(re-)added option to launch timetable on the current day; reinstated functionality to launch app on CanteenFragment.kt

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

@@ -3,10 +3,13 @@ package com.denizk0461.studip.activity
 import android.os.Bundle
 import androidx.core.view.WindowCompat
 import androidx.fragment.app.FragmentActivity
+import androidx.lifecycle.ViewModelProvider
 import androidx.navigation.fragment.NavHostFragment
 import androidx.navigation.fragment.findNavController
 import androidx.navigation.ui.setupWithNavController
+import com.denizk0461.studip.R
 import com.denizk0461.studip.databinding.ActivityMainBinding
+import com.denizk0461.studip.viewmodel.MainViewModel
 
 /**
  * Main activity that handles all common fragments. This is opened on app launch.
@@ -16,10 +19,17 @@ class MainActivity : FragmentActivity() {
     // View binding
     private lateinit var binding: ActivityMainBinding
 
+    // View model
+    private lateinit var viewModel: MainViewModel
+
     override fun onCreate(savedInstanceState: Bundle?) {
         WindowCompat.setDecorFitsSystemWindows(window, false)
         super.onCreate(savedInstanceState)
 
+        // Instantiate view model
+        viewModel = ViewModelProvider.AndroidViewModelFactory(application)
+            .create(MainViewModel::class.java)
+
         // Inflate view binding and bind to this activity
         binding = ActivityMainBinding.inflate(layoutInflater)
         setContentView(binding.root)
@@ -28,5 +38,25 @@ class MainActivity : FragmentActivity() {
         binding.navView.setupWithNavController(
             binding.navHostFragmentContentMain.getFragment<NavHostFragment>().findNavController()
         )
+
+        setNavigationGraph()
+    }
+
+    /**
+     * Sets the navigation graph for the fragments. Also sets the start destination.
+     */
+    private fun setNavigationGraph() {
+        val navHostFragment = supportFragmentManager
+            .findFragmentById(R.id.nav_host_fragment_content_main) as NavHostFragment
+        val navController = navHostFragment.navController
+
+        val navGraph = navController.navInflater.inflate(R.navigation.main_nav_graph)
+        navGraph.setStartDestination(if (viewModel.preferenceLaunchCanteen) {
+            R.id.canteen
+        } else {
+            R.id.schedule
+        })
+
+        navController.graph = navGraph
     }
 }