Android-Developer-Basic · duten · Jul 9, 2025
diff --git a/app/build.gradle b/app/build.gradle
@@ -42,6 +42,9 @@ dependencies {
     implementation 'androidx.appcompat:appcompat:1.5.1'
     implementation 'com.google.android.material:material:1.6.1'
     implementation 'androidx.constraintlayout:constraintlayout:2.1.4'
+    implementation 'androidx.fragment:fragment-ktx:1.8.8'
+    implementation 'com.google.android.material:material:1.5.0'
+    implementation 'androidx.fragment:fragment:1.8.8'
     testImplementation 'junit:junit:4.13.2'
     androidTestImplementation 'androidx.test.ext:junit:1.1.3'
     androidTestImplementation 'androidx.test.espresso:espresso-core:3.4.0'

diff --git a/app/src/main/AndroidManifest.xml b/app/src/main/AndroidManifest.xml
@@ -15,12 +15,20 @@
         <activity
             android:name=".MainActivity"
             android:exported="true">
+        </activity>
+        <activity
+            android:name=".ActivityA"
+            android:exported="true">
             <intent-filter>
                 <action android:name="android.intent.action.MAIN" />
 
                 <category android:name="android.intent.category.LAUNCHER" />
             </intent-filter>
         </activity>
+        <activity
+            android:name=".ActivityB"
+            android:exported="true">
+        </activity>
     </application>
 
 </manifest>
diff --git a/app/src/main/java/otus/gpb/homework/fragments/ActivityA.kt b/app/src/main/java/otus/gpb/homework/fragments/ActivityA.kt
@@ -0,0 +1,18 @@
+package otus.gpb.homework.fragments
+
+import android.os.Bundle
+import androidx.appcompat.app.AppCompatActivity
+
+class ActivityA : AppCompatActivity() {
+
+    override fun onCreate(savedInstanceState: Bundle?) {
+        super.onCreate(savedInstanceState)
+        setContentView(R.layout.activity_fragment_a)
+
+        if (savedInstanceState == null) {
+            supportFragmentManager.beginTransaction()
+                .replace(R.id.fragment_activity_container, FragmentA())
+                .commit()
+        }
+    }
+}
diff --git a/app/src/main/java/otus/gpb/homework/fragments/ActivityB.kt b/app/src/main/java/otus/gpb/homework/fragments/ActivityB.kt
@@ -0,0 +1,37 @@
+package otus.gpb.homework.fragments
+
+import android.content.res.Configuration
+import android.graphics.Color
+import android.os.Bundle
+import androidx.appcompat.app.AppCompatActivity
+
+class ActivityB : AppCompatActivity() {
+
+    override fun onCreate(savedInstanceState: Bundle?) {
+        super.onCreate(savedInstanceState)
+        setContentView(R.layout.activity_fragment_b)
+
+        if (savedInstanceState == null) {
+            val currentOrientation = resources.configuration.orientation
+            val fragmentBA = FragmentBA.newInstance(Color.WHITE)
+
+            if (currentOrientation == Configuration.ORIENTATION_PORTRAIT) {
+                supportFragmentManager.beginTransaction()
+                    .replace(R.id.fragment_b_activity_container, fragmentBA)
+                    .commit()
+            } else {
+                val fragmentBB = FragmentBB.newInstance(Color.YELLOW)
+
+                supportFragmentManager.beginTransaction()
+                    .replace(R.id.fragment_container_ba_land, fragmentBA)
+                    .replace(R.id.fragment_container_bb_land, fragmentBB)
+                    .commit()
+            }
+        }
+    }
+
+    companion object {
+        const val REQUEST_KEY_COLOR = "request_key_color"
+        const val BUNDLE_KEY_COLOR = "bundle_key_color"
+    }
+}
diff --git a/app/src/main/java/otus/gpb/homework/fragments/ChildFragmentAA.kt b/app/src/main/java/otus/gpb/homework/fragments/ChildFragmentAA.kt
@@ -0,0 +1,66 @@
+package otus.gpb.homework.fragments
+
+import android.content.Context
+import android.graphics.Color
+import android.os.Bundle
+import android.view.LayoutInflater
+import android.view.View
+import android.view.ViewGroup
+import android.widget.Button
+import androidx.fragment.app.Fragment
+
+class ChildFragmentAA : Fragment() {
+
+    private var listener: ParentFragmentListener? = null
+    private var backgroundColor: Int = Color.WHITE
+
+
+    override fun onAttach(context: Context) {
+        super.onAttach(context)
+        if (parentFragment is ParentFragmentListener) {
+            listener = parentFragment as ParentFragmentListener
+        } else {
+            throw RuntimeException("${parentFragment} must implement ParentFragmentListener")
+        }
+    }
+
+    override fun onCreate(savedInstanceState: Bundle?) {
+        super.onCreate(savedInstanceState)
+        arguments?.let {
+            backgroundColor = it.getInt(ARG_BACKGROUND_COLOR)
+        }
+    }
+
+    override fun onCreateView(
+        inflater: LayoutInflater,
+        container: ViewGroup?,
+        savedInstanceState: Bundle?
