Replaced fragment switching functionality in MainActivity.kt with Navigation component, simplifying logic significantly; upgraded to AGP 8.0.1

app/src/main/java/com/denizk0461/studip/activity/MainActivity.kt

@@ -3,15 +3,10 @@ package com.denizk0461.studip.activity
 import android.os.Bundle
 import androidx.core.view.WindowCompat
 import androidx.fragment.app.FragmentActivity
-import androidx.fragment.app.FragmentTransaction
+import androidx.navigation.fragment.NavHostFragment
-import androidx.lifecycle.Lifecycle
+import androidx.navigation.fragment.findNavController
-import com.denizk0461.studip.R
+import androidx.navigation.ui.setupWithNavController
 import com.denizk0461.studip.databinding.ActivityMainBinding
-import com.denizk0461.studip.db.AppRepository
-import com.denizk0461.studip.fragment.EventFragment
-import com.denizk0461.studip.fragment.CanteenFragment
-import com.denizk0461.studip.fragment.SettingsFragment
-import com.denizk0461.studip.model.SettingsPreferences
 
 /**
  * Main activity that handles all common fragments. This is opened on app launch.
@@ -21,91 +16,17 @@ class MainActivity : FragmentActivity() {
     // View binding
     private lateinit var binding: ActivityMainBinding
 
-    /*
-     * Tag for the currently active fragment; set on activity launch to the fragment that will be
-     * shown first.
-     */
-    private var currentFragment: String = "event"
-
     override fun onCreate(savedInstanceState: Bundle?) {
         WindowCompat.setDecorFitsSystemWindows(window, false)
         super.onCreate(savedInstanceState)
 
-        /*
-         * Instantiate repository object that is accessed by the fragments' view models to retrieve
-         * data.
-         */
-//        Dependencies.repo = AppRepository(application)
-
         // Inflate view binding and bind to this activity
         binding = ActivityMainBinding.inflate(layoutInflater)
         setContentView(binding.root)
 
-        // Set up navigation view bar to launch fragments
+        // Set up bottom navigation view to navigate between fragments
-        binding.navView.setOnItemSelectedListener { item ->
+        binding.navView.setupWithNavController(
-            // Launch fragment based on the item that has been clicked
+            binding.navHostFragmentContentMain.getFragment<NavHostFragment>().findNavController()
-            loadFragment(when (item.itemId) {
+        )
-                R.id.food -> "canteen"
-                R.id.settings -> "settings"
-                else -> "event"
-            })
-        }
-
-        // Set up bottom nav bar and the initial fragment when the app launches
-        if (savedInstanceState == null) {
-            // Open the fragment that the user specified to open on app start
-            if (AppRepository.getRepositoryInstance(application)
-                    .getBooleanPreference(SettingsPreferences.LAUNCH_CANTEEN_ON_START)
-            ) {
-                // Open canteen fragment
-                binding.navView.selectedItemId = R.id.food
-                currentFragment = "canteen"
-            } else {
-                // Open event fragment
-                binding.navView.selectedItemId = R.id.plan
-                currentFragment = "event"
-            }
-
-            // Launch the fragment defined in currentFragment
-            loadFragment(currentFragment)
-        }
-    }
-
-    /**
-     * Loads a given fragment.
-     *
-     * @param type  tag for the fragment that is to be opened
-     * @return      true on success, false if another fragment is currently instantiating
-     */
-    private fun loadFragment(type: String): Boolean {
-
-        // Find the fragment that is to be opened, or create it if it hasn't been instantiated yet
-        val fragment = supportFragmentManager.findFragmentByTag(type) ?: getFragment(type)
-
-        // Don't interrupt the current fragment's lifecycle if it isn't fully initialised
-        if (fragment.lifecycle.currentState != Lifecycle.State.INITIALIZED) {
-            return false
-        }
-
-        // Start the transaction to show the new fragment
-        supportFragmentManager.beginTransaction()
-            .replace(R.id.nav_host_fragment_content_main, fragment, type)
-            .setTransition(FragmentTransaction.TRANSIT_FRAGMENT_FADE)
-            .commit()
-
-        // Success
-        return true
-    }
-
-    /**
-     * Retrieve fragment by its tag.
-     *
-     * @param type  tag for the corresponding fragment
-     * @return      the corresponding fragment
-     */
-    private fun getFragment(type: String) = when (type) {
-        "canteen" -> CanteenFragment() // CanteenFragment.kt
-        "settings" -> SettingsFragment() // SettingsFragment.kt
-        else -> EventFragment() // on unknown value or "event", launch EventFragment.kt
     }
 }

app/src/main/java/com/denizk0461/studip/adapter/StudIPEventItemAdapter.kt

@@ -24,6 +24,7 @@ import java.util.*
  */
 class StudIPEventItemAdapter(
     private val currentDay: Int,
+    private val highlightNextCourse: Boolean,
     private val onClickListener: OnClickListener,
 ) : RecyclerView.Adapter<StudIPEventItemAdapter.EventViewHolder>() {
 
