Question

说我有一个像这样的父组件：

function Recipe(recipe) {
  const [pageState, updatePageState] = useState("view");

  return (
    <div className="border-b-2 border-gray-300 py-2">
      <div className="h-full flex-col md:flex md:flex-row md:justify-between md:items-start">
        <div
          className="order-2 flex flex-col flex-1 px-2 h-full md:h-72 lg:h-64 md:flex-col md:justify-between md:order-1 md:w-1/2 lg:w-3/4"
        >          
          <RecipeActions pageState = {pageState} triggerParentUpdate = {state => updatePageState(state)} />
        </div>
      </div>
    </div>
  )
}

，并且我在下面的子组件中尝试更新父组件中的pageState。我已经尝试了几次迭代，但是都没有运气。

function RecipeActions(pageState, {triggerParentUpdate}){
  const [open, moreActions] = useState(false);

  function editRecipe(){
    triggerParentUpdate(pageState);
  }

  return(
    <div className="flex">
    <span className={`${pageState=='view' ? 'hidden' : ''} ml-1 sm:ml-2 md:ml-1 lg:ml-2 shadow-sm rounded-md`}>
      <button
        onClick={editRecipe}
        type="button"
        className="inline-flex items-center px-3 sm:px-4 py-2 border border-gray-300 text-sm leading-5 font-medium rounded-md text-gray-700 bg-white hover:text-gray-500 focus:outline-none focus:shadow-outline-blue focus:border-blue-300 active:text-gray-800 active:bg-gray-50 active:text-gray-800 transition duration-150 ease-in-out"
      >
        <svg className="h-5 w-5 text-gray-500" fill="currentColor" viewBox="0 0 20 20">
          <path d="M17.414 2.586a2 2 0 00-2.828 0L7 10.172V13h2.828l7.586-7.586a2 2 0 000-2.828z" />
          <path
            fillRule="evenodd"
            d="M2 6a2 2 0 012-2h4a1 1 0 010 2H4v10h10v-4a1 1 0 112 0v4a2 2 0 01-2 2H4a2 2 0 01-2-2V6z"
            clipRule="evenodd"
          />
        </svg>
        <p className="hidden sm:block sm:pl-2 md:hidden lg:block">Edit</p>
      </button>
    </span>
  </div>
  )
}

Answer 1

我知道了。参见以下摘要：

重要的是要确保将道具作为单个数组传递给孩子，在调用函数（例如onClick={() => triggerParentUpdate('edit')}）以及将update函数传递给子对象时，应该有一个函数。父母的孩子，您需要像这样的<RecipeActions pageState = {pageState} triggerParentUpdate = {updatePageState} />

父母

function Recipe(recipe) {
  const [pageState, setPageState] = useState("view");

  const updatePageState = (state) => {
    setPageState(state);
  } 

  return (
    <div className="border-b-2 border-gray-300 py-2">
      <div className="h-full flex-col md:flex md:flex-row md:justify-between md:items-start">
        <div
          className="order-2 flex flex-col flex-1 px-2 h-full md:h-72 lg:h-64 md:flex-col md:justify-between md:order-1 md:w-1/2 lg:w-3/4"
        >          
          <RecipeActions pageState = {pageState} triggerParentUpdate = {updatePageState} />
        </div>
      </div>
    </div>
  )
}

孩子

function RecipeActions({pageState, triggerParentUpdate}){
  const [open, moreActions] = useState(false);

  return(
    <div className="flex">
    <span className={`${pageState=='view' ? 'hidden' : ''} ml-1 sm:ml-2 md:ml-1 lg:ml-2 shadow-sm rounded-md`}>
      <button
        onClick={() => triggerParentUpdate('edit')}
        type="button"
        className="inline-flex items-center px-3 sm:px-4 py-2 border border-gray-300 text-sm leading-5 font-medium rounded-md text-gray-700 bg-white hover:text-gray-500 focus:outline-none focus:shadow-outline-blue focus:border-blue-300 active:text-gray-800 active:bg-gray-50 active:text-gray-800 transition duration-150 ease-in-out"
      >
        <svg className="h-5 w-5 text-gray-500" fill="currentColor" viewBox="0 0 20 20">
          <path d="M17.414 2.586a2 2 0 00-2.828 0L7 10.172V13h2.828l7.586-7.586a2 2 0 000-2.828z" />
          <path
            fillRule="evenodd"
            d="M2 6a2 2 0 012-2h4a1 1 0 010 2H4v10h10v-4a1 1 0 112 0v4a2 2 0 01-2 2H4a2 2 0 01-2-2V6z"
            clipRule="evenodd"
          />
        </svg>
        <p className="hidden sm:block sm:pl-2 md:hidden lg:block">Edit</p>
      </button>
    </span>
  </div>
  )
}

这是我从this page看到的另一个示例

import React from 'react';

function App() {
  const [fruits, setFruits] = React.useState([
    { id: '1', name: 'Apple', isFavorite: false },
    { id: '2', name: 'Peach', isFavorite: true },
    { id: '3', name: 'Strawberry', isFavorite: false },
  ]);

  function handleClick(item) {
    const newFruits = fruits.map((fruit) => {
      if (fruit.id === item.id) {
        return {
          id: fruit.id,
          name: fruit.name,
          isFavorite: !fruit.isFavorite,
        };
      } else {
        return fruit;
      }
    });

    setFruits(newFruits);
  }

  return (
    <div>
      <h3>with no styling</h3>

      <Basket items={fruits} onClick={handleClick} />
    </div>
  );
}

function Basket({ items, onClick }) {
  return (
    <ul>
      {items.map((item) => (
        <li key={item.id}>
          {item.name}
          <button type="button" onClick={() => onClick(item)}>
            {item.isFavorite ? 'Unlike' : 'Like'}
          </button>
        </li>
      ))}
    </ul>
  );
}

export default App;

使用UseState React Hook从子组件更新父组件状态

1 个答案: