Cable-Desktop/js/views/message_list_view.js

97 lines
3.9 KiB
JavaScript

/*
* vim: ts=4:sw=4:expandtab
*/
(function () {
'use strict';
window.Whisper = window.Whisper || {};
Whisper.MessageListView = Whisper.ListView.extend({
tagName: 'ul',
className: 'message-list',
itemView: Whisper.MessageView,
events: {
'scroll': 'onScroll',
'reset-scroll': 'resetScrollPosition'
},
onScroll: function() {
this.measureScrollPosition();
if (this.$el.scrollTop() === 0) {
this.$el.trigger('loadMore');
}
},
measureScrollPosition: function() {
if (this.el.scrollHeight === 0) { // hidden
return;
}
this.scrollPosition = this.$el.scrollTop() + this.$el.outerHeight();
this.scrollHeight = this.el.scrollHeight;
this.shouldStickToBottom = this.scrollPosition === this.scrollHeight;
if (this.shouldStickToBottom) {
this.bottomOffset = 0;
} else {
this.bottomOffset = this.scrollHeight - this.$el.scrollTop();
}
},
resetScrollPosition: function() {
var scrollPosition = this.scrollPosition;
if (this.scrollHeight !== this.el.scrollHeight) {
scrollPosition = this.el.scrollHeight * this.scrollPosition / this.scrollHeight;
}
this.$el.scrollTop(scrollPosition - this.$el.outerHeight());
},
scrollToBottomIfNeeded: function() {
this.$el.scrollTop(this.el.scrollHeight - this.bottomOffset);
},
addOne: function(model) {
var view;
if (model.isExpirationTimerUpdate()) {
view = new Whisper.ExpirationTimerUpdateView({model: model}).render();
} else if (model.get('type') === 'keychange') {
view = new Whisper.KeyChangeView({model: model}).render();
} else {
view = new this.itemView({model: model}).render();
this.listenTo(view, 'beforeChangeHeight', this.measureScrollPosition);
this.listenTo(view, 'afterChangeHeight', this.scrollToBottomIfNeeded);
}
var index = this.collection.indexOf(model);
if (index === this.collection.length - 1) {
// add to the bottom.
this.$el.append(view.el);
this.$el.scrollTop(this.el.scrollHeight); // TODO: Avoid scrolling if user has manually scrolled up?
this.measureScrollPosition();
} else if (index === 0) {
// add to top
this.measureScrollPosition();
this.$el.prepend(view.el);
this.scrollToBottomIfNeeded();
} else {
// insert
this.measureScrollPosition();
var next = this.$('#' + this.collection.at(index + 1).id);
var prev = this.$('#' + this.collection.at(index - 1).id);
if (next.length > 0) {
view.$el.insertBefore(next);
} else if (prev.length > 0) {
view.$el.insertAfter(prev);
} else {
// scan for the right spot
var elements = this.$el.children();
if (elements.length > 0) {
for (var i = 0; i < elements.length; ++i) {
var m = this.collection.get(elements[i].id);
var m_index = this.collection.indexOf(m);
if (m_index > index) {
view.$el.insertBefore(elements[i]);
break;
}
}
} else {
this.$el.append(view.el);
}
}
this.scrollToBottomIfNeeded();
}
},
});
})();