I have a tree model and use QDataWidgetMapper to map the model data to some widgets.
In the model, some of the data are flagged as read-only, so, what I would like to do is to let the mapped widget, say, a QLineEdit, be able to act upon this flag and set itself to readonly when the model data it points to is readonly.
Any help is appreciated!
Qt's QAbstractDataModel interface doesn't expose writability of a piece of data as an attribute: there's nothing you can read to know whether an item can be modified or not. One could think of some non-general hacks, such as attempting to write back the current value of the item to check if it can be changed. They are but hacks, e.g. a model fulfilling the contract mandated by Qt might return true from setData even on a read-only item if the new value equals old value.
If you're using a model that exposes the writability attribute, you'll need to derive from QDataWidgetMapper and implement that functionality yourself.
I am trying to use the drag & drop functionality on a QTreeView with an underlying QStandardModelItem. The default behavior of the widget is perfect for me until it gets to the drop part where I need to perform some operation. Hence, I am going to override the dropEvent(QDropEvent *event) method of my TreeView where I would like to decode the dropped mime data.
The formats of the data I find in the mime object are "application/x-qabstractitemmodeldatalist" and "application/x-qstandarditemmodeldatalist". Does anyone know how to decode the associated data (or where to find some documentation on it) ?
That mime type is the default type for item views. The qt already handles this when drop is made; To enable drag'n drop do:
itemView->setSelectionMode(QAbstractItemView::SingleSelection);
itemView->setDragEnabled(true);
itemView->viewport()->setAcceptDrops(true);
itemView->setDropIndicatorShown(true);
itemView->setDragDropMode(QAbstractItemView::InternalMove);
To change default behavior take a look at:
http://doc.qt.io/qt-5/model-view-programming.html#using-drag-and-drop-with-item-views
When you create a Data Extender for a CME list – for instance to add a column for the Schema as in this example – it all works fine and dandy whenever you do actions that force a List reload.
However, some actions don’t force a list reload (like editing a component in a folder, then saving & closing) and it looks like Anguilla is loading the data for the item that changed using a different mechanism that loads only the data for the item in question (which makes sense).
If I would want my extended list view to behave properly and also load my additional attributes whenever a given item changes (instead of only when the list view is reloaded) what else do I need to do?
I found how Anguilla takes care of this. When you implement a Data Extender, you are extending the information regarding the items displayed in the list, which basically means that you are extending the Data (Model) behind the item in question.
Each Item in Tridion has its own class in the Anguilla Framework, for example a Component has its own Tridion.ContentManager.Component javascript "class".
Having said this, and going back to the example that shows the schema name of the component, we are not actually extending the model, since that information is already available in the component. However, we need to overwrite the methods exposed on each used for displaying information in the lists the item is in, in this case a Component.
So, when we deal with a Data Extender, if we want a full implementation of this functionality, we not only need to define the data extender:
<ext:dataextender
name="IntelligentDataExtender"
type="Com.Tridion.PS.Extensions.IntelligentDataExtender,PS.GUI.Extensions">
<ext:description>Shows extra info</ext:description>
</ext:dataextender>
But also we need to define what's the column we are adding:
<ext:lists>
<ext:add>
<ext:extension name="IntelligentColumnExtender"
assignid="IntelligentDataColumnExtender">
<ext:listDefinition>
<ext:selectornamespaces/>
<ext:columns>
<column
xmlns="http://www.sdltridion.com/2009/GUI/extensions/List"
id="IntelligentData"
type="data"
title="Additional Info"
selector="#ExtendedInfo"
translate="String"/>
</ext:columns>
</ext:listDefinition>
<ext:apply>
<ext:view name="DashboardView" />
</ext:apply>
</ext:extension>
</ext:add>
</ext:lists>
Once we have this, the GUI will display the column we just added: "Additional Info"
Well, now we need to achieve the list refreshing when the item is edited/checked-out and in, etc...
For that, we need to extend the model and implement a few methods in the Object we are extending. In this example I am extending the Page object, so whenever a page is edited, the row in the list we want to update gets refreshed, together with the rest of the cells in the table.
