Arrays 从API映射函数组件中的数组
我想在选择器react native中调用并显示API。我不明白如何在功能组件中,在映射部分中这样做,以便它获得值Arrays 从API映射函数组件中的数组,arrays,react-native,react-native-android,fetch-api,picker,Arrays,React Native,React Native Android,Fetch Api,Picker,我想在选择器react native中调用并显示API。我不明白如何在功能组件中,在映射部分中这样做,以便它获得值 import React, {useState,useEffect} from 'react'; import {View, StyleSheet, Picker} from 'react-native'; const App = () => { const [selectedValue, setSelectedValue] = useState([]);
import React, {useState,useEffect} from 'react';
import {View, StyleSheet, Picker} from 'react-native';
const App = () => {
const [selectedValue, setSelectedValue] = useState([]);
useEffect(() => {
fetch('https://aboutreact.herokuapp.com/demosearchables.php')
.then(response => response.json())
.then(responseJson => {
console.log(responseJson.results)
setSelectedValue(responseJson.results)
})
.catch((error) => {
console.error(error);
});
}, []);
return (
<View style={{flex: 1,backgroundColor:'white'}}>
<Picker
selectedValue={selectedValue.id}
style={{ width: '100%' }}
onValueChange={(itemValue) => setSelectedValue({ id: itemValue })}>
{ ???.map((selectedValue, i) => {
return <Picker.Item key={i} value={selectedValue.id} label={selectedValue.name} />
})}
</Picker>
</View>
)
}
export default App
import React,{useState,useffect}来自“React”;
从“react native”导入{View,StyleSheet,Picker};
常量应用=()=>{
常量[selectedValue,setSelectedValue]=useState([]);
useffect(()=>{
取('https://aboutreact.herokuapp.com/demosearchables.php')
.then(response=>response.json())
.然后(responseJson=>{
console.log(responseJson.results)
setSelectedValue(responseJson.results)
})
.catch((错误)=>{
控制台错误(error);
});
}, []);
报税表(
setSelectedValue({id:itemValue})}>
{???.map((selectedValue,i)=>{
返回
})}
)
}
导出默认应用程序
选择器的初始值
import React,{useState,useffect}来自“React”;
从“react native”导入{View,StyleSheet,Picker};
常量应用=()=>{
const[values,setValues]=React.useState([]);
常量[selectedValue,setSelectedValue]=useState(null);
useffect(()=>{
取('https://aboutreact.herokuapp.com/demosearchables.php')
.then(response=>response.json())
.然后(responseJson=>{
设置值(responseJson.results)
})
.catch((错误)=>{
控制台错误(error);
});
}, []);
报税表(
setSelectedValue({id:itemValue})}>
{values.map((值,i)=>{
返回
})}
)
}
选择器的初始值
import React,{useState,useffect}来自“React”;
从“react native”导入{View,StyleSheet,Picker};
常量应用=()=>{
const[values,setValues]=React.useState([]);
常量[selectedValue,setSelectedValue]=useState(null);
useffect(()=>{
取('https://aboutreact.herokuapp.com/demosearchables.php')
.then(response=>response.json())
.然后(responseJson=>{
设置值(responseJson.results)
})
.catch((错误)=>{
控制台错误(error);
});
}, []);
报税表(
setSelectedValue({id:itemValue})}>
{values.map((值,i)=>{
返回
})}
)
}
selectedValue
是数组还是与对象?我这样问是因为const[selectedValue,setSelectedValue]=useState([])
声明它是一个数组,然后此:(itemValue)=>setSelectedValue({id:itemValue})
声明它是一个带有id键的对象…感谢您的关注,您的问题有助于我了解。selectedValue
是数组还是is and对象?我这样问是因为const[selectedValue,setSelectedValue]=useState([])
声明它是一个数组,然后此:(itemValue)=>setSelectedValue({id:itemValue})
声明它是一个具有id键的对象…感谢您的关注,您的问题有助于我了解。。
import React, {useState,useEffect} from 'react';
import {View, StyleSheet, Picker} from 'react-native';
const App = () => {
const [values, setValues] = React.useState([]);
const [selectedValue, setSelectedValue] = useState(null);
useEffect(() => {
fetch('https://aboutreact.herokuapp.com/demosearchables.php')
.then(response => response.json())
.then(responseJson => {
setValues(responseJson.results)
})
.catch((error) => {
console.error(error);
});
}, []);
return (
<View style={{flex: 1,backgroundColor:'white'}}>
<Picker
selectedValue={selectedValue ? selectedValue.id : null}
style={{ width: '100%' }}
onValueChange={(itemValue) => setSelectedValue({ id: itemValue })}>
{ values.map((value, i) => {
return <Picker.Item key={i} value={value.id} label={value.name} />
})}
</Picker>
</View>
)
}