Bootstrap V4系列 学习入门教程之 组件-输入组（Input group）
- 输入组（Input group）
- Basic example
- 一、Wrapping 包装
- 二、Sizing 尺寸
- 三、Multiple addons 多个插件
- 四、Button addons 按钮插件
- 五、Buttons with dropdowns 带下拉按钮
- 六、Custom forms 自定义表单
- 6.1 Custom select 自定义选择
- 6.2 Custom file input 自定义文件输入
输入组（Input group）
通过在文本输入、自定义选择和自定义文件输入的任一侧添加文本、按钮或按钮组，可以轻松扩展表单控件。
Basic example
在输入的两侧放置一个插件或按钮。您也可以在输入的两侧放置一个。记住将<label>s放在输入组之外。
<!--Basic example-->
<div class="input-group mb-3">
<div class="input-group-prepend">
<span class="input-group-text" id="basic-addon1">@</span>
</div>
<input type="text" class="form-control" placeholder="Username" aria-label="Username" aria-describedby="basic-addon1">
</div>
<div class="input-group mb-3">
<input type="text" class="form-control" placeholder="Recipient's username" aria-label="Recipient's username" aria-describedby="basic-addon2">
<div class="input-group-append">
<span class="input-group-text" id="basic-addon2">@example.com</span>
</div>
</div>
<label for="basic-url">Your vanity URL</label>
<div class="input-group mb-3">
<div class="input-group-prepend">
<span class="input-group-text" id="basic-addon3">https://example.com/users/</span>
</div>
<input type="text" class="form-control" id="basic-url" aria-describedby="basic-addon3">
</div>
<div class="input-group mb-3">
<div class="input-group-prepend">
<span class="input-group-text">$</span>
</div>
<input type="text" class="form-control" aria-label="Amount (to the nearest dollar)">
<div class="input-group-append">
<span class="input-group-text">.00</span>
</div>
</div>
<div class="input-group">
<div class="input-group-prepend">
<span class="input-group-text">With textarea</span>
</div>
<textarea class="form-control" aria-label="With textarea"></textarea>
</div>
页面展示效果：
一、Wrapping 包装
默认情况下，输入组通过flex-wrap:wrap 进行包装，以适应输入组内的自定义表单字段验证。您可以使用.flex-nowrap 禁用此功能。
<div class="input-group flex-nowrap">
<div class="input-group-prepend">
<span class="input-group-text" id="addon-wrapping">@</span>
</div>
<input type="text" class="form-control" placeholder="Username" aria-label="Username" aria-describedby="addon-wrapping">
</div>
页面展示效果：
二、Sizing 尺寸
将相对的表单大小类添加到.input-group 组本身，其中的内容将自动调整大小——不需要在每个元素上重复表单控件大小类。
不支持对单个输入组元素进行大小调整。
<div class="input-group input-group-sm mb-3">
<div class="input-group-prepend">
<span class="input-group-text" id="inputGroup-sizing-sm">Small</span>
</div>
<input type="text" class="form-control" aria-label="Sizing example input" aria-describedby="inputGroup-sizing-sm">
</div>
<div class="input-group mb-3">
<div class="input-group-prepend">
<span class="input-group-text" id="inputGroup-sizing-default">Default</span>
</div>
<input type="text" class="form-control" aria-label="Sizing example input" aria-describedby="inputGroup-sizing-default">
</div>
<div class="input-group input-group-lg">
<div class="input-group-prepend">
<span class="input-group-text" id="inputGroup-sizing-lg">Large</span>
</div>
<input type="text" class="form-control" aria-label="Sizing example input" aria-describedby="inputGroup-sizing-lg">
</div>
页面展示效果：
三、Multiple addons 多个插件
支持多个附加组件，可以与复选框和单选框输入版本混合使用。
<div class="input-group mb-3">
<div class="input-group-prepend">
<span class="input-group-text">$</span>
<span class="input-group-text">0.00</span>
</div>
<input type="text" class="form-control" aria-label="Dollar amount (with dot and two decimal places)">
</div>
<div class="input-group">
<input type="text" class="form-control" aria-label="Dollar amount (with dot and two decimal places)">
<div class="input-group-append">
<span class="input-group-text">$</span>
<span class="input-group-text">0.00</span>
</div>
</div>
页面展示效果：
四、Button addons 按钮插件
<div class="input-group mb-3">
<div class="input-group-prepend">
<button class="btn btn-outline-secondary" type="button" id="button-addon1">Button</button>
</div>
<input type="text" class="form-control" placeholder="" aria-label="Example text with button addon" aria-describedby="button-addon1">
</div>
<div class="input-group mb-3">
<input type="text" class="form-control" placeholder="Recipient's username" aria-label="Recipient's username" aria-describedby="button-addon2">
<div class="input-group-append">
<button class="btn btn-outline-secondary" type="button" id="button-addon2">Button</button>
</div>
</div>
<div class="input-group mb-3">
<div class="input-group-prepend" id="button-addon3">
<button class="btn btn-outline-secondary" type="button">Button</button>
<button class="btn btn-outline-secondary" type="button">Button</button>
</div>
<input type="text" class="form-control" placeholder="" aria-label="Example text with two button addons" aria-describedby="button-addon3">
</div>
<div class="input-group">
<input type="text" class="form-control" placeholder="Recipient's username" aria-label="Recipient's username with two button addons" aria-describedby="button-addon4">
<div class="input-group-append" id="button-addon4">
