Navigation Drawer (Side Menu)

<?xml version="1.0" encoding="utf-8"?>
<!-- DrawerLayout = the side menu slides over the main content -->
<androidx.drawerlayout.widget.DrawerLayout 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/drawerLayout"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:fitsSystemWindows="true"
    tools:openDrawer="start">

    <!-- 1st child: main content -->
    <androidx.coordinatorlayout.widget.CoordinatorLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent">

        <com.google.android.material.appbar.AppBarLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content">

            <com.google.android.material.appbar.MaterialToolbar
                android:id="@+id/toolbar"
                android:layout_width="match_parent"
                android:layout_height="?attr/actionBarSize" />
        </com.google.android.material.appbar.AppBarLayout>

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:orientation="vertical"
            app:layout_behavior="@string/appbar_scrolling_view_behavior">

            <!-- Screens (fragments) are swapped here by the Navigation Component -->
            <androidx.fragment.app.FragmentContainerView
                android:id="@+id/nav_host"
                android:name="androidx.navigation.fragment.NavHostFragment"
                android:layout_width="match_parent"
                android:layout_height="0dp"
                android:layout_weight="1"
                app:defaultNavHost="true"
                app:navGraph="@navigation/nav_graph" />

            <com.google.android.material.bottomnavigation.BottomNavigationView
                android:id="@+id/bottomNav"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                app:menu="@menu/bottom_nav_menu" />
        </LinearLayout>

        <com.google.android.material.floatingactionbutton.FloatingActionButton
            android:id="@+id/fab"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_gravity="bottom|end"
            android:layout_marginEnd="16dp"
            android:layout_marginBottom="96dp"
            android:contentDescription="@string/add_note"
            app:srcCompat="@drawable/ic_add" />
    </androidx.coordinatorlayout.widget.CoordinatorLayout>

    <!-- 2nd child: the drawer itself -->
    <com.google.android.material.navigation.NavigationView
        android:id="@+id/navView"
        android:layout_width="wrap_content"
        android:layout_height="match_parent"
        android:layout_gravity="start"
        app:headerLayout="@layout/nav_header"
        app:menu="@menu/drawer_menu" />
</androidx.drawerlayout.widget.DrawerLayout>

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="176dp"
    android:background="@color/brand"
    android:gravity="bottom"
    android:orientation="vertical"
    android:padding="16dp">

    <ImageView
        android:layout_width="64dp"
        android:layout_height="64dp"
        android:background="@drawable/bg_circle_white"
        android:contentDescription="@string/app_name"
        android:padding="12dp"
        android:src="@drawable/ic_note"
        app:tint="@color/brand" />

    <TextView
        android:id="@+id/tvUserName"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="12dp"
        android:text="@string/app_name"
        android:textAppearance="?attr/textAppearanceTitleMedium"
        android:textColor="@android:color/white" />

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/tagline"
        android:textColor="#E0FFFFFF" />
</LinearLayout>

<?xml version="1.0" encoding="utf-8"?>
<menu xmlns:android="http://schemas.android.com/apk/res/android">
    <group android:checkableBehavior="single">
        <item android:id="@+id/notesFragment" android:icon="@drawable/ic_note" android:title="@string/menu_notes" />
        <item android:id="@+id/favoritesFragment" android:icon="@drawable/ic_star" android:title="@string/menu_favourites" />
        <item android:id="@+id/subjectsFragment" android:icon="@drawable/ic_subject" android:title="@string/menu_subjects" />
        <item android:id="@+id/statsFragment" android:icon="@drawable/ic_stats" android:title="@string/menu_stats" />
    </group>
    <item android:title="@string/menu_more">
        <menu>
            <item android:id="@+id/settingsFragment" android:icon="@drawable/ic_settings" android:title="@string/menu_settings" />
            <item android:id="@+id/helpFragment" android:icon="@drawable/ic_help" android:title="@string/menu_help" />
            <item android:id="@+id/action_share" android:icon="@drawable/ic_share" android:title="@string/share_app" />
        </menu>
    </item>
</menu>

package com.codingeasily.studentdiary

import android.Manifest
import android.content.Intent
import android.os.Build
import android.os.Bundle
import androidx.activity.OnBackPressedCallback
import androidx.activity.result.contract.ActivityResultContracts
import androidx.appcompat.app.AppCompatActivity
import androidx.core.view.GravityCompat
import androidx.core.view.isVisible
import androidx.navigation.NavController
import androidx.navigation.fragment.NavHostFragment
import androidx.navigation.ui.AppBarConfiguration
import androidx.navigation.ui.NavigationUI
import androidx.navigation.ui.navigateUp
import androidx.navigation.ui.setupActionBarWithNavController
import androidx.navigation.ui.setupWithNavController
import com.codingeasily.studentdiary.data.SettingsStore
import com.codingeasily.studentdiary.databinding.ActivityMainBinding
import com.codingeasily.studentdiary.databinding.NavHeaderBinding
import com.codingeasily.studentdiary.reminder.NotificationHelper
import com.google.android.material.snackbar.Snackbar

