我有以下几点:

<div>{{modal.title}}</div>

有没有一种方法可以限制字符串的长度,比如20个字符?

一个更好的问题是,有没有一种方法可以将字符串更改为截断并显示。如果超过20个字符?


当前回答

这里是简单的一行修复没有css。

{{ myString | limitTo: 20 }}{{myString.length > 20 ? '...' : ''}}

其他回答

我创建了这个指令,很容易做到这一点,截断字符串到指定的限制,并添加了一个“显示更多/更少”切换。你可以在GitHub上找到它:https://github.com/doukasd/AngularJS-Components

它可以这样使用:

<p data-dd-collapse-text="100">{{veryLongText}}</p>

下面是指令:

// a directive to auto-collapse long text
app.directive('ddCollapseText', ['$compile', function($compile) {
return {
    restrict: 'A',
    replace: true,
    link: function(scope, element, attrs) {

        // start collapsed
        scope.collapsed = false;

        // create the function to toggle the collapse
        scope.toggle = function() {
            scope.collapsed = !scope.collapsed;
        };

        // get the value of the dd-collapse-text attribute
        attrs.$observe('ddCollapseText', function(maxLength) {
            // get the contents of the element
            var text = element.text();

            if (text.length > maxLength) {
                // split the text in two parts, the first always showing
                var firstPart = String(text).substring(0, maxLength);
                var secondPart = String(text).substring(maxLength, text.length);

                // create some new html elements to hold the separate info
                var firstSpan = $compile('<span>' + firstPart + '</span>')(scope);
                var secondSpan = $compile('<span ng-if="collapsed">' + secondPart + '</span>')(scope);
                var moreIndicatorSpan = $compile('<span ng-if="!collapsed">...</span>')(scope);
                var toggleButton = $compile('<span class="collapse-text-toggle" ng-click="toggle()">{{collapsed ? "less" : "more"}}</span>')(scope);

                // remove the current contents of the element
                // and add the new ones we created
                element.empty();
                element.append(firstSpan);
                element.append(secondSpan);
                element.append(moreIndicatorSpan);
                element.append(toggleButton);
            }
        });
    }
};
}]);

和一些CSS去它:

.collapse-text-toggle {
font-size: 0.9em;
color: #666666;
cursor: pointer;
}
.collapse-text-toggle:hover {
color: #222222;
}
.collapse-text-toggle:before {
content: '\00a0(';
}
.collapse-text-toggle:after {
content: ')';
}

我发现最简单的解决方案是让材料设计(1.0.0-rc4)来做这项工作。md-input-container将为您完成这项工作。它连接了字符串,添加了省略,它还有一个额外的好处,允许你点击它来获得全文,所以它是整个玉米卷饼。您可能需要设置md-input-container的宽度。

HTML:

<md-input-container>
   <md-select id="concat-title" placeholder="{{mytext}}" ng-model="mytext" aria-label="label">
      <md-option ng-selected="mytext" >{{mytext}}
      </md-option>
   </md-select>
</md-input-container>

CS:

#concat-title .md-select-value .md-select-icon{
   display: none; //if you want to show chevron remove this
}
#concat-title .md-select-value{
   border-bottom: none; //if you want to show underline remove this
}

由于只在字符串长度超过限制时才需要省略号,因此使用ng-if添加省略号似乎比使用绑定更合适。

{{ longString | limitTo: 20 }}<span ng-if="longString.length > 20">&hellip;</span>

下面是一个用于截断文本的自定义过滤器。它的灵感来自于EpokK的解决方案,但根据我的需求和口味进行了修改。

angular.module('app').filter('truncate', function () {

    return function (content, maxCharacters) {

        if (content == null) return "";

        content = "" + content;

        content = content.trim();

        if (content.length <= maxCharacters) return content;

        content = content.substring(0, maxCharacters);

        var lastSpace = content.lastIndexOf(" ");

        if (lastSpace > -1) content = content.substr(0, lastSpace);

        return content + '...';
    };
});

这里是单元测试,所以你可以看到它应该如何表现:

describe('truncate filter', function () {

    var truncate,
        unfiltered = " one two three four ";

    beforeEach(function () {

        module('app');

        inject(function ($filter) {

            truncate = $filter('truncate');
        });
    });

    it('should be defined', function () {

        expect(truncate).to.be.ok;
    });

    it('should return an object', function () {

        expect(truncate(unfiltered, 0)).to.be.ok;
    });

    it('should remove leading and trailing whitespace', function () {

        expect(truncate(unfiltered, 100)).to.equal("one two three four");
    });

    it('should truncate to length and add an ellipsis', function () {

        expect(truncate(unfiltered, 3)).to.equal("one...");
    });

    it('should round to word boundaries', function () {

        expect(truncate(unfiltered, 10)).to.equal("one two...");
    });

    it('should split a word to avoid returning an empty string', function () {

        expect(truncate(unfiltered, 2)).to.equal("on...");
    });

    it('should tolerate non string inputs', function () {

        expect(truncate(434578932, 4)).to.equal("4345...");
    });

    it('should tolerate falsey inputs', function () {

        expect(truncate(0, 4)).to.equal("0");

        expect(truncate(false, 4)).to.equal("fals...");
    });
});

使用自定义Angular过滤器限制字数: 下面是我如何使用Angular过滤器来限制使用自定义过滤器显示的字数。

HTML:

<span>{{dataModelObject.TextValue | limitWordsTo: 38}} ......</span>

角/ Javascript代码

angular.module('app')
.filter('limitWordsTo', function () {
    return function (stringData, numberOfWords) {
        //Get array of words (determined by spaces between words)
        var arrayOfWords = stringData.split(" ");

        //Get loop limit
        var loopLimit = numberOfWords > arrayOfWords.length ? arrayOfWords.length : numberOfWords;

        //Create variables to hold limited word string and array iterator
        var limitedString = '', i;
        //Create limited string bounded by limit passed in
        for (i = 0; i < loopLimit; i++) {
            if (i === 0) {
                limitedString = arrayOfWords[i];
            } else {
                limitedString = limitedString + ' ' + arrayOfWords[i];
            }
        }
        return limitedString;
    }; 
}); //End filter