Question

如何在onValueChange等事件中放入两个函数？

我试过

  onValueChange={(selected) => this.setState({selected}),this.state.eventOnChange}>

Answer 1

怎么样：

using std::string;

// Returns a string by value
string s1() {
  return "hello";  // This implicitly creates a std::string
}

// Also returns a string by value
string s2() {
  string s = "how are you";
  return s;
}

// Returns a pointer to a string - the caller is responsible for deleting
string* s3() {
  string* s = new string;
  *s = "this is a string";
  return s;
}

// Does not work - do not use!
string* this_does_not_work() {
  string s = "i am another string";
  // Here we are returning a pointer to a locally allocated string.
  // The string will be destroyed when this function returns, and the
  // pointer will point at some random memory, not a string! 
  // Do not do this!
  return &s;
}

int main() {
  string v1 = s1();
  // ...do things with v1...
  string v2 = s2();
  // ...do things with v2...
  string* v3 = s3();
  // ...do things with v3...
  // We now own v3 and have to deallocate it!
  delete v3;
}

Answer 2

Component.setState（）是异步的，可能会在第二次调用时锁定，但它仍在执行第一次调用。

在回调中执行第二次调用，如下所示：

onValueChange=
    { (selected) => {
        this.setState(
            {category:selected},() => {this.filter();} // Add Functions That's you want to call.
        )
    }
}

Answer 3

解决了以下代码：

<TextInput
      style={{height: 40, width: 200, borderColor: 'gray', borderWidth: 1, }}

      onChangeText={(text) => this.setState({
        text
      }, () => {
        this._onChangeText();
      })
      } 
      autoCorrect={false}
      underlineColorAndroid='rgba(0,0,0,0)'
      value={this.state.text}
    />

感谢@pinewood。

Answer 4

onValueChange={(itemValue, itemIndex) =>  this.setState({id: itemValue}),this.getOtherFunction }

React-Native中的两个函数

4 个答案: