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按下提交按钮后，我使用获取按钮从 git api 获取有关 git 用户的信息。获取信息后，我将其写入数据库，然后使用 setStateuserIsFetched: true并有条件地渲染组件。

问题是，在我更改状态后，userIsFetched: true我看到了一秒钟我的<Chat />组件，但随后我看到了<Signup />组件。在控制台中，我看到状态已删除。如果我使用 xmlhttprequest 那么它工作正常。为什么会这样？

var database = firebase.database();

/*function readData() {
  return firebase.database().ref('users/0dc2074d-f7db-4746-91bd-d6e61498b666').once('value')
  .then((data)=>data.val())
}*/

class Chat extends React.Component { 
  render() {
    return (<div>
        <div className="row">
          <div className="col">header</div>
        </div>
        <div className="row" >
          <div className="col-10">one</div>
          <div className="col-2">two</div>
        </div>
        <div className="row">
          <div className="col">footer</div>
        </div>
      </div>)
  }
}

class SignIn extends React.Component {
    constructor(props) {
    super(props);
    this.state = {
      signLogin: ''
    }
    this.handleSubmit = this.handleSubmit.bind(this);
    this.handleChange = this.handleChange.bind(this);
  }

    handleSubmit() {
    this.props.handleSignInSubmit(this.state.signLogin);
    }

    handleChange(event) {
    this.setState({
      signLogin: event.target.value
    })
  }
  render() {
    return (<div>
   <form className="form-signin" onSubmit={this.handleSubmit}>
        <h2 className="form-signin-heading">Please sign in</h2>
        <br/>
        <label className="sr-only">Name</label>
        <input type="text" className="form-control" placeholder="Name" required="" autoFocus="" onChange={this.handleChange} value={this.state.value}/>
        <br/>
        <button className="btn btn-lg btn-primary btn-block" type="submit">Sign in</button>
      </form>
      </div>)
  }
}

class App extends React.Component {
  constructor(props) {
    super(props);
    this.state = {

    }
    this.handleSignInSubmit = this.handleSignInSubmit.bind(this);
  }

  handleSignInSubmit(signLogin) {
  fetch(`https://api.github.com/users/${signLogin}`)
  .then((response)=>response.json())
  .then((user)=>this.writeUserData(uuidv4(), user.name, user.avatar_url))
  .then(()=>this.setState({userIsFetched: true}))
  .catch( alert );
  }

  writeUserData(userId, userName, userAvatarUrl) {
  firebase.database().ref('users/' + userId)
    .set({
    userName: userName,
    userAvatarUrl : userAvatarUrl
  });
}

    render() {
      console.log(this.state)
    return this.state.userIsFetched ? <Chat /> : <SignIn handleSignInSubmit={this.handleSignInSubmit}/>
    }
}



ReactDOM.render(<App/>, document.getElementById("root"));

这是工作示例：https ://codepen.io/RinatRezyapov/pen/WEEqJW

尝试输入 RinatRezyapov 并单击提交。

4

1 回答 1

0

我忘记添加了 

    event.preventDefault();

在SignIn的提交

handleSubmit() {
this.props.handleSignInSubmit(this.state.signLogin);
}

现在它可以工作了

  handleSubmit(event) {
  event.preventDefault();
  this.props.handleSignInSubmit(this.state.signLogin);
  }
于 2017-08-20T05:15:09.087 回答