一、监听数据变化
1、监听数据变化有两种，深度和浅度，形式如下：
vm.$watch(name,fnCb); //浅度
vm.$watch(name,fnCb,{deep:true}); //深度监视
2、实例用法
2.1-1浅度监听：当点击页面，弹出发生变化了，a的值变为1，b的值变为101
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>浅度监听1</title>
<meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1.0, user-scalable=0">
<meta name="apple-mobile-web-app-capable" content="yes">
<meta name="apple-mobile-web-app-status-bar-style" content="black">
<style> </style>
<script src="vue.js"></script>
<script> window.onload=function(){
var vm=new Vue({
el:'#box',
data:{
a:111,
b:2
}
}); vm.$watch('a',function(){
alert('发生变化了'); this.b=this.a+100;
}); document.onclick=function(){
vm.a=1;
};
}; </script>
</head>
<body>
<div id="box">
{{a}}
<br>
{{b}}
</div> </body>
</html>
2.1-2浅度监听：点击页面之后，弹出“发生变化了”，页面变为
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>浅度监听2</title>
<meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1.0, user-scalable=0">
<meta name="apple-mobile-web-app-capable" content="yes">
<meta name="apple-mobile-web-app-status-bar-style" content="black">
<style> </style>
<script src="vue.js"></script>
<script> window.onload=function(){
var vm=new Vue({
el:'#box',
data:{
json:{name:'strive',age:16},
b:2
}
}); vm.$watch('json',function(){
alert('发生变化了');
}); document.onclick=function(){
vm.json.name='aaa';
};
}; </script>
</head>
<body>
<div id="box">
{{json | json}}
<br>
{{b}}
</div> </body>
</html>
2.2深度监听：可以监视对象
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>深度监听</title>
<meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1.0, user-scalable=0">
<meta name="apple-mobile-web-app-capable" content="yes">
<meta name="apple-mobile-web-app-status-bar-style" content="black">
<style> </style>
<script src="vue.js"></script>
<script> window.onload=function(){
var vm=new Vue({
el:'#box',
data:{
json:{name:'strive',age:16},
b:2
}
}); vm.$watch('json',function(){
alert('发生变化了');
},{deep:true}); document.onclick=function(){
vm.json.name='aaa';
};
}; </script>
</head>
<body>
<div id="box">
{{json | json}}
<br>
{{b}}
</div> </body>
</html>
运行结果：
二、自定义指令
vue中自带的指令往往有时候满足不了我们实际的需求，例如当小于9时显示为09，当大于9时显示为原本的数。所以我们这个时候就需要自己定义一些指令
1、基本语法
自定义指令:
属性: Vue.directive(指令名称,function(参数){
this.el -> 原生DOM元素
}); <div v-red="参数"></div> 指令名称: v-red -> red * 注意: 必须以 v-开头
2、基本用法
2.1 v-red -> red
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>自定义指令</title>
<meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1.0, user-scalable=0">
<meta name="apple-mobile-web-app-capable" content="yes">
<meta name="apple-mobile-web-app-status-bar-style" content="black">
<style> </style>
<script src="vue.js"></script>
<script>
Vue.directive('red',function(){ //和下面的v-red相对应
this.el.style.background='red';
}); window.onload=function(){
var vm=new Vue({
el:'#box',
data:{
msg:'welcome'
}
});
}; </script>
</head>
<body>
<div id="box">
<span v-red>
asdfasd
</span>
</div> </body>
</html>
运行结果：
2.2、自定义指令参数为变量的用法
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>自定义指令参数用法</title>
<meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1.0, user-scalable=0">
<meta name="apple-mobile-web-app-capable" content="yes">
<meta name="apple-mobile-web-app-status-bar-style" content="black">
<style> </style>
<script src="vue.js"></script>
<script>
Vue.directive('red',function(color){ //将下面的a的值传给color
this.el.style.background=color;
}); window.onload=function(){
var vm=new Vue({
el:'#box',
data:{
a:'blue'
}
});
}; </script>
</head>
<body>
<div id="box">
<span v-red="a"> //是上面的变量a
asdfasd
</span>
</div> </body>
</html>
运行结果：
2.3参数为值的用法
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>参数为值的用法</title>
<meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1.0, user-scalable=0">
<meta name="apple-mobile-web-app-capable" content="yes">
<meta name="apple-mobile-web-app-status-bar-style" content="black">
