滚屏加载

Posted 2020-09-05 Lonely existence, lonely burni

滚屏加载

另外一种可行的性能解决方案就是滚屏加载，又称”Endless Scrolling,“ “unpagination”，这是用于大量数据集显示的时候，
又不想表格分页，所以一般放在页面最底部，当滚动屏幕到达页面底部的时候，就会尝试加载一个序列的数据集，追加在页面底部。
在Angular社区有开源组件ngInfiniteScroll http://binarymuse.github.io/ngInfiniteScroll/index.html实现滚屏加载。下面是官方Demo：

HTML：

<div ng-app=‘myApp‘ ng-controller=‘DemoController‘>
  <div infinite-scroll=‘reddit.nextPage()‘ infinite-scroll-disabled=‘reddit.busy‘ infinite-scroll-distance=‘1‘>
    <div ng-repeat=‘item in reddit.items‘>
      <span class=‘score‘>{{item.score}}</span>
      <span class=‘title‘>
        <a ng-href=‘{{item.url}}‘ target=‘_blank‘>{{item.title}}</a>
      </span>
      <small>by {{item.author}} -
        <a ng-href=‘http://reddit.com{{item.permalink}}‘ target=‘_blank‘>{{item.num_comments}} comments</a>
      </small>
      <div style=‘clear: both;‘></div>
    </div>
    <div ng-show=‘reddit.busy‘>Loading data...</div>
  </div>
</div>

javascript：
var myApp = angular.module(‘myApp‘, [‘infinite-scroll‘]);
myApp.controller(‘DemoController‘, [‘$scope‘, ‘Reddit‘, function($scope, Reddit) {
  $scope.reddit = new Reddit();
}]);
// Reddit constructor function to encapsulate HTTP and pagination logic
myApp.factory(‘Reddit‘, [‘$http‘, function($http) {
  var Reddit = function() {
    this.items = [];
    this.busy = false;
    this.after = ‘‘;
  };
  Reddit.prototype.nextPage = function() {
    if (this.busy) return;
    this.busy = true;
    var url = ‘http://api.reddit.com/hot?after=‘ + this.after + ‘&jsonp=JSON_CALLBACK‘;
    $http.jsonp(url).success(function(data) {
      var items = data.data.children;
      for (var i = 0; i < items.length; i++) {
        this.items.push(items[i].data);
      }
      this.after = ‘t3_‘ + this.items[this.items.length - 1].id;
      this.busy = false;
    }.bind(this));
  };
  return Reddit;
}]);