1 files changed, 129 insertions, 0 deletions
diff --git a/ui/src/main/java/com/wireguard/android/activity/MainActivity.kt b/ui/src/main/java/com/wireguard/android/activity/MainActivity.kt
new file mode 100644
index 00000000..087ca08e
--- /dev/null
+++ b/ui/src/main/java/com/wireguard/android/activity/MainActivity.kt
@@ -0,0 +1,129 @@
+/*
+ * Copyright © 2017-2025 WireGuard LLC. All Rights Reserved.
+ * SPDX-License-Identifier: Apache-2.0
+ */
+package com.wireguard.android.activity
+
+import android.content.Intent
+import android.os.Bundle
+import android.view.Menu
+import android.view.MenuItem
+import android.view.View
+import androidx.activity.OnBackPressedCallback
+import androidx.activity.addCallback
+import androidx.appcompat.app.ActionBar
+import androidx.fragment.app.FragmentManager
+import androidx.fragment.app.FragmentTransaction
+import androidx.fragment.app.commit
+import com.wireguard.android.R
+import com.wireguard.android.fragment.TunnelDetailFragment
+import com.wireguard.android.fragment.TunnelEditorFragment
+import com.wireguard.android.model.ObservableTunnel
+
+/**
+ * CRUD interface for WireGuard tunnels. This activity serves as the main entry point to the
+ * WireGuard application, and contains several fragments for listing, viewing details of, and
+ * editing the configuration and interface state of WireGuard tunnels.
+ */
+class MainActivity : BaseActivity(), FragmentManager.OnBackStackChangedListener {
+    private var actionBar: ActionBar? = null
+    private var isTwoPaneLayout = false
+    private var backPressedCallback: OnBackPressedCallback? = null
+
+    private fun handleBackPressed() {
+        val backStackEntries = supportFragmentManager.backStackEntryCount
+        // If the two-pane layout does not have an editor open, going back should exit the app.
+        if (isTwoPaneLayout && backStackEntries <= 1) {
+            finish()
+            return
+        }
+
+        if (backStackEntries >= 1)
+            supportFragmentManager.popBackStack()
+
+        // Deselect the current tunnel on navigating back from the detail pane to the one-pane list.
+        if (backStackEntries == 1)
+            selectedTunnel = null
+    }
+
+    override fun onBackStackChanged() {
+        val backStackEntries = supportFragmentManager.backStackEntryCount
+        backPressedCallback?.isEnabled = backStackEntries >= 1
+        if (actionBar == null) return
+        // Do not show the home menu when the two-pane layout is at the detail view (see above).
+        val minBackStackEntries = if (isTwoPaneLayout) 2 else 1
+        actionBar!!.setDisplayHomeAsUpEnabled(backStackEntries >= minBackStackEntries)
+    }
+
+    override fun onCreate(savedInstanceState: Bundle?) {
+        super.onCreate(savedInstanceState)
+        setContentView(R.layout.main_activity)
+        actionBar = supportActionBar
+        isTwoPaneLayout = findViewById<View?>(R.id.master_detail_wrapper) != null
+        supportFragmentManager.addOnBackStackChangedListener(this)
+        backPressedCallback = onBackPressedDispatcher.addCallback(this) { handleBackPressed() }
+        onBackStackChanged()
+    }
+
+    override fun onCreateOptionsMenu(menu: Menu): Boolean {
+        menuInflater.inflate(R.menu.main_activity, menu)
+        return true
+    }
+
+    override fun onOptionsItemSelected(item: MenuItem): Boolean {
+        return when (item.itemId) {
+            android.R.id.home -> {
+                // The back arrow in the action bar should act the same as the back button.
+                onBackPressedDispatcher.onBackPressed()
+                true
+            }
+
+            R.id.menu_action_edit -> {
+                supportFragmentManager.commit {
+                    replace(if (isTwoPaneLayout) R.id.detail_container else R.id.list_detail_container, TunnelEditorFragment())
+                    setTransition(FragmentTransaction.TRANSIT_FRAGMENT_FADE)
+                    addToBackStack(null)
+                }
+                true
+            }
+            // This menu item is handled by the editor fragment.
+            R.id.menu_action_save -> false
+            R.id.menu_settings -> {
+                startActivity(Intent(this, SettingsActivity::class.java))
+                true
+            }
+
+            else -> super.onOptionsItemSelected(item)
+        }
+    }
+
+    override fun onSelectedTunnelChanged(
+        oldTunnel: ObservableTunnel?,
+        newTunnel: ObservableTunnel?
+    ): Boolean {
+        val fragmentManager = supportFragmentManager
+        if (fragmentManager.isStateSaved) {
+            return false
+        }
+
+        val backStackEntries = fragmentManager.backStackEntryCount
+        if (newTunnel == null) {
+            // Clear everything off the back stack (all editors and detail fragments).
+            fragmentManager.popBackStackImmediate(0, FragmentManager.POP_BACK_STACK_INCLUSIVE)
+            return true
+        }
+        if (backStackEntries == 2) {
+            // Pop the editor off the back stack to reveal the detail fragment. Use the immediate
+            // method to avoid the editor picking up the new tunnel while it is still visible.
+            fragmentManager.popBackStackImmediate()
+        } else if (backStackEntries == 0) {
+            // Create and show a new detail fragment.
+            fragmentManager.commit {
+                add(if (isTwoPaneLayout) R.id.detail_container else R.id.list_detail_container, TunnelDetailFragment())
+                setTransition(FragmentTransaction.TRANSIT_FRAGMENT_FADE)
+                addToBackStack(null)
+            }
+        }
+        return true
+    }
+}