flutter pub add nil根據套件公開資料產生的選型評估，僅供參考。
nil 包提供了一個極簡且效能優化的 widget，當包含在 widget 樹中時，它不會渲染任何內容。它適用於需要佔位符或條件 widget 的情境，這些 widget 不會增加佈局或渲染開銷。與 SizedBox.shrink() 或 Container() 不同，nil 對 widget 樹的效能沒有任何影響，非常適合在外部處理可見性條件的動態 UI 邏輯中使用。它輕量且安全，適用於複雜或經常更新的 UI。
以下為關聯原始碼儲存庫的 README 原文快照，最新內容請造訪原始碼儲存庫。
A simple widget to add in the widget tree when you want to show nothing, with minimal impact on performance.
Sometimes, according to a condition, we want to display nothing. Usually when we can't return null, we would return something like const SizedBox() for example.
This is good, but it has some performance impacts since SizedBox creates a RenderObject. The RenderObject lives in the render tree and some computations are performed on it, even if it paints nothing on the screen.
We can do better, we can have a widget which does not create a RenderObject, while being still valid. The Nil widget is the minimal implementation for this use case. It only creates an Element and does nothing while it's building. Because the optimal way to use it, is to call const Nil(), it also comes with a nil constant that you can use everywhere (which is a const Nil()).
import 'package:nil/nil.dart';
return Builder(
builder: (_) {
if (condition) {
return const MyWidget();
} else {
return nil;
}
},
);
This widget is not intended to be used in widgets accepting multiple children (e.g. Rows, Columns, etc.). The best option is to not add a widget in the list if you don't want it to be displayed. Moreover using a Nil widget in such a case, can have unexpected results.
I'm working on my packages on my free-time, but I don't have as much time as I would. If this package or any other package I created is helping you, please consider to sponsor me so that I can take time to read the issues, fix bugs, merge pull requests and add features to these packages.
Feel free to contribute to this project.
If you find a bug or want a feature, but don't know how to fix/implement it, please fill an issue.
If you fixed a bug or implemented a feature, please send a pull request.