Решение к домашней работе Fragments

app/build.gradle

@@ -8,7 +8,7 @@ kotlin {
 }
 
 android {
-    compileSdk 34
+    compileSdk 36
     namespace "otus.gpb.homework.fragments"
 
     defaultConfig {
@@ -21,6 +21,10 @@ android {
         testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
     }
 
+    buildFeatures {
+        viewBinding true
+    }
+
     buildTypes {
         release {
             minifyEnabled false
@@ -42,6 +46,8 @@ 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.activity:activity:1.11.0'
+    implementation 'androidx.fragment:fragment-ktx:1.8.9'
     testImplementation 'junit:junit:4.13.2'
     androidTestImplementation 'androidx.test.ext:junit:1.1.3'
     androidTestImplementation 'androidx.test.espresso:espresso-core:3.4.0'

app/src/main/AndroidManifest.xml

@@ -12,6 +12,15 @@
         android:supportsRtl="true"
         android:theme="@style/Theme.Fragments"
         tools:targetApi="31">
+        <activity
+            android:name=".ThirdActivity"
+            android:exported="false" />
+        <activity
+            android:name=".SecondActivity"
+            android:exported="false" />
+        <activity
+            android:name=".FirstActivity"
+            android:exported="false" />
         <activity
             android:name=".MainActivity"
             android:exported="true">

app/src/main/java/otus/gpb/homework/fragments/ExchangeDataExt.kt

@@ -0,0 +1,31 @@
+package otus.gpb.homework.fragments
+
+import androidx.core.os.bundleOf
+import androidx.fragment.app.Fragment
+import androidx.fragment.app.setFragmentResult
+import androidx.fragment.app.setFragmentResultListener
+
+const val COLOR_REQUEST_KEY = "request_key"
+const val COLOR_RESULT_KEY = "result_key"
+
+fun Fragment.sendResult(data: Int, isTablet: Boolean = false) {
+    if (isTablet) {
+        requireActivity().supportFragmentManager.setFragmentResult(COLOR_REQUEST_KEY, bundleOf(COLOR_RESULT_KEY to data))
+    } else {
+        setFragmentResult(COLOR_REQUEST_KEY, bundleOf(COLOR_RESULT_KEY to data))
+    }
+}
+
+fun Fragment.observeResult(isTablet: Boolean = false, callback: (Int) -> Unit) {
+    if (isTablet) {
+        requireActivity().supportFragmentManager.setFragmentResultListener(COLOR_REQUEST_KEY, viewLifecycleOwner) { _, bundle ->
+            val data = bundle.getInt(COLOR_RESULT_KEY)
+            callback(data)
+        }
+    } else {
+        setFragmentResultListener(COLOR_REQUEST_KEY) { _, bundle ->
+            val data = bundle.getInt(COLOR_RESULT_KEY)
+            callback(data)
+        }
+    }
+}

app/src/main/java/otus/gpb/homework/fragments/FirstActivity.kt

@@ -0,0 +1,27 @@
+package otus.gpb.homework.fragments
+
+import android.os.Bundle
+import androidx.appcompat.app.AppCompatActivity
+import otus.gpb.homework.fragments.databinding.ActivityFirstBinding
+
+class FirstActivity : AppCompatActivity() {
+    private var binding: ActivityFirstBinding? = null
+    private lateinit var fragmentA: FragmentA
+
+    override fun onCreate(savedInstanceState: Bundle?) {
+        super.onCreate(savedInstanceState)
+        binding = ActivityFirstBinding.inflate(layoutInflater)
+        setContentView(binding?.root)
+
+        if (savedInstanceState == null) {
+            fragmentA = FragmentA()
+        } else {
+            fragmentA = supportFragmentManager.findFragmentByTag("FragmentA") as FragmentA
+        }
+
+        supportFragmentManager.beginTransaction()
+            .replace(R.id.fragmentA_container, fragmentA, "FragmentA")
+            .addToBackStack(null)
+            .commit()
+    }
+}

