我是前端开发的新手，我一直在尝试将模态设置到屏幕的中央，但是它不会从屏幕的最右侧移动。我正在使用的CSS是“ bootstrap / dist / css / bootstrap.min.css”。我需要创建自己的CSS文件来解决此问题吗？
import React, { Component } from "react";
import "./App.css";
import LoginPage from "./LoginPage";
import "bootstrap/dist/css/bootstrap.min.css";
import { Modal, Button } from "react-bootstrap";
import ReactTelephoneInput from "react-telephone-input/es/ReactTelephoneInput";
class App extends Component {
state = {
selectLoginOption: false,
userLoginOption: false,
restaurantLoginOption: false,
deliveryAgentLoginOption: false,
closeAllOptionsOfSelectionForm: false
};
style = {
left: 0
};
login = () => { debugger;
let obj={}
obj.email=this.state.email;
fetch('/login',
{
header:{
"Accept": "application/json",
"Content-Type": "application/json"
},
method:'POST',
type:"cors",
body:JSON.stringify({obj})
}
).then(function(res){ debugger; return res.json(); })
.then(function(data){ console.log( JSON.stringify( data ) ) })
}
register = () => { debugger;
let obj={}
obj.user_email=this.state.useremail;
obj.user_name=this.state.username;
obj.userPassword = this.state.userpassword;
obj.user_phonenum = this.state.userphonenumber;
fetch('/userRegistration',{
method: 'POST',
headers: {
'Content-Type': 'application/json',
},
body:JSON.stringify({
user_email: this.state.useremail,
user_name:this.state.username,
userPassword : this.state.userpassword,
user_phonenum : this.state.userphonenumber
})
}
).then(function(res){ debugger; return res.json(); })
.then(function(data){ console.log( JSON.stringify( data ) ) })
}
DeliveryAgentregister = () => { debugger;
fetch('/AgentRegistration',{
method: 'POST',
headers: {
'Content-Type': 'application/json',
},
body:JSON.stringify({
deliveryAgent_Name: this.state.DeliveryAgentName,
deliveryAgent_EmailID:this.state.DeliveryAgentEmailID,
deliveryAgent_Password : this.state.DeliveryAgentPassword,
deliveryAgent_ConfirmPassword : this.state.DeliveryAgentConfirmPassword,
deliveryAgent_PhoneNumber: this.state.DeliveryAgentPhoneNumber
})
}
).then(function(res){ debugger; return res.json(); })
.then(function(data){ console.log( JSON.stringify( data ) ) })
}
selectLoginOption = () =>{
this.setState({selectLoginOption: true})
}
userLoginOption = () => {
this.setState({ userLoginOption: true, selectLoginOption:false, restaurantLoginOption: false, deliveryAgentLoginOption: false });
}
restaurantLoginOption = () => {
this.setState({ userLoginOption: false, selectLoginOption:false, restaurantLoginOption: true, deliveryAgentLoginOption: false });
}
deliveryAgentLoginOption = () => {
this.setState({ userLoginOption: false, selectLoginOption:false, restaurantLoginOption: false, deliveryAgentLoginOption: true });
}
closeAllOptionsOfSelectionForm= () => {
this.setState({ userLoginOption: false, selectLoginOption:false, restaurantLoginOption: false, deliveryAgentLoginOption: false });
}
getTitle() {
if (this.state.userLoginOption) {
return "User Login";
} else if (this.state.restaurantLoginOption) {
return "Restaurant Login";
} else if (this.state.deliveryAgentLoginOption) {
return "Delivery Agent Login";
}
}
render() {
const { country, region } = this.state;
return (
<div className="App">
<header>
<link href="//maxcdn.bootstrapcdn.com/bootstrap/4.1.1/css/bootstrap.min.css" rel="stylesheet" id="bootstrap-css"/>
<script src="//maxcdn.bootstrapcdn.com/bootstrap/4.1.1/js/bootstrap.min.js"></script>
<script src="//cdnjs.cloudflare.com/ajax/libs/jquery/3.2.1/jquery.min.js"></script>
<link href="//maxcdn.bootstrapcdn.com/bootstrap/4.1.1/css/bootstrap.min.css" rel="stylesheet" id="bootstrap-css"/>
<script src="//maxcdn.bootstrapcdn.com/bootstrap/4.1.1/js/bootstrap.min.js"></script> <script src="//cdnjs.cloudflare.com/ajax/libs/jquery/3.2.1/jquery.min.js"></script>
<link href="//netdna.bootstrapcdn.com/bootstrap/3.0.0/css/bootstrap.min.css" rel="stylesheet" id="bootstrap-css"/>
<script src="//netdna.bootstrapcdn.com/bootstrap/3.0.0/js/bootstrap.min.js"></script>
<script src="//code.jquery.com/jquery-1.11.1.min.js"></script>
<nav class=" navbar navbar-expand-lg navbar-dark ">
<div class="container">
<a class="navbar-brand " href="#">YumDrop</a>
<div class="collapse navbar-collapse" id="navBarLinks">
<ul class="navbar-nav mr-auto">
<li class="nav-item" >
<a class="nav-link" onClick={this.selectLoginOption}>Login</a>
</li>
<li class="nav-item" id="SignUpID">
<a class="nav-link" href="#">Sign Up</a>
</li>
</ul>
</div>
</div>
</nav>
</header>
<div class="view rgba-black-light">
<div class="">
<br/><br/><br/><br/><br/><br/><br/>
<li>
<p id="para" >Are you hungry?</p>
</li>
<ul class="list-unstyled">
<br/><br/><br/><br/>
<li>
<div class="form-row" data-wow-delay="0.4s">
<div class="col-md-5" id="firstbar">
<div class="md-form">
<select className="form-control" id="exampleFormControlSelect1">
<option>Bloomington, Indiana</option>
<option>Indianapolis, Indiana</option>
</select>
</div>
</div>
<div className="col-md-4">
<div className="md-form">
<input type="text"
placeholder="Search for food, cuisines, restaurants here.."