<style> </style>
<script src="vue.js"></script>
<script>
Vue.directive('red',function(color){
this.el.style.background=color;
}); window.onload=function(){
var vm=new Vue({
el:'#box'
});
}; </script>
</head>
<body>
<div id="box">
<span v-red="'blue'"> //这里的blue就是普通的值
asdfasd
</span>
</div> </body>
</html>
运行结果：
2.4自定义指令就是默认绑定的bind
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>自定义指令</title>
<meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1.0, user-scalable=0">
<meta name="apple-mobile-web-app-capable" content="yes">
<meta name="apple-mobile-web-app-status-bar-style" content="black">
<style> </style>
<script src="vue.js"></script>
<script>
Vue.directive('red',{
bind:function(){
this.el.style.background='red';
}
}); window.onload=function(){
var vm=new Vue({
el:'#box'
});
}; </script>
</head>
<body>
<div id="box">
<span v-red>
asdfasd
</span>
</div> </body>
</html>
运行结果：
2.5自定指令进行拖拽小实例：可以进行拖拽
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>自定义指令--拖拽小实例</title>
<meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1.0, user-scalable=0">
<meta name="apple-mobile-web-app-capable" content="yes">
<meta name="apple-mobile-web-app-status-bar-style" content="black">
<style>
</style>
<script src="vue.js"></script>
<script>
Vue.directive('drag',function(){
var oDiv=this.el;
oDiv.onmousedown=function(ev){
var disX=ev.clientX-oDiv.offsetLeft;
var disY=ev.clientY-oDiv.offsetTop; document.onmousemove=function(ev){
var l=ev.clientX-disX;
var t=ev.clientY-disY;
oDiv.style.left=l+'px';
oDiv.style.top=t+'px';
};
document.onmouseup=function(){
document.onmousemove=null;
document.onmouseup=null;
};
};
}); window.onload=function(){
var vm=new Vue({
el:'#box',
data:{
msg:'welcome'
}
});
}; </script>
</head>
<body>
<div id="box">
<div v-drag :style="{width:'100px', height:'100px', background:'blue', position:'absolute', right:0, top:0}"></div>
<div v-drag :style="{width:'100px', height:'100px', background:'red', position:'absolute', left:0, top:0}"></div>
</div> </body>
</html>
三、过滤器
3.1、配合事件使用的过滤器：debounce—>延迟执行事件
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>debounce--延迟执行</title>
<meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1.0, user-scalable=0">
<meta name="apple-mobile-web-app-capable" content="yes">
<meta name="apple-mobile-web-app-status-bar-style" content="black">
<style> </style>
<script src="vue.js"></script>
<script> </script>
</head>
<body>
<div id="box">
<input type="text" @keyup="show | debounce 2000"> //按键之后，将过2秒弹出1
</div>
<script> var vm=new Vue({
data:{ },
methods:{
show:function(){
alert(1);
}
}
}).$mount('#box'); </script>
</body>
</html>
3.2配合数据使用的过滤器
3.2.1：limitBy用法
基本用法
limitBy 限制几个
limitBy 参数(取几个)
limitBy 取几个 从哪开始
limitBy 限制几个，
limitBy 参数(取几个)
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>limitBy 限制几个</title>
<meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1.0, user-scalable=0">
<meta name="apple-mobile-web-app-capable" content="yes">
<meta name="apple-mobile-web-app-status-bar-style" content="black">
<style> </style>
<script src="vue.js"></script>
<script> </script>
</head>
<body>
<div id="box">
<ul>
<li v-for="val in arr | limitBy 2"> //限制显示为2个，也可改为参数
{{val}}
</li>
</ul>
</div>
<script> var vm=new Vue({
data:{
arr:[1,2,3,4,5]
},
methods:{ }
}).$mount('#box'); </script>
</body>
</html>
运行结果：
limitBy 取几个 从哪开始
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>limitBy</title>
<meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1.0, user-scalable=0">
<meta name="apple-mobile-web-app-capable" content="yes">
<meta name="apple-mobile-web-app-status-bar-style" content="black">
<style> </style>
<script src="vue.js"></script>
<script> </script>
</head>
<body>
<div id="box">
<ul>
<li v-for="val in arr | limitBy 2 arr.length-2">
