/**
* This jQuery plugin displays pagination links inside the selected elements.
*
* This plugin needs at least jQuery 1.4.2
*
* @author Gabriel Birke (birke *at* d-scribe *dot* de)
* @version 2.2
* @param {int}
* maxentries Number of entries to paginate
* @param {Object}
* opts Several options (see README for documentation)
* @return {Object} jQuery Object
*/
(function($) {
/**
* @class Class for calculating pagination values
*
* 下面的写法我的理解是定义一个我任务的构造方法，或者方法，或者对象
* $.PaginationCalculator，这个$.PaginationCalculator对象中有两个参数
*/
$.PaginationCalculator = function(maxentries, opts) {
this.maxentries = maxentries;
this.opts = opts;
}
/**
* 对这个对象进行扩展$.PaginationCalculator，为它添加numPages方法，getInterval方法。
*/
$.extend($.PaginationCalculator.prototype, {
/**
* Calculate the maximum number of pages
*
* @method
* @returns {Number}
* 编写一个获得页码的方法
*
*/
numPages : function() {
return Math.ceil(this.maxentries / this.opts.items_per_page);
},
/**
* Calculate start and end point of pagination links depending on
* current_page and num_display_entries.
*
* @returns {Array}
*/
getInterval : function(current_page) {
var ne_half = Math.floor(this.opts.num_display_entries / 2);
var np = this.numPages();
var upper_limit = np - this.opts.num_display_entries;
var start = current_page > ne_half ? Math.max(Math.min(current_page
- ne_half, upper_limit), 0) : 0;
var end = current_page > ne_half ? Math.min(current_page + ne_half
+ (this.opts.num_display_entries % 2), np) : Math.min(
this.opts.num_display_entries, np);
return {
start : start,
end : end
};
}
});
// Initialize jQuery object container for pagination renderers，下面的方式是定义一个对象
$.PaginationRenderers = {}
/**
* @class Default renderer for rendering pagination links
*
* 再次定义一个$.PaginationRenderers.defaultRenderer对象
*/
$.PaginationRenderers.defaultRenderer = function(maxentries, opts) {
this.maxentries = maxentries;
this.opts = opts;
this.pc = new $.PaginationCalculator(maxentries, opts);
}
$.extend($.PaginationRenderers.defaultRenderer.prototype,
{
/**
* Helper function for generating a single link (or a
* span tag if it's the current page)
*
* @param {Number}
* page_id The page id for the new item
* @param {Number}
* current_page
* @param {Object}
* appendopts Options for the new item: text
* and classes
* @returns {jQuery} jQuery object containing the link
*/
createLink : function(page_id, current_page, appendopts) {
var lnk, np = this.pc.numPages();
page_id = page_id < 0 ? 0 : (page_id < np ? page_id
: np - 1); // Normalize page id to sane
// value
appendopts = $.extend( {
text : page_id + 1,
classes : ""
}, appendopts || {});
if (page_id == current_page) {
lnk = $("<a class='current'>" + appendopts.text
+ "</a>");
} else {
lnk = $("<a>" + appendopts.text + "</a>").attr(
'href',
this.opts.link_to.replace(/__id__/,
page_id));
}
if (appendopts.classes) {
lnk.addClass(appendopts.classes);
}
lnk.data('page_id', page_id);
return lnk;
},
// Generate a range of numeric links
appendRange : function(container, current_page, start,
end, opts) {
var i;
for (i = start; i < end; i++) {
this.createLink(i, current_page, opts)
.appendTo(container);
}
},
getLinks : function(current_page, eventHandler) {
var begin, end, interval = this.pc
.getInterval(current_page), np = this.pc
.numPages(), fragment = $("<div class='pagination'></div>");
// Generate "Previous"-Link
if (this.opts.prev_text
&& (current_page > 0 || this.opts.prev_show_always)) {
fragment.append(this.createLink(
current_page - 1, current_page, {
text : this.opts.prev_text,
classes : "prev"
}));
}
// Generate starting points
if (interval.start > 0
&& this.opts.num_edge_entries > 0) {
end = Math.min(this.opts.num_edge_entries,
interval.start);
this.appendRange(fragment, current_page, 0,
end, {
classes : 'sp'
});
if (this.opts.num_edge_entries < interval.start
&& this.opts.ellipse_text) {
$(
"<span class='pagination-break'>"
+ this.opts.ellipse_text
+ "</span>").appendTo(
fragment);
}
}
// Generate interval links
this.appendRange(fragment, current_page,
interval.start, interval.end);
// Generate ending points
if (interval.end < np
&& this.opts.num_edge_entries > 0) {
if (np - this.opts.num_edge_entries > interval.end
