Javascript 更新React钩子对象元素
我有一个下拉列表,用户可以在其中选择他们想要设置todo的日期。 根据日期,我将添加Javascript 更新React钩子对象元素,javascript,react-native,react-hooks,Javascript,React Native,React Hooks,我有一个下拉列表,用户可以在其中选择他们想要设置todo的日期。 根据日期,我将添加true 通过选择字段,例如Monday,如果用户选择午后,并且还选择了晚间,则午后字段不得受到影响。这可能吗。请帮帮我 这是我的密码 const ToDo = () =>{ const [selectedCat, setSelected] = useState('') const [mon, setMon] = useState([{ 'morning':[],
true
通过选择字段,例如Monday
,如果用户选择午后
,并且还选择了晚间
,则午后字段不得受到影响。这可能吗。请帮帮我
这是我的密码
const ToDo = () =>{
const [selectedCat, setSelected] = useState('')
const [mon, setMon] = useState([{
'morning':[],
'afternoon':[],
'evening':[]
}])
const days = [
{itemName: "Select a day"},{itemName: "Monday"},
{itemName: "Tuesday"},
{itemName: "Wednesday"},{itemName: "Thursday"},
{itemName: "Friday"},{itemName: "Saturday"},
{itemName: "Sunday"}
]
const whichDay = () =>{
switch(selectedCat){
case selectedCat === 'Monday':
setMon({
"morning": true
})
default:
break
}
}
return(
<Picker
mode="dropdown"
selectedValue={selectedCat}
onValueChange={(itemValue, itemIndex) => setSelected(itemValue) && whichDay()}
>
{category.map((item, index) => (
<Picker.Item
label={item.itemName}
value={item.itemName}
index={index}
/>))}
</Picker>
)
}
const ToDo=()=>{
const[selectedCat,setSelected]=使用状态(“”)
常量[mon,setMon]=useState([{
“早上好”:[],
“下午”:[],
‘晚上’:[]
}])
常数天数=[
{itemName:“选择一天”},{itemName:“星期一”},
{itemName:“星期二”},
{itemName:“星期三”},{itemName:“星期四”},
{itemName:“星期五”},{itemName:“星期六”},
{itemName:“Sunday”}
]
常量whichDay=()=>{
开关(已选择Cat){
案例选择CAT==‘星期一’:
塞蒙({
“早晨”:真的吗
})
违约:
打破
}
}
返回(
setSelected(itemValue)&&whichDay()}
>
{category.map((项目,索引)=>(
))}
)
}
const ToDo=()=>{
const[selectedCat,setSelected]=使用状态(“”)
常量[mon,setMon]=useState([{
“早上好”:[],
“下午”:[],
‘晚上’:[]
}])
常数天数=[
{itemName:“选择一天”},{itemName:“星期一”},
{itemName:“星期二”},
{itemName:“星期三”},{itemName:“星期四”},
{itemName:“星期五”},{itemName:“星期六”},
{itemName:“Sunday”}
]
常量whichDay=()=>{
开关(已选择Cat){
案例选择CAT==‘星期一’:
setMon((aAlreadySelectedState)=>{return{
“早上”:没错,
…aAlreadySelectedState
}})
违约:
打破
}
}
返回(
setSelected(itemValue)&&whichDay()}
>
{category.map((项目,索引)=>(
))}
)
}
const ToDo=()=>{
const[selectedCat,setSelected]=使用状态(“”)
常量[mon,setMon]=useState([{
“早上好”:[],
“下午”:[],
‘晚上’:[]
}])
常数天数=[
{itemName:“选择一天”},{itemName:“星期一”},
{itemName:“星期二”},
{itemName:“星期三”},{itemName:“星期四”},
{itemName:“星期五”},{itemName:“星期六”},
{itemName:“Sunday”}
]
常量whichDay=()=>{
开关(已选择Cat){
案例选择CAT==‘星期一’:
setMon((aAlreadySelectedState)=>{return{
“早上”:没错,
…aAlreadySelectedState
}})
违约:
打破
}
}
返回(
setSelected(itemValue)&&whichDay()}
>
{category.map((项目,索引)=>(
))}
)
}
const ToDo = () =>{
const [selectedCat, setSelected] = useState('')
const [mon, setMon] = useState([{
'morning':[],
'afternoon':[],
'evening':[]
}])
const days = [
{itemName: "Select a day"},{itemName: "Monday"},
{itemName: "Tuesday"},
{itemName: "Wednesday"},{itemName: "Thursday"},
{itemName: "Friday"},{itemName: "Saturday"},
{itemName: "Sunday"}
]
const whichDay = () =>{
switch(selectedCat){
case selectedCat === 'Monday':
setMon((aAlreadySelectedState)=>{return {
"morning": true,
...aAlreadySelectedState
}})
default:
break
}
}
return(
<Picker
mode="dropdown"
selectedValue={selectedCat}
onValueChange={(itemValue, itemIndex) => setSelected(itemValue) && whichDay()}
>
{category.map((item, index) => (
<Picker.Item
label={item.itemName}
value={item.itemName}
index={index}
/>))}
</Picker>
)
}