public async Task <int> getHistoryMessage()
{
IEnumerable <IAVIMMessage> messages;
if (oldestMessage == null)
{
messages = (await conversation.QueryMessageAsync(limit: MessagePerPage));
}
else
{
messages = (await conversation.QueryMessageAsync(
beforeMessageId: oldestMessage.Id,
beforeTimeStamp: oldestMessage.ServerTimestamp,
limit: MessagePerPage));
}
foreach (var message in messages.Reverse())
{
if (message is AVIMTextMessage)
{
var textMessage = (AVIMTextMessage)message;
MessageItem newItem = fromIMTextMessage(textMessage);
itemList.Insert(0, newItem);
}
}
List <IAVIMMessage> list = messages.ToList();
if (list.Count > 0)
{
oldestMessage = list[0];
}
return(list.Count);
}
//上拉到顶部刷新出历史聊天记录
private async void Received_ScrollChanged(object sender, ScrollChangedEventArgs e)
{
ScrollViewer viewer = e.OriginalSource as ScrollViewer;
if (viewer != null)
{
if (viewer.VerticalOffset == 0 && Conversation != null)
{
//加载历史记录
var earliestMessages = await Conversation.QueryMessageAsync(limit : 20);
List <Message> earliestMessageList = new List <Message>();
foreach (AVIMMessage message in earliestMessages)
{
earliestMessageList.Add(new Message(message));
}
InviteFriend.MessageList.InsertRange(0, earliestMessageList);
received.ItemsSource = null;
received.ItemsSource = InviteFriend.MessageList;
//聚焦最新的消息
received.ScrollIntoView(received.Items.GetItemAt(InviteFriend.MessageList.Count - 1));
}
}
}
