鼠标拖动改变DIV等网页元素的大小的最佳实践

2021-07-03 15:04

阅读：369

标签：没有 sem tde 情况鼠标 down stop 边框引入

1.初次实现

1.1 html代码

html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
    head>
        meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
        title>div change width by dragtitle>
        script src="../jQuery/jquery-1.8.3.min.js" type="text/javascript">script>
    head>

    body>
        h1>div change width by dragh1>
        div id="pos" style="color:red">div>
        
        div id="myDiv" style="border:2px solid red;width:300px;height:50px;margin-left: 100px;margin-top: 20px">div>
    body>
html>

1.2 js代码

　　　　　　　　　 var eleLeft = $(‘#myDiv‘).offset().left;
                var isMouseDown = false;
                var borderLen = 4; //左右边框
                
                $(‘#myDiv‘).bind({
                    mousedown:function(e){
                        var ele = $(this);
                        var rightPos = eleLeft + ele.width() + borderLen;
                        if(rightPos-5  rightPos){
                            isMouseDown = true;

                        }
                    },
            
                    mousemove:function(e){
                        var ele =  $(this);
                        var rightPos = eleLeft + ele.width() + borderLen;
                        $(‘#pos‘).text("x:"+e.pageX + " eleLeft:"+eleLeft+" rightPos:"+rightPos);

                        if(rightPos-5  rightPos){
                            ele.css(‘cursor‘,‘e-resize‘);
                        }else{
                            if(!isMouseDown){
                                ele.css(‘cursor‘,‘auto‘);
                            }
                        }
                        if(isMouseDown){
                            ele.width((e.pageX-eleLeft-borderLen)+‘px‘);  //新鼠标位置-div距左-borderLen
                        }
                    },
                    mouseup:function(e){
                        isMouseDown = false;
                    }
                });

1.3 结果

只能往左拖动使div宽度变小，往右拖动没有用！原因往右拖动鼠标mousemove事件无法被div捕获了。拖动时也很难停下来！所以得改进。

2.再次改进

　　　　　　　　　　$(‘#myDiv‘).bind({
                    mousedown:function(e){
                        var ele = $(this);
                        var rightPos = eleLeft + ele.width() + borderLen;
                        if(rightPos-5  rightPos){
                            isMouseDown = true;
                        }
                    }
                });

                $(‘body‘).bind({
                    mousemove:function(e){
                        var ele = $(‘#myDiv‘);
                        var rightPos = eleLeft + ele.width() + borderLen;
                        $(‘#pos‘).text("x:"+e.pageX + " eleLeft:"+eleLeft+" rightPos:"+rightPos);

                        if(rightPos-5  rightPos){
                            ele.css(‘cursor‘,‘e-resize‘);
                        }else{
                            if(!isMouseDown){
                                ele.css(‘cursor‘,‘auto‘);
                            }
                        }
                        if(isMouseDown){
                            ele.width((e.pageX-eleLeft-borderLen)+‘px‘);  
                        }
                    },
                    mouseup:function(e){
                        isMouseDown = false;
                    }
                });

这次解决了上述问题，可以往右拖，并且随时可以停下来了。到这里就完成了吗？NO!

当我引入一个其他div，并且阻止mouseup事件冒泡情况怎么样呢？答案是，拖动到这个其它div上放开鼠标后无法停止下来！

div id="otherDiv" style="border: 2px solid blue;width: 200px;height: 200px;margin-left: 400px">div>

　　　　　　　　　$(‘#otherDiv‘).mouseup(function(e){
                    //e.preventDefault(); //阻止默认行为
                    e.stopPropagation(); //阻止事件冒泡(导致body捕获不到mouseup事件)
                });

3.完美解决

拖动停止可能受到其它元素的干扰，怎么解决？想到一些弹出层点击其它其它地方隐藏的功能，让我想到了，加一个遮罩层，让mouseup事件总是可以响应，不就搞定了嘛！

　　　　　　　　$(‘#myDiv‘).bind({
                    mousedown:function(e){
                        var ele = $(this);
                        var rightPos = eleLeft + ele.width() + borderLen;
                        if(rightPos-5  rightPos){
                            isMouseDown = true;

