JQuery UI提供的API极大简化了拖拽功能的开发。只需要分别在拖拽源(source)和目标(target)上调用draggable和droppable两个函数即可。
拖拽原理
首先要明确几个概念。
ource:拖拽源,要拖动的元素。
taerget:拖放目标,能够放入source的容器。
拖拽的动作分解如下:
1. drag start:在拖拽源(source)上按下鼠标并开始移动
2. drag move: 移动过程中
3. drag enter: 移动进入目标(target)容器
4. drag leave: 移出目标(target)容器
5. drop: 在目标(target)容器上释放鼠标
6. drag end: 结束
在html5之前,页面元素不直接支持拖拽事件。所以都是通过监听鼠标事件并记录拖拽状态的方式来实现拖拽功能。
最简单的例子
最简单的拖拽是不改变元素所在的容器,而只改变其位置。例子如下:
<html>
<head></head>
<body>
<div id="container">
<div id="dragsource">
<p>拽我!</p>
</div>
</div><!-- End container -->
<script type="text/javascript" src="js/jquery-1.7.min.js"></script>
<script type="text/javascript" src="js/jquery-ui-1.8.16.custom.min.js"></script>
<script>
$(function() {
$( "#dragsource" ).draggable();
})
</script>
</body>
</html>
<html>
<head></head>
<body>
<div id="container">
<div id="dragsource">
<p>拽我!</p>
</div>
</div><!-- End container -->
<div id="droppalbe" style="width: 300px;height:300px;background-color:gray">
<p>Drop here</p>
</div>
<script type="text/javascript" src="js/jquery-1.7.min.js"></script>
<script type="text/javascript" src="js/jquery-ui-1.8.16.custom.min.js"></script>
<script>
$(function() {
$( "#dragsource" ).draggable();
$( "#droppable" ).droppable();
})
</script>
</body>
</html>
<html>
<head>
</head>
<body>
<div id="dragsource">
<p id="targetMsg">:-|</p>
</div>
<div id="droppable" style="background-color:gray;height:300">
<p>Can drop! </p>
</div>
<script type="text/javascript" src="js/jquery-1.7.min.js"></script>
<script type="text/javascript" src="js/jquery-ui-1.8.16.custom.min.js"></script>
<script>
$(function() {
$( "#dragsource" ).draggable({
start: function(event,ui) {
$(this).find("p").html(":-S");
},
stop:function(event,ui){
$(this).find("p").html(":-|");
}
});
$( "#droppable" ).droppable({
activate: function(event,ui) {
$(this).find("p").html( "Drop here !" );
},
over: function(event,ui) {
$( this ).find( "p" ).html( "Oh, Yeah!" );
},
out: function(event,ui) {
$( this ).find( "p" ).html( "Don't leave me!" );
},
drop: function( event, ui ) {
$( this ).find( "p" ).html( "I've got it!" );
}
});
})
</script>
</body>
</html>
<html>
<head></head>
<body>
<div id="dragsource">
<p>拽我!</p>
</div>
<div id="container" style="background-color:gray;height:300">
</div><!-- End container -->
<script type="text/javascript" src="js/jquery-1.7.min.js"></script>
<script type="text/javascript" src="js/jquery-ui-1.8.16.custom.min.js"></script>
<script>
$(function() {
$( "#dragsource" ).draggable({
helper:"clone"
});
$("#container").droppable({
drop:function(event,ui){
$(this).append($("<p style='position:absolute;left:"+
ui.offset.left+";top:"+ui.offset.top+"'>clone</p>"));
}
});
})
</script>
</body>
</html>
<html>
<head></head>
<body>
<div id="dragX">
<p>--</p>
</div>
<div id="dragY">
<p>|</p>
</div>
<script type="text/javascript" src="js/jquery-1.7.min.js"></script>
<script type="text/javascript" src="js/jquery-ui-1.8.16.custom.min.js"></script>
<script>
$(function() {
$("#dragX").draggable({axis:"x"});
$("#dragY").draggable({axis:"y"});
});
</script>
</body>
</html>
<html>
<head></head>
<body>
<div id="container" style="background-color:gray;height:300">
<div id="draggable1" style="background-color:red;height:20;width:100">
<p>in parent</p>
</div>
<div id="draggable2" style="background-color:green;height:20;width:100">
<p>in regin</p>
</div>
<script type="text/javascript" src="js/jquery-1.7.min.js"></script>
<script type="text/javascript" src="js/jquery-ui-1.8.16.custom.min.js"></script>
<script>
$(function() {
$("#draggable1" ).draggable({containment: "parent" });
$("#draggable2").draggable({containment: [20,20,300,200] });
});
</script>
</body>
</html>
<html>
<head>
<style>
.draggable {background-color:green; width: 90px; height: 80px; padding: 5px; float: left; margin: 0 10px 10px 0; font-size: .9em; }
</style>
</head>
<body>
<div id="container" style="background-color:gray;height:300">
<div id="draggable1" class="draggable">
<p>吸附到其他可拖拽元素</p>
</div>
<div id="draggable2" class="draggable">
<p>吸附到容器</p>
</div>
<div id="draggable3" class="draggable">
<p>吸附到网格(30x30)</p>
</div>
</div><!--container-->
<script type="text/javascript" src="js/jquery-1.7.min.js"></script>
<script type="text/javascript" src="js/jquery-ui-1.8.16.custom.min.js"></script>
<script>
$(function() {
$("#draggable1").draggable({ snap: true });
$("#draggable2").draggable({ snap: "#container"});
$("#draggable3").draggable({grid: [30,30]});
});
</script>
</body>
</html>
<div id="draggable">
<p>handle</p>
</div>
……
<script>
$("#draggable").draggable({handle:"p"});
</script>
<html>
<head>
<style>
.draggable {background-color:green; width: 90px; height: 80px; padding: 5px; float: left; margin: 0 10px 10px 0; font-size: .9em; }
.droppable { width: 300px; height: 300px; background-color:red}
</style>
</head>
<body>
<div id="draggable2" class="draggable">
<p>I revert when I'm not dropped</p>
</div>
<div id="droppable" class="droppable">
<p>Drop me here</p>
</div>
<script type="text/javascript" src="js/jquery-1.7.min.js"></script>
<script type="text/javascript" src="js/jquery-ui-1.8.16.custom.min.js"></script>
<script>
$(function() {
$( "#draggable2" ).draggable({ revert: "invalid",cursor: "move", cursorAt: { top: 56, left: 56 } });
$( "#droppable" ).droppable({
activeClass: "ui-state-hover",
hoverClass: "ui-state-active",
drop: function( event, ui ) {
$( this )
.addClass( "ui-state-highlight" )
.find( "p" )
.html( "Dropped!" );
}
});
});
</script>
</body>
</html>