javascript - que - ¿Cómo detener el comportamiento predeterminado de dragend en arrastrar y soltar?

que es drag and drop

Question

Me cuesta sumar este error en palabras. Así que hice el video del error. Básicamente, cuando se llama a dragEnd, el elemento se anima como si fuera al lugar original. Cómo detener el comportamiento predeterminado? Hice un violín y un codepen para esto también.

Tengo dos listas para mi ejemplo, cuando llamo a dragEnd después de soltar el botón del mouse. El elemento de una lista anima a ir a la lista de su lugar original en lugar del lugar donde va a estar.

Código JS:

''use strict'';

var source = null; var heightWidth = null; var lastDragOverElementId = null; var dragImageSource = null;

function listItemDragStartHandler(event) {
    source = event.currentTarget;
    heightWidth = [];
    heightWidth.push(source.offsetHeight);
    heightWidth.push(source.offsetWidth);
    event.dataTransfer.setData(''text/html'', event.currentTarget.innerHTML);
    event.dataTransfer.effectAllowed = ''move'';
    // Drag image logic
    dragImageSource = source.cloneNode(true);
    dragImageSource.style.position = ''absolute'';
    // Don''t show the element
    dragImageSource.style.top = ''0px'';
    dragImageSource.style.left = ''-'' + String(window.innerWidth) + ''px'';
    // dragImageSource.style.left = ''-100px'';
    var toTiltElement = dragImageSource.getElementsByClassName(''item-list-element'')[0];
    toTiltElement.style.transform = ''rotate(5deg)'';
    document.body.append(dragImageSource);
    event.dataTransfer.setDragImage(dragImageSource, heightWidth[1]/2, heightWidth[0]/2); }

function dragoverHandler(event) {
    event.preventDefault();
    event.dataTransfer.dropEffect = ''move'';
    source.style.display = ''none'';
    var currentElement = event.currentTarget;
    var listContainer = currentElement.parentNode;
    if (lastDragOverElementId != currentElement.getAttribute(''id'')) {
        lastDragOverElementId = currentElement.getAttribute(''id'');
        if(document.getElementById(''grayed-empty-node'') !== null) {
            if(currentElement.getAttribute(''id'') !== ''grayed-empty-node'') {
                document.getElementById(''grayed-empty-node'').remove();
            }
        }
        var isGrayEmptyNodeThere = document.getElementById(''grayed-empty-node'');   //
        if(isGrayEmptyNodeThere === null) {
            var emptyNode = document.getElementById(''empty-node'').cloneNode(true);
            emptyNode.removeAttribute(''id'');
            emptyNode.setAttribute(''id'', ''grayed-empty-node'');
            emptyNode.setAttribute(''class'', ''fade-in'');
            emptyNode.style.height = String(heightWidth[0]) + ''px'';
            emptyNode.style.width = String(heightWidth[1]) + ''px'';
            listContainer.insertBefore(emptyNode, currentElement);
        }
    } }

function dragLeaveHandler(event) {
    event.preventDefault();
    var currentElement = event.currentTarget;
    var listContainer = currentElement.parentNode;
    var elementList = listContainer.getElementsByClassName(''item-template-container'');
    var visibleElementList = [];
    var i = 0;
    for (i=0; i<elementList.length; i++) {
        if (elementList[i].style.display !== ''none'') {
            visibleElementList.push(elementList[i]);
        }
    }
    // Last element ondragleave handler should be delayed, otherwise it
    // would spin off chain reaction.
    var lastVisibleElement = visibleElementList[visibleElementList.length - 1];
    // Basically last element
    if (currentElement.id === lastVisibleElement.getAttribute(''id'')) {
        lastVisibleElement.removeAttribute(''ondragleave'');
        if(document.getElementById(''grayed-empty-node'') !== null) {
            document.getElementById(''grayed-empty-node'').remove();
        }
        var isGrayEmptyNodeThere = document.getElementById(''grayed-empty-node'');
        if(isGrayEmptyNodeThere === null) {
            var listContainer = currentElement.parentNode;
            var emptyNode = document.getElementById(''empty-node'').cloneNode(true);
            emptyNode.removeAttribute(''id'');
            emptyNode.setAttribute(''id'', ''grayed-empty-node'');
            emptyNode.setAttribute(''class'', ''fade-in'');
            emptyNode.style.height = String(heightWidth[0]) + ''px'';
            emptyNode.style.width = String(heightWidth[1]) + ''px'';
            listContainer.insertBefore(emptyNode, null);
        }
        // This delayed the chain reaction
        setTimeout(function() {
            visibleElementList[visibleElementList.length - 1].setAttribute(''ondragleave'', ''dragLeaveHandler(event);'');
        }, 500);
    // When event is on last element set the lastDragOverElementId to null
    // then dragover to lastVisibleElement(second last element) can be handled
    // otherwise dragover to second last element won''t show placeholder.
    lastDragOverElementId = null;
    } }

