Adds getFragmentIndexInStackBySameType function to Navigator

medusalib/build.gradle

@@ -1,5 +1,6 @@
 apply plugin: 'com.android.library'
 apply plugin: 'kotlin-android'
+apply plugin: 'kotlin-parcelize'
 
 android {
     namespace 'com.trendyol.medusalib'
@@ -29,7 +30,7 @@ android {
 
 ext {
     PUBLISH_GROUP_ID = 'com.trendyol'
-    PUBLISH_VERSION = '0.10.4'
+    PUBLISH_VERSION = '0.11.0'
     PUBLISH_ARTIFACT_ID = 'medusa'
     PUBLISH_DESCRIPTION = "Android Fragment Stack Controller"
     PUBLISH_URL = "https://github.com/Trendyol/medusa"

medusalib/src/main/java/com/trendyol/medusalib/navigator/MultipleStackNavigator.kt

@@ -6,7 +6,6 @@ import androidx.fragment.app.FragmentManager
 import androidx.lifecycle.DefaultLifecycleObserver
 import androidx.lifecycle.LifecycleOwner
 import androidx.lifecycle.MutableLiveData
-import androidx.lifecycle.Observer
 import com.trendyol.medusalib.navigator.controller.FragmentManagerController
 import com.trendyol.medusalib.navigator.data.FragmentData
 import com.trendyol.medusalib.navigator.data.StackItem
@@ -212,14 +211,23 @@ open class MultipleStackNavigator(
         lifecycleOwner: LifecycleOwner,
         destinationChangedListener: (Fragment) -> Unit
     ) {
-        destinationChangeLiveData.observe(
-            lifecycleOwner,
-            Observer { fragment ->
-                if (fragment != null) {
-                    destinationChangedListener(fragment)
+        destinationChangeLiveData.observe(lifecycleOwner) { fragment ->
+            if (fragment != null) {
+                destinationChangedListener(fragment)
+            }
+        }
+    }
+
+    override fun getFragmentIndexInStackBySameType(tag: String?): Int {
+        if (tag.isNullOrEmpty()) return -1
+        fragmentStackState.fragmentTagStack.forEach { stack ->
+            stack.forEachIndexed { index, stackItem ->
+                if (stackItem.fragmentTag == tag) {
+                    return stack.size - index - 1
                 }
             }
-        )
+        }
+        return -1
     }
 
     private fun initializeStackState() {

medusalib/src/main/java/com/trendyol/medusalib/navigator/Navigator.kt

@@ -152,30 +152,46 @@ interface Navigator {
      */
     fun onSaveInstanceState(outState: Bundle)
 
-    /*
-    * Initializes fragment stack state and adds related root fragments to your
-    * container if savedState is null. Otherwise reads and deserialize
-    * fragment stack state from given bundle.
-    * @param outState savedInstanceState parameter of onCreate method in
+    /**
+     * Initializes fragment stack state and adds related root fragments to your
+     * container if savedState is null. Otherwise reads and deserialize
+     * fragment stack state from given bundle.
+     *
+     * @param savedState savedInstanceState parameter of onCreate method in
      * your fragments or activities
-    */
+     */
     fun initialize(savedState: Bundle?)
 
     /**
      * Listeners
      */
 
-    /*
-    Observes any changes made in fragment back stack with the given lifecycle.
-    All implementation of Navigator interface must guarantee following points:
-    - View lifecycle of the fragments that is observed by the listener must be at least in
-    STARTED state.
+    /**
+     * Observes any changes made in fragment back stack with the given lifecycle.
+     * All implementation of Navigator interface must guarantee following points:
+     *
+     * - View lifecycle of the fragments that is observed by the listener must be at least in
+     * STARTED state.
+     *
+     * - destinationChangedListener must be removed when the given lifecycle owner is reached
+     * DESTROYED state
+     */
+    fun observeDestinationChanges(
+        lifecycleOwner: LifecycleOwner,
+        destinationChangedListener: (Fragment) -> Unit,
+    )
 
