For #19258: Replace default Android back button with a custom icon.

app/src/main/java/org/mozilla/fenix/HomeActivity.kt

@@ -82,6 +82,7 @@ import org.mozilla.fenix.ext.navigateBlockingForAsyncNavGraph
 import org.mozilla.fenix.ext.measureNoInline
 import org.mozilla.fenix.ext.metrics
 import org.mozilla.fenix.ext.nav
+import org.mozilla.fenix.ext.setNavigationIcon
 import org.mozilla.fenix.ext.settings
 import org.mozilla.fenix.home.HomeFragmentDirections
 import org.mozilla.fenix.home.intent.CrashReporterIntentProcessor
@@ -717,6 +718,7 @@ open class HomeActivity : LocaleAwareAppCompatActivity(), NavHostActivity {
             setSupportActionBar(navigationToolbar)
             // Add ids to this that we don't want to have a toolbar back button
             setupNavigationToolbar()
+            setNavigationIcon(R.drawable.ic_back_button)
 
             isToolbarInflated = true
         }

app/src/main/java/org/mozilla/fenix/ext/Activity.kt

@@ -12,9 +12,12 @@ import android.app.role.RoleManager
 import android.content.Intent
 import android.os.Build
 import android.provider.Settings
+import androidx.annotation.DrawableRes
+import androidx.appcompat.app.AppCompatActivity
 import androidx.core.os.bundleOf
 import org.mozilla.fenix.BrowserDirection
 import org.mozilla.fenix.HomeActivity
+import org.mozilla.fenix.R
 import org.mozilla.fenix.settings.SupportUtils
 
 /**
@@ -108,6 +111,20 @@ private fun Activity.navigateToDefaultBrowserAppsSettings() {
     }
 }
 
+/**
+ * Sets the icon for the back (up) navigation button.
+ * @param icon The resource id of the icon.
+ */
+fun Activity.setNavigationIcon(
+    @DrawableRes icon: Int
+) {
+    (this as? AppCompatActivity)?.supportActionBar?.let {
+        it.setDisplayHomeAsUpEnabled(true)
+        it.setHomeAsUpIndicator(icon)
+        it.setHomeActionContentDescription(R.string.action_bar_up_description)
+    }
+}
+
 const val REQUEST_CODE_BROWSER_ROLE = 1
 const val SETTINGS_SELECT_OPTION_KEY = ":settings:fragment_args_key"
 const val SETTINGS_SHOW_FRAGMENT_ARGS = ":settings:show_fragment_args"

app/src/main/java/org/mozilla/fenix/ext/Fragment.kt

@@ -35,6 +35,7 @@ fun Fragment.getPreferenceKey(@StringRes resourceId: Int): String = getString(re
  */
 fun Fragment.showToolbar(title: String) {
     (requireActivity() as AppCompatActivity).title = title
+    activity?.setNavigationIcon(R.drawable.ic_back_button)
     (activity as NavHostActivity).getSupportActionBarAndInflateIfNecessary().show()
 }
 

app/src/main/java/org/mozilla/fenix/library/LibraryPageView.kt

@@ -44,5 +44,7 @@ open class LibraryPageView(
         activity?.title = title
         val toolbar = activity?.findViewById<Toolbar>(R.id.navigationToolbar)
         toolbar?.setToolbarColors(foregroundColor, backgroundColor)
+        toolbar?.setNavigationIcon(R.drawable.ic_back_button)
+        toolbar?.navigationIcon?.setTint(foregroundColor)
     }
 }

app/src/main/java/org/mozilla/fenix/library/history/HistoryFragment.kt

@@ -105,6 +105,7 @@ class HistoryFragment : LibraryPageFragment<HistoryItem>(), UserInteractionHandl
             view.historyLayout,
             historyInteractor
         )
+        showToolbar(getString(R.string.library_history))
 
         return view
     }
@@ -161,7 +162,6 @@ class HistoryFragment : LibraryPageFragment<HistoryItem>(), UserInteractionHandl
 
     override fun onResume() {
         super.onResume()
-        showToolbar(getString(R.string.library_history))
     }
 
     override fun onCreateOptionsMenu(menu: Menu, inflater: MenuInflater) {

app/src/main/java/org/mozilla/fenix/settings/about/AboutFragment.kt

@@ -25,6 +25,7 @@ import org.mozilla.fenix.crashes.CrashListActivity
 import org.mozilla.fenix.ext.navigateBlockingForAsyncNavGraph
 import org.mozilla.fenix.ext.requireComponents
 import org.mozilla.fenix.ext.settings
+import org.mozilla.fenix.ext.showToolbar
 import org.mozilla.fenix.settings.SupportUtils
 import org.mozilla.fenix.settings.about.AboutItemType.LICENSING_INFO
 import org.mozilla.fenix.settings.about.AboutItemType.PRIVACY_NOTICE
@@ -53,7 +54,7 @@ class AboutFragment : Fragment(), AboutPageListener {
         appName = getString(R.string.app_name)
         headerAppName =
             if (Config.channel.isRelease) getString(R.string.daylight_app_name) else appName
-        activity?.title = getString(R.string.preferences_about, appName)
+        showToolbar(getString(R.string.preferences_about, appName))
 
         return rootView
     }

app/src/main/res/drawable/ic_back_button.xml

@@ -0,0 +1,13 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+    android:width="24dp"
+    android:height="24dp"
+    android:viewportWidth="24"
+    android:viewportHeight="24">
+    <path
+        android:fillColor="?primaryText"
+        android:pathData="M20.25,11.5H5.461L11.431,5.53C11.724,5.237 11.724,4.762 11.431,4.469C11.138,4.176 10.663,4.176 10.37,4.469L3,11.839V12.66L10.37,20.03C10.516,20.176 10.708,20.25 10.9,20.25C11.092,20.25 11.284,20.177 11.43,20.03C11.723,19.737 11.723,19.262 11.43,18.969L5.461,13H20.25C20.664,13 21,12.664 21,12.25C21,11.836 20.664,11.5 20.25,11.5Z" />
+</vector>

app/src/main/res/values/strings.xml

@@ -1713,4 +1713,7 @@
 
     <!-- Content description radio buttons with a link to more information -->
     <string name="radio_preference_info_content_description">Click for more details</string>
+
+    <!-- Content description for the action bar "up" button -->
+    <string name="action_bar_up_description">Navigate up</string>
 </resources>