function dragEndHandler(event) {
    event.preventDefault();
    // Check the dropEffect
    dragImageSource.remove();
    var listElement = document.getElementById(''grayed-empty-node'')
    var listContainer = listElement.parentNode;
    if (event.dataTransfer.dropEffect === ''none'') {
        var grayEmptyNode = document.getElementById(''grayed-empty-node'');
        // When grayEmptyNode is null, that will append at the end.
        listContainer.insertBefore(source, grayEmptyNode);
        source.style.display = '''';
        if(document.getElementById(''grayed-empty-node'') !== null) {
            document.getElementById(''grayed-empty-node'').remove();
        }
    } else if (event.dataTransfer.dropEffect === ''move'') {
        var grayEmptyNode = document.getElementById(''grayed-empty-node'');
        // When grayEmptyNode is null, that will append at the end.
        listContainer.insertBefore(source, grayEmptyNode);
        source.style.display = '''';
        if(document.getElementById(''grayed-empty-node'') !== null) {
            document.getElementById(''grayed-empty-node'').remove();
        }
    } }

function delete_item(event) {
    var currentElement = event.currentTarget;
    var grandParentOfDelete = currentElement.parentNode.parentNode;
    grandParentOfDelete.remove(); }

function add_item() {
    var item_text_node = document.getElementsByName(''add-item-text'')[0]
    var item_text = item_text_node.value;
    if (item_text.length > 0) {
        var item_template = document.getElementById(''item-template-container'');
        var item_clone = item_template.cloneNode(true);
        item_clone.removeAttribute(''id'');
        var random_id = (new Date().getTime() +
            parseInt(Math.random(0, 1000) * 1000))
        item_clone.setAttribute(''id'', random_id);
        var clone_text = item_clone.getElementsByClassName(''item-text'')[0];
        clone_text.textContent = item_text;
        // reset the value
        item_text_node.value = '''';
        var item_list = document.getElementById(''item-list'');
        item_list.appendChild(item_clone);
    } else {
        alert(''No text?? Add some text!'');
    } }

function add_item_2() {
    var item_text_node = document.getElementsByName(''add-item-text-2'')[0]
    var item_text = item_text_node.value;
    if (item_text.length > 0) {
        var item_template = document.getElementById(''item-template-container'');
        var item_clone = item_template.cloneNode(true);
        item_clone.removeAttribute(''id'');
        var random_id = (new Date().getTime() +
            parseInt(Math.random(0, 1000) * 1000))
        item_clone.setAttribute(''id'', random_id);
        var clone_text = item_clone.getElementsByClassName(''item-text'')[0];
        clone_text.textContent = item_text;
        // reset the value
        item_text_node.value = '''';
        var item_list = document.getElementById(''item-list-2'');
        item_list.appendChild(item_clone);
    } else {
        alert(''No text?? Add some text!'');
    } }

function onEnterInInput() {
    var e = e || window.event;
    if (e.keyCode == 13) {
        add_item()
    } }

function sample_data() {
    for(var i=0;i<10;i++){
        var item_text_node = document.getElementsByName(''add-item-text'')[0]
        item_text_node.value = i;
        var item_text_node_2 = document.getElementsByName(''add-item-text-2'')[0]
        item_text_node_2.value = i;
        add_item();
        add_item_2();
    } }

window.onload = function () {
    sample_data(); }

Código HTML:

<!DOCTYPE html>
<html>
<head>
    <title>List task</title>
    <script type="text/javascript" src="list-task.js"></script>
    <link rel="stylesheet" type="text/css" href="list-task.css">
    <script>
      document.write(''<script src="http://'' + (location.host || ''localhost'').split('':'')[0] +
      '':35729/livereload.js?snipver=1"></'' + ''script>'')
    </script>
</head>
<body>
    <div id="container">
        <div id="list-1">
            <div id="add-item-div">
                <input type="text" name="add-item-text" onkeypress="onEnterInInput(event);">
                <button id="add-item" onclick="add_item(event)">Add Item</button>
            </div>
            <div id="item-list">
            </div>
        </div>
        <div id="list-2">
            <div id="add-item-div-2">
                <input type="text" name="add-item-text-2" onkeypress="onEnterInInput(event);">
                <button id="add-item-2" onclick="add_item_2(event)">Add Item</button>
            </div>
            <div id="item-list-2">
            </div>
        </div>
        <div id="item-template-container" class="item-template-container" draggable="true" ondragstart="listItemDragStartHandler(event);" ondragover="dragoverHandler(event);" ondragend="dragEndHandler(event);" ondragleave="dragLeaveHandler(event);" ondrop="onDropHandler(event);">
            <div class="item-list-element">
                <div class="item-text"></div>
                <div class="delete-item-div">
                    <button class="delete-item" onclick="delete_item(event);">Delete</button>
                </div>
            </div>
        </div>
        <div id="empty-node">&nbsp;</div>
    </div>
</body>
</html>

Video que describe el error: https://www.youtube.com/watch?v=Uz_ukKdg1O0&feature=youtu.be

Nota : observé el comportamiento en Mac, no estoy seguro acerca de Linux y Windows.

Answer 1

En su gestor de eventos dragend debe detectar si el mouse está sobre el graybox en la lista en la que desea colocarlo. Tenga en cuenta que necesitará escribir la lógica para consultar el elemento grayBoxInOtherList pero esto es lo que deberá hacer:

if ($(grayBoxInOtherList).parent().find(":hover")) {
    listContainer.insertBefore(source, grayEmptyNode);
}

Solo haga esto si está pasando el mouse sobre grayBoxInOtherList: listContainer.insertBefore(source, grayEmptyNode);