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问题:

Check this PLNKR , i have implemented typeahead control, By default in type ahead control they are not setting any max-height or height to list, but as per requirement i have to fix height of list to 110px. So, when we have longer list at a time only 4 data will be shown and rest can be seen by scrolling down. Scrolling is working while user click on scroll up/down arrows, but it's not working with keyboard up/down keys.

The problem is explained in steps:-

Type something i.e "a" to get data in typeahead (list will be populated)
Press down-arrow key (focus will be on list item)
Press down-arrow key 4-5 time to go further down (When we traverse down to list, scroll is not getting moved.)
It always show top 4 items in list. Ideal behavior is it should shift.

User is able to scroll by clicking on scroll manually but with arrow key it's not scrolling.

HTML

<!doctype html>
<html ng-app="ui.bootstrap.demo">
<head>
 <script src="//ajax.googleapis.com/ajax/libs/angularjs/1.2.16/angular.js"></script>
 <script src="//angular-ui.github.io/bootstrap/ui-bootstrap-tpls-0.12.0.js"></script>
 <script src="example.js"></script>
 <link href="//netdna.bootstrapcdn.com/bootstrap/3.1.1/css/bootstrap.min.css" rel="stylesheet">
 <link href="style.css" rel="stylesheet">
</head>
<body>
<div class='container-fluid' ng-controller="TypeaheadCtrl">
  <h4>Static arrays</h4>
  <pre>Model: {{selected | json}}</pre>
  <input type="text" ng-model="selected" typeahead="state for state in states | filter:$viewValue | limitTo:8" class="form-control">
 </div>
</body>
</html>

CSS

.dropdown-menu{
 height:110px;
 overflow:auto;
}

javascript datalist

$scope.states = ['Alabama', 'Alaska', 'Arizona', 'Arkansas', 'California', 'Colorado', 'Connecticut', 'Delaware', 'Florida', 'Georgia', 'Hawaii', 'Idaho', 'Illinois', 'Indiana', 'Iowa', 'Kansas', 'Kentucky', 'Louisiana', 'Maine', 'Maryland', 'Massachusetts', 'Michigan', 'Minnesota', 'Mississippi', 'Missouri', 'Montana', 'Nebraska', 'Nevada', 'New Hampshire', 'New Jersey', 'New Mexico', 'New York', 'North Dakota', 'North Carolina', 'Ohio', 'Oklahoma', 'Oregon', 'Pennsylvania', 'Rhode Island', 'South Carolina', 'South Dakota', 'Tennessee', 'Texas', 'Utah', 'Vermont', 'Virginia', 'Washington', 'West Virginia', 'Wisconsin', 'Wyoming'];

回答1:

Here is the working plunker

In this I have override ui-bootstrap typeahead as suggested in the answer.

Following are the changes I need to make it work:

Added following line in typeaheadMatch directive (line - 335 of ui.bootstrap.typeahead.js file in the plunker)

element[0].focus();

Added shouldFocus directive (line - 314 -350)

.directive('shouldFocus', function(){
  return {
   restrict: 'A',
   link: function(scope,element,attrs){
     scope.$watch(attrs.shouldFocus,function(newVal,oldVal){
       element[0].scrollIntoView(false);
     });
   }
 };
})

and finally added directive in li (line - 372)

should-focus=\"isActive($index)\"

回答2:

@user1690588 answer works great. Only problem is that when the last item in the list is active and you press the down key. the scrollToView tothe first item does not work. I added a check to ensure newVal is true which seems to fix this.

  if (newVal) { 
    element[0].scrollIntoView(false);
  }

http://plnkr.co/edit/05yoHSlhvX740tgiRRXm

回答3:

I used another approach to solve this problem, as none of the solutions here satisfying. Mainly:

reaching the last item and pressing the DOWN key should bring the first item into view
hovering items with the cursor should not make the Typeahead popup scroll
using mouse scroll wheel should not trigger weird behaviors on the Typeahead popup
fix should avoid modifying AngularUI Bootstrap sources

Extending AngularUI Bootstrap directives and listening to only specific key events seems to provide a cleaner workaround as you can see here: http://plnkr.co/edit/QuZw7j?p=preview

angular.module('ui.bootstrap.demo')
    .directive('typeahead', function () {
        return {
            restrict: 'A',
            priority: 1000, // Let's ensure AngularUI Typeahead directive gets initialized first!
            link: function (scope, element, attrs) {
                // Bind keyboard events: arrows up(38) / down(40)
                element.bind('keydown', function (evt) {
                    if (evt.which === 38 || evt.which === 40) {
                        // Broadcast a possible change of the currently active option:
                        // (Note that we could pass the activeIdx value as event data but AngularUI Typeahead directive
                        //  has its own local scope which makes it hard to retrieve, see:
                        //  https://github.com/angular-ui/bootstrap/blob/7b7039b4d94074987fa405ee1174cfe7f561320e/src/typeahead/typeahead.js#L104)
                        scope.$broadcast('TypeaheadActiveChanged');
                    }
                });
            }
        };
    }).directive('typeaheadPopup', function () {
        return {
            restrict: 'EA',
            link: function (scope, element, attrs) {
                var unregisterFn = scope.$on('TypeaheadActiveChanged', function (event, data) {
                    if(scope.activeIdx !== -1) {
                        // Retrieve active Typeahead option:
                        var option = element.find('#' + attrs.id + '-option-' + scope.activeIdx);
                        if(option.length) {
                            // Make sure option is visible:
                            option[0].scrollIntoView(false);
                        }
                    }
                });

                // Ensure listener is unregistered when $destroy event is fired:
                scope.$on('$destroy', unregisterFn);
             }
        };
    });

Tested with AngularJS 1.4.5 & AngularUI Bootstrap 0.13.4, but this should work with other recent versions.

[Note that I had to manually include jQuery, as the one preloaded by Plunker (jQuery v1.8.3) will fail retrieving the current active option.]

回答4:

The accepted solution will fail if the main window is already scrolling. @user1690588 was on the right track.

Edit the ui-bootstrap-tpls-0.13.3.js and drop this in around line 5205 above .filter('typeaheadHighlight') at least until the AngularUI team decides to fix this. As well as applying the other change to the template that the accepted solution references.

.directive('shouldFocus', function () {
    return {
        restrict: 'A',
        link: function (scope, element, attrs) {
            scope.$watch(attrs.shouldFocus, function (newVal, oldVal) {
                if (newVal && element.prop("class").indexOf("active")) {
                    var par = element.parent("ul");
                    var scrollingTo = element.offset().top - par.offset().top + par.scrollTop();
                    // uncomment below section if you want the selected content to be 
                    // viewed at half the box height
                    // scrollingTo = scrollingTo - (par.height() / 2); 
                    par.scrollTop(scrollingTo);
                }
            });
        }
    }
})

Also if you want to get rid of the mouse artifact where it starts scrolling up until it hits the first entry or down till hits the last entry then remove from the template the ng-mouseenter attribute.