app/src/main/java/otus/gpb/homework/fragments/FragmentA.kt

@@ -0,0 +1,82 @@
+package otus.gpb.homework.fragments
+
+import android.content.Context
+import android.os.Bundle
+import androidx.fragment.app.Fragment
+import android.view.LayoutInflater
+import android.view.View
+import android.view.ViewGroup
+import android.widget.Button
+import android.widget.Toast
+import androidx.activity.OnBackPressedCallback
+import androidx.core.view.isVisible
+import otus.gpb.homework.fragments.databinding.FragmentABinding
+
+class FragmentA : Fragment() {
+    private var _binding: FragmentABinding? = null
+    val binding get() = _binding!!
+
+    override fun onAttach(context: Context) {
+        super.onAttach(context)
+
+        requireActivity().onBackPressedDispatcher.addCallback(
+            this,
+            object : OnBackPressedCallback(true) {
+                override fun handleOnBackPressed() {
+                    val count = childFragmentManager.backStackEntryCount
+                    Toast.makeText(requireContext(), "BackStack count: $count", Toast.LENGTH_SHORT)
+                        .show()
+                    when {
+                        count > 1 -> childFragmentManager.popBackStack()
+                        count == 1 -> {
+                            binding.buttonA.visibility = View.VISIBLE
+                            binding.textViewA.visibility = View.VISIBLE
+
+                            childFragmentManager.popBackStack()
+                        }
+                        count == 0 -> requireActivity().finish()
+                        else -> {
+                            isEnabled = false
+                            requireActivity().onBackPressedDispatcher.onBackPressed()
+                        }
+                    }
+                }
+            })
+    }
+
+    override fun onCreateView(
+        inflater: LayoutInflater, container: ViewGroup?,
+        savedInstanceState: Bundle?
+    ): View {
+        _binding = FragmentABinding.inflate(inflater, container, false)
+        val view = binding.root
+        return view
+    }
+
+    override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
+        super.onViewCreated(view, savedInstanceState)
+        binding.buttonA.setOnClickListener {
+            openFragmentAA()
+        }
+    }
+
+    private fun openFragmentAA() {
+        val fragmentAA = FragmentAA()
+
+        sendResult(ColorGenerator.generateColor())
+
+        childFragmentManager.beginTransaction()
+            .replace(R.id.containerA, fragmentAA)
+            .addToBackStack(null)
+            .commit()
+
+        binding.buttonA.visibility = View.GONE
+        binding.textViewA.visibility = View.GONE
+    }
+
+    override fun onDestroyView() {
+        super.onDestroyView()
+        _binding = null
+    }
+
+}

app/src/main/java/otus/gpb/homework/fragments/FragmentAA.kt

@@ -0,0 +1,52 @@
+package otus.gpb.homework.fragments
+
+import android.os.Bundle
+import androidx.fragment.app.Fragment
+import android.view.LayoutInflater
+import android.view.View
+import android.view.ViewGroup
+import androidx.core.os.bundleOf
+import otus.gpb.homework.fragments.databinding.FragmentAaBinding
+
+class FragmentAA : Fragment() {
+    private var _binding: FragmentAaBinding? = null
+    private val binding get() = _binding!!
+
+    override fun onCreateView(
+        inflater: LayoutInflater, container: ViewGroup?,
+        savedInstanceState: Bundle?
+    ): View {
+        _binding = FragmentAaBinding.inflate(inflater, container, false)
+        val view = binding.root
+        observeResult(true) { color ->
+            binding.containerAA.setBackgroundColor(color)
+        }
+        return view
+    }
+
+    override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
+        super.onViewCreated(view, savedInstanceState)
+        binding.buttonAB.setOnClickListener {
+            openFragmentAB()
+        }
+    }
+
+    private fun openFragmentAB() {
+        val fragmentAB = FragmentAB()
+        val color = ColorGenerator.generateColor()
+        fragmentAB.arguments = bundleOf("color" to color)
+        childFragmentManager.beginTransaction()
+            .replace(R.id.containerAA, fragmentAB)
+            .addToBackStack(null)
+            .commit()
+
+        binding.buttonAB.visibility = View.GONE
+        binding.textViewB.visibility = View.GONE
+    }
+
+    override fun onDestroyView() {
+        super.onDestroyView()
+        _binding = null
+    }
+
+}

