如何为每个选项在ng-option中应用字体家族 [英] How to apply font-family in ng-option for each option

问题描述

我想显示一个组合框，其所有选项字体都将不同.

I want to show a combobox whose all option font will be different.

在AngluarJS中使用ng-options指令填充<select>标记的选项时，我无法弄清楚如何为每个选项设置字体系列.

When using the ng-options directive in AngluarJS to fill in the options for a <select> tag I cannot figure out how to set the font-family for each option.

$scope.reportFontload=["Andale Mono","Arial","Arial Black","Bitstream Charter","Century Schoolbook L","Comic Sans MS","Courier 10 Pitch","Courier New","DejaVu Sans"];

<select ng-options="font for font in reportFontload" ng-model="selected">
 <option value="" disabled selected>Font Family</option>        
 </select>

对于ng-repeat，如果我曾经申请过style="font-family:{{font}}".它适用于ng-repeat中的每个选项.

For ng-repeat if i use to apply style="font-family:{{font}}". It works for each and every option in the ng-repeat.

这里是示例:小提琴

<select ng-model="selected">
  <option value="" disabled selected>Fonts</option> 
  <option ng-repeat="font in reportFontload" value={{font}} style="font-family:{{font}}">{{font}}</option>
</select>

我需要知道，为什么font-family在ng-option中不起作用.指导我任何可能的答案.

I need to know , Why font-family is not works in ng-option. Guide me any possible answer.

推荐答案

我创建了一个optionsAttribute指令，该指令可以在ngOptions呈现选项标签后转换其属性.

I have created an optionsAttribute directive that can transform the attributes of your option tags after they are rendered by ngOptions.

演示

DEMO

指令

.directive('optionsAttribute', function($parse, $timeout) {
  return {
    restrict: 'A',
    compile: function(tElem, tAttr) {
      var transform = $parse(tAttr.optionsAttributeTransform);
      return function(scope, elem, attr) {
        scope.$watch(attr.optionsAttribute, function(data) {

          var options = elem.children();
          options = Array.prototype.slice.call(options, options.length - data.length);

          angular.forEach(options, function(option, index) {
            var optionElement = angular.element(option);
            var newAttribute;
            var label;

            if(angular.isDefined(attr.optionsAttributeTransform)) {
              newAttribute = transform(scope, { 
                $data: data[index],
                $label: option.innerHTML,
                $index: index
              });

              angular.forEach(newAttribute, function(value, attribute) {
                optionElement.attr(attribute, value);
              });
            }

          });

        });
      };
    }
  };
});

用法

1. 在optionsAttribute指令的ngOptions指令中提供您提供的数组值.

1. Provide the array value you have provided in the ngOptions directive in the optionsAttribute directive.

例如

<select ng-options="font for font in reportFontload"
        options-attribute="reportFontload">
</select>

1. 在optionsAttributeTransform指令中添加一个回调，该回调返回一个json对象，该对象表示要附加在每个option s标记中的属性.回调本身具有2个值:

1. Add a callback in the optionsAttributeTransform directive that returns an json object that represents the attributes to be appended in each of the options tag. The callback itself is provided with 2 values:

$ data -表示#1中提供的数组中的每个项目.

$data - represents each of the item in the array provided in #1.

$ index -表示$data的索引.

例如

HTML

<select ng-options="font for font in reportFontload"
        ng-model="selected"
        options-attribute="reportFontload"
        options-attribute-transform="{ 'style': 'font-family: ' + $data }">
</select>

或替代方法是提供函数回调

or an alternative is to provide a function callback

JAVASCRIPT

$scope.transform = function(fontFamily) {
  return { 'style': 'font-family ' + fontFamily };
};

HTML

<select ng-options="font for font in reportFontload"
        ng-model="selected"
        options-attribute="reportFontload"
        options-attribute-transform="transform($data)">
</select>

---

限制

该指令仅限于数组，不包括对象，尽管有一种方法可以调整当前指令以使其与对象一起使用，但是当前实现已经足以解决OP的问题.

The directive is only limited towards array, objects excluded, although there is a way to tweak the current directive to also work with objects, but the current implementation is already sufficient for the OP's problem.

更新

我对上面的指令进行了调整，使其也可以用于对象集合，用法仍然是相同的:

I tweaked the directive above to also work with object collections, the usage still says the same:

演示

DEMO

(function(ng) {

    'use strict';

    var app = ng.module('options.attribute', []);

    app.directive('optionsAttribute', function($parse) {
        return {
            restrict: 'A',
            compile: function(tElem, tAttr) {

                var transform = $parse(tAttr.optionsAttributeTransform);

                return function(scope, elem, attr) {

                    scope.$watch(attr.optionsAttribute, function(collection) {

                        var options = elem.children();

                        collection = new Collection(collection);

                        options = Array.prototype.slice.call(options, options.length - collection.getLength());

                        ng.forEach(options, function(option, index) {

                            var newAttributes = transform(scope, {
                                $data: collection.getItem(index),
                                $label: option.innerHTML,
                                $index: collection.getIndex(index)
                            });

                            var optionElement = angular.element(option);

                            ng.forEach(newAttributes, function(value, attribute) {

                                optionElement.attr(attribute, value);

                            });

                        });

                    }, true);

                };

            }
        };
    });

    function Collection(collection) {

        var self = this;
        var indexes;

        if(angular.isObject(collection)) {

            if(Object.keys) {
                indexes = Object.keys(collection);
            } else {
                ng.forEach(collection, function(item, index) {
                    indexes.push(index);
                });
            }

            self.getItem = function(index) {
                return collection[indexes[index]];
            };

            self.getLength = function() {
                return indexes.length;
            };

            self.getIndex = function(index) {
                return indexes[index];
            };

        } else if(angular.isArray(collection)) {

            self.getItem = function(index) {
                return collection[index];
            };

            self.getLength = function() {
                return collection.length;
            };

            self.getIndex = function(index) {
                return index;
            };

        }

    }


})(angular);

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