我想建立迷你网聊 - 当查看网站我设置显示5消息,如果查看更多,您可以单击按钮。所有的事情都很好,但是当我删除1个节点时,firebase自动添加最后一个节点,我该如何防止它?例如:我有节点A,B,C,D,E,F,G。我已经加载了列表C,D,E,F,G但是当我删除1时,它会自动将B添加到列表中。Firebase - 防止child_added与删除时limitToLast
<div id="messgesDiv">
<center><h3>Message</h3></center>
</div>
<div style="margin-top: 20px;">
<input type="text" id="nameInput" placeholder="Name">
<input type="text" id="messageInput" placeholder="Message" data-id="">
<input type="text" id="idproject" placeholder="ID Project">
</div>
<button id="delete">Delete Test</button>
<button id="edit">Edit</button>
<button id="loadmore">Load more</button>
<button id="showlastkey">Show last key</button>
我的JavaScript
$('#loadmore').click(function() {
i = 0; old = first;
myDataRef.orderByKey().endAt(first).limitToLast(6).on('child_added', function (snapshot){
if(i == 0)
first = snapshot.key();
var message = snapshot.val();
if(snapshot.key() != old)
displayChatMessage(message.name, message.text, message.idproject, 'old');
i++;
console.log('myDataRef.orderByKey().endAt(first).limitToLast(6)');
});
});
$("#messageInput").keypress(function (e){
if(e.keyCode == 13){ //Enter
var name = $("#nameInput").val();
var text = $("#messageInput").val();
var idproject = $("#idproject").val();
if($("#messageInput").data("id")=='')
{
myDataRef.push({name: name, text: text, idproject: idproject});
}
else
{
myDataRef.child(key).update({name: name, text: text, idproject: idproject});
$('#messageInput').attr('data-id', '');
}
$("#messageInput").val("");
}
});
myDataRef.limitToLast(5).on('child_added', function (snapshot){
if(i == 0)
first = snapshot.key();
var message = snapshot.val();
displayChatMessage(snapshot.key(), message.name, message.text, message.idproject, 'new');
i++;
console.log(snapshot.key());
console.log(' myDataRef.limitToLast(5)');
});
function displayChatMessage(key, name, text, idproject, status){
//console.log(name + " -- " + text + " -- " +idproject);
if(status == 'new')
{
$('<div/>', { 'data-id': key , 'class' : 'test'}).text(text + " - ").prepend($('<em/>').text(name+": ")).append("IdProject: "+idproject).appendTo($("#messgesDiv"));
$("#messgesDiv")[0].scrollTop = $("#messgesDiv")[0].scrollHeight;
}
else
{
$('<div/>', { 'data-id': key , 'class' : 'test'}).text(text + " - ").prepend($('<em/>').text(name+": ")).append("IdProject: "+idproject).insertAfter($("center"));
$("#messgesDiv")[0].scrollTop = $("#messgesDiv")[0].scrollHeight;
}
}
$('#delete').click(function() {
myDataRef.child(key).remove();
$('#messgesDiv').filter('[data-id="'+key+'"]').remove();
});