@@ -80,10 +81,11 @@ class StudIPEventItemAdapter(
         val theme = holder.binding.root.context.theme
 
         /*
-         * Highlight the next upcoming course of the day if the day of the adapter matches the
+         * Highlight the next upcoming course of the day if the user selected the option, if the day
-         * current day, and if no other course has been highlighted, to avoid double highlighting.
+         * of the adapter matches the current day, and if no other course has been highlighted, to
+         * avoid double highlighting.
          */
-        if (!isAnyCourseHighlighted && currentItem.isCurrentCourse(currentCalendar)) {
+        if (highlightNextCourse && !isAnyCourseHighlighted && currentItem.isCurrentCourse(currentCalendar)) {
             // Ensure that no other course will be highlighted
             isAnyCourseHighlighted = true
 

app/src/main/java/com/denizk0461/studip/fragment/CanteenFragment.kt

@@ -124,17 +124,6 @@ class CanteenFragment : AppFragment() {
             chip.setOnCheckedChangeListener { buttonView, newValue ->
                 // Save the preference change to persistent storage
                 setPreference(pref, newValue)
-
-                /*
-                 * Force an animation on click. This is a subpar method from StackOverflow. Since
-                 * it removes the view before immediately adding it back, this method causes a
-                 * flicker.
-                 * TODO implement a more efficient / better-looking method
-                 * TODO order the chips alphabetically?
-                 */
-//                val index = binding.chipsPreference.indexOfChild(buttonView)
-//                binding.chipsPreference.removeView(buttonView)
-//                binding.chipsPreference.addView(buttonView, index)
             }
         }
 
@@ -152,6 +141,8 @@ class CanteenFragment : AppFragment() {
 
             // Let the adapter know of the new amount of dates (pages) to display
             viewPagerAdapter.itemCount = dates.size
+
+            openingHours = viewModel.getCanteenOpeningHours()
         }
 
         // Assign the adapter to the view pager

app/src/main/java/com/denizk0461/studip/fragment/EventPageFragment.kt

@@ -48,7 +48,11 @@ class EventPageFragment : AppFragment(), StudIPEventItemAdapter.OnClickListener
         currentDay = arguments?.getInt("currentDay") ?: -1
 
         // Instantiate event adapter with the current day
-        eventAdapter = StudIPEventItemAdapter(currentDay, this)
+        eventAdapter = StudIPEventItemAdapter(
+            currentDay,
+            viewModel.preferenceCourseHighlighting,
+            this,
+        )
 
         // Inflate view binding
         _binding = RecyclerViewBinding.inflate(inflater, container, false)

app/src/main/java/com/denizk0461/studip/viewmodel/CanteenPageViewModel.kt

@@ -43,7 +43,6 @@ class CanteenPageViewModel(app: Application) : AppViewModel(app) {
     /**
      * This value determines which canteen the user has selected.
      */
-    var preferenceColour: Boolean
+    val preferenceColour: Boolean
-        get() = repo.getBooleanPreference(SettingsPreferences.COLOUR_PREFS)
+        get() = repo.getBooleanPreference(SettingsPreferences.COLOUR_PREFS, defaultValue = true)
-        set(newValue) { repo.setPreference(SettingsPreferences.COLOUR_PREFS, newValue) }
 }

app/src/main/java/com/denizk0461/studip/viewmodel/EventPageViewModel.kt

@@ -2,6 +2,7 @@ package com.denizk0461.studip.viewmodel
 
 import android.app.Application
 import androidx.lifecycle.LiveData
+import com.denizk0461.studip.model.SettingsPreferences
 import com.denizk0461.studip.model.StudIPEvent
 
