day 215

android-basics-kotlin-words-app-activities/app/src/main/java/com/example/wordsapp/LetterAdapter.kt

@@ -23,6 +23,7 @@ import android.view.ViewGroup
 import android.view.accessibility.AccessibilityNodeInfo
 import android.widget.Button
 import androidx.annotation.RequiresApi
+import androidx.navigation.findNavController
 import androidx.recyclerview.widget.RecyclerView
 
 
@@ -68,15 +69,8 @@ class LetterAdapter :
 
         // Assigns a [OnClickListener] to the button contained in the [ViewHolder]
         holder.button.setOnClickListener {
-            val context = holder.view.context
-            // Create an intent with a destination of DetailActivity
-            val intent = Intent(context, DetailActivity::class.java)
-            // Add the selected letter to the intent as extra data
-            // The text of Buttons are [CharSequence], a list of characters,
-            // so it must be explicitly converted into a [String].
-            intent.putExtra(WordListFragment.LETTER, holder.button.text.toString())
-            // Start an activity using the data and destination from the Intent.
-            context.startActivity(intent)
+            val action = LetterListFragmentDirections.actionLetterListFragmentToWordListFragment(letter = holder.button.text.toString())
+            holder.view.findNavController().navigate(action)
         }
     }
 

android-basics-kotlin-words-app-activities/app/src/main/java/com/example/wordsapp/MainActivity.kt

@@ -20,6 +20,9 @@ import android.view.Menu
 import android.view.MenuItem
 import androidx.appcompat.app.AppCompatActivity
 import androidx.core.content.ContextCompat
+import androidx.navigation.NavController
+import androidx.navigation.fragment.NavHostFragment
+import androidx.navigation.ui.setupActionBarWithNavController
 import androidx.recyclerview.widget.GridLayoutManager
 import androidx.recyclerview.widget.LinearLayoutManager
 import androidx.recyclerview.widget.RecyclerView
@@ -29,10 +32,19 @@ import com.example.wordsapp.databinding.ActivityMainBinding
  * Main Activity and entry point for the app. Displays a RecyclerView of letters.
  */
 class MainActivity : AppCompatActivity() {
+    private lateinit var navController: NavController
+
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
 
         val binding = ActivityMainBinding.inflate(layoutInflater)
         setContentView(binding.root)
+        val navHostFragment = supportFragmentManager.findFragmentById(R.id.nav_host_fragment) as NavHostFragment
+        navController = navHostFragment.navController
+        setupActionBarWithNavController(navController)
     }
+
+    override fun onSupportNavigateUp(): Boolean {
+        return navController.navigateUp() || super.onSupportNavigateUp()
+    }2
 }

android-basics-kotlin-words-app-activities/app/src/main/res/layout/activity_main.xml

@@ -15,14 +15,16 @@
 -->
 <FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
     xmlns:tools="http://schemas.android.com/tools"
+    xmlns:app="http://schemas.android.com/apk/res-auto"
     android:layout_width="match_parent"
     android:layout_height="match_parent"
     tools:context=".MainActivity">
 
-    <androidx.recyclerview.widget.RecyclerView
-        android:id="@+id/recycler_view"
+    <androidx.fragment.app.FragmentContainerView
         android:layout_width="match_parent"
         android:layout_height="match_parent"
-        android:clipToPadding="false"
-        android:padding="16dp" />
+        android:id="@+id/nav_host_fragment"
+        android:name="androidx.navigation.fragment.NavHostFragment"
+        app:defaultNavHost="true"
+        app:navGraph="@navigation/nav_graph" />
 </FrameLayout>

android-basics-kotlin-words-app-activities/app/src/main/res/navigation/nav_graph.xml

@@ -0,0 +1,26 @@
+<?xml version="1.0" encoding="utf-8"?>
+<navigation xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:app="http://schemas.android.com/apk/res-auto"
+    xmlns:tools="http://schemas.android.com/tools"
+    android:id="@+id/nav_graph.xml"
+    app:startDestination="@id/letterListFragment">
+
+    <fragment
+        android:id="@+id/letterListFragment"
+        android:name="com.example.wordsapp.LetterListFragment"
+        android:label="fragment_letter_list"
+        tools:layout="@layout/fragment_letter_list" >
+        <action
+            android:id="@+id/action_letterListFragment_to_wordListFragment"
+            app:destination="@id/wordListFragment" />
+    </fragment>
+    <fragment
+        android:id="@+id/wordListFragment"
+        android:name="com.example.wordsapp.WordListFragment"
+        android:label="fragment_word_list"
+        tools:layout="@layout/fragment_word_list" >
+        <argument
+            android:name="letter"
+            app:argType="string" />
+    </fragment>
+</navigation>