&& this.opts.ellipse_text) {
$(
"<span class='pagination-break'>"
+ this.opts.ellipse_text
+ "</span>").appendTo(
fragment);
}
begin = Math.max(np
- this.opts.num_edge_entries,
interval.end);
this.appendRange(fragment, current_page, begin,
np, {
classes : 'ep'
});
}
// Generate "Next"-Link
if (this.opts.next_text
&& (current_page < np - 1 || this.opts.next_show_always)) {
fragment.append(this.createLink(
current_page + 1, current_page, {
text : this.opts.next_text,
classes : "next"
}));
}
$('a', fragment).click(eventHandler);
return fragment;
}
});
// Extend jQuery，编写一个插件
$.fn.pagination = function(maxentries, opts) {
// Initialize options with default values
opts = $.extend( {
items_per_page : 1,
num_display_entries : 4,
current_page : 0,
num_edge_entries : 1,
link_to : "#",
prev_text : "<i></i>上一页",
next_text : "下一页 <i></i>",
ellipse_text : "...",
prev_show_always : true,
next_show_always : true,
renderer : "defaultRenderer",
show_if_single_page : false,
load_first_page : false,
callback : function() {
return false;
}
}, opts || {});
var containers = this, renderer, links, current_page;
// goto
$(".page-btn").one("click", function() {
var allPage = $(".allPage").text();
// console.log(allPage);
var goPage = $(".page-go input").val() - 1; // 跳转页数
if (goPage > -1 && goPage < allPage) {
opts.current_page = goPage;
$("#Pagination").pagination(allPage, opts);
} else {
$("#Pagination").pagination(allPage);
}
// 清空用户跳转页数
$(".page-go input").val("");
});
/**
* This is the event handling function for the pagination links.
*
* @param {int}
* page_id The new page number
*/
function paginationClickHandler(evt) {
var links, new_current_page = $(evt.target).data('page_id'), continuePropagation = selectPage(new_current_page);
if (!continuePropagation) {
evt.stopPropagation();
}
return continuePropagation;
}
/**
* This is a utility function for the internal event handlers. It sets
* the new current page on the pagination container objects, generates a
* new HTMl fragment for the pagination links and calls the callback
* function.
*/
function selectPage(new_current_page) {
// update the link display of a all containers
containers.data('current_page', new_current_page);
links = renderer.getLinks(new_current_page, paginationClickHandler);
containers.empty();
links.appendTo(containers);
// call the callback and propagate the event if it does not return
// false
var continuePropagation = opts.callback(new_current_page,
containers);
return continuePropagation;
}
// -----------------------------------
// Initialize containers
// -----------------------------------
current_page = parseInt(opts.current_page);
containers.data('current_page', current_page);
// Create a sane value for maxentries and items_per_page
maxentries = (!maxentries || maxentries < 0) ? 1 : maxentries;
opts.items_per_page = (!opts.items_per_page || opts.items_per_page < 0) ? 1
: opts.items_per_page;
if (!$.PaginationRenderers[opts.renderer]) {
throw new ReferenceError("Pagination renderer '" + opts.renderer
+ "' was not found in jQuery.PaginationRenderers object.");
}
renderer = new $.PaginationRenderers[opts.renderer](maxentries, opts);
// Attach control events to the DOM elements
var pc = new $.PaginationCalculator(maxentries, opts);
var np = pc.numPages();
containers.bind('setPage', {
numPages : np
}, function(evt, page_id) {
if (page_id >= 0 && page_id < evt.data.numPages) {
selectPage(page_id);
return false;
}
});
containers.bind('prevPage', function(evt) {
var current_page = $(this).data('current_page');
if (current_page > 0) {
selectPage(current_page - 1);
}
return false;
});
containers.bind('nextPage', {
numPages : np
}, function(evt) {
var current_page = $(this).data('current_page');
if (current_page < evt.data.numPages - 1) {
selectPage(current_page + 1);
}
return false;
});
// When all initialisation is done, draw the links
links = renderer.getLinks(current_page, paginationClickHandler);
containers.empty();
if (np > 1 || opts.show_if_single_page) {
links.appendTo(containers);
}
// call callback function
if (opts.load_first_page) {
opts.callback(current_page, containers);
}
} // End of $.fn.pagination block
})(jQuery);
