Dart 有两种传参方法:位置参数和命名参数。位置参数你可能会比较熟悉:
int sumUp(int a, int b, int c) {return a b c;
}
// int total sumUp(1, 2, 3);在 Dart 里,你可以将这些参数包裹在方括号中,使其变成可选位置参数&…
实现后的效果 case 5:{try{var res await DioManager().friend_getSelectionTopic(params: {});print(成功msg-----------res.msg);print(成功code-----------res.code);print(成功code-----------res.data.toString());}catch(err){print(最外部捕获msg-----------err.msg);p…
Flutter官网中Dart资源的链接:
Bootstrap into Dart
Language tour 包含Dart语法的最佳介绍,如强类型、闭包(lambda表达式)、函数库、lexical scoping、顶级函数、命名参数、async / await,等
Library tour Dart核心库的介绍&a…
Exceptions
Dart 中的异常信息捕获处理:
try {breedMoreLlamas();
} on OutOfLlamasException {// A specific exceptionbuyMoreLlamas();
} on Exception catch (e) {// Anything else that is an exceptionprint(Unknown exception: $e);
} catch (e) {// No sp…
变量和内置的类型 Final and const
如果您从不打算更改变量,请使用final或const,而不是var或者一个类型。 final变量只能设置一次; const变量是编译时常量。 (Const变量是隐式final的。)final的顶级或类变量在第一次使用时被初始…
一直卡在building a flutter app for general distribution;
AS Message窗口显示 依赖下载失败:
1、修改仓库地址的配置:android/build.gradle repositories {maven { url https://download.flutter.io }maven { url "https://maven.a…
布局 RowWidget 的详细讲解
代码实例:
import package:flutter/material.dart;void main() {runApp(MyApp());
}class MyApp extends StatelessWidget {// This widget is the root of your application.overrideWidget build(BuildContext context) {return Mate…
文章目录 字符串插值(String interpolation)空变量 null避空运算符条件属性访问集合字面量箭头语法 字符串插值(String interpolation)
下面是一些使用字符串插值的例子: Here are some examples of using string interpolation:
String result
字符…
1、Dart 方法介绍
方法的构成:返回值 方法名 参数
int sum1(int a, int b) {return a b;
}返回值类型可缺省
sum2(int a, int b) {return a b;
}参数类型可缺省
sum3(a, b) {return a b;
}可通过 { } 设置可选参数;并为可选参数设置默认值
int…
简记一个Flutter错误:
Using hardware rendering with device sdk gphone64 x86 64. If you notice graphics artifacts, consider enabling software rendering with “–enable-software-rendering”. Launching lib\main.dart on sdk gphone64 x86 64 in debug …
我们先来看一段代码
main() {Object a "111";print(a.length); // 错误的dynamic b "111";print(b.length);String c "111";print(c.length);
}首先,让我们逐行分析代码:
main() {Object a "111";print…
dart笔记 Dart 库 - 文章信息 -
Author: Jack Lee (jcLee95) Visit me at: https://jclee95.blog.csdn.netEmail: 291148484163.com. Shenzhen ChineAddress of this article:https://blog.csdn.net/qq_28550263/article/details/131506108 【介绍】:本文介绍 Dart…
Flutter开发笔记 Flutter 组件(二)文本 与 输入框组件 - 文章信息 -
Author: Jack Lee (jcLee95) Visit me at: https://jclee95.blog.csdn.netEmail: 291148484163.com. Shenzhen ChineAddress of this article:https://blog.csdn.net/qq_28550263/art…
flutter
Error: No named parameter with the name ‘shadowThemeOnly’.
报错信息如下:
../../flutter/.pub-cache/hosted/pub.flutter-io.cn/flutter_cupertino_date_picker-1.0.262/lib/src/date_picker.dart:103:34: Error: No named parameter with the nam…
flutter笔记 骨架化加载器 - 文章信息 -
Author: Jack Lee (jcLee95) Visit me at: https://jclee95.blog.csdn.netEmail: 291148484163.com. Shenzhen ChinaAddress of this article:https://blog.csdn.net/qq_28550263/article/details/134224135 【介绍】:本文介…