Infinite Lists
由于手机不适合使用多页面显示posts，Infinite Lists成为各种新闻、咨询类app的标配。为了在ionic框架中使用到Infinite Lists，我们首先学习ion-list。
ion-list
ion-list使用
在ionic中，通过使用ion-list和ion-item来展示数据，通过ng-repeat循环输出，如demo（使用ionic start mydemo tabs命令生成ionic demo）中的templates/tab-friends.html中显示：
<ion-list>
<ion-item ng-repeat="friend in friends" type="item-text-wrap" href="#/tab/friend/{{friend.id}}">
{{friend.name}}
</ion-item>
</ion-list>
假如我们返回到html的数据，每次都为20项，则但屏幕划到最后一项或前几项时，则需要监听检测到，并且载入下一个20项数据，从而达到无止境的下滑刷新载入更多的目标。这里，ionic提供了ion-infinite-scroll directive。
ion-infinite-scroll function is more like a scroll detector: it detects when a user is scrolled to a given point above the bottom of the view (default 1%, or 99% of the way down), and executes a function.
所以需要在html中添加这个directive，如下：
<ion-list>
<ion-item ng-repeat="friend in friends" type="item-text-wrap" href="#/tab/friend/{{friend.id}}">
{{friend.name}}
</ion-item>
<ion-infinite-scroll on-infinite="addFriends()"></ion-infinite-scroll>
</ion-list>
在controller中添加addFriends()函数，和载入数据。
同时，在重新完全载入数据后，需要发送一个scroll.infiniteScrollComplete事件，告诉directive，我们完成了这个动作，系统会清理scroller和为下一次的载入数据，重新绑定这一事件。
修改friends controller
通过修改controller，让list一次载入20个friends数据，这样达到Infinite Lists效果，如下修改js/controllers.js中FriendsCtrl：
.controller('FriendsCtrl', function($scope, Friends) {
var currentStart = 0;
$scope.friends = [];
$scope.addFriends = function() {
for (var i = currentStart; i < currentStart+20; i++) {
$scope.friends.push(Friends.get(currentStart));
}
currentStart += 20;
$scope.$broadcast('scroll.infiniteScrollComplete');
};
$scope.addFriends();
//$scope.friends = Friends.all();
})
service添加mock数据
在service端，调用Friends factory如下：
.factory('Friends', function() {
// Might use a resource here that returns a JSON array
// Some fake testing data
var friends = [
{ id: 0, name: 'Scruff McGruff' },
{ id: 1, name: 'G.I. Joe' },
{ id: 2, name: 'Miss Frizzle' },
{ id: 3, name: 'Ash Ketchum' },
{ id: 4, name: 'Scruff McGruff' },
{ id: 5, name: 'G.I. Joe' },
{ id: 6, name: 'Miss Frizzle' },
{ id: 7, name: 'Ash Ketchum' },
{ id: 8, name: 'Scruff McGruff' },
{ id: 9, name: 'G.I. Joe' },
{ id: 10, name: 'Miss Frizzle' },
{ id: 11, name: 'Ash Ketchum' },{ id: 0, name: 'Scruff McGruff' },
{ id: 12, name: 'G.I. Joe' },
{ id: 13, name: 'Miss Frizzle' },
{ id: 14, name: 'Ash Ketchum' },
{ id: 15, name: 'Scruff McGruff' },
{ id: 16, name: 'G.I. Joe' },
{ id: 17, name: 'Miss Frizzle' },
{ id: 18, name: 'Ash Ketchum' },
{ id: 19, name: 'Scruff McGruff' },
{ id: 20, name: 'G.I. Joe' },
{ id: 21, name: 'Miss Frizzle' },
{ id: 22, name: 'Ash Ketchum' },
{ id: 23, name: 'Scruff McGruff' },
{ id: 24, name: 'G.I. Joe' },
{ id: 25, name: 'Miss Frizzle' },
{ id: 26, name: 'Ash Ketchum' },
{ id: 27, name: 'Scruff McGruff' },
{ id: 28, name: 'G.I. Joe' },
{ id: 29, name: 'Miss Frizzle' },
{ id: 30, name: 'Ash Ketchum' },
{ id: 31, name: 'Scruff McGruff' },
{ id: 32, name: 'G.I. Joe' },
{ id: 33, name: 'Miss Frizzle' },
{ id: 34, name: 'Ash Ketchum' },
{ id: 35, name: 'Scruff McGruff' },
{ id: 36, name: 'G.I. Joe' },
{ id: 37, name: 'Miss Frizzle' },
{ id: 38, name: 'Ash Ketchum' },
{ id: 39, name: 'Scruff McGruff' }
];
return {
all: function() {
return friends;
},
get: function(friendId) {
// Simple index lookup
return friends[friendId];
}
}
测试
使用python命令，测试：
python -m SimpleHTTPServer 8000
ion-infinite-scroll 参数
<ion-content ng-controller="MyController">
<ion-infinite-scroll
on-infinite="loadMore()"
distance="1%">
</ion-infinite-scroll>
</ion-content>
主要有三个参数：
on-infinite：expression；含义：What to call when the scroller reaches the bottom.
distance (optional) string； 含义：The distance from the bottom that the scroll must reach to trigger the on-infinite expression. Default: 1%.
icon(optional) string；含义：The icon to show while loading. Default: 'ion-loading-d'.
也可以添加ng-if来判断是否还有更多数据可以载入，如：
<ion-infinite-scroll
ng-if="moreDataCanBeLoaded()"
icon="ion-loading-c"
on-infinite="loadMoreData()">
</ion-infinite-scroll>
更多的ion-list使用，参照官网