-    - destinationChangedListener must be removed when the given lifecycle owner is reached
-    DESTROYED state
+    /**
+     * Retrieves the index of a [Fragment] within the fragment stack based on the specified tag.
+     * If the tag is null or empty, returns -1.
+     * Iterates through the fragment stack to find the specified tag.
+     * Returns the index of the [Fragment] relative to the top of its stack if found; otherwise,
+     * returns -1.
+     *
+     * @param tag The tag of the [Fragment] to search for within the stack.
+     * @return The index of the [Fragment] within its stack if found; otherwise, -1.
      */
-    fun observeDestinationChanges(lifecycleOwner: LifecycleOwner,
-                                  destinationChangedListener: (Fragment) -> Unit)
+    fun getFragmentIndexInStackBySameType(tag: String?): Int
 
     interface NavigatorListener {
 
@@ -214,11 +230,8 @@ interface Navigator {
          * fragment.
          * @return NavigatorTransaction type (ATTACH_DETACH or SHOW_HIDE)
          *
-         * @see https://github.com/Trendyol/medusa/wiki/Fragment-Lifecycle
+         * @see <a href="https://github.com/Trendyol/medusa/wiki/Fragment-Lifecycle">Fragment Lifecycle</a>
          */
         fun getNavigatorTransaction(): NavigatorTransaction
     }
 }
-
-
-

medusalib/src/main/java/com/trendyol/medusalib/navigator/data/StackItem.kt

@@ -1,31 +1,7 @@
 package com.trendyol.medusalib.navigator.data
 
-import android.os.Parcel
 import android.os.Parcelable
+import kotlinx.parcelize.Parcelize
 
-data class StackItem(val fragmentTag: String, val groupName: String = "") : Parcelable {
-    constructor(parcel: Parcel) : this(
-        requireNotNull(parcel.readString()),
-        requireNotNull(parcel.readString())
-    )
-
-    override fun writeToParcel(parcel: Parcel, flags: Int) {
-        parcel.writeString(fragmentTag)
-        parcel.writeString(groupName)
-    }
-
-    override fun describeContents(): Int {
-        return 0
-    }
-
-    companion object CREATOR : Parcelable.Creator<StackItem> {
-        override fun createFromParcel(parcel: Parcel): StackItem {
-            return StackItem(parcel)
-        }
-
-        override fun newArray(size: Int): Array<StackItem?> {
-            return arrayOfNulls(size)
-        }
-    }
-
-}
+@Parcelize
+data class StackItem(val fragmentTag: String, val groupName: String = "") : Parcelable

medusalib/src/test/java/com/trendyol/medusalib/navigator/MultipleStackNavigatorBackstackOrderTest.kt