+    ): View? {
+        val view = inflater.inflate(R.layout.child_fragment_aa, container, false)
+        view.setBackgroundColor(backgroundColor)
+        val openChildFragmentABButton: Button =
+            view.findViewById(R.id.button_open_child_fragment_ab)
+        openChildFragmentABButton.setOnClickListener {
+            listener?.onOpenChildFragmentABClicked()
+        }
+        return view
+    }
+
+    override fun onDetach() {
+        super.onDetach()
+        listener = null
+    }
+
+    companion object {
+        private const val ARG_BACKGROUND_COLOR = "background_color"
+
+        fun newInstance(color: Int): ChildFragmentAA {
+            val fragment = ChildFragmentAA()
+            val args = Bundle().apply {
+                putInt(ARG_BACKGROUND_COLOR, color)
+            }
+            fragment.arguments = args
+            return fragment
+        }
+    }
+}
diff --git a/app/src/main/java/otus/gpb/homework/fragments/ChildFragmentAB.kt b/app/src/main/java/otus/gpb/homework/fragments/ChildFragmentAB.kt
@@ -0,0 +1,43 @@
+package otus.gpb.homework.fragments
+
+import android.graphics.Color
+import android.os.Bundle
+import android.view.LayoutInflater
+import android.view.View
+import android.view.ViewGroup
+import androidx.fragment.app.Fragment
+
+class ChildFragmentAB : Fragment() {
+
+    private var backgroundColor: Int = Color.WHITE
+
+    override fun onCreate(savedInstanceState: Bundle?) {
+        super.onCreate(savedInstanceState)
+        arguments?.let {
+            backgroundColor = it.getInt(ARG_BACKGROUND_COLOR, Color.WHITE)
+        }
+    }
+
+    override fun onCreateView(
+        inflater: LayoutInflater,
+        container: ViewGroup?,
+        savedInstanceState: Bundle?
+    ): View? {
+        val view = inflater.inflate(R.layout.child_fragment_ab, container, false)
+        view?.setBackgroundColor(backgroundColor)
+        return view
+    }
+
+    companion object {
+        private const val ARG_BACKGROUND_COLOR = "background_color_ab"
+
+        fun newInstance(color: Int): ChildFragmentAB {
+            val fragment = ChildFragmentAB()
+            val args = Bundle().apply {
+                putInt(ARG_BACKGROUND_COLOR, color)
+            }
+            fragment.arguments = args
+            return fragment
+        }
+    }
+}
diff --git a/app/src/main/java/otus/gpb/homework/fragments/FragmentA.kt b/app/src/main/java/otus/gpb/homework/fragments/FragmentA.kt
@@ -0,0 +1,105 @@
+package otus.gpb.homework.fragments
+
+import android.os.Bundle
+import android.view.LayoutInflater
+import android.view.View
+import android.view.ViewGroup
+import android.widget.Button
+import androidx.activity.OnBackPressedCallback
+import androidx.fragment.app.Fragment
+import androidx.fragment.app.FragmentManager
+
+
+class FragmentA : Fragment(), ParentFragmentListener {
+
+    private lateinit var openChildFragmentAAButton: Button
+    private lateinit var onBackPressedCallback: OnBackPressedCallback
+
+    private val childBackStackListener = FragmentManager.OnBackStackChangedListener {
+        updateOpenChildButtonVisibility()
+    }
+
+
+    override fun onCreateView(
+        inflater: LayoutInflater,
+        container: ViewGroup?,
+        savedInstanceState: Bundle?
