react-native-dropdown-picker默认值

Question

有没有人有在react-native-dropdown-picker使用的hooks e函数库中使用的默认值的示例，或者其他库可以使这个msm函数更简单。

导出默认函数OrphanageData() {

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

return (

<>
     <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>
</>

)}

Answer 1

这可能会有帮助(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)}
          .....
    />
  );
}