I want to make my TreeView remember the selected items after refresh/setInput. (Let's pretend the Java TreeView doesn't remember the state). Since the TreeView will get setInput, so the element reference won't persist.
I am thinking to store the selected element by its full path in an ArrayList<String>. (e.g. it looks like ["root_name", "2nd_level_name", "3rd_level_name", "node_name"]). With the full path, I can locate the same element in the refreshed TreeView again.
I was wondering if there's any better way doing this? Or any existing libraries in Java can do this?
Related
Right now we have an element on the page that is not allowing users to tab out of it. The element was created in Java as a GWT component, I don't really know too much about GWT so I can't really describe it further.
Anyways, I know where I need to tell the component to tab to the next element in the tab order, but I don't know what commands to use to do so. Is there a way to retrieve the tab order of HTML elements in Java? If there is, I can just pick the next element in the list and set it to be focussed.
Using GWT com.google.gwt.dom.client.Element you can access and set the tabIndex value of any GWT component (i.e. html element). If you're using a Widget class you can use myWidget.getElement().getTabIndex() and setTabIndex(1).
In HTML you cannot just pick the next element with the tab out of the box, you can however maintain the tab indexes order in the order you expect.
I want to design a ContextMenu with a TreeView functionality. I didnt found anything how can be done. I want to design a custom TableMenu (that button at the end of table header which can show hide the columns), using a treeView structure in ContextMenu, so the user can show/hide a group of columns, like 1-3, 4-6, and so on, or any kind of grouping, but still keeping the one by one show/hiding. The best way would be a tree structure, so if the user hides the parent all of its children are hidden and vice-versa.
Is there any possibility to adapt somehow the TreeView into ContextMenu?
I would like something like this with CheckBoxes for instance:
Each parent node would be an item that represents a group of columns, and each child would be a column.
P.S.
I know how to create and add a custom ContextMenu as tableMenu (I have got it from here : https://gist.github.com/Roland09/d92829cdf5e5fee6fee9) , I'm interested in how to set a tree structure to context menu instead of the list structure.
I also know that I can add the parent like a "simple" item to the context menu, then handle as a parent, but then I Have to implement every functionality of a TreeItem, but I prefer a much simpler way if it exists.
Program Outline:
I plan to make a simple Java program that will load Vehicle objects (Vehicle being the superclass, EnginedVehicle and GoodsVehicle being the subclasses) from an XML file into an ArrayList which will then be displayed on a JList. The user will be able to show/hide the different Vehicle types using check boxes, add a new vehicle type or press the selected item in the JList and edit or delete it. The program will then put the Objects back into the ArrayList where it can be then saved back to the XML file.
Question: So, I am completely fine with the loading of the XML file into the ArrayList and putting that object onto the JList but the thing that is hurting my head is thinking about how I am going to:
What is the best way of getting the object back from the JList ready for it to be modified or deleted and put back into the ArrayList?
How would I show/hide the different types of Vehicles in the JList using the check boxes?
I understand this may seem a lot but, this is my first post and I am new to the community and I have fairly good knowledge of Java and OOP programming but I have just finished writing a fairly big website and going back to Java is a headache.
Since your ArrayList should be equal in size (item count) to your JList, your JList will have the index you're interested based on selection. Regardless if you want to modify or delete the item, store what index it was at and remove the item from the JList (You should be using a DefaultListModel). Use this index value to get the object from your ArrayList. If you're modifying, modify your object as needed, you shouldn't have to remove the object from the ArrayList for modifications, and place it back into your DefaultListModel. If it's a delete, then just remove the object from your ArrayList using the index value you stored.
As far as displaying (show/hide), clear your DefaultListModel (which will clear your JList), iterate through your ArrayList and add the items to the DefaultListModel that match your checkbox selection criteria.
EDIT:
I didn't take into consideration of possibly modifying/deleting items when items are hidden. For this, may want your objects to have a field that stores what index they are at in the ArrayList. This way when you do your filter, I would copy the items from your "Master" ArrayList into a sub list that you can populate your DefaultListModel. Then you apply the same logic to this sublist when selecting an item from you JList, then take your changes from your sublist and apply them to the "Master" ArrayList.
Keep in mind that when you remove an item, you'll have to reassign all items index location from that point on down.
I'm sure there is probably a cleaner way of doing this, but this is what first comes to mind for me.
I don't know if I'm horribly mistaken, but why change to a JList at all? Do you use your JList as a parameter to visualize the information in it? If yes, why dont you use your ArrayList instead? Then the checkboxes only change the visibility ot the Items of the List. So you dont have to care about indices, because they stay the same. And new entries, can be made as well... maybe im wrong but i guess you got kind of a GUI for the user to browse/alter/add new vehicles?
I generated a decision tree based on a set of data, then I converted this data to a xml file, after that I put it into a JTree. This part works fine but now I have to take a new instance(which contains the data received from the user), find it's place in the decision tree and change that node's color. And I can't find a way to do that. I am using weka and the J48 classifier to generate the decision tree. The xml is created in the Luc Sorel style: http://www.lucsorel.com/media/downloads/sample_decision_tree.xml
The first thing I tried was to classify the instance using the algorithm but that gets me only the class where it belongs, and I don't know how to locate it in the JTree.
What should I do? Any ideeas?
Like JTable, JTree uses a flyweight renderer to draw nodes. As the default renderer is a JLabel, you can set the foreground color or make the label opaque and set the background color. This related example changes the icon for emphasis. More examples may be found here.
Addendum: I cannot find … the node that I should color.
When getTreeCellRendererComponent() is called, value is a reference to the node to be rendered, and the tree parameter allows access to the TreeModel as a whole via getModel(). This example shows how to search a tree.
What i want to do:
I want to make the menu of my application customizable, giving the user the possibility of changing the order of the menus. For this i have build a tree (rich:tree) representing the menus in my application. By drag-n-drop the user can change the order of the menus.
The menus are kept in a xhtml file (a hierarchical structure of rich:menuGroup and rich:menuItems)
What my problem is:
When the user finishes drag-n-drop, on save i should generate xhtml code corresponding to my tree. More concrete: For each parent node in the tree generate a rich:menuGroup and for each leaf node generate a rich:menuItem. By traversing the tree i should build a hierarchical structure with menu groups containing other menu groups and/or menu items.
Is there any tool or easy way for doing this?
It would be a real pain to traverse the tree and manually concatenate hard-coded strings or something like that.
Thanks
You can use ui:repeat tag, and create menuGroups from an array in the backing bean that you created according to the tree structure. In the array, properties of each menuGroup should be provided.