+    ): View? {
+        val view = inflater.inflate(R.layout.fragment_parent_a, container, false)
+
+        openChildFragmentAAButton = view.findViewById(R.id.button_open_fragment_aa)
+
+        openChildFragmentAAButton.setOnClickListener {
+            openChildFragmentAA()
+        }
+
+        onBackPressedCallback = object : OnBackPressedCallback(true) {
+            override fun handleOnBackPressed() {
+                if (childFragmentManager.backStackEntryCount > 0) {
+                    childFragmentManager.popBackStack()
+                } else {
+                    isEnabled = false
+                    requireActivity().onBackPressedDispatcher.onBackPressed()
+                    isEnabled = true
+                }
+            }
+        }
+        requireActivity().onBackPressedDispatcher.addCallback(
+            viewLifecycleOwner,
+            onBackPressedCallback
+        )
+
+        childFragmentManager.addOnBackStackChangedListener(childBackStackListener)
+        updateOpenChildButtonVisibility()
+        return view
+    }
+
+    override fun onDestroyView() {
+        super.onDestroyView()
+        childFragmentManager.removeOnBackStackChangedListener(childBackStackListener)
+    }
+
+    private fun updateOpenChildButtonVisibility() {
+        val hasChildFragment =
+            childFragmentManager.findFragmentById(R.id.parent_fragment_a_child_container) != null
+        val isChildBackStackEmpty = childFragmentManager.backStackEntryCount == 0
+
+        if (hasChildFragment && isChildBackStackEmpty) {
+        } else if (!hasChildFragment && isChildBackStackEmpty) {
+            openChildFragmentAAButton.visibility = View.VISIBLE
+        } else {
+            openChildFragmentAAButton.visibility = View.GONE
+        }
+
+        openChildFragmentAAButton.visibility =
+            if (childFragmentManager.backStackEntryCount == 0 && childFragmentManager.findFragmentById(
+                    R.id.parent_fragment_a_child_container
+                ) == null
+            ) View.VISIBLE else View.GONE
+        openChildFragmentAAButton.visibility =
+            if (childFragmentManager.backStackEntryCount == 0) View.VISIBLE else View.GONE
+    }
+
+    private fun openChildFragmentAA() {
+        val randomColor = ColorGenerator.generateColor()
+        val childFragmentAA = ChildFragmentAA.newInstance(randomColor)
+        childFragmentManager.beginTransaction()
+            .replace(R.id.parent_fragment_a_child_container, childFragmentAA)
+            .addToBackStack("ChildFragmentAA")
+            .commit()
+        openChildFragmentAAButton.visibility = View.GONE
+    }
+
+    private fun openChildFragmentAB() {
+        val randomColor = ColorGenerator.generateColor()
+        val childFragmentAB = ChildFragmentAB.newInstance(randomColor)
+        childFragmentManager.beginTransaction()
+            .replace(R.id.parent_fragment_a_child_container, childFragmentAB)
+            .addToBackStack("ChildFragmentAB")
+            .commit()
+    }
+
+    override fun onOpenChildFragmentABClicked() {
+        openChildFragmentAB()
+    }
+}
diff --git a/app/src/main/java/otus/gpb/homework/fragments/FragmentBA.kt b/app/src/main/java/otus/gpb/homework/fragments/FragmentBA.kt
@@ -0,0 +1,87 @@
+package otus.gpb.homework.fragments
+
+import android.content.res.Configuration
+import android.graphics.Color
+import android.os.Bundle
+import android.view.LayoutInflater
+import android.view.View
+import android.view.ViewGroup
+import android.widget.Button
+import androidx.fragment.app.Fragment
+
+class FragmentBA : Fragment() {
+
+    private var backgroundColor: Int = Color.WHITE
+    private lateinit var openFragmentBBButton: Button
+
+    override fun onCreate(savedInstanceState: Bundle?) {
+        super.onCreate(savedInstanceState)
+        arguments?.let {
+            backgroundColor = it.getInt(ARG_BACKGROUND_COLOR, Color.WHITE)
+        }
+    }
+
+    override fun onCreateView(
+        inflater: LayoutInflater,
+        container: ViewGroup?,
+        savedInstanceState: Bundle?
+    ): View? {
+        val view = inflater.inflate(
+            R.layout.fragment_ba,
+            container,
+            false
+        )
+        view.setBackgroundColor(backgroundColor)
+        return view
+    }
+
+    override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
+        super.onViewCreated(view, savedInstanceState)
+
+        parentFragmentManager.setFragmentResultListener(
+            ActivityB.REQUEST_KEY_COLOR,
+            viewLifecycleOwner
+        ) { requestKey, bundle ->
+            if (requestKey == ActivityB.REQUEST_KEY_COLOR) {
+                val newColor = bundle.getInt(ActivityB.BUNDLE_KEY_COLOR, Color.WHITE)
+                view.setBackgroundColor(newColor)
+                this.backgroundColor = newColor
+            }
+        }
+
+        openFragmentBBButton = view.findViewById(R.id.button_open_fragment_bb)
+
+        val currentOrientation = resources.configuration.orientation
+        if (currentOrientation == Configuration.ORIENTATION_PORTRAIT) {
+            openFragmentBBButton.visibility = View.VISIBLE
+            openFragmentBBButton.setOnClickListener {
+                openFragmentBBInPortrait()
+            }
+        } else {
+            openFragmentBBButton.visibility = View.GONE
+        }
+    }
+
+    private fun openFragmentBBInPortrait() {
+        val randomColor = ColorGenerator.generateColor()
+        val fragmentBB = FragmentBB.newInstance(randomColor)
+
+        parentFragmentManager.beginTransaction()
+            .replace(R.id.fragment_b_activity_container, fragmentBB)
+            .addToBackStack("FragmentBBFromBA")
+            .commit()
+    }
+
+    companion object {
+        private const val ARG_BACKGROUND_COLOR = "background_color_ba"
+
+        fun newInstance(color: Int): FragmentBA {
+            val fragment = FragmentBA()
+            val args = Bundle().apply {
+                putInt(ARG_BACKGROUND_COLOR, color)
+            }
+            fragment.arguments = args
+            return fragment
+        }
+    }
+}