Get list ID and selected item ID

Question

I use SharePoint Online and working in Visual Studio with SharePoint hosted app

I need to get list id and the id of the SELECTED item in the list

And i use a ribbon button to show a dialog and want the id to show in it

This is the code I am using:

var clientContext, hostweburl, parentContext, parentWeb, listItems;

clientContext = new SP.ClientContext.get_current();
hostweburl = decodeURIComponent(getQueryStringParameter("SPHostUrl"));
parentContext = new SP.AppContextSite(clientContext, hostweburl);
parentWeb = parentContext.get_web();
listItems = parentWeb.get_lists().getByTitle("RibbonTestSimon").getItems("");


$(document).ready(function () {
    clientContext.load(listItems);
    clientContext.executeQueryAsync(OnSuccess, OnFail);
});


function OnSuccess() {
    var listString = "";
    var listEnumerator = listItems.getEnumerator();
while (listEnumerator.moveNext()) {
    var currentItem = listEnumerator.get_current();
    listString += "<br/> " + currentItem.get_item('Title');
}
$('#divAllaItems').html(listString);
}


function OnFail() {
    alert("Error");
}


function getQueryStringParameter(paramToRetrieve) {
    var params =
    document.URL.split("?")[1].split("&");
    var strParams = "";
    for (var i = 0; i < params.length; i = i + 1) {
        var singleParam = params[i].split("=");
        if (singleParam[0] == paramToRetrieve)
            return singleParam[1];
    }
}

This is the code for the ribbon button in this code i have the code that open a dialog box can that be the reason why it isnt work

<?xml version="1.0" encoding="utf-8"?>
<Elements xmlns="http://schemas.microsoft.com/sharepoint/">
  <CustomAction Id="31f85d51-7911-4be4-b56e-0a165adcad5e.RibbonTest"
            RegistrationType="List"
            RegistrationId="100"
            Location="CommandUI.Ribbon"
            Sequence="10001"
            Title="RibbonTest"
            HostWebDialog="TRUE"
            HostWebDialogWidth="480"
            HostWebDialogHeight="240">
<CommandUIExtension>
  <!-- 
  Update the UI definitions below with the controls and the command actions
  that you want to enable for the custom action.
  -->
  <CommandUIDefinitions>
    <CommandUIDefinition Location="Ribbon.ListItem.Actions.Controls._children">
      <Button Id="Ribbon.ListItem.Actions.RibbonTestButton"
              Alt="RibbonTest"
              Sequence="100"
              Command="Invoke_RibbonTestButtonRequest"
              LabelText="RibbonTest"
              TemplateAlias="o1"
              Image32by32=/>
    </CommandUIDefinition>
  </CommandUIDefinitions>
  <CommandUIHandlers>
    <CommandUIHandler
              Command="Invoke_RibbonTestButtonRequest"
              CommandAction="~appWebUrl/Pages/Default.aspx?{StandardTokens}&amp;SPListItemId={SelectedItemId}&amp;SPListId={SelectedListId}" />
  </CommandUIHandlers>
</CommandUIExtension >

Answer 1

var clientContext =  SP.ClientContext.get_current(); // Gets current site context
var id =  GetItemID(); //retrieve selected list item id to update data
var listId = SP.ListOperation.Selection.getSelectedList();
var oList = context.get_web().get_lists().getById(listId); 
this.oListItem = oList.getItemById(id);

function GetItemID()
{ 
     var selectedItems = SP.ListOperation.Selection.getSelectedItems(); // Retrieve selected items
     var count = SP.ListOperation.Selection.getSelectedItems().length;// CountDictionary(selectedItems);
     if (count > 0) { return selectedItems[0].id; } else { return null; }
}

Answer 2

    var clientContext, hostweburl, parentContext, parentWeb, listItems;

clientContext = new SP.ClientContext.get_current();
hostweburl = decodeURIComponent(getQueryStringParameter("SPHostUrl"));
parentContext = new SP.AppContextSite(clientContext, hostweburl);
parentWeb = parentContext.get_web();
var id =  GetItemID(); // Gets Selected item's ID 
var listId = SP.ListOperation.Selection.getSelectedList();
var oList = context.get_web().get_lists().getById(listId); 
this.oListItem = oList.getItemById(id);
//listItems = parentWeb.get_lists().getByTitle("RibbonTestSimon").getItems("");


$(document).ready(function () {
    clientContext.load(listItems);
    clientContext.executeQueryAsync(OnSuccess, OnFail);
});

function GetItemID()
{ 
     var selectedItems = SP.ListOperation.Selection.getSelectedItems(); // Retrieve selected items
     var count = SP.ListOperation.Selection.getSelectedItems().length;// CountDictionary(selectedItems);
     if (count > 0) { return selectedItems[0].id; } else { return null; }
}

function OnSuccess() {
    var listString = "";
    var listEnumerator = listItems.getEnumerator();
while (listEnumerator.moveNext()) {
    var currentItem = listEnumerator.get_current();
    listString += "<br/> " + currentItem.get_item('Title');
}
$('#divAllaItems').html(listString);
}


function OnFail() {
    alert("Error");
}


function getQueryStringParameter(paramToRetrieve) {
    var params =
    document.URL.split("?")[1].split("&");
    var strParams = "";
    for (var i = 0; i < params.length; i = i + 1) {
        var singleParam = params[i].split("=");
        if (singleParam[0] == paramToRetrieve)
            return singleParam[1];
    }
}

Answer 3

This Answer was what i was looking for:

var clientContext, hostweburl, parentContext, parentWeb, selectedItems, itemIds, listId;

clientContext = new SP.ClientContext.get_current();
hostweburl = decodeURIComponent(getQueryStringParameter("SPHostUrl"));
listId = decodeURIComponent(getQueryStringParameter("SPListId"));
itemIds = decodeURIComponent(getQueryStringParameter("SPListItemId")).split(',');
parentContext = new SP.AppContextSite(clientContext, hostweburl);
parentWeb = parentContext.get_web();
selectedItems = parentWeb.get_lists().getById(listId).getItemById(itemIds);

function itemLoop(color)
{
    var i;
    for (i = 0; i < itemIds.length; i++)
    {
        selectedItems = parentWeb.get_lists().getById(listId).getItemById(itemIds[i]);
        selectedItems.set_item('Color', color);
        selectedItems.update();
        clientContext.load(selectedItems);
    }
    clientContext.executeQueryAsync(function () { window.parent.postMessage('CloseCustomActionDialogRefresh', '*'); }, function (sender, args) { alert('Error:' + args.get_message()); });

}