To extend the model we need to define what types are we extending, in this example I am going to use the "Page" class as an example. First of all you need to define the model extension in the config file of your Editor:
<cfg:group name="Com.Tridion.PS.Extensions.UI.Model"
merger="Tridion.Web.UI.Core.Configuration.Resources.DomainModelProcessor"
merge="always">
<cfg:domainmodel name="Com.Tridion.PS.Extensions.UI.Model">
<cfg:fileset>
<cfg:file type="script">/Scripts/PSPage.js</cfg:file>
</cfg:fileset>
<cfg:services />
</cfg:domainmodel>
</cfg:group>
and
<ext:modelextensions>
<cfg:itemtypes>
<cfg:itemtype id="tcm:64" implementation="Com.Tridion.PS.Extensions.UI.PSPage" />
</cfg:itemtypes>
</ext:modelextensions>
As you can see I am extending the Page by using the "Com.Tridion.PS.Extensions.UI.PSPage" class that is defined in the Javascript file "/Scripts/PSPage.js".
The only method that handles the row refreshing is the following:
Com.Tridion.PS.Extensions.UI.PSPage.prototype.getListItemXmlAttributes
= function PSPage$getListItemXmlAttributes(customAttributes) {
var attribs = {};
var p = this.properties;
if (customAttributes) {
for (var attr in customAttributes) {
attribs[attr] = customAttributes[attr];
}
}
//This adds my custom column back when the item is updated
attribs["ExtendedInfo"] = p.extendedInfo;
return this.callBase(
"Tridion.ContentManager.Page",
"getListItemXmlAttributes",
[attribs])
};
As you can see I am implementing the "ExtendedInfo" attribute which is the one displayed in my additional column.
There's more than just adding a Data Extender when dealing with adding a column to our lists. I will write a post in my blog here to provide with a fully working example.
I hope it makes sense.
Well, Jaime correctly described how CME updates changed items in Lists. But I want to add some additional information on how List controls, domain model List and Items are interact with each other. This might help you building your own extension with similar functionality.
Most of the domain model List items inherit from Tridion.ContentManager.ListTcmItems class. On the moment when any List item, based on mentioned class, is loaded it will be registered in Lists Registry (and un-registered when the List is unloaded). This will allow Model to use registered Lists as source of static data for Items and to update changed Items data in these Lists.
Update Item static data
For example, we have loaded ListCategories and there is only one Category in the List:
var pub = $models.getItem("tcm:0-1-1");
var list = pub.getListCategories();
list.load();
// After list is loaded
list.getXml();
That getXml() returns an XML like (simplified):
<tcm:ListCategories>
<tcm:Item ID="tcm:1-4-512" Type="512" Title="Keys" />
</tcm:ListCategories>
After that, if you try to get some static data for Category "Keys" it will be already set:
var category = $models.getItem("tcm:1-4-512");
category.isLoaded(); // return false
category.isStaticLoaded(); // return false
category.getTitle(); // return undefined
category.getStaticTitle(); // return "Keys"!
That is possible because $models.getItem call will do two things: it will return an existing (or create a new) domain model object and call $models.updateItemData method with it. This method call will go through all registered Lists in the Lists Registry and for all Lists whose TimeStamp bigger than Item's Last Update TimeStamp will call list.updateItemData with the model object.
The updateItemData method will check if the passed Item is in the list and if it is, then the Item will be updated with the static data that is available from the List.
Updating data of changed Items in the List
When a domain model Item is modified (updated, removed, created new) one of these methods is called:
$models.itemUpdated
$models.itemRemoved
These methods will go through the Lists in Lists Registry and call list.itemUpdated (or list.itemRemoved). These methods will check is passed Item is contained in their List and if so they will update the List xml from the Item data.
For that purpose there is a getListItemXmlNode method in the Tridion.ContentManager.Item class. This method will build List xml node based on the array of attributes, provided by getListItemXmlAttributes method on the Item. That's what Jaime mentioned in his answer.
If the List xml was updated, one of these events will be fired on List object:
itemadd
itemupdate
itemremove
Listening to these events on a List object in your view will allow you to timely update your List Control.
So if you want this mechanism to work with your extension, stick to these rules:
If you are creating new domain model List object - it should inherit Tridion.ContentManager.ListTcmItems class or it should implement the getId(), itemUpdated(item), itemsUpdated(item), itemRemoved(item) and updateItemData(item) methods
If you want to see changes in List control - attach handlers to corresponding events on the domain model List object and update your List control
If you are creating new domain model Item - it should inherit Tridion.ContentManager.Item class and you should improve getListItemXmlAttributes method to return correct array of attributes for the List
The CME will indeed update the items in the list dynamically after the save occurs, without going to the server.
To do so, it calls a method named "getListItemXml" which returns the update XML element for the list. It will then update or add this element, which will update or add the item in the list view.
getListItemXml is a method of the different Model objects.