{{val}}
</li>
</ul>
</div>
<script> var vm=new Vue({
data:{
arr:[1,2,3,4,5]
},
methods:{ }
}).$mount('#box'); </script>
</body>
</html>
运行结果：取2个，从数组的倒数第二个开始取
3.2.2、filterBy 过滤数据
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>filterBy的用法</title>
<meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1.0, user-scalable=0">
<meta name="apple-mobile-web-app-capable" content="yes">
<meta name="apple-mobile-web-app-status-bar-style" content="black">
<style> </style>
<script src="vue.js"></script>
<script> </script>
</head>
<body>
<div id="box">
<input type="text" v-model="a">
<ul>
<li v-for="val in arr | filterBy a">
{{val}}
</li>
</ul>
</div>
<script> var vm=new Vue({
data:{
arr:['width','height','background','orange'],
a:''
},
methods:{ }
}).$mount('#box'); </script>
</body>
</html>
运行结果：当在文本框输入w时只会出现width,其余的都将被过滤掉
3.2.3、orderBy:倒序还是正序排列
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>orderBy倒序排列，1为正序，-1为倒序</title>
<meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1.0, user-scalable=0">
<meta name="apple-mobile-web-app-capable" content="yes">
<meta name="apple-mobile-web-app-status-bar-style" content="black">
<style> </style>
<script src="vue.js"></script>
<script> </script>
</head>
<body>
<div id="box">
<input type="text" v-model="a">
<ul>
<li v-for="val in arr | orderBy -1"> //这里的-1也可为变量
{{val}}
</li>
</ul>
</div>
<script> var vm=new Vue({
data:{
arr:['width','height','background','orange'],
a:''
},
methods:{ }
}).$mount('#box'); </script>
</body>
</html>
运行结果：
四、自定义过滤器
1、基本语法
自定义过滤器: model ->过滤 -> view
Vue.filter(name,function(input){ });
2.基本用法
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>自定义过滤器</title>
<meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1.0, user-scalable=0">
<meta name="apple-mobile-web-app-capable" content="yes">
<meta name="apple-mobile-web-app-status-bar-style" content="black">
<style> </style>
<script src="vue.js"></script>
<script> </script>
</head>
<body>
<div id="box">
{{a | toDou}}
</div>
<script>
Vue.filter('toDou',function(input){ //自定义过滤器
return input<10?'0'+input:''+input;
});
var vm=new Vue({
data:{
a:9
},
methods:{ }
}).$mount('#box'); </script>
</body>
</html>
运行结果：
3、自定义时间转化器
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>自定义时间转化器</title>
<meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1.0, user-scalable=0">
<meta name="apple-mobile-web-app-capable" content="yes">
<meta name="apple-mobile-web-app-status-bar-style" content="black">
<style> </style>
<script src="vue.js"></script>
<script> </script>
</head>
<body>
<div id="box">
{{a | date}}
</div>
<script>
Vue.filter('date',function(input){
var oDate=new Date(input);
return oDate.getFullYear()+'-'+(oDate.getMonth()+1)+'-'+oDate.getDate()+' '+oDate.getHours()+':'+oDate.getMinutes()+':'+oDate.getSeconds();
}); var vm=new Vue({
data:{
a:Date.now()
},
methods:{ }
}).$mount('#box'); </script>
</body>
</html>
运行结果：
五、自定义键盘信息
1、基本 语法
自定义键盘信息:
Vue.directive('on').keyCodes.ctrl=17;
Vue.directive('on').keyCodes.myenter=13;
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>自定义键盘信息</title>
<meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1.0, user-scalable=0">
<meta name="apple-mobile-web-app-capable" content="yes">
<meta name="apple-mobile-web-app-status-bar-style" content="black">
<style> </style>
<script src="vue.js"></script>
<script>
//ctrl->17
/*document.onkeydown=function(ev){
console.log(ev.keyCode);
};*/
Vue.directive('on').keyCodes.ctrl=17; // ctrl
Vue.directive('on').keyCodes.myenter=13; //enter window.onload=function(){
var vm=new Vue({
el:'#box',
data:{
a:'blue'
},
methods:{
show:function(){
alert(1);
}
}
});
}; </script>
</head>
<body>
<div id="box">
<input type="text" @keydown.myenter="show | debounce 2000">
</div> </body>
</html>
运行结果：当按下enter键之后过2秒弹出1