I am trying to create a cell browser , gettign help from GWT Showcase
Here i am creating CellBrowser
final MultiSelectionModel<MyDTO> selectionModel = new MultiSelectionModel<MyDTO>();
CellBrowser cellBrowser = new CellBrowser(new ContactTreeViewModel(selectionModel), null);
What i am not getting is that , What is ContactTreeViewModel? I have read the class contacttreeviewmodel in GwtShowcase , but couldnt understand, what is it exactly
thanks for the help
It's your view model, that is the interface between the tree view and your actual model (in MVC or MVP parlance). The CellBrowser (same for a CellTree) will ask your TreeViewModel for the nodes of the tree (in the form of NodeInfo objects), their children, how to display them (the associated Cell), how to select them (the associated SelectionModel: you can have a tree where you can only select nodes from the 2nd level, and/or only one node per branch at the 2nd level, or any node, or ...), and finally how to update them (the ValueUpdater).
Basically (disclaimer: this is a simplification of the process!), each level in the tree is a CellList that a NodeInfo is responsible for. The setDataDisplay associates that CellList with the NodeInfo so that changes to the model can be reflected in the tree, then the Cell, ProvidesKey, SelectionModel and ValueUpdater all have the same behavior as for a CellList. The CellBrowser asks your NodeInfo for them in order to setup the CellList. When expanding a node, the CellBrowser asks your TreeViewModel for the NodeInfo associated to the expanded node and uses it to create a new CellList.
The ContactTreeViewModel from the Showcase is thus a specific implementation of the TreeViewModel to display contacts (the model) as a tree.
The GWT showcase is an example of what you can do with code samples.
I think you should read the documentation of cell widgets before trying to understand such a code from scratch.
Here is the documentation, read it, and retry to understand the code.
https://developers.google.com/web-toolkit/doc/latest/DevGuideUiCellWidgets#available
Related
I'm developing an application based on the netbeans platform.
The problem I'm having is this; I have a TopComponent that contains two panels, A and B, each with a ExplorerManager. I have two BeanTreeViews in each panel with different sets of nodes. When I change selection in the A panel, the nodes in the B panel will be created. Now, I'd like to be able to select a node in the B panel and see it's properties in the default property view. But I still have a selected node in the A panel, and therefore the property view only says 'Multiple objects.' Is there any way to keep the selection in the A panel from spreading to the PropertyView?
I'd like to be able to use NodeActions on both sets of nodes, and therefore I've added
associateLookup(new ProxyLookup(
ExplorerUtils.createLookup(PanelA.getExlporerManager(), map),
ExplorerUtils.createLookup(PanelB.getExplorerManager(), map)
));
to the TopComponent if i only associate PanelA's ExplorerManager then this isn't a problem.
Ok some after testing around I found a solution that works for me. Perhaps I was a bit quick to post this question. Anyway;
In the TopComponent I did
associateLookup(new ProxyLookup(
ExplorerUtils.createLookup(PanelA.getExlporerManager(), map)
));
Then only the Nodes in PanelA will be spread to the PropertyView. And then to get the NodeActions to work in PanelB, I made it implement Lookup.Provider, and created it's Lookup with
lookup = ExplorerUtils.createLookup(explorerManager, map);
GXT 2.25.
I have a screen with a layout container with a TableLayout with two columns. The left column has a tree grid. The right column is a layout container with table layout, one column.
When I click on various items on the tree grid, I want to display editable fields in the layout container on the right that match to the item clicked on.
When I first start the form and am loading the data from the server, I add text to the layout container and it seems to be fine.
After the text is loaded, I call secondLayout.removeAll() to remove all items. Then I click on an item in the tree. The selection method calls secondLayout.removeAll() and then adds a new text item "Loaded..." for testing.
private LayoutContainer secondaryLayout;
And then...
secondaryLayout.removeAll();
secondaryLayout.add(new Text("Loaded..."));
Ideas?
After making structural changes to a container, be sure to invoke (in GXT 2) the layout method to re-run the layout routines. The alternative is to configure the LayoutContainer to re-run layouts on each modification (using setLayoutOnChange), but that would in this case be at least two re-layouts - one for removeAll, and another for each new object added. Could be needlessly expensive, so better to run once and for all when you are finished making changes.
(Worth pointing out perhaps that GXT 2.2.5 is just over two years old, 2.2.6, 2.3.0 have gone out since then, and it is being superseded by GXT 3. In GXT 3, the method here would be forceLayout.)
somehow I have the feeling that I miss the forest for the trees. I have a CellBrowser filled with categorys and I have a search dialog to find the categorys by name. If I now select a category in the search dialog I also want it to be selected in the CellBrowser.
What I can already do is, find the node in the category tree. I also have the path from the root node to the leaf. I can open the nodes until the selected leaf (getCellBrowser().getRootTreeNode().setChildOpen(i, true). But how do I select the leaf itself?
And frankly speaking, is that the right way to do it? (I doubt it somehow)
Greetings Ole
Selecting an Object in the CellWidgets can be done by via the SelectionModel.
