React 子组件state内数组修改页面不刷新问题

1.在子组件内对数组进行删减后打印数据有变化可是页面没从新渲染

原始写法

 deleteBtnClick(index){
        let tempList = this.state.attachList;
        tempList.splice(index,1)
        this.setState({
            attachList: tempList
        });
    }

解决办法

 deleteBtnClick(index){
        let tempList = this.state.attachList;
        tempList.splice(index,1)
        this.setState((prevState) =>{
            delete prevState.attachList;
            return prevState;
        })
        this.setState({
            attachList:tempList
        })

    }