422 lines
9.4 KiB
Markdown
422 lines
9.4 KiB
Markdown
Flutter 备忘清单
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===
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包含 Flutter 常用的组件、布局、方法等。初学者的完整快速参考
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入门
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---
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### macOS 操作系统上安装和配置
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```bash
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$ sudo softwareupdate --install-rosetta --agree-to-license
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```
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<!--rehype:className=wrap-text-->
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在 [Apple 芯片的 Mac 电脑](https://support.apple.com/zh-cn/HT211814) 上，还需要安装 [Rosetta 2](https://github.com/flutter/website/pull/7119#issuecomment-1124537969) 环境因为 一些辅助工具 仍然需要，通过手动运行上面的命令来安装
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#### 获取 Flutter SDK
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- 安装包来获取最新的 stable Flutter SDK：
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- Intel [`flutter_macos_3.3.8-stable.zip`](https://storage.flutter-io.cn/flutter_infra_release/releases/stable/macos/flutter_macos_3.3.8-stable.zip)
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- Apple 芯片 [`flutter_macos_arm64_3.3.8-stable.zip`](https://storage.flutter-io.cn/flutter_infra_release/releases/stable/macos/flutter_macos_arm64_3.3.8-stable.zip)
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想要获取到其他版本的安装包，请参阅 [SDK 版本列表](https://flutter.cn/docs/development/tools/sdk/releases) 页面
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- 将文件解压到目标路径, 比如:
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```bash
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$ cd ~/development
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$ unzip ~/Downloads/flutter_macos_3.3.8-stable.zip
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```
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<!--rehype:className=wrap-text-->
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- 配置 `flutter` 的 PATH 环境变量：
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```bash
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$ export PATH="$PATH:`pwd`/flutter/bin"
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```
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- 运行 `flutter doctor` 命令
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<!--rehype:className=style-timeline-->
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### Windows 操作系统上安装和配置
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- 点击下方的安装包，获取 stable 发行通道的 Flutter SDK 最新版本：
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- [flutter_windows_3.3.8-stable.zip](https://storage.flutter-io.cn/flutter_infra_release/releases/stable/windows/flutter_windows_3.3.8-stable.zip)
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- 要查看其他发行通道和以往的版本，请参阅 [SDK 版本列表](https://flutter.cn/docs/development/tools/sdk/releases) 页面
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- 将压缩包解压，然后把其中的 `flutter` 目录整个放在你想放置 `Flutter SDK` 的路径中（例如 `C:\src\flutter`）
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- 更新 `path` 环境变量，在开始菜单的搜索功能键入`「env」`，然后选择 `编辑系统环境变量`。在 **`用户变量`** 一栏中，检查是否有 **`Path`** 这个条目：
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- 如果存在这个条目，以 `;` 分隔已有的内容，加入 `flutter\bin` 目录的完整路径。
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- 如果不存在的话，在用户环境变量中创建一个新的 Path 变量，然后将 `flutter\bin` 所在的完整路径作为新变量的值
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<!--rehype:className=style-timeline-->
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如果你不想安装指定版本的安装包。可以忽略步骤 `1` 和 `2`。从 `GitHub` 上的 `Flutter repo` 获取源代码，并根据需要，切换到指定的分支或标签
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```bash
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C:\src>git clone https://github.com/flutter/flutter.git -b stable
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```
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<!--rehype:className=wrap-text-->
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基础组件
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---
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### Text 样式文本
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```dart
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Text("Hello world",
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textAlign: TextAlign.left,
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);
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Text("Hello world! I'm Jack. "*4,
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maxLines: 1,
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overflow: TextOverflow.ellipsis,
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);
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Text("Hello world",
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textScaleFactor: 1.5,
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);
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```
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### TextStyle 指定文本显示的样式
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```dart
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Text("Hello world",
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style: TextStyle(
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color: Colors.blue,
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fontSize: 18.0,
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height: 1.2,
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fontFamily: "Courier",
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background: Paint()..color=Colors.yellow,
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decoration:TextDecoration.underline,
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decorationStyle: TextDecorationStyle.dashed
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),
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);
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```
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<!--rehype:className=wrap-text-->
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### TextSpan 文本的一个“片段”
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```dart
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Text.rich(TextSpan(
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children: [
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TextSpan(
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text: "Home: "
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),
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TextSpan(
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text: "https://flutter.dev",
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style: TextStyle(
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color: Colors.blue
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),
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recognizer: _tapRecognizer
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),
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]
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))
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```
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### DefaultTextStyle 文本默认样式
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<!--rehype:wrap-class=row-span-4-->
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```dart
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DefaultTextStyle(
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// 1.设置文本默认样式
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style: TextStyle(
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color:Colors.red,
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fontSize: 20.0,
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),
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textAlign: TextAlign.start,
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child: Column(
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crossAxisAlignment: CrossAxisAlignment.start,
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children: <Widget>[
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Text("hello world"),
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Text("I am Jack"),
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Text("I am Jack",
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style: TextStyle(
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inherit: false, //2.不继承默认样式
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color: Colors.grey
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),
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),
