我想更改数组的值以在渲染之前显示新数组。我首先使用componentWillMount来调用我的函数。我的函数更改函数中的数组
import recipeData from '../Helpers/RecipeData'
componentWillMount(){
this._selectRicipe()
}
constructor(props) {
super(props)
this.state = {
myRecipeData: recipeData
}
}
_selectRicipe(){
for (let i = 0; i < recipeData.length; i++) {
for (let j = 0; j < this.props.listIngredients.length; j++) {
if (this.props.listIngredients[j].name == recipeData[i].type) {
newData = []
console.log(this.props.listIngredients[j].name)
newData = recipeData[i].name
this.setState({ myRecipeData: newData })
console.log("new RecipeData 1 : " + this.state.myRecipeData[i].name)
}
}
}
}
render() {
console.log("..New..recipe.. " + this.state.myRecipeData[0].name);
return (
<FlatList
data={this.state.myRecipeData}
keyExtractor={(item) => item.id.toString()}
renderItem={({ item }) => <RecipeDesc recipeData={item} />}
>
</FlatList>
)
}
在我的RecipDesc组件中,我实际上得到了数据,我可以得到我尝试发送新数组的第一个未修改的数组的值,因为另一个视图可能需要使用异步操作?
谢谢
我看一下您的代码,发现您处于setState循环中,它将影响您的应用程序性能。我如下修改
constructor(props) {
super(props)
this.state = {
myRecipeData: recipeData
}
}
//please do it in the componentDidMount
componDidMount() {
this._selectRicipe()
}
_selectRicipe(){
let newData = [] // avoid to define a object in the loop repeately
for (let i = 0; i < recipeData.length; i++) {
for(let j = 0; j < this.props.listIngredients.length; j++){
if(this.props.listIngredients[j].name == recipeData[i].type){
console.log(this.props.listIngredients[j].name)
newData.push(recipeData[i].name)
// the flatlist neeed data is arry and not loop to
// setState
// this.setState({ myRecipeData: newData })
console.log("new RecipeData 1 :
"+this.state.myRecipeData[i].name)
}
}
}
this.setState({myRecipeData:newData})}
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