anchor.diff:        logger.printError('Please check ${manifest.path} for errors.');
         return null;
       }
  -    final String packageId = manifests.first.getAttribute('package');
  -
  -    String launchActivity;
  +    final String? packageId = manifests.first.getAttribute('package');
  +
  +    String? launchActivity;
       for (final XmlElement activity in document.findAllElements('activity')) {
  -      final String enabled = activity.getAttribute('android:enabled');
  +      final String? enabled = activity.getAttribute('android:enabled');
         if (enabled != null && enabled == 'false') {
           continue;
         }
   
         for (final XmlElement element in activity.findElements('intent-filter')) {
  -        String actionName = '';
  -        String categoryName = '';
  +        String? actionName = '';
  +        String? categoryName = '';
           for (final XmlNode node in element.children) {
             if (node is! XmlElement) {
               continue;
             }
  -          final XmlElement xmlElement = node as XmlElement;
  -          final String name = xmlElement.getAttribute('android:name');
  +          final String? name = node.getAttribute('android:name');
             if (name == 'android.intent.action.MAIN') {
               actionName = name;
             } else if (name == 'android.intent.category.LAUNCHER') {
               categoryName = name;
             }
           }
  -        if (actionName.isNotEmpty && categoryName.isNotEmpty) {
  -          final String activityName = activity.getAttribute('android:name');
  +        if (actionName != null && categoryName != null && actionName.isNotEmpty && categoryName.isNotEmpty) {
  +          final String? activityName = activity.getAttribute('android:name');
             launchActivity = '$packageId/$activityName';
             break;
           }
  
positive.code: 
        // Handle level out
        while (currentElement.parent != null && level <= currentElement.level) {
          currentElement = currentElement.parent;
        }
  
        if (level > currentElement.level) {
  
negative.code:   /// Creates a new AndroidApk from an existing APK.
    ///
    /// Returns `null` if the APK was invalid or any required tooling was missing.
    static AndroidApk? fromApk(
      File apk, {
      required AndroidSdk androidSdk,
      required ProcessManager processManager,
      required UserMessages userMessages,
      required Logger logger,
      required ProcessUtils processUtils,
    }) {
      final String? aaptPath = androidSdk.latestVersion?.aaptPath;
      if (aaptPath == null || !processManager.canRun(aaptPath)) {
        logger.printError(userMessages.aaptNotFound);
        return null;
  