 /**
@@ -17,4 +18,14 @@ class EventPageViewModel(app: Application) : AppViewModel(app) {
      * @return  Stud.IP events for a certain day exposed through a LiveData object
      */
     fun getEventsForDay(day: Int): LiveData<List<StudIPEvent>> = repo.getEventsForDay(day)
+
+    /**
+     * This value determines whether the user wants to have the next course in their schedule
+     * highlighted.
+     */
+    val preferenceCourseHighlighting: Boolean
+        get() = repo.getBooleanPreference(
+            SettingsPreferences.COURSE_HIGHLIGHTING,
+            defaultValue = true
+        )
 }

app/src/main/java/com/denizk0461/studip/viewmodel/SettingsViewModel.kt

@@ -15,7 +15,10 @@ class SettingsViewModel(app: Application) : AppViewModel(app) {
      * highlighted.
      */
     var preferenceCourseHighlighting: Boolean
-        get() = repo.getBooleanPreference(SettingsPreferences.COURSE_HIGHLIGHTING)
+        get() = repo.getBooleanPreference(
+            SettingsPreferences.COURSE_HIGHLIGHTING,
+            defaultValue = true
+        )
         set(newValue) { repo.setPreference(SettingsPreferences.COURSE_HIGHLIGHTING, newValue) }
 
     /**
@@ -36,7 +39,7 @@ class SettingsViewModel(app: Application) : AppViewModel(app) {
      * This value determines which canteen the user has selected.
      */
     var preferenceColour: Boolean
-        get() = repo.getBooleanPreference(SettingsPreferences.COLOUR_PREFS)
+        get() = repo.getBooleanPreference(SettingsPreferences.COLOUR_PREFS, defaultValue = true)
         set(newValue) { repo.setPreference(SettingsPreferences.COLOUR_PREFS, newValue) }
 
     /**

app/src/main/res/layout/activity_main.xml

@@ -13,6 +13,7 @@
         android:layout_width="0dp"
         android:layout_height="0dp"
         app:defaultNavHost="true"
+        app:navGraph="@navigation/main_nav_graph"
         app:layout_constraintTop_toTopOf="parent"
         app:layout_constraintBottom_toTopOf="@+id/nav_view"
         app:layout_constraintStart_toStartOf="parent"

app/src/main/res/layout/fragment_canteen.xml

@@ -44,6 +44,15 @@
 
             </androidx.appcompat.widget.LinearLayoutCompat>
 
+            <TextView
+                android:id="@+id/app_title_bar"
+                android:layout_width="match_parent"
+                android:layout_height="48dp"
+                android:text="@string/title_food"
+                android:textSize="32sp"
+                android:fontFamily="@font/lato_bolditalic"
+                android:layout_marginHorizontal="16dp"/>
+
             <HorizontalScrollView
                 android:id="@+id/scroll_view_chip"
                 android:layout_width="match_parent"
@@ -181,15 +190,6 @@
 
             </HorizontalScrollView>
 
-            <TextView
-                android:id="@+id/app_title_bar"
-                android:layout_width="match_parent"
-                android:layout_height="48dp"
-                android:text="@string/title_food"
-                android:textSize="32sp"
-                android:fontFamily="@font/lato_bolditalic"
-                android:layout_marginHorizontal="16dp"/>
-
         </androidx.appcompat.widget.LinearLayoutCompat>
 
         <com.google.android.material.tabs.TabLayout

app/src/main/res/menu/nav_view_items.xml

@@ -1,12 +1,12 @@
 <?xml version="1.0" encoding="utf-8"?>
 <menu xmlns:android="http://schemas.android.com/apk/res/android">
     <item
-        android:id="@+id/plan"
+        android:id="@+id/schedule"
         android:icon="@drawable/design"
         android:title="@string/nav_schedule"
         android:enabled="true"/>
     <item
-        android:id="@+id/food"
+        android:id="@+id/canteen"
         android:icon="@drawable/restaurant"
         android:title="@string/nav_food"
         android:enabled="true"/>

app/src/main/res/navigation/main_nav_graph.xml

@@ -0,0 +1,22 @@
+<?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/main_nav_graph"
+    app:startDestination="@id/schedule">
+
+    <fragment
+        android:id="@+id/schedule"
+        android:name="com.denizk0461.studip.fragment.EventFragment"
+        android:label="EventFragment"
+        tools:layout="@layout/fragment_event"/>
+    <fragment
+        android:id="@+id/canteen"
+        android:name="com.denizk0461.studip.fragment.CanteenFragment"
+        android:label="CanteenFragment"/>
+    <fragment
+        android:id="@+id/settings"
+        android:name="com.denizk0461.studip.fragment.SettingsFragment"
+        android:label="SettingsFragment"
+        tools:layout="@layout/fragment_settings"/>
+</navigation>

build.gradle

@@ -1,6 +1,6 @@
 // Top-level build file where you can add configuration options common to all sub-projects/modules.
 plugins {
-    id 'com.android.application' version '8.0.0' apply false
+    id 'com.android.application' version '8.0.1' apply false
-    id 'com.android.library' version '8.0.0' apply false
+    id 'com.android.library' version '8.0.1' apply false
     id 'org.jetbrains.kotlin.android' version '1.8.20' apply false
 }