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react-native-dropdown-picker 默认值

[英]react-native-dropdown-picker default value

does anyone have an example of a default value used in the library react-native-dropdown-picker used hooks e function, or another libre that makes this msm function simpler.有没有人有一个在库 react-native-dropdown-picker 中使用的默认值的例子,使用 hooks e 函数,或者另一个使这个 msm 函数更简单的 libre。

export default function OrphanageData() {导出默认函数 OrphanageData() {

const [date, setDate] = useState(new Date())
const [value, setValue] = useState();
const [items, setItems] = useState([{}]);
let controller;

return (返回 (

<>
     <StatusBar backgroundColor="#15c3d6"/>

    <ScrollView style={styles.container} contentContainerStyle={{ padding: 24 }}>
    
        <Text style={styles.title}>Compras</Text>
        

        <Text style={styles.label}> ID - Brinco</Text>
        <TextInput
            style={styles.input}
        />

    <DropDownPicker
        items={items}
        controller={instance => controller = instance}
        onChangeList={(items, callback) => {
            new Promise((resolve, reject) => resolve(setItems(items)))
                .then(() => callback())
                .catch(() => {});
        }}
    
        defaultValue={value}
        onChangeItem={item => setValue(item.value)}
    />    

      

        <RectButton style={styles.nextButton} onPress={() => {}}>
            <Text style={styles.nextButtonText}>Cadastrar</Text>
        </RectButton>
    </ScrollView>
</>

) } ) }

This might help (Using Hooks)这可能会有所帮助(使用钩子)

export default function OrphanageData() {

  const [value, setValue] = useState('usa');
  const [items, setItems] = useState([
         {label: 'USA', value: 'usa'},
         {label: 'UK', value: 'uk'},
         {label: 'France', value: 'france'},
    ]);

  return(
    <DropDownPicker
          items={items}
          defaultValue={value}
          onChangeItem={item => setValue(item.value)}
          .....
    />
  );
}

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