@@ -0,0 +1,167 @@
+package com.trendyol.medusalib.navigator
+
+import androidx.fragment.app.Fragment
+import androidx.fragment.app.testing.launchFragmentInContainer
+import com.google.common.truth.Truth.assertThat
+import com.trendyol.medusalib.TestChildFragment
+import com.trendyol.medusalib.TestParentFragment
+import org.junit.Test
+import org.junit.runner.RunWith
+import org.robolectric.RobolectricTestRunner
+
+@RunWith(RobolectricTestRunner::class)
+class MultipleStackNavigatorBackstackOrderTest {
+
+    @Test
+    fun `given MultipleStackNavigator with empty stack and null as tag, when calling getFragmentIndexInStackBySameType, should return -1`() {
+        launchFragmentInContainer<TestParentFragment>().onFragment { fragment ->
+            // Given
+            val sut = MultipleStackNavigator(
+                fragmentManager = fragment.childFragmentManager,
+                containerId = TestParentFragment.CONTAINER_ID,
+                rootFragmentProvider = listOf({ TestChildFragment.newInstance("root 1") }),
+            )
+            sut.initialize(null)
+
+            // When
+            val actual = sut.getFragmentIndexInStackBySameType(null)
+
+            // Then
+            assertThat(actual).isEqualTo(-1)
+        }
+    }
+
+    @Test
+    fun `given MultipleStackNavigator with empty stack and nonnull tag, when calling getFragmentIndexInStackBySameType, should return -1`() {
+        launchFragmentInContainer<TestParentFragment>().onFragment { fragment ->
+            // Given
+            val sut = MultipleStackNavigator(
+                fragmentManager = fragment.childFragmentManager,
+                containerId = TestParentFragment.CONTAINER_ID,
+                rootFragmentProvider = listOf({ TestChildFragment.newInstance("root 1") }),
+            )
+            sut.initialize(null)
+
+            // When
+            val actual = sut.getFragmentIndexInStackBySameType("random-tag")
+
+            // Then
+            assertThat(actual).isEqualTo(-1)
+        }
+    }
+
+    @Test
+    fun `given MultipleStackNavigator with stack with single fragment and nonnull tag, when calling getFragmentIndexInStackBySameType for current fragment, should return 0`() {
+        launchFragmentInContainer<TestParentFragment>().onFragment { fragment ->
+            // Given
+            val sut = MultipleStackNavigator(
+                fragmentManager = fragment.childFragmentManager,
+                containerId = TestParentFragment.CONTAINER_ID,
+                rootFragmentProvider = listOf({ TestChildFragment.newInstance("root 1") }),
+            )
+            sut.initialize(null)
+
+            sut.start(TestChildFragment.newInstance("child fragment"))
+
+            fragment.childFragmentManager.executePendingTransactions()
+
+            // When
+            val actual = sut.getFragmentIndexInStackBySameType(sut.getCurrentFragment()?.tag)
+
+            // Then
+            assertThat(actual).isEqualTo(0)
+        }
+    }
+
+    @Test
+    fun `given MultipleStackNavigator with stack with multiple fragment and nonnull tag, when calling getFragmentIndexInStackBySameType for first child fragment, should return 2`() {
+        launchFragmentInContainer<TestParentFragment>().onFragment { fragment ->
+            // Given
+            val sut = MultipleStackNavigator(
+                fragmentManager = fragment.childFragmentManager,
+                containerId = TestParentFragment.CONTAINER_ID,
+                rootFragmentProvider = listOf({ TestChildFragment.newInstance("root 1") }),
+            )
+            sut.initialize(null)
+
+            val fragments = mutableListOf<Fragment>()
+            sut.observeDestinationChanges(fragment.viewLifecycleOwner) {
+                fragments.add(it)
+            }
+
+            sut.start(TestChildFragment.newInstance("child fragment 1"))
+            sut.start(TestChildFragment.newInstance("child fragment 2"))
+            sut.start(TestChildFragment.newInstance("child fragment 3"))
+            fragment.childFragmentManager.executePendingTransactions()
+
+            // When
+            val actual = sut.getFragmentIndexInStackBySameType(fragments[1].tag)
+
+            // Then
+            assertThat(actual).isEqualTo(2)
+        }
+    }
+
+    @Test
+    fun `given MultipleStackNavigator with stack with multiple fragment and nonnull tag, when calling getFragmentIndexInStackBySameType for last child fragment, should return 0`() {
+        launchFragmentInContainer<TestParentFragment>().onFragment { fragment ->
+            // Given
+            val sut = MultipleStackNavigator(
+                fragmentManager = fragment.childFragmentManager,
+                containerId = TestParentFragment.CONTAINER_ID,
+                rootFragmentProvider = listOf({ TestChildFragment.newInstance("root 1") }),
+            )
+            sut.initialize(null)
+
+            val fragments = mutableListOf<Fragment>()
+            sut.observeDestinationChanges(fragment.viewLifecycleOwner) {
+                fragments.add(it)
+            }
+
+            sut.start(TestChildFragment.newInstance("child fragment 1"))
+            sut.start(TestChildFragment.newInstance("child fragment 2"))
+            fragment.childFragmentManager.executePendingTransactions()
+
+            // When
+            val actual = sut.getFragmentIndexInStackBySameType(fragments[2].tag)
+
+            // Then
+            assertThat(actual).isEqualTo(0)
+        }
+    }
+
+    @Test
+    fun `given MultipleStackNavigator with stack with multiple root fragments and nonnull tag and switch tab, when calling getFragmentIndexInStackBySameType for first child in switched tab, should return 1`() {
+        launchFragmentInContainer<TestParentFragment>().onFragment { fragment ->
+            // Given
+            val sut = MultipleStackNavigator(
+                fragmentManager = fragment.childFragmentManager,
+                containerId = TestParentFragment.CONTAINER_ID,
+                rootFragmentProvider = listOf(
+                    { TestChildFragment.newInstance("root 1") },
+                    { TestChildFragment.newInstance("root 2") },
+                ),
+            )
+            sut.initialize(null)
+
+            val fragments = mutableListOf<Fragment>()
+            sut.observeDestinationChanges(fragment.viewLifecycleOwner) {
+                fragments.add(it)
+            }
+
+            sut.start(TestChildFragment.newInstance("child fragment 1"))
+            sut.start(TestChildFragment.newInstance("child fragment 2"))
+            sut.switchTab(1)
+            sut.start(TestChildFragment.newInstance("child fragment 1"))
+            sut.start(TestChildFragment.newInstance("child fragment 1"))
+
+            fragment.childFragmentManager.executePendingTransactions()
+
+            // When
+            val actual = sut.getFragmentIndexInStackBySameType(fragments[4].tag)
+
+            // Then
+            assertThat(actual).isEqualTo(1)
+        }
+    }
+}