id="form5" className="form-control validate"/>
</div>
</div>
<div className="col-md-12" id="buttonOrder">
<div className="md-form">
<button className="btn btn-lg btn-danger">Order</button>
</div>
</div>
</div>
</li>
</ul>
</div>
</div>
<Modal show={this.state.selectLoginOption} onHide={this.closeAllOptionsOfSelectionForm} animation={false} >
<Modal.Header className="modelheader">
<Modal.Title className="modeltitle">
<strong>Select Login</strong>
</Modal.Title>
</Modal.Header>
<Modal.Body>
<div className="container">
<div className="row">
<div className="main">
<form role="form">
<button onClick={this.userLoginOption} className="btn btn btn-primary">User </button><br/>
<button onClick={this.restaurantLoginOption} className="btn btn btn-primary">Restaurant </button><br/>
<button onClick={this.deliveryAgentLoginOption} className="btn btn btn-primary">Delivery Agent </button>
</form>
</div>
</div>
</div>
</Modal.Body>
</Modal >
<Modal
show={
this.state.deliveryAgentLoginOption || this.state.userLoginOption || this.state.restaurantLoginOption
}
onHide={this.closeAllOptionsOfSelectionForm} animation={false} centered >
<Modal.Header>
<Modal.Title>{this.getTitle()}</Modal.Title>
</Modal.Header>
<Modal.Body>
<div class="container">
<div className="row">
<div className="main">
<h3>Please Log In, or <a href="#">Sign Up</a></h3>
<div className="row">
<div className="col-xs-6 col-sm-6 col-md-6">
<a href="#" className="btn btn-lg btn-primary btn-block">Facebook</a>
</div>
<div className="col-xs-6 col-sm-6 col-md-6">
<a href="#" className="btn btn-lg btn-info btn-block">Google</a>
</div>
</div>
<div className="login-or">
<hr className="hr-or"/>
<span className="span-or">or</span>
</div>
<form role="form">
<div className="form-group">
<label htmlFor="inputUsernameEmail">Username or email</label>
<input type="text" className="form-control" id="inputUsernameEmail"/>
</div>
<div className="form-group">
<a className="pull-right" href="#">Forgot password?</a>
<label htmlFor="inputPassword">Password</label>
<input type="password" className="form-control" id="inputPassword"/>
</div>
<div className="checkbox pull-right">
<label>
<input type="checkbox"/>
Remember me </label>
</div>
<button type="submit" className="btn btn btn-primary">
Log In
</button>
</form>
</div>
</div></div>
</Modal.Body>
</Modal>
<div className="auto-container">
<div className="row">
<div className="column col-lg-6 col-md-12 col-sm-12">
<div className="sec-title">
<h2>Choose from multi cuisines available</h2>
</div>
</div>
</div>
</div>
<div className="container" id="ContainerID">
<div className="row">
<div className="col-12 col-md-4 image-grid-item">
<div id="img3"
className="entry-cover image-grid-cover has-image">
<a href="#" className="image-grid-clickbox"></a>
<a href="#" className="cover-wrapper">Indian Food</a>
</div>
</div>
<div className="col-12 col-md-4 image-grid-item">
<div id="img2"
className="entry-cover image-grid-cover has-image">
<a href="#" className="image-grid-clickbox"></a>
<a href="#" className="cover-wrapper">Indian Food</a>
</div>
</div>
<div className="col-12 col-sm-6 col-md-4 image-grid-item">
<div id="img1" className="entry-cover image-grid-cover has-image">
<a href="#" className="image-grid-clickbox"></a>
<a href="#" className="cover-wrapper">Burgers </a>
</div>
</div>
<div className="col-17 col-md-4 image-grid-item">
<div id="img4" className="entry-cover image-grid has-image">
<a href="#" className="image-grid-clickbox"></a>
<a href="#" className="cover-wrapper">Mexican Food</a>
</div>
</div>
<div className="col-12 col-sm-6 col-md-4 image-grid-item">
<div id="img5" className="entry-cover imagegrid has-image">
<a href="#" className="image-grid-clickbox"></a>
<a href="#" className="cover-wrapper">Chinese Food </a>
</div>
</div>
</div>
</div>
</div>
);
}
}
导出默认应用；
答案 0 :(得分：0)
由于您没有显示当前的CSS代码，因此我们无法确定您做错了什么，但这是一种可行的方法：
采用模态div，将其位置设置为absolute或fixed，为其指定特定的宽度和高度，然后将边距设置为auto。这将自动使模态水平居中。
此外，由于位置不是相对于文档中的同级元素，因此我们还应该将div的top，left，right和bottom属性设置为零为这种方法起作用。
#modal {
/*Position and width*/
position: fixed;
width: 30%;
height: fit-content;
/*NOTE: If you want your modal's position to be absolute or fixed, you should also include:*/
top: 0;
left: 0;
right: 0;
bottom: 0;
/*Centering horizintally*/
margin: auto;
/*Purely visual stuff*/
border: 2px solid #ccc;
border-radius: 3px;
background-color: ghostwhite;
text-align:center;
}<div id="modal">
<p>Some sample text</p>
<button type="button">click me</button>
</div>
答案 1 :(得分：0)
如果我是对的，那么您使用的是“ react-bootstrap”中的Modal。
我认为您错过了导入引导CSS文件。
在index.js中添加以下导入语句
import 'bootstrap/dist/css/bootstrap.min.css';
然后自动模式将出现在屏幕中央。