"external nofollow" href="mailto:{@link">{@link guide/expression expression}
"external nofollow" href="http://blog.csdn.net/aitangyong/article/details/48972643">http://blog.csdn.net/aitangyong/article/details/48972643
"color: #ff0000">一、使用方法
html
<div ng-controller="ctrl">
<h2>$watch</h2>
<div>
<input type="text" ng-model="value1"/>
</div>
<div ng-bind="w1"></div>
<h2>$watchGroup</h2>
<div>
<input type="text" ng-model="value2"/>
<input type="text" ng-model="value3"/>
</div>
<div ng-bind="w2"></div>
<h2>$watchCollection</h2>
<ul>
<li ng-repeat="v in arr" ng-bind="v"></li>
</ul>
<div ng-bind="w3"></div>
</div>
js
angular.module('nickApp', [])
.controller("ctrl", ["$scope", "$timeout", function ($scope, $timeout) {
// $watch
var watcher = $scope.$watch("value1", function (newVal, oldVal) {
$scope.w1 = "$watch--" + "new:" + newVal + ";" + "old:" + oldVal;
if (newVal == 'clear') {//设置一个注销监听的条件
watcher(); //注销监听
}
});
// $watchGroup
$scope.$watchGroup(["value2", "value3"], function (newVal, oldVal) {
//注意：newVal与oldVal都返回的是一个数组
$scope.w2 = "$watchGroup--" + "new:" + newVal + ";" + "old:" + oldVal;
});
// $watchCollection
$scope.arr = ['nick', 'ljy', 'ljj', 'zhw'];
$scope.$watchCollection('arr', function (newVal, oldVal) {
$scope.w3 = "$watchCollection--" + "new:" + newVal + ";" + "old:" + oldVal;
});
$timeout(function () {
$scope.arr = ['my', 'name', 'is', 'nick'];
}, 2000);
}])
二、小案例
html
<h2>小案例</h2>
<ul>
<li ng-repeat="item in items.goodsArr">
<p ng-bind="item.goods"></p>
<p>
<span>单价：</span>
<span ng-bind="item.price"></span>
</p>
<div>
<input type="number" ng-model="item.num">
<span>个</span>
</div>
</li>
</ul>
<div>
<span>总计：</span>
<span ng-bind="items.sum"></span>
<span>元</span>
</div>
js
// 小案例
.factory('watchService', [function () {
var items = {
goodsArr: [{
goods: 'goods1',
price: 10,
num: ''
}, {
goods: 'goods2',
price: 20,
num: ''
}],
sum: 0
};
return {
getItemsSave: function () {
return items;
}
};
}])
.controller('bodyCtl', ['$scope', 'watchService', function ($scope, watchService) {
$scope.items = watchService.getItemsSave();
// 这里要监听数量变化计算综合
//一 只监听所有num变化计算总额
var watchArr = [];
$scope.items.goodsArr.forEach(function (v, i) {
watchArr.push("items.goodsArr[" + i + "]['num']");
});
$scope.$watchGroup(watchArr, function (newVal, oldVal) { //注意：newVal与oldVal都返回的是一个数组
$scope.items.sum = 0;
$scope.items.goodsArr.forEach(function (v, i) {
$scope.items.sum += v.price * (v.num > 0 "htmlcode">
<!DOCTYPE html>
<html ng-app="nickApp">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="initial-scale=1, maximum-scale=1, user-scalable=no, width=device-width">
<title>angular之$watch、$watchGroup、$watchCollection</title>
<script src="/UploadFiles/2021-04-02/angular.min.js">
以上所述是小编给大家介绍的Angular中的$watch、$watchGroup、$watchCollection，希望对大家有所帮助，如果大家有任何疑问欢迎给我留言，小编会及时回复大家的！