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],
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),
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);
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```
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<!--rehype:className=wrap-text-->
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### 字体设置加载
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<!--rehype:wrap-class=row-span-4-->
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- 在 asset 中声明，要先在 `pubspec.yaml` 中声明它
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```yaml
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flutter:
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fonts:
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- family: Raleway
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fonts:
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- asset: assets/fonts/Raleway-Regular.ttf
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- asset: assets/fonts/Raleway-Medium.ttf
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weight: 500
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- asset: assets/fonts/Raleway-SemiBold.ttf
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weight: 600
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- family: AbrilFatface
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fonts:
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- asset: assets/fonts/abrilfatface/AbrilFatface-Regular.ttf
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```
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- 将字体文件复制到在 `pubspec.yaml` 中指定的位置
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- 使用字体
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```dart
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// 声明文本样式
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const textStyle = const TextStyle(
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fontFamily: 'Raleway',
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);
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// 使用文本样式
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var buttonText = const Text(
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"Use the font for this text",
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style: textStyle,
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);
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```
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<!--rehype:className=style-timeline-->
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### ElevatedButton "漂浮"按钮
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```dart
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ElevatedButton(
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child: Text("normal"),
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onPressed: () {},
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);
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```
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### TextButton 文本按钮
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```dart
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TextButton(
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child: Text("normal"),
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onPressed: () {},
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)
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```
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### OutlineButton 边框阴影且背景透明按钮
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```dart
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OutlineButton(
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child: Text("normal"),
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onPressed: () {},
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)
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```
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### IconButton 可点击的图标按钮
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```dart
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IconButton(
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icon: Icon(Icons.thumb_up),
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onPressed: () {},
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)
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```
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### 带图标的按钮
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```dart
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ElevatedButton.icon(
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icon: Icon(Icons.send),
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label: Text("发送"),
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onPressed: _onPressed,
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),
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OutlineButton.icon(
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icon: Icon(Icons.add),
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label: Text("添加"),
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onPressed: _onPressed,
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),
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TextButton.icon(
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icon: Icon(Icons.info),
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label: Text("详情"),
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onPressed: _onPressed,
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),
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```
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### 从 asset 中加载图片
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- 在工程根目录下创建一个`images目录`，并将图片 `aaa.png` 拷贝到该目录。
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- 在 `pubspec.yaml` 中的 `flutter` 部分添加如下内容：
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```yaml
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assets:
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- images/aaa.png
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```
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注意: 由于 yaml 文件对缩进严格，所以必须严格按照每一层两个空格的方式进行缩进，此处 assets 前面应有两个空格。
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- 加载该图片
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```dart
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Image(
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image: AssetImage("images/aaa.png"),
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width: 100.0
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);
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```
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Image 也提供了一个快捷的构造函数 `Image.asset` 用于从 `asset` 中加载、显示图片：
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```dart
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Image.asset("images/aaa.png",
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width: 100.0,
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)
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```
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<!--rehype:className=style-timeline-->
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### 从网络加载图片
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```dart
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Image(
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image: NetworkImage(
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"https://avatars2.githubusercontent.com/u/20411648?s=460&v=4"),
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width: 100.0,
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)
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```
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<!--rehype:className=wrap-text-->
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Image 也提供了一个快捷的构造函数 `Image.network` 用于从网络加载、显示图片：
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```dart
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Image.network(
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"https://avatars2.githubusercontent.com/u/20411648?s=460&v=4",
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width: 100.0,
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)
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```
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<!--rehype:className=wrap-text-->
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### Image 参数
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<!--rehype:wrap-class=row-span-2-->
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```dart
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const Image({
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...
