如何增加和减少angularjs中的值？
[英]How can I increment and decrement a value in angularjs?
问题描述
I have one value initially - let's call it x. 
我最初有一个值 - 让我们称之为x。 Selecting the increment button should increase "+1" to the value. 选择增量按钮应该增加“+1”值。 If I select decrement, x should decrease by -1. 如果我选择减量，则x应减少-1。
However, what actually happens is that when I press the increment button, it increases +1 but if i click decrement, it decreases -2. 然而，实际发生的是，当我按下增量按钮时，它会增加+1，但如果我点击减少，它会减少-2。 It should only be increased/decreased by 1 value only. 它应该只增加/减少1个值。 Also don't require continuous iteration (count++ and count--). 也不需要连续迭代（count ++和count--）。 it would be better if "count" is taken as variable inside .js file, not mentioning it in html as ng-init="count=15" . 如果将“count”作为变量放在.js文件中，而不是在html中将其称为ng-init =“count = 15”，那会更好。
<div ng-controller="CounterController">
<button ng-click="count = {{count}}+1" ng-init="count=15">
Increment
</button>
count: {{count}}
<button ng-click="count = {{(count) - 1}}">
Decrement
</button>
<div>
4 个解决方案
解决方案1
9 2014-12-01 11:52:24
Simply this should work, 这应该工作，
<div>
<button ng-click="count = count+1" ng-init="count=15">
Increment
</button>
count: {{count}}
<button ng-click="count = count - 1">
Decrement
</button>
<div>
解决方案2
3 2014-12-01 11:41:50
The problem is because you using '{{' in ng-click, it's inserting value there, so after angular 'rendering', actual code looks like: 问题是因为你在ng-click中使用'{{'，它在那里插入值，所以在角'渲染'之后，实际代码如下所示：
<div ng-controller="CounterController">
<button ng-click="count = 15+1" ng-init="count=15">
Increment
</button>
count: {{count}}
<button ng-click="count = 15 - 1">
Decrement
</button>
<div>
but you want to work with reference. 但你想参考。 So just remove '{{' and '}}' and it will work. 所以只需删除“{{”和“}}”即可。
解决方案3
2 2014-12-01 12:31:34
"Exactly 1 value to be incremented or decremented" “正好增加或减少1个值”
<div ng-controller="CounterController">
<button ng-click="increment();">
Increment
</button>
count: {{count}}
<button ng-click="decrement();">
Decrement
</button>
<div>
Controller: 控制器：
angular.module('myApp', [])
.controller('CounterController', function($scope) {
var incremented = false;
var decremented = false;
$scope.count = 15;
$scope.increment = function() {
if (incremented) { return; }
$scope.count++;
incremented = true;
};
$scope.decrement = function() {
if (decremented) { return; }
$scope.count--;
decremented = true;
};
});
If you want the user to be able to repeatedly do this, then... 如果您希望用户能够重复执行此操作，那么......
angular.module('myApp', [])
.controller('CounterController', function($scope) {
$scope.count = 15;
var max = $scope.count + 1;
var min = $scope.count - 1;
$scope.increment = function() {
if ($scope.count >= max) { return; }
$scope.count++;
};
$scope.decrement = function() {
if ($scope.count <= min) { return; }
$scope.count--;
};
});
JS Fiddle - http://jsfiddle.net/HB7LU/8673/ JS小提琴 - http://jsfiddle.net/HB7LU/8673/
解决方案4
0 2016-02-04 18:38:24
Here is a sample working code and caters to the following: 1) increases and decreases the counter by one 2) does not use continuous iteration 3) does not use ng-init 4) works for $scope.count = 15 下面是一个示例工作代码并满足以下要求：1）将计数器增加或减少一个2）不使用连续迭代3）不使用ng-init 4）适用于$ scope.count = 15
(The replies already provided by Rasalom and smallatom helped and so did the link: http://www.w3schools.com/angular/angular_events.asp ) （Rasalom和smallatom已经提供的回复有助于链接： http ： //www.w3schools.com/angular/angular_events.asp ）
<!DOCTYPE html>
<html>
<script src="http://ajax.googleapis.com/ajax/libs/angularjs/1.4.8/angular.min.js"></script>
<body>
<div ng-app="myApp" ng-controller="myCtrl">
<button ng-click="count = count+1">
Increment
</button>
count: {{ count }}
<button ng-click="count = count-1">
Decrement
</button>
</div>
<script>
var app = angular.module('myApp', []);
app.controller('myCtrl', function($scope) {
$scope.count = 15;
});
</script>
</body>
</html>
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