第一次运行时，本机异步会变为null

Question

我试图在用户输入他们的姓名和电话号码后将用户信息发送到服务器。当用户输入他们的信息时，我能够获得正确的信息。但是，当我第一次运行应用程序时，我得到this.state.name和this.state.phone的空数据而不是空字符串。

以下是我的代码：

constructor(){
  super()
  this.clearData = this.clearData.bind(this)
  this.persistData = this.persistData.bind(this)

  this.state = {
    name: '',
    phone: ''
  }
}

submit(){
  let collection = {}
  collection.name = this.state.name,
    collection.email = this.state.phone,
    console.warn(collection)
  var url = 'http://localhost:3000/users';
  fetch(url, {
    method: 'POST', // or 'PUT'
    body: JSON.stringify(collection), // data can be `string` or {object}!
    headers: {
      'Content-Type': 'application/json'
    }
  }).then(res => res.json())
    .then(response => console.log('Success:', JSON.stringify(response)))
    .catch(error => console.error('Error:', error));
}

persistData(){
  let name = this.state.name
  let phone = this.state.phone
  AsyncStorage.setItem('name', name)
  AsyncStorage.setItem('phone', phone)
  this.setState({ name: name, persistedName: name, phone: phone, persistedPhone: phone })
}

check(){
  AsyncStorage.getItem('name').then((name) => {
    this.setState({ name: name, persistedName: name })
  })
  AsyncStorage.getItem('phone').then((phone) => {
    this.setState({ phone: phone, persistedPhone: phone })
  })
}

componentWillMount(){
  this.check()
}

render() {

  ////Here I am getting null! 
  console.log(this.state.name)
  console.log(this.state.phone)

  return ()
    < View >
    <TouchableOpacity
      onPress={() => { this.persistData(); this.submit(); }}>
      <Text> submit button </Text>
    </TouchableOpacity>
    </View >
}

当我第一次运行我的应用程序时，我想为this.state.name和this.state.phone获取空字符串。有没有办法可以做到这一点？