目錄

• 1、前言
• 2、實現
• 3、為何不使用HTML拖放API實現？
• 4、總結

1、前言

拖拽排序對於小夥伴們來說應該不陌生，平時工作的時候，可能會選擇使用類似Sortable.這樣的開源庫來實現需求。但在完成需求後，大家有沒有沒想過拖拽排序是如何實現的呢？我花了點時間研究了一下，今天分享給大家。

2、實現

 {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

.grid {
    display: flex;
    flex-wrap: wrap;
    margin: 0 -15px -15px 0;
    touch-action: none;
    user-select: none;
}

.grid-item {
    width: 90px;
    height: 90px;
    line-height: 88px;
    text-align: center;
    margin: 0 15px 15px 0;
    background: #FFF;
    border: 1px solid #d6d6d6;
    list-style: none;
}

.active {
    background: #c8ebfb;
}

.clone-grid-item {
    position: fixed;
    left: 0;
    top: 0;
    z-index: 1;
    width: 90px;
    height: 90px;
    line-height: 88px;
    text-align: center;
    background: #FFF;
    border: 1px solid #d6d6d6;
    opacity: 0.8;
    list-style: none;
}

<ul class="grid">
    <li class="grid-item">item1</li>
    <li class="grid-item">item2</li>
    <li class="grid-item">item3</li>
    <li class="grid-item">item4</li>
    <li class="grid-item">item5</li>
    <li class="grid-item">item6</li>
    <li class="grid-item">item7</li>
    <lwww.cppcns.com
 
i class="grid-item">item8</li>
    <li class="grid-item">item9</li>
    <li class="grid-item">item10</li>
</ul>

採用ES6 Class寫法：

class Draggable {
    constructor(options) {
        this.parent = options.element; // 父級元素
        this.clongtROnDSbSeElementClassName = options.cloneElementClassName; // 克隆元素類名
        this.isPointerdown = false;
        this.diff = { x: 0,y: 0 }; // 相對於上一次移動差值
        this.drag = { element: null,index: 0,lastIndex: 0 }; // 拖拽元素
        this.drop = { element: null,lastIndex: 0 }; // 釋放元素
        this.clone = { element: null,x: 0,y: 0 };
        this.lastPointermove = { x: 0,y: 0 };
        this.rectList = []; // 用於儲存拖拽項getBoundingClientRect()方法獲得的資料
        this.init();
    }
    init() {
        this.getRect();
        this.bindEventListener();
    }
    // 獲取元素位置資訊
    getRect() {
        this.rectList.length = 0;
        for (const item of this.parent.children) {
            this.rectList.push(item.getBoundingClientRect());
        }
    }
    handlePointerdown(e) {
        // 如果是滑鼠點選，只響應左鍵
        if (e.pointerType === 'mouse' && e.button !== 0) {
 www.cppcns.com
 