Assuming that you have defined a SelectionModel (i.e. SingleSelectionModel) for your CellBrowser/TreeViewModel you can just select a node in a CellBrowser by calling:
selectionModel.setSelected(MyObject, true);
MyObject is the object/type which is displayed as a node in your CellBrowser.
Note you can have different types/objects for each CellBrowser level.
SelectionModel will use either a KeyProvider or the equals function to select the object.
I'm building a Qt plugin with multiple forms. I have a main form which has a tree widget placed on the left of the form.
I want to add items to this tree, such that clicking on these items would load the corresponding form on the same form. But I want the tree widget to be active so that I can select any other form also.
I was able to display a form on the main form using the following code:
Form1 *myform;
myform=new Form1(this);
myform->show();
where Form1 is the class of the form i intend to display. However this, covers up the tree widget also. And I have to do a string comparison of the item in tree being clicked to display the appropriate form.
Can someone please help me with this as I'm very new to Qt programming.
Thanks
ixM has a good suggestion. The first step should definitely be to use layouts in your main window - separating the tree from the rest of the window - where you are going to put your form. I would suggest using a splitter, because then the user can resize the two halves. You can set the splitter as the main widget of your CentralWidget in your main window.
QSplitter splitter = new QSplitter(CentralWidget);
splitter->setOrientation(Qt::Horizontal);
splitter->setHandleWidth(3);
splitter->setChildrenCollapsible(false);
MyTree= new QTreeWidget(splitter);
splitter->addWidget(MyTree);
Then add your tree widget to the splitter, which will be on the left side.
The next step is to add a placeholder widget on the right side of your splitter. We are also going to add a layout inside that widget. This layout is very important we are going to use it later.
QWidget WidgetRightSide = new QWidget(splitter);
QVBoxLayout setupLayout= new QVBoxLayout(WidgetRightSide);
setupLayout->setSpacing(0);
setupLayout->setContentsMargins(0, 0, 0, 0);
Now, at this point, this is where my answer really differs from the previous answer. You could use a QStackedWidget. That is certainly an option. The problem with that is that you have to create and load all your forms at the beginning. That uses way more memory, and will take longer to start up. That's not so bad if you have 2-5 forms, but when we are talking about 20, 30 or more forms that's really ugly.
So what I would suggest instead, is that when the user selects something in the tree, we will remove the old form, and add the newly selected form at that point.
When the selected item in the tree changes this is now what we have to do.
First, remove all the stuff from the previously selection form.
QLayoutItem *_Item;
while ((_Item = setupLayout->takeAt(0)))
delete _Item;
Next, figure out what form to show next, and create it.
QWidget *ActiveSetupForm = NULL;
if ( I need to load form 1)
{
ActiveSetupForm = new YourNewForm( WidgetRightSide);
}
else ...
And lastly, add your new form to our layout.
if(ActiveSetupForm)
{
setupLayout->addWidget(pActiveSetupForm);
}
Just as a side note. Layouts are tricky to do by hand. I would strongly suggest that you look into using the QtDesigner when you are creating your forms. It makes life soooo much easier. If you would like to know more about it check out this link.
I don't exactly understand what you are trying to achieve but the bit of code you are showing suggests that you do not use the layouts provided by Qt.
If your goal is to be able to dynamically load a form depending on the item that was clicked in the tree, you could achieve that by having a layout (let's say QHBoxLayout) where you would insert your tree and a QStackedWidget in which you could "store" each form (by using addWidget()) and choose which one you want to display by calling setCurrentIndex().
I am using gwt 2.3 version.I am using gwt tree in my application.
Here is my code:
public void onModuleLoad() {
// Create a tree with a few items in it.
TreeItem root = new TreeItem("root");
root.addItem("item0");
root.addItem("item1");
root.addItem("item2");
// Add a CheckBox to the tree
TreeItem item = new TreeItem(new CheckBox("item3"));
root.addItem(item);
Tree t = new Tree();
t.addItem(root);
// Add it to the root panel.
RootPanel.get().add(t);
}
There is a item with check box.I want add image to this tree item.But I am not able to do this as I already added one widget check box.Is there any other way add image to tree item with check box??
TreeItem has a TreeItem(Widget w) constructor.
You can put anything you want in there. So write a small widget that has an image and text next to each other in a div and the Tree will render it correctly.
You are already using it in your example code. So just write one more widget that combines the CheckBox with an image in a FlowPanel or HorizontalPanel. Whatever you want.
This is something that made me whack my head for a while also. Basically I found 2 options:
Use SmartGWT, it has nice customizable tree widgets that let you change the pictures of the nodes:
http://www.smartclient.com/smartgwt/showcase/#tree_databinding_local
Use GWT's tree-image:
http://google-web-toolkit.googlecode.com/svn/javadoc/1.5/com/google/gwt/user/client/ui/TreeImages.html
If you ask me, SmartGWT is somewhat demanding and rigid, and you might not like the fact that it doesn't let you go to the low leves like GWT does but it does have a nice set of customizable tree widgets. TreeImage on the other hand lets you still work with pure GWT (which I think is better overall), but it doesn't let you customize the tree as much as Smart GWT does