Add file styles.xml at location android/app/src/main/res/values with the following content:
``` <?xml version="1.0" encoding="utf-8"?> <resources> <color name="ic_launcher_background">#143543</color> <!-- Theme applied to the Android Window while the process is starting when the OS's Dark Mode setting is off --> <style name="LaunchTheme" parent="@android:style/Theme.Light.NoTitleBar"> <!-- Show a splash screen on the activity. Automatically removed when the Flutter engine draws its first frame --> <item name="android:windowBackground">@drawable/launch_background</item> </style> <!-- Theme applied to the Android Window as soon as the process has started. This theme determines the color of the Android Window while your Flutter UI initializes, as well as behind your Flutter UI while its running.
This Theme is only used starting with V2 of Flutter's Android embedding. --> <style name="NormalTheme" parent="@android:style/Theme.Light.NoTitleBar"> <item name="android:windowBackground">?android:colorBackground</item> </style> </resources> ```

This could be an `AppBar` which is located inside a `Scaffold`. Try looking for it in the project and delete it.
Alternatively this could be based on the android activitie's theme. In the android specific module, open the manifest.xml file and check which themes are used in the activities:
```XML <manifest ...> <application ...> <activity android:name=".MainActivity" android:exported="true" android:launchMode="singleTop" android:theme="@style/LaunchTheme" android:configChanges="orientation|keyboardHidden|keyboard|screenSize|smallestScreenSize|locale|layoutDirection|fontScale|screenLayout|density|uiMode" android:hardwareAccelerated="true" android:windowSoftInputMode="adjustResize"> ... </activity>
<meta-data android:name="io.flutter.embedding.android.NormalTheme" android:resource="@style/NormalTheme" />
... </application> </manifest>
```
In this case, flutter uses `LaunchTheme` and after the launch it applies `NormalTheme`.
Open then the styles.xml file (usually located at: `android/app/src/main/res/values/styles.xml`). Find the styles that match the styles which are used by the activity and check if they both inherit from a `NoTitleBar` style.
```XML <?xml version="1.0" encoding="utf-8"?> <resources> <!-- Theme applied to the Android Window while the process is starting when the OS's Dark Mode setting is off --> <style name="LaunchTheme" parent="@android:style/Theme.Light.NoTitleBar"> <!-- Show a splash screen on the activity. Automatically removed when Flutter draws its first frame --> <item name="android:windowBackground">@drawable/launch_background</item> </style> <!-- Theme applied to the Android Window as soon as the process has started. This theme determines the color of the Android Window while your Flutter UI initializes, as well as behind your Flutter UI while its running.
This Theme is only used starting with V2 of Flutter's Android embedding. --> <style name="NormalTheme" parent="@android:style/Theme.Light.NoTitleBar"> <item name="android:windowBackground">?android:colorBackground</item> </style> </resources>
```