当前位置:网站首页>(DART) usage supplement
(DART) usage supplement
2022-07-06 22:56:00 【Xiaobai is more than that】
1. Post operators : ? 、!
String? name;
// Adding a question mark allows the static check to pass , Represents a nullable type ,String? Is a nullable type String.
DateTime? _lastPressedAt;
DateTime.now().difference(_lastPressedAt!)
// Suffixed ! Will turn the expression on the left into the corresponding Non empty type
// Like all other transformations , Use ! Some static security will be lost . These transformations must be done at runtime
Reference article :
Dart Post operator ! flutter Question mark symbol
2.late keyword
late PageController pageController;
// ( effect ) Explicitly declare a non empty variable , But not initialized
Reference article :
dart in late The role of keywords
边栏推荐
- #DAYU200体验官# 首页aito视频&Canvas绘制仪表盘(ets)
- UDP programming
- Mysql 身份认证绕过漏洞(CVE-2012-2122)
- 项目复盘模板
- MySQL实现字段分割一行转多行的示例代码
- Balanced Multimodal Learning via On-the-fly Gradient Modulation(CVPR2022 oral)
- UE4蓝图学习篇(四)--流程控制ForLoop和WhileLoop
- Aardio - does not declare the method of directly passing float values
- On the problems of born charge and non analytical correction in phonon and heat transport calculations
- three. JS gorgeous bubble effect
猜你喜欢
Designed for decision tree, the National University of Singapore and Tsinghua University jointly proposed a fast and safe federal learning system
MATLAB小技巧(27)灰色预测
Matlab tips (27) grey prediction
【全网首发】Redis系列3:高可用之主从架构的
Rust knowledge mind map XMIND
#DAYU200体验官# 首页aito视频&Canvas绘制仪表盘(ets)
Word2vec (skip gram and cbow) - pytorch
How to confirm the storage mode of the current system by program?
DR-Net: dual-rotation network with feature map enhancement for medical image segmentation
Enterprises do not want to replace the old system that has been used for ten years
随机推荐
Introduction to network basics
The difference between enumeration and define macro
The ceiling of MySQL tutorial. Collect it and take your time
cuda 探索
Case recommendation: An Qing works with partners to ensure that the "smart court" is more efficient
UVa 11732 – strcmp() Anyone?
ICLR 2022 | 基于对抗自注意力机制的预训练语言模型
TypeScript获取函数参数类型
2014阿里巴巴web前实习生项目分析(1)
MySQL教程的天花板,收藏好,慢慢看
儿童睡衣(澳大利亚)AS/NZS 1249:2014办理流程
浅谈网络安全之文件上传
European Bioinformatics Institute 2021 highlights report released: nearly 1million proteins have been predicted by alphafold
NPM cannot install sharp
AdaViT——自适应选择计算结构的动态网络
What are the specific steps and schedule of IELTS speaking?
DockerMySQL无法被宿主机访问的问题解决
mysql拆分字符串作为查询条件的示例代码
OpenSSL:适用TLS与SSL协议的全功能工具包,通用加密库
CUDA exploration