                            //创建遮罩层，防止mouseup事件被其它元素阻止冒泡，导致mouseup事件无法被body捕获，导致拖动不能停止
                            var bodyWidth = $(‘body‘).width();
                            var bodyHeight = $(‘body‘).height();
                            $(‘body‘).append(‘
‘);
                        }
                    }
                });

                $(‘body‘).bind({
                    mousemove:function(e){
                        var ele = $(‘#myDiv‘);
                        var rightPos = eleLeft + ele.width() + borderLen;
                        $(‘#pos‘).text("x:"+e.pageX + " eleLeft:"+eleLeft+" rightPos:"+rightPos);

                        if(rightPos-5  rightPos){
                            ele.css(‘cursor‘,‘e-resize‘);
                        }else{
                            if(!isMouseDown){
                                ele.css(‘cursor‘,‘auto‘);
                            }
                        }
                        if(isMouseDown){
                            ele.width((e.pageX-eleLeft-borderLen)+‘px‘); 
                        }
                    },
                    mouseup:function(e){
                        isMouseDown = false;
                        $(‘#mask‘).remove();
                    }
                });

                $(‘#otherDiv‘).mouseup(function(e){
                    //e.preventDefault(); //阻止默认行为
                    e.stopPropagation(); //阻止事件冒泡(导致body捕获不到mouseup事件)
                });

4.完整代码和最终效果

html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
    head>
        meta http-equiv="Content-Type" content="text/html; charset=utf-8" />

        title>div change width by dragtitle>

        script src="../jQuery/jquery-1.8.3.min.js" type="text/javascript">script>
        
        
    head>

    body>
        h1>div change width by dragh1>
        
        div id="pos" style="color:red">div>
        
        
        div id="myDiv" style="border:2px solid red;width:300px;height:50px;margin-left: 100px;margin-top: 20px">div>

        div id="otherDiv" style="border: 2px solid blue;width: 200px;height: 200px;margin-left: 400px">div>
    body>
    

    script type="text/javascript">
            $(document).ready(function(){
                var eleLeft = $(‘#myDiv‘).offset().left;
                var isMouseDown = false;
                var borderLen = 4; //左右边框

                $(‘#myDiv‘).bind({
                    mousedown:function(e){
                        var ele = $(this);
                        var rightPos = eleLeft + ele.width() + borderLen;
                        if(rightPos-5  e.pageX && e.pageX  rightPos){
                            isMouseDown = true;

                            //创建遮罩层，防止mouseup事件被其它元素阻止冒泡，导致mouseup事件无法被body捕获，导致拖动不能停止
                            var bodyWidth = $(‘body‘).width();
                            var bodyHeight = $(‘body‘).height();
                            $(‘body‘).append(‘‘);
                        }
                    }
                });

                $(‘body‘).bind({
                    mousemove:function(e){
                        var ele = $(‘#myDiv‘);
                        var rightPos = eleLeft + ele.width() + borderLen;
                        $(‘#pos‘).text("x:"+e.pageX + " eleLeft:"+eleLeft+" rightPos:"+rightPos);

                        if(rightPos-5  e.pageX && e.pageX  rightPos){
                            ele.css(‘cursor‘,‘e-resize‘);
                        }else{
                            if(!isMouseDown){
                                ele.css(‘cursor‘,‘auto‘);
                            }
                        }
                        if(isMouseDown){
                            ele.width((e.pageX-eleLeft-borderLen)+‘px‘); 
                        }
                    },
                    mouseup:function(e){
                        isMouseDown = false;
                        $(‘#mask‘).remove();
                    }
                });

                $(‘#otherDiv‘).mouseup(function(e){
                    //e.preventDefault(); //阻止默认行为
                    e.stopPropagation(); //阻止事件冒泡(导致body捕获不到mouseup事件)
                });
            });
        script>
html>