So how do you take advantage of this? I'm not sure.
Perhaps you could overwrite the method (or maybe getListItemXmlAttributes is best) with your own to add the additional data?
There is also an "itemupdate" event fired whenever an item is updated in the list.
You can hook into that by doing something like this:
var myEventHandler = function(event)
{
$log.message("Item updated. TridionEvent object passed: " + event);
}
var view = $display.getView();
var list = view.getListObject("uri-of-Folder");
list.addEventListener("itemupdate", myEventHandler);
I suppose you could use that to update the list entry for the item after the fact.
Be sure to call removeEventHandler at some point too.
None of this is optimal, obviously.
But I don't know of any extension point that would solve this particular problem.
I think I would (attempt to) implement this by monitoring the items in a folder periodically and updating that list after this polling mechanism had detected a change in that folder.
For example, I would write some javascript timeout or interval that runs in the background and checks the items in the current folder. If it detects a change, it triggers the update of the list.
Alternatively, you could also try to intercept the action that changed your list (e.g. the creation of a new item), maybe by means of an event system, and as such update your list. I don't think this is much different than the first approach, as I think it still implies some level of polling from the GUI side.
I am currently using databinding on a group of spark form elements and want to know if the data class I am bound to is dirty.
It might be nice if spark "Form" elements would trigger a change event that bubbled up to and was caught by a spark "Form". Then I could just add an event listener to the form. But I don't see something like that.
So besides comparing a copy of the original data class to the bound data class OR adding a change event to each form element and capturing that event, what's an easy way of knowing a class object has changed?
Make an extension of TextInput or whatever other input elements you'll have in your form then in your components creation complete register a listener for the change event, in the handler dispatch a bubbling event, then in your document that contains the form use your custom elements and add a listener via AS3 to the Form for the event you dispatched and stop it's propagation at that point.
Otherwise I think your second solution of change handler on each wouldn't be too bad. If you have a lot of elements in the form or it's dynamic you could write a function that steps through the form items of the form and checks their children then you just have to write a switch that deals with each class type (you can use http://www.actionscriptdeveloper.co.uk/getting-the-class-of-an-object-in-as3/on each of the child elements to determine what type it is, then if it's a TextInput or whatever register the appropriate event to call your commonly used function, just be sure it has a generic Event as it's parameter since all other Events will be sub-classes thereof).
So far as I know there is no easy way to listen for changes to the underlying data from the ArrayCollection or other wrapper ListCollectionView data structures. Part of the problem is the elements added a collection aren't required to implement any sort of interface to allow for listeners to be registered. That is, the data elements aren't necessarily event dispatchers, the only other way for this information to be communicated to the List would be if the data elements had a handle on all lists that contain that element and they mark something on the lists to indicate "dirty" when any property is set. These are all achievable within the constraints of the language but aren't provided out of the box as the usage for them is probably limited and could potentially unnecessarily bloat the cpu usage of the ListCollectionView in other cases.
I have a local SQLite database that contains a tree (as Nested Sets). In an AIR application, I want to display that tree in a tree control and provide means to change the nodes' names and copy, move, add or delete nodes.
Now, I'm hiccupping a little on where to put which code. Obviously, I have a class which will perform operations like load / update / insert / delete against the database. This would load the whole tree into some storage variable and save changes made by the user back to the db.
Should this class be the dataProvider, the dataDescriptor or an extension of the Tree control itself? And when the user requests an operation like adding a node, should that update the dataProvider and let the database handler react on an event, or should it call the database handler's method and then update the dataProvider? I'd say that the latter is better, because it's easier to not update the Tree's data if something goes wrong with the db query.
There's methods to add and remove nodes in the DefaultDataDescriptor and in the Tree class (protected methods in the latter), should I use / extend those or ignore them?
The reason I'm confused about this is that, according to the docs, a Tree control uses the object stored in its 'dataDescriptor' property to parse and manipulate the actual data which is stored inside its 'dataProvider' property.
This seems to make sense, until you realize that unless you subclass it, it's never the Tree control that manipulates data (with the exception of drag&drop, if that's enabled), and it's not the dataDescriptor, either. Rather, in all examples, manipulating data happens directly via the dataProvider object and that triggers event handlers in the Tree control.
What is it I don't get here?
Take a look at mx.controls.treeClasses.HierarchicalCollectionView. It is not part of the public API, but its full source is available as part of Flex. The Tree controller uses this class internally to handle various data sources.