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首页 > 解决方案 > Javascript 待办事项列表应用程序。我无法删除最后剩余的 li 并清除所有按钮不起作用，只有本地存储被删除

javascript - Javascript 待办事项列表应用程序。我无法删除最后剩余的 li 并清除所有按钮不起作用，只有本地存储被删除

问题描述

我遇到了关于我的 todo 应用程序的 2 个问题。我只是根据其中一个 Youtube 教程进行编码，以提高我的 Javascript 知识。我无法删除待办事项列表中最后剩余的 li，但本地存储显示它已被删除。与我的全部清除按钮一样，本地存储已被删除，但我的 li 仍在显示。除此之外，点击清除所有按钮后，即使仍然显示，我也无法将其一一删除（我的猜测是本地存储已为空，没有更多数据可删除）。感谢您以后的回复！

const inputBox = document.querySelector('.input-container input')
const addBtn = document.querySelector('.input-container button')
const todo = document.querySelector('.todo-list')
const deleteAllBtn = document.querySelector('.footer button')
// input button
inputBox.onkeyup = () => {
    let userData= inputBox.value;
    if (userData.trim() != 0 ) {
        addBtn.classList.add('active')
    } else {
        addBtn.classList.remove('active');
    }
}
showTask();

//adding it to local storage
addBtn.onclick = () => {
    let userData = inputBox.value;
    let getLocalStorage = localStorage.getItem("New Todo")
    if (getLocalStorage == null) {
        listArr = [];
    } else {
        listArr = JSON.parse(getLocalStorage);
    }
    listArr.push(userData);
    localStorage.setItem("New Todo", JSON.stringify(listArr));
    showTask();
    addBtn.classList.remove('active');
}

//add task
function showTask() {
    let getLocalStorage = localStorage.getItem("New Todo")
    if (getLocalStorage == null) {
        listArr = [];
    } else {
        listArr = JSON.parse(getLocalStorage);
    }
    const pendingNumb = document.querySelector('.pending');
    pendingNumb.textContent= listArr.length;
    let newLiTag = '';
    listArr.forEach((element, index) => {
        newLiTag += `<li> ${element} <span onclick="deleteTask(${index})";><i class="fas fa-trash-alt"></i></span></li>
        `;
        todo.innerHTML = newLiTag;
        inputBox.value = '';
    });
}

//delete task
function deleteTask(index) {
    let getLocalStorage = localStorage.getItem("New Todo");
    listArr = JSON.parse(getLocalStorage);
    listArr.splice(index, 1);
    localStorage.setItem("New Todo", JSON.stringify(listArr));
    showTask();
}

//delete all task
deleteAllBtn.onclick = () => {
    listArr = [];
    localStorage.setItem("New Todo", JSON.stringify(listArr));
    showTask();
}
.todo-list {
    margin: 10px 0;
    width: 360px;
    height: 260px;
    max-height: 250px;
    overflow-y: auto;  
}

.todo-list li {
    position: relative;
    list-style-type: none;
    background: #f2f2f2;
    margin: 5px 0;
    display: flex;
    justify-content: space-between;
    padding: 5px 5px;
    overflow: hidden;
}

.todo-list li span {
    position: absolute;
    right: -30px;
    top: 0;
    background: #d00000;
    color: #fff;
    width: 35px;
    height: 35px;
    padding-top: 5px;
    text-align: center;
    transition: all 0.3s ease;
    cursor: pointer;
}

.todo-list li:hover span {
    right: 0;
}

.footer {
    font-size: 17px;
    font-weight: bold;
    margin: 0 10px;
}

.footer span {
    margin: 0 10px;
}

.footer button {
    height: 2.5rem;
    width: 5rem;
    font-size: 1rem;
    color: #fff;
    background: #d00000;
    border: none;
    cursor: pointer;  
}
<div class="container">
        <h1>TODO list</h1>
        <div class="input-container">
            <input type="text" class="input" placeholder="Input Text Here">
            <button><i class="fas fa-plus"></i></button>
        </div>
        <ul class="todo-list">
        
        </ul>

        <div class="footer">
            <span>You have<span class="pending">0</span>pending task left</span>
            <button>Clear All</button>
        </div>

标签： javascript

解决方案

您应该更新todoforEach 之外的元素

function showTask() {
    let getLocalStorage = localStorage.getItem("New Todo")
    if (getLocalStorage == null) {
        listArr = [];
    } else {
        listArr = JSON.parse(getLocalStorage);
    }
    const pendingNumb = document.querySelector('.pending');
    pendingNumb.textContent = listArr.length;
    let newLiTag = '';
    listArr.forEach((element, index) => {
        newLiTag += `<li> ${element} <span onclick="deleteTask(${index})";><i class="fas fa-trash-alt"></i></span></li>
    `;
    });
    //move it here
    todo.innerHTML = newLiTag;
    inputBox.value = '';
}

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