官方 GitHub 地址 : https://github.com/flutter Flutter 中文社区 : https://flutter.cn/ Flutter 实用教程 : https://flutter.cn/docs/cookbook Flutter CodeLab : https://codelabs.flutter-io.cn/ Dart 中文...
error;/// Returns whether this snapshot contains a non-null [data] value./// This can be false even when the asynchronous computation has completed/// successfully, if the computation did not return a non-null value. For/// example, a [Future<void>] will complete with the null value ...
FutureProvider：你可以用它从firestore中检索一个文档，并在等待时显示一个加载屏幕，但不能在之后对其...
error;/// Returns whether this snapshot contains a non-null [data] value./// This can be false even when the asynchronous computation has completed/// successfully, if the computation did not return a non-null value. For/// example, a [Future<void>] will complete with the null value ...
而其他部件可能使用变异后的值。解决方案是消除不一致性。使用ChangeNotifierProvider，通常有两种情况：...
在Flutter中,build方法是一个重要的函数,用于构建Flutter小部件的用户界面。它负责生成小部件的布局和外观,并且会在小部件状态发生变化时自动调用以更新界面。 由于build方法的调用是由Flutter框架自动管理的,频繁调用build方法可能会导致性能下降和界面卡顿。因此,为了优化应用的性能,我们通常希望限制多次调用build方法的情况...
/// example, a [Future<void>] will complete with the null value even if it /// completes successfully. bool get hasData => data != null; /// Returns whether this snapshot contains a non-null [error] value. /// /// This is always true if the asynchronous computation's last resul...
For querying in Flutter, you can check the API reference for its equivalence. FirebaseFirestore.instance .collection('players') .where('rank', isGreaterThanOrEqualTo: 2) .where('rank', isLessThanOrEqualTo: 10) .snapshots() Here's a sample that I posted previously that filters and ...
first you assign your _getData() future function to a variable (_myData) with the same return type, after that, you can override it's value in setState() that will rebuild the UI and therefor run the future again. in code it will looks like this.(from you example): ...
FutureProvider：你可以用它从firestore中检索一个文档，并在等待时显示一个加载屏幕，但不能在之后对其...