Support WebView back button

app/src/main/java/org/traccar/manager/MainFragment.kt

@@ -38,7 +38,9 @@ import android.webkit.WebChromeClient
 import android.webkit.WebView
 import android.webkit.WebViewClient
 import android.webkit.WebViewFragment
+import androidx.activity.addCallback
 import androidx.appcompat.app.AlertDialog
+import androidx.appcompat.app.AppCompatActivity
 import androidx.core.app.ActivityCompat
 import androidx.core.content.ContextCompat
 import androidx.localbroadcastmanager.content.LocalBroadcastManager
@@ -91,6 +93,14 @@ class MainFragment : WebViewFragment() {
                 .beginTransaction().replace(android.R.id.content, StartFragment())
                 .commitAllowingStateLoss()
         }
+
+        (activity as AppCompatActivity).onBackPressedDispatcher.addCallback {
+            if (webView.canGoBack()) {
+                webView.goBack();
+            } else {
+                activity.onBackPressed()
+            }
+        }
     }
 
     private val broadcastReceiver: BroadcastReceiver = object : BroadcastReceiver() {