedbottombar:library:1.0.2'
+implementation 'nl.joery.animatedbottombar:library:1.0.4'
 ```
 
 Define `AnimatedBottomBar` in your XML layout with custom attributes.

library/build.gradle

@@ -5,14 +5,14 @@ apply plugin: 'com.jfrog.bintray'
 apply plugin: 'com.github.dcendents.android-maven'
 
 ext {
-    bintrayRepo = "AnimatedBottomBar"
-    bintrayName = "nl.joery.animatedbottombar"
+    bintrayRepo = 'AnimatedBottomBar'
+    bintrayName = 'nl.joery.animatedbottombar'
 
     publishedGroupId = 'nl.joery.animatedbottombar'
-    libraryName = 'library'
+    libraryName = 'l1ibrary'
     artifact = 'library'
 
-    libraryVersion = '1.0.2'
+    libraryVersion = '1.0.4'
     libraryDescription = 'A customizable and easy to use BottomBar navigation view with sleek animations.'
     siteUrl = 'https://github.com/Droppers/AnimatedBottomBar'
     gitUrl = 'https://github.com/Droppers/AnimatedBottomBar.git'
@@ -23,7 +23,7 @@ ext {
 
     licenseName = 'The MIT License'
     licenseUrl = 'https://github.com/Droppers/AnimatedBottomBar/blob/master/LICENSE'
-    allLicenses = ["MIT"]
+    allLicenses = ['MIT']
 }
 
 android {
@@ -35,8 +35,8 @@ android {
         versionCode 1
         versionName libraryVersion
 
-        testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
-        consumerProguardFiles "consumer-rules.pro"
+        testInstrumentationRunner 'androidx.test.runner.AndroidJUnitRunner'
+        consumerProguardFiles 'consumer-rules.pro'
     }
 
     buildTypes {
@@ -55,7 +55,7 @@ android {
 }
 
 dependencies {
-    implementation fileTree(dir: "libs", include: ["*.jar"])
+    implementation fileTree(dir: 'libs', include: ['*.jar'])
     implementation "org.jetbrains.kotlin:kotlin-stdlib:$kotlin_version"
     implementation 'androidx.core:core-ktx:1.2.0'
     implementation 'androidx.appcompat:appcompat:1.1.0'

library/src/main/java/nl/joery/animatedbottombar/AnimatedBottomBar.kt

@@ -258,7 +258,10 @@ class AnimatedBottomBar @JvmOverloads constructor(
      * @param title The title of the tab.
      * @param id A unique identifier of a tab.
      */
-    fun createTab(icon: Drawable, title: String, @IdRes id: Int = -1): Tab {
+    fun createTab(icon: Drawable?, title: String, @IdRes id: Int = -1): Tab {
+        if (icon == null) {
+            throw IllegalArgumentException("Icon drawable cannot be null.")
+        }
         return Tab(icon, title, id)
     }
 
@@ -271,7 +274,7 @@ class AnimatedBottomBar @JvmOverloads constructor(
      */
     fun createTab(@DrawableRes iconRes: Int, title: String, @IdRes id: Int = -1): Tab {
         val icon = ContextCompat.getDrawable(context, iconRes)
-        return createTab(icon!!, title, id)
+        return createTab(icon, title, id)
     }
 
     /**

library/src/main/java/nl/joery/animatedbottombar/Extensions.kt

@@ -8,12 +8,12 @@ import androidx.annotation.ColorInt
 import androidx.core.content.ContextCompat
 
 @ColorInt
-fun Context.getColorResCompat(@AttrRes id: Int): Int {
+internal fun Context.getColorResCompat(@AttrRes id: Int): Int {
     return ContextCompat.getColor(this, getResourceId(id))
 }
 
 @ColorInt
-fun Context.getTextColor(@AttrRes id: Int): Int {
+internal fun Context.getTextColor(@AttrRes id: Int): Int {
     val typedValue = TypedValue()
     theme.resolveAttribute(id, typedValue, true)
     val arr = obtainStyledAttributes(
@@ -26,11 +26,11 @@ fun Context.getTextColor(@AttrRes id: Int): Int {
     return color
 }
 
-fun Context.getResourceId(id: Int): Int {
+internal fun Context.getResourceId(id: Int): Int {
     val resolvedAttr = TypedValue()
     theme.resolveAttribute(id, resolvedAttr, true)
     return resolvedAttr.run { if (resourceId != 0) resourceId else data }
 }
 
-val Int.px: Int
+internal val Int.px: Int
     get() = (this * Resources.getSystem().displayMetrics.density).toInt()

library/src/main/java/nl/joery/animatedbottombar/TabIndicator.kt

@@ -150,14 +150,14 @@ internal class TabIndicator(
             return
         }
 
-        if (!animate || lastIndex == -1) {
+        val newView = parent.getChildAt(newIndex)
+        if (!animate || lastIndex == -1 || newView == null) {
             parent.postInvalidate()
             return
         }
 
         lastSelectedIndex = lastIndex
 
-        val newView = parent.getChildAt(newIndex)
         animator = ValueAnimator.ofFloat(currentLeft, newView.left.toFloat()).apply {
             duration = bottomBar.tabStyle.animationDuration.toLong()
             interpolator = bottomBar.tabStyle.animationInterpolator