<button class="btn btn-outline-secondary" type="button">Button</button>
<button class="btn btn-outline-secondary" type="button">Button</button>
</div>
</div>
页面展示效果：
五、Buttons with dropdowns 带下拉按钮
<div class="input-group mb-3">
<div class="input-group-prepend">
<button class="btn btn-outline-secondary dropdown-toggle" type="button" data-toggle="dropdown" aria-expanded="false">Dropdown</button>
<div class="dropdown-menu">
<a class="dropdown-item" href="#">Action</a>
<a class="dropdown-item" href="#">Another action</a>
<a class="dropdown-item" href="#">Something else here</a>
<div role="separator" class="dropdown-divider"></div>
<a class="dropdown-item" href="#">Separated link</a>
</div>
</div>
<input type="text" class="form-control" aria-label="Text input with dropdown button">
</div>
<div class="input-group">
<input type="text" class="form-control" aria-label="Text input with dropdown button">
<div class="input-group-append">
<button class="btn btn-outline-secondary dropdown-toggle" type="button" data-toggle="dropdown" aria-expanded="false">Dropdown</button>
<div class="dropdown-menu">
<a class="dropdown-item" href="#">Action</a>
<a class="dropdown-item" href="#">Another action</a>
<a class="dropdown-item" href="#">Something else here</a>
<div role="separator" class="dropdown-divider"></div>
<a class="dropdown-item" href="#">Separated link</a>
</div>
</div>
</div>
页面展示效果：
六、Custom forms 自定义表单
输入组包括对自定义选择和自定义文件输入的支持。不支持这些的浏览器默认版本。
6.1 Custom select 自定义选择
<div class="input-group mb-3">
<div class="input-group-prepend">
<label class="input-group-text" for="inputGroupSelect01">Options</label>
</div>
<select class="custom-select" id="inputGroupSelect01">
<option selected>Choose...</option>
<option value="1">One</option>
<option value="2">Two</option>
<option value="3">Three</option>
</select>
</div>
<div class="input-group mb-3">
<select class="custom-select" id="inputGroupSelect02">
<option selected>Choose...</option>
<option value="1">One</option>
<option value="2">Two</option>
<option value="3">Three</option>
</select>
<div class="input-group-append">
<label class="input-group-text" for="inputGroupSelect02">Options</label>
</div>
</div>
<div class="input-group mb-3">
<div class="input-group-prepend">
<button class="btn btn-outline-secondary" type="button">Button</button>
</div>
<select class="custom-select" id="inputGroupSelect03" aria-label="Example select with button addon">
<option selected>Choose...</option>
<option value="1">One</option>
<option value="2">Two</option>
<option value="3">Three</option>
</select>
</div>
<div class="input-group">
<select class="custom-select" id="inputGroupSelect04" aria-label="Example select with button addon">
<option selected>Choose...</option>
<option value="1">One</option>
<option value="2">Two</option>
<option value="3">Three</option>
</select>
<div class="input-group-append">
<button class="btn btn-outline-secondary" type="button">Button</button>
</div>
</div>
页面展示效果：
6.2 Custom file input 自定义文件输入
此示例使用自定义文件浏览器组件，该组件依赖于单独的
bs-custom-file-input自定义文件输入插件。
<div class="input-group mb-3">
<div class="input-group-prepend">
<span class="input-group-text" id="inputGroupFileAddon01">Upload</span>
</div>
<div class="custom-file">
<input type="file" class="custom-file-input" id="inputGroupFile01" aria-describedby="inputGroupFileAddon01">
<label class="custom-file-label" for="inputGroupFile01">Choose file</label>
</div>
</div>
<div class="input-group mb-3">
<div class="custom-file">
<input type="file" class="custom-file-input" id="inputGroupFile02">
<label class="custom-file-label" for="inputGroupFile02" aria-describedby="inputGroupFileAddon02">Choose file</label>
</div>
<div class="input-group-append">
<span class="input-group-text" id="inputGroupFileAddon02">Upload</span>
</div>
</div>
<div class="input-group mb-3">
<div class="input-group-prepend">
<button class="btn btn-outline-secondary" type="button" id="inputGroupFileAddon03">Button</button>
</div>
<div class="custom-file">
<input type="file" class="custom-file-input" id="inputGroupFile03" aria-describedby="inputGroupFileAddon03">
<label class="custom-file-label" for="inputGroupFile03">Choose file</label>
</div>
</div>
<div class="input-group">
<div class="custom-file">
<input type="file" class="custom-file-input" id="inputGroupFile04" aria-describedby="inputGroupFileAddon04">
<label class="custom-file-label" for="inputGroupFile04">Choose file</label>
</div>
<div class="input-group-append">
<button class="btn btn-outline-secondary" type="button" id="inputGroupFileAddon04">Button</button>
</div>
</div>
页面展示效果：
自定义文件输入插件:
<script src="https://cdn.jsdelivr.net/npm/bs-custom-file-input/dist/bs-custom-file-input.js"></script>
您应该等待文档就绪事件，并调用init方法使您的自定义文件输入动态。我们公开了一个随处可用的全局变量：bsCustomFileInput
<script>
$(document).ready(function () {
bsCustomFileInput.init()
})
</script>
一切准备就绪后，你应该看到页面的上传效果：