app/src/main/java/otus/gpb/homework/fragments/FragmentAB.kt

@@ -0,0 +1,29 @@
+package otus.gpb.homework.fragments
+
+import android.os.Bundle
+import android.view.LayoutInflater
+import android.view.View
+import android.view.ViewGroup
+import androidx.fragment.app.Fragment
+import otus.gpb.homework.fragments.databinding.FragmentAbBinding
+
+class FragmentAB : Fragment() {
+    private var _binding: FragmentAbBinding? = null
+    private val binding get() = _binding!!
+
+    override fun onCreateView(
+        inflater: LayoutInflater, container: ViewGroup?,
+        savedInstanceState: Bundle?
+    ): View {
+        _binding = FragmentAbBinding.inflate(inflater, container, false)
+        val view = binding.root
+        val color = arguments?.getInt("color") ?: 0
+        binding.containerAB.setBackgroundColor(color)
+        return view
+    }
+
+    override fun onDestroyView() {
+        super.onDestroyView()
+        _binding = null
+    }
+}

app/src/main/java/otus/gpb/homework/fragments/FragmentB.kt

@@ -0,0 +1,27 @@
+package otus.gpb.homework.fragments
+
+import android.os.Bundle
+import androidx.fragment.app.Fragment
+import android.view.LayoutInflater
+import android.view.View
+import android.view.ViewGroup
+import otus.gpb.homework.fragments.databinding.FragmentBBinding
+
+class FragmentB : Fragment() {
+    private var _binding: FragmentBBinding? = null
+    private val binding get() = _binding!!
+
+    override fun onCreateView(
+        inflater: LayoutInflater, container: ViewGroup?,
+        savedInstanceState: Bundle?
+    ): View {
+        _binding = FragmentBBinding.inflate(inflater, container, false)
+        val view = binding.root
+        return view
+    }
+
+    override fun onDestroyView() {
+        super.onDestroyView()
+        _binding = null
+    }
+}

app/src/main/java/otus/gpb/homework/fragments/FragmentBA.kt

@@ -0,0 +1,85 @@
+package otus.gpb.homework.fragments
+
+import android.content.Context
+import android.os.Bundle
+import androidx.fragment.app.Fragment
+import android.view.LayoutInflater
+import android.view.View
+import android.view.ViewGroup
+import android.widget.Toast
+import androidx.activity.OnBackPressedCallback
+import androidx.fragment.app.setFragmentResultListener
+import otus.gpb.homework.fragments.databinding.FragmentBABinding
+
+class FragmentBA : Fragment() {
+    private var _binding: FragmentBABinding? = null
+    private val binding get() = _binding!!
+    private var isTablet = false
+
+    override fun onAttach(context: Context) {
+        super.onAttach(context)
+
+        requireActivity().onBackPressedDispatcher.addCallback(
+            this,
+            object : OnBackPressedCallback(true) {
+                override fun handleOnBackPressed() {
+                    val count = childFragmentManager.backStackEntryCount
+                    Toast.makeText(requireContext(), "BackStack count: $count", Toast.LENGTH_SHORT)
+                        .show()
+                    when {
+                        count > 1 -> childFragmentManager.popBackStack()
+                        count == 1 -> {
+                            binding.buttonBA.visibility = View.VISIBLE
+                            childFragmentManager.popBackStack()
+                        }
+
+                        count == 0 -> requireActivity().finish()
+                        else -> {
+                            isEnabled = false
+                            requireActivity().onBackPressedDispatcher.onBackPressed()
+                        }
+                    }
+                }
+            })
+    }
+
+    override fun onCreateView(
+        inflater: LayoutInflater, container: ViewGroup?,
+        savedInstanceState: Bundle?
+    ): View {
+        _binding = FragmentBABinding.inflate(inflater, container, false)
+        return binding.root
+    }
+
+    override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
+        super.onViewCreated(view, savedInstanceState)
+
+        isTablet = requireActivity().findViewById<View>(R.id.fragment1) != null
+
+        observeResult(isTablet) { color ->
+            binding.containerBA.setBackgroundColor(color)
+        }
+
+        if (isTablet) {
+            binding.buttonBA.visibility = View.GONE
+        }
+
+        binding.buttonBA.setOnClickListener {
+            openFragmentBB()
+        }
+    }
+
+    private fun openFragmentBB() {
+        val fragmentBB = FragmentBB()
+        parentFragmentManager.beginTransaction()
+            .replace(R.id.containerBA, fragmentBB, "FragmentBB")
+            .addToBackStack(null)
+            .commit()
+
+        binding.buttonBA.visibility = View.GONE
+    }
+
+    fun showButtonBA() {
+        binding.buttonBA.visibility = View.VISIBLE
+    }
+}