/**
 * The only Activity. It hosts: Toolbar + Navigation Drawer + Bottom Navigation + FAB
 * and a NavHostFragment that swaps the screens (fragments).
 */
class MainActivity : AppCompatActivity() {

    private lateinit var binding: ActivityMainBinding
    private lateinit var navController: NavController
    private lateinit var appBarConfiguration: AppBarConfiguration

    // Android 13+: ask for notification permission (result comes back here)
    private val notificationPermission =
        registerForActivityResult(ActivityResultContracts.RequestPermission()) { granted ->
            if (!granted) {
                Snackbar.make(binding.root, R.string.notifications_off, Snackbar.LENGTH_LONG).show()
            }
        }

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        binding = ActivityMainBinding.inflate(layoutInflater)
        setContentView(binding.root)
        setSupportActionBar(binding.toolbar)

        val navHost = supportFragmentManager.findFragmentById(R.id.nav_host) as NavHostFragment
        navController = navHost.navController

        // Top-level screens show the ☰ (drawer) icon; other screens show ←
        val topLevel = setOf(
            R.id.notesFragment, R.id.subjectsFragment, R.id.statsFragment,
            R.id.favoritesFragment, R.id.settingsFragment, R.id.helpFragment
        )
        appBarConfiguration = AppBarConfiguration(topLevel, binding.drawerLayout)
        setupActionBarWithNavController(navController, appBarConfiguration)
        binding.bottomNav.setupWithNavController(navController)
        binding.navView.setupWithNavController(navController)

        // Drawer has one extra item ("Share app") that is not a screen
        binding.navView.setNavigationItemSelectedListener { item ->
            if (item.itemId == R.id.action_share) shareApp()
            else NavigationUI.onNavDestinationSelected(item, navController)
            binding.drawerLayout.closeDrawer(GravityCompat.START)
            true
        }

        // Show bottom bar only on the 3 main tabs, FAB only on the notes list
        val bottomScreens = setOf(R.id.notesFragment, R.id.subjectsFragment, R.id.statsFragment)
        navController.addOnDestinationChangedListener { _, destination, _ ->
            binding.bottomNav.isVisible = destination.id in bottomScreens
            if (destination.id == R.id.notesFragment) binding.fab.show() else binding.fab.hide()
        }
        binding.fab.setOnClickListener { navController.navigate(R.id.action_global_editor) }

        // Close the drawer with the back button before leaving the screen
        onBackPressedDispatcher.addCallback(this, object : OnBackPressedCallback(true) {
            override fun handleOnBackPressed() {
                if (binding.drawerLayout.isDrawerOpen(GravityCompat.START)) {
                    binding.drawerLayout.closeDrawer(GravityCompat.START)
                } else {
                    isEnabled = false
                    onBackPressedDispatcher.onBackPressed()
                    isEnabled = true
                }
            }
        })

        askNotificationPermission()
    }

    override fun onResume() {
        super.onResume()
        // The name can change in Settings, so refresh the drawer header every time
        val header = NavHeaderBinding.bind(binding.navView.getHeaderView(0))
        header.tvUserName.text = getString(R.string.hello_user, SettingsStore(this).userName)
    }

    override fun onSupportNavigateUp(): Boolean =
        navController.navigateUp(appBarConfiguration) || super.onSupportNavigateUp()

    private fun askNotificationPermission() {
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.TIRAMISU && !NotificationHelper.canNotify(this)) {
            notificationPermission.launch(Manifest.permission.POST_NOTIFICATIONS)
        }
    }

    private fun shareApp() {
        val send = Intent(Intent.ACTION_SEND).apply {
            type = "text/plain"
            putExtra(Intent.EXTRA_TEXT, getString(R.string.share_text))
        }
        startActivity(Intent.createChooser(send, getString(R.string.share_app)))
    }
}