           return;
        }
        if (e.target === this.parent) {
            return;
        }
        this.isPointerdown = true;
        this.parent.setPointerCapture(e.pointerId);
        this.lastPointermove.x = e.clientX;
        this.lastPointermove.y = e.clientY;
        this.drag.element = e.target;
        this.drag.element.classList.add('active'gtROnDSbS);
        this.clone.element = this.drag.element.cloneNode(true);
        this.clone.element.className = this.cloneElementClassName;
        this.clone.element.style.transition = 'none';
        const i = [].indexOf.call(this.parent.children,this.drag.element);
        this.clone.x = this.rectList[i].left;
        this.clone.y = this.rectList[i].top;
        this.drag.index = i;
        this.drag.lastIndex = i;
        this.clone.element.style.transform = 'translate3d(' + this.clone.x + 'px,' + this.clone.y + 'px,0)';
        document.body.appendChild(this.clone.element);
    }
    handlePointermove(e) {
        if (this.isPointerdown) {
            this.diff.x = e.clientX - this.lastPointermove.x;
            this.diff.y = e.clientY - this.lastPointermove.y;
            this.lastPointermove.x = e.clientX;
            this.lastPointermove.y = e.clientY;
            this.clone.x += this.diff.x;
            this.clone.y += this.diff.y;
            this.clone.element.style.transform = 'translate3d(' + this.clone.x + 'px,0)';
            for (let i = 0; i < this.rectList.length; i++) {
                // 碰撞檢測
                if (e.clientX > this.rectList[i].left && e.clientX < this.rectList[i].right &&
                    e.clientY > this.rectList[i].top && e.clientY < this.rectList[i].bottom) {
                    this.drop.element = this.parent.children[i];
                    this.drop.lastIndex = i;
                    if (this.drag.element !== this.drop.element) {
                        if (this.drag.index < i) {
                            this.parent.insertBefore(this.drag.element,this.drop.element.nextElementSibling);
                            this.drop.index = i - 1;
                        } else {
                            this.parent.insertBefore(this.drag.element,this.drop.element);
                            this.drop.index = i + 1;
                        }
                        this.drag.index = i;
                        const dragRect = this.rectList[this.drag.index];
                        const lastDragRect = this.rectList[this.drag.lastIndex];
                        const dropRect = this.rectList[this.drop.index];
                        const lastDropRect = this.rectList[this.drop.lastIndex];
                        this.drag.lastIndex = i;
                        this.drag.element.style.transition = 'none';
                        this.drop.element.style.transition = 'none';
                        this.drag.element.style.transform = 'translate3d(' + (lastDragRect.left - dragRect.left) + 'px,' + (lastDragRect.top - dragRect.top) + 'px,0)';
                        this.drop.element.style.transform = 'translate3d(' + (lastDropRect.left - dropRect.left) + 'px,' + (lastDropRect.top - dropRect.top) + 'px,0)';
                        this.drag.element.offsetLeft; // 觸發重繪
                        this.drag.element.style.transition = 'transform 150ms';
                        this.drop.element.style.transition = 'transform 150ms';
                        this.drag.element.style.transform = 'translate3d(0px,0px,0px)';
                        this.drop.element.style.transform = 'translate3d(0px,0px)';
                    }
                    break;
                }
            }
        }
    }
    handlePointerup(e) {
        if (this.isPointerdown) {
            this.isPointerdown = false;
            this.drag.element.classList.remove('active');
            this.clone.element.remove();
        }
    }
    handlePointercancel(e) {
        if (this.isPointerdown) {
            this.isPointerdown = false;
            this.drag.element.classList.remove('active');
            this.clone.element.remove();
        }
    }
    bindEventListener() {
        this.handlePointerdown = this.handlePointerdown.bind(this);
        this.handlePointermove = this.handlePointermove.bind(this);
        this.handlePointerup = this.handlePointerup.bind(this);
        this.handlePointercancel = this.handlePointercancel.bind(this);
        this.getRect = this.getRect.bind(this);
        this.parent.addEventListener('pointerdown',this.handlePointerdown);
        this.parent.addEventListener('pointermove',this.handlePointermove);
        this.parent.addEventListener('pointerup',this.handlePointerup);
        this.parent.addEventListener('pointercancel',this.handlePointercancel);
        window.addEventListener('scroll',this.getRect);
        window.addEventListener('resize',this.getRect);
        window.addEventListener('orientationchange',this.getRect);
    }
    unbindEventListener() {
        this.parent.removeEventListener('pointerdown',this.handlePointerdown);
        this.parent.removeEventListener('pointermove',this.handlePointermove);
        this.parent.removeEventListener('pointerup',this.handlePointerup);
        this.parent.removeEventListener('pointercancel',this.handlePointercancel);
        window.removeEventListener('scroll',this.getRect);
        window.removeEventListener('resize',this.getRect);
        window.removeEventListener('orientationchange',this.getRect);
    }
}
// 例項化
new Draggable({
    element: document.querySelector('.grid'),cloneElementClassName: 'clone-grid-item'
});

Demo：jsdemo.codeman.top/html/dragga…

3、為何不使用HTML拖放API實現？

因為原生HTML拖放API在移動端無法使用，所以為了相容PC端和移動端，使用了PointerEvent事件實現拖拽邏輯。

4、總結

拖拽排序的基本功能已經實現，但還存在很多不足。像巢狀拖拽，跨列表拖拽，拖拽到底部自動滾動等功能都未實現。

到此這篇關於js 實現拖拽排序詳情的文章就介紹到這了,更多相關js 實現拖拽排序內容請搜尋我們以前的文章或繼續瀏覽下面的相關文章希望大家以後多多支援我們！