此範例所實作的放下目標會顯示一份表格,以列出放下的項目所提供的每一種資料格式。
預設的行為原本是允許在應用程式內拖曳文字、連結和影像。此範例會覆寫預設的拖入行為,覆寫對象則會做為放下目標的 div 元素。為了讓不可編輯的內容能夠接受拖入手勢,主要步驟在於同時對
dragenter
和
dragover
事件發生時所傳送的事件物件呼叫
preventDefault()
方法。回應
drop
事件時,處理常式會將傳輸的資料轉換成 HTML 列元素,然後再將該列插入表格中以供顯示。
<html>
<head>
<title>Drag-and-drop</title>
<script language="javascript" type="text/javascript" src="AIRAliases.js"></script>
<script language="javascript">
function init(){
var target = document.getElementById('target');
target.addEventListener("dragenter", dragEnterOverHandler);
target.addEventListener("dragover", dragEnterOverHandler);
target.addEventListener("drop", dropHandler);
var source = document.getElementById('source');
source.addEventListener("dragstart", dragStartHandler);
source.addEventListener("dragend", dragEndHandler);
emptyRow = document.getElementById("emptyTargetRow");
}
function dragStartHandler(event){
event.dataTransfer.effectAllowed = "copy";
}
function dragEndHandler(event){
air.trace(event.type + ": " + event.dataTransfer.dropEffect);
}
function dragEnterOverHandler(event){
event.preventDefault();
}
var emptyRow;
function dropHandler(event){
for(var prop in event){
air.trace(prop + " = " + event[prop]);
}
var row = document.createElement('tr');
row.innerHTML = "<td>" + event.dataTransfer.getData("text/plain") + "</td>" +
"<td>" + event.dataTransfer.getData("text/html") + "</td>" +
"<td>" + event.dataTransfer.getData("text/uri-list") + "</td>" +
"<td>" + event.dataTransfer.getData("application/x-vnd.adobe.air.file-list") +
"</td>";
var imageCell = document.createElement('td');
if((event.dataTransfer.types.toString()).search("image/x-vnd.adobe.air.bitmap") > -1){
imageCell.appendChild(event.dataTransfer.getData("image/x-vnd.adobe.air.bitmap"));
}
row.appendChild(imageCell);
var parent = emptyRow.parentNode;
parent.insertBefore(row, emptyRow);
}
</script>
</head>
<body onLoad="init()" style="padding:5px">
<div>
<h1>Source</h1>
<p>Items to drag:</p>
<ul id="source">
<li>Plain text.</li>
<li>HTML <b>formatted</b> text.</li>
<li>A <a href="http://www.adobe.com">URL.</a></li>
<li><img src="icons/AIRApp_16.png" alt="An image"/></li>
<li style="-webkit-user-drag:none;">
Uses "-webkit-user-drag:none" style.
</li>
<li style="-webkit-user-select:none;">
Uses "-webkit-user-select:none" style.
</li>
</ul>
</div>
<div id="target" style="border-style:dashed;">
<h1 >Target</h1>
<p>Drag items from the source list (or elsewhere).</p>
<table id="displayTable" border="1">
<tr><th>Plain text</th><th>Html text</th><th>URL</th><th>File list</th><th>Bitmap Data</th></tr>
<tr id="emptyTargetRow"><td> </td><td> </td><td> </td><td> </td><td> </td></tr>
</table>
</div>
</div>
</body>
</html>
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