Question

我尝试在注销时更新我的NavBar，这是我写的代码：

App.js：

class App extends Component {
  constructor(props){
    super(props);
    this.state = {};  
    this.handleLogout = this.handleLogout.bind(this); 
  }

  handleLogout(){
    sessionStorage.clear(); 
    this.setState({loggedIn: false});
  }

  componentWillMount(){
      if(sessionStorage.getItem('access_token') != null && sessionStorage.getItem('id_token') != null){
          this.setState({loggedIn: true}); 
      }
      else{
          this.setState({loggedIn: false}); 
      } 
  }
  render() {
    return (
        <BrowserRouter>
          <div>
            <title>Webshop</title> 
            <NavBar loggedIn={this.state.loggedIn} />
            <Switch>
                    {/*Routes need to be include in App.js otherwise root can't find the paths*/}
                    <Route exact path='/' component={Home}/>
                    <Route exact path='/categories' component={Categories}/>
                    <Route exact path='/login' component={Login}/>
                    <Route exact path='/register' component={Register}/>
                    {(this.state.loggedIn) ? 
                    <Route exact path='/logout' render={(props) => (<Logout logOutHandler={this.handleLogout} {...props}/>)} /> 
                    : null}
                    <Route render={function(){
                        return (<NotFound/>); 
                    }}/>
                </Switch>
              <Footer/>
          </div>  
        </BrowserRouter>
    );
  }
}

NavBar.js：

class NavBar extends Component {
    constructor(props) {
        super(props);
        this.loggedIn = this.props.loggedIn; 
        this.toggle = this.toggle.bind(this);
        this.state = {
          isOpen: false
        }; 
    }

    toggle() {
        this.setState({
          isOpen: !this.state.isOpen
        });
    }

    render(){
        return(
            <div>
                <link rel='stylesheet' href='https://maxcdn.bootstrapcdn.com/font-awesome/4.7.0/css/font-awesome.min.css'/>
                <Navbar color="faded" light expand="md">
                    <NavLink className='navbar-brand' exact to='/'>
                        <img src={logo} alt='Brand' width='35px' height='35px'/>
                    </NavLink>
                    <NavbarToggler onClick={this.toggle} />
                    <Collapse isOpen={this.state.isOpen} navbar>
                        <Nav className="mr-auto" navbar>
                            <NavItem>
                                <NavLink className='nav-link' exact to='/categories'>
                                    Categories
                                </NavLink>
                            </NavItem>
                        </Nav>
                        <Nav className='mx-auto' navbar>
                            <Form inline>
                                <FormGroup>
                                    <Input size='sm' type="text" name="search" placeholder="Search" />
                                </FormGroup>
                                <Button size='sm'><i className='fa fa-search'></i></Button>
                            </Form>
                        </Nav>
                        <Nav className="ml-auto" navbar>

                            <NavItem>
                                <NavLink className='nav-link' exact to='/cart'>
                                    <i className='fa fa-shopping-cart'></i>
                                </NavLink>
                            </NavItem>

                            {(this.loggedIn) ?
                            <NavItem>
                                <NavLink className='nav-link' exact to='/profile'>
                                    <i className='fa fa-user'></i> 
                                </NavLink>
                            </NavItem>
                            : null }

                            {(this.loggedIn) ?

                            <NavItem>
                                <NavLink className='nav-link' exact to='/logout'>
                                    <i className='fa fa-sign-out'></i>
                                </NavLink>
                            </NavItem>
                            : 
                            <NavItem>
                                <NavLink className='nav-link' exact to='/login'>
                                    <i className='fa fa-sign-in'></i>
                                </NavLink>
                            </NavItem>
                            }
                        </Nav>
                    </Collapse>
                </Navbar>
            </div>
        );
    }
}

LogOut.js：

class Logout extends Component{
    constructor(props){
        super(props);

        this.handleLogout = this.handleLogout.bind(this); 

    }

    handleLogout(){
        sessionStorage.clear();
        this.props.logOutHandler(); 
        //window.location.replace('/login'); 
    }

    render(){
        return(
            <div>
                <Container className="content-container">
                    <Row className="justify-content-md-center">
                        <Col md={4}>
                            <Card>
                                <CardBody>
                                    <img className="logoutImage" src={logo} width='130' height='130px' alt='Logo'/>
                                    <hr></hr>
                                    <CardText>
                                        Clicking "Logout" will log you out from webshop [NAME]
                                    </CardText>
                                    <Link exact to='/'>
                                    <Button size='sm' className='float-left' color='default'>Cancel</Button>
                                    </Link>
                                    <Link excat to='/login'>
                                        <Button size='sm'className='float-right' color='secondary' onClick={this.handleLogout}>Logout</Button>
                                    </Link>
                                </CardBody>
                            </Card>
                        </Col>
                    </Row>
                </Container>

            </div>
        )
    }
}

我试图将状态更新为loggedIn = false。单击Logout.js中的注销按钮。这应该触发方法handleLogout，它触发this.props.logOutHandler中的方法，该方法触发App.js中的handleLogout，此方法应该将状态更新为loggedIn = false。但不知何故状态loggedIn =总是如此，直到我刷新页面。

我可以使用window.location.replace（＆＃39; / login＆＃39;）来处理这个错误但是我想要一个没有刷新页面的解决方案而只重新渲染NavBar组件

Answer 1

在您的NavBar.js中，您不需要在构造函数中执行this.loggedIn = this.props.loggedIn，这可能会导致问题。

您可以直接在render：

中访问道具

this.props.loggedIn ? {node} : null

而不是：

this.loggedIn ? {node} : null

希望这有帮助。

在Logout Reactjs上更新NavBar

1 个答案: