最近学习了Vue.js
找到了计算属性computed，于是写了个栗子玩玩，于是就有了下面的这些
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<!-- 开发环境版本，包含了有帮助的命令行警告 -->
<script src="https://cdn.jsdelivr.net/npm/vue/dist/vue.js"></script>
<!-- 生产环境版本，优化了尺寸和速度 -->
<!-- <script src="https://cdn.jsdelivr.net/npm/vue"></script> -->
<title>可以拉长的div</title>
</head>
<body>
<div id="app">
<div :style="wh" style="background-color: green;">
{{wh}}
</div>
</div>
</body>
<script type="text/javascript">
var app = new Vue({
el:"#app",
data:{
wh:{
width:250,
height:250
}
},
computed:{
wh:{
width:function(){
return this.wh.width + "px";
},
height:function(){
return this.wh.height + "px";
}
}
},
methods:{
},
watch: {
}
});
</script>
</html>
执行的结果却是 { "width": 250, "height": 250 },???怎么没有生效，写错了？？，去网上搜了一下，都是跟官网一样写的栗子，我就…
仔细分析了一下，原来里面写的是get和set方法，这样写不会识别，而且名字与data中的重复了，vue优先使用了data中的
更改了一下，
computed:{
wh2:function(){
return {
width:this.wh.width + "px",
height:this.wh.height + "px"
}
}
},
<div :style="wh2" style="background-color: green;">
以下是我写的Demo的半成品
<!DOCTYPE html>
<html>
<head>
<base href="../../">
<meta charset="utf-8" />
<!-- 开发环境版本，包含了有帮助的命令行警告 -->
<script src="https://cdn.jsdelivr.net/npm/vue/dist/vue.js"></script>
<!-- 生产环境版本，优化了尺寸和速度 -->
<!-- <script src="https://cdn.jsdelivr.net/npm/vue"></script> -->
<link rel="stylesheet" type="text/css" href="css/main.css"/>
<title>vue示例</title>
<style type="text/css">
#app{
width: 100%;
height: 100%;
}
</style>
</head>
<body>
<div id="app" @mouseup="mouseUp" @mousemove="mouseMove">
<div @mousedown="mouseDown" :style="[styleObj,styleObj2]" style="background-color: green;">
</div>
</div>
</body>
<script type="text/javascript">
var app = new Vue({
el:"#app",
data:{
mouseIsClick:false,
mouseLayerX:0,
mouseLayerY:0,
styleObj:{
width:250,
height:250,
cursor:"auto"
},
},
computed:{
styleObj2:function(){
return {
width:this.styleObj.width + "px",
height:this.styleObj.height + "px"
}
}
},
methods:{
//鼠标按下时
mouseDown:function(e){
//按下的状态
this.mouseIsClick = true;
this.mouseLayerX = e.layerX;
this.mouseLayerY = e.layerY;
},
//鼠标松开时
mouseUp:function(e){
//清除按下的状态
if(this.mouseIsClick){
this.mouseIsClick = false;
}
},
//鼠标移动时
mouseMove:function(e){
// e = e || window.event; // 事件
// let target = e.target || e.srcElement; // 获得事件源
let maxWidth = this.styleObj.width;
let minWidth = this.styleObj.width - 5;
let maxHeight = this.styleObj.height;
let minHeight = this.styleObj.height - 5;
if((minWidth <= e.layerX && e.layerX <= maxWidth) && (minHeight <= e.layerY && e.layerY <= maxHeight)){
this.styleObj.cursor = "move";
//如果出现了小手,则证明在我们规定的可拖动区
}else if(minWidth <= e.layerX && e.layerX <= maxWidth){
this.styleObj.cursor = "e-resize";
}else if(minHeight <= e.layerY && e.layerY <= maxHeight){
this.styleObj.cursor = "n-resize";
}else{
this.styleObj.cursor = "auto";
}
//如果鼠标按下了,则根据鼠标的移动更改宽和高
if(this.mouseIsClick){
// if((minWidth - 10) <= e.layerX || (minHeight - 10) <= e.layerY){
let x = e.layerX - this.mouseLayerX;
let y = e.layerY - this.mouseLayerY;
this.styleObj.width += x;
this.styleObj.height += y;
this.mouseLayerX = e.layerX;
this.mouseLayerY = e.layerY;
// }
}
},
out:function(e){
}
},
watch: {
}
});
</script>
</html>
可以拖动这个绿方块，会变大，往里拖会变小，在右边和下边会显示出左右箭头和上线箭头，和移动箭头（emm是不是叫指针能好点），但是现在有写不满意，以后有时间再改改
这是我的解决方案，欢迎补充