我试过的(不能正常工作):
代码:
<script>
var app = angular.module('app', ['firebase']);
app.controller('ctrl', function ($scope, $firebaseArray, $timeout) {
$scope.data = [];
var _n = Math.ceil(($(window).height() - 50) / (350)) + 1;
var start = 0;
var end = _n - 1;
var lastScore = <%=lastScore%>;
console.log("FIRST FIRST FIRST LAST SCORE:" + lastScore);
var firstElementsLoaded = false;
$scope.getDataset = function() {
fb.orderByChild('score').endAt(lastScore).limitToLast(_n).on("child_added", function(dataSnapshot) {
lastScore = dataSnapshot.child("score").val() - 1;
console.log("LAST TOP LIKED:"+ lastScore);
$scope.data.push(dataSnapshot.val());
$scope.$apply();
console.log("THE VALUE:"+$scope.data);
$scope.data.splice(start, end).concat($scope.data.reverse());
$scope.$apply();
start = start + _n;
end = end + _n
firstElementsLoaded = true;
});
};
$scope.getDataset();
window.addEventListener('scroll', function() {
if (firstElementsLoaded == true) {
if (window.scrollY === document.body.scrollHeight - window.innerHeight) {
$scope.$apply($scope.getDataset());
}
}
});
});
// Compile the whole <body> with the angular module named "app"
angular.bootstrap(document.body, ['app']);
问题:
我如何还原数据客户端以根据他们的分数(从最高到最低)从上到下获取我的帖子？
我想要实现的目标:
根据分数降序获取我的帖子，这对于无限滚动有点棘手。
最佳答案
由于帖子是倒序显示的，你应该将“页”的顺序倒过来(使用endAt而不是startAt)，并且在每个页面中将帖子倒序排列.
另见 this answer
示例
设置:
$scope.data = [];
var n = Math.ceil(($(window).height() - 50) / (350)) + 1;
var firstElementsLoaded = false;
var lastScore = MAX_SCORE, lastKey
scroll事件监听函数:
$scope.getDataset = function() {
fb.orderByChild('score')
.endAt(lastScore, lastKey)
//endAt is inclusive, take one more for the n-th
.limitToLast(n + firstElementsLoaded)
.once('value', loadPosts)
function loadPosts(snapshot) {
var posts = snapshot.val()
function compare(a, b) {
if (posts[a].score != posts[b].score) {
return b.score - a.score
}
if (a < b) return 1
if (a > b) return -1
return 0
}
//skip the post included by endAt
var ordered = Object.keys(posts).sort(compare).slice(firstElementsLoaded)
lastKey = ordered[ordered.length-1]
lastScore = posts[lastKey].score
ordered.forEach(function(key) {
$scope.data.push(posts[key])
})
$scope.$apply();
firstElementsLoaded = true;
}
}
为了更优雅的方式，您可以尝试反向存储分数，或者使用额外的值。
fb.orderByChild('reversedScore')
关于javascript - 如何使用 firebase 按降序在我的无限滚动中首先显示我的热门帖子？，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/41433089/