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this.width, // 图片的宽
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this.height, // 图片高度
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this.color, // 图片的混合色值
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this.colorBlendMode, // 混合模式
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this.fit,// 缩放模式
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// 对齐方式
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this.alignment = Alignment.center,
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// 重复方式
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this.repeat = ImageRepeat.noRepeat,
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...
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})
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```
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### Switch 单选开关
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```dart
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Switch(
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value: true,//当前状态
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onChanged:(value){
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// 重新构建页面
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},
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),
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```
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### Checkbox 复选框
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<!--rehype:wrap-class=row-span-2-->
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```dart
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Checkbox(
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value: true,
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// 选中时的颜色
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activeColor: Colors.red,
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onChanged:(value){
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// ...
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},
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)
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```
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### TextField 文本输入框
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```dart
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TextField(
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autofocus: true,
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onChanged: (v) {
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print("onChange: $v");
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}
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)
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```
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### LinearProgressIndicator 线性、条状的进度条
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模糊进度条(会执行一个动画)
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```dart
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LinearProgressIndicator(
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backgroundColor: Colors.grey[200],
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valueColor: AlwaysStoppedAnimation(Colors.blue),
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),
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```
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<!--rehype:className=wrap-text-->
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进度条显示 `50%`
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```dart
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LinearProgressIndicator(
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backgroundColor: Colors.grey[200],
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valueColor: AlwaysStoppedAnimation(Colors.blue),
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value: .5,
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)
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```
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<!--rehype:className=wrap-text-->
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### CircularProgressIndicator 圆形进度条
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模糊进度条(会执行一个旋转动画)
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```dart
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CircularProgressIndicator(
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backgroundColor: Colors.grey[200],
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valueColor: AlwaysStoppedAnimation(Colors.blue),
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),
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```
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<!--rehype:className=wrap-text-->
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进度条显示 `50%`，会显示一个半圆
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```dart
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CircularProgressIndicator(
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backgroundColor: Colors.grey[200],
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valueColor: AlwaysStoppedAnimation(Colors.blue),
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value: .5,
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),
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```
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<!--rehype:className=wrap-text-->
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### 自定义尺寸
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线性进度条高度指定为 `3`
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```dart
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SizedBox(
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height: 3,
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child: LinearProgressIndicator(
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backgroundColor: Colors.grey[200],
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valueColor: AlwaysStoppedAnimation(Colors.blue),
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value: .5,
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),
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),
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```
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圆形进度条直径指定为 `100`
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```dart
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SizedBox(
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height: 100,
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width: 100,
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child: CircularProgressIndicator(
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backgroundColor: Colors.grey[200],
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valueColor: AlwaysStoppedAnimation(Colors.blue),
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value: .7,
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),
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),
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```
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另见
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---
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- [Dart 备忘清单](./dart.md) _(jaywcjlove.github.io)_
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- [flutter 官网](https://flutter.dev) _(flutter.dev)_
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- [flutter 中文开发者社区](https://flutterchina.club/) _(flutterchina.club)_
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