Develop Reference

Combobox doesn't react to ".setValue()" nor ".select()"

This is my code:
comboBoxInstance.setInputPrompt("Something...");
comboBoxInstance.setNullSelectionAllowed(false);
Cookie comboCookie = getCookieByName("combo");
comboBoxInstance.select((comboCookie != null) ? comboCookie.getValue() : null);
final TextField textFieldInstance = new TextField("Textfield");
textFieldInstance.setInputPrompt("Something...");
Cookie tfCookie = getCookieByName("tf");
textFieldInstance.setValue((tfCookie != null) ? tfCookie.getValue() : null);
The problem is that the textfield works pretty well with the "Cookie setup". Only the combobox is refusing to work like it should.
The output is like this:
I've tried to use .setValue() instead of .select() but this has pretty much the same effect. I've also made sure that both the Cookie itself and the correct value are provided.
It may help to have a look at the part where the cookie is generated:
Cookie comboCookie = new Cookie("combo", comboBoxInstance.getValue().toString());
cookieProcessing(costcentreCookie); //<- sets maxage and vaadin related stuff (like adding the cookie)
Edit:
A few points to the data flow.
I'm generating a ComboBox with a SimpleJDBCConnectionPool's SQLContainer as the data container (coming from a TableQuery). Here's the initialization (executed in the constructor) in the combobox class:
private void init() throws SQLException {
this.setContainerDataSource(generateContainer());
this.setItemCaptionPropertyId("something");
}
The private method generateContainer() returns the SQLContainer of course.
This happens if I click on a particular button which opens up a dialog. This dialog is the fragment shown in the picture above. The combobox - of course - is part of it.
What one is supposed to do now is setting his data (get an item of the ComboBox) and hit save. The save button executes the routine to store the cookies. It's the code already mentioned above (Cookie comboCookie = new Cookie(...).
Okay, now the user is going to open up the dialog again. It's not important whether he reloads the application or just reopens the dialog (or does something else). It's basically the same in the app.
The dialog opens up and initializes the combobox (and the textfield) once again. However, this time it's supposed to gather the data out of the stored cookies. This is were the issue happens. This works well for the textfields (there are two but I've omitted one for shortening reasons) but not for the combobox, even tough it should've the exact same data as before. Hold in mind that it's the exact same class with the exact same initialization as when we stored the cookies in the first place.
I've the vague presumption, that it has to do something how the code is stacked. Maybe it hasn't finished loading the datacontainer while trying to set the appropriated value which then can't be found.
Edit2:
I've finally managed to reveal something. The ComboBox is indeed empty when the ".select()" is executed. However, this means, that the ComboBox is left untouched (it's only kind of "linked" to the datacontainer) until someone drops down the items. As soon as this happens, the items are there and I can possibly select them.
Is it supposed to work like this? O.o Am I able to fully initialize the combobox before I do something else? Something like:
private void init() throws SQLException {
this.setContainerDataSource(generateContainer());
this.setItemCaptionPropertyId("something");
this.gatherTheItems();
}
Edit3 - Test with ".setImmediate(true)"
I've changed the init to:
private void init() throws SQLException {
this.setContainerDataSource(generateContainer());
this.setItemCaptionPropertyId("SOMETHING");
this.setImmediate(true);
}
This didn't change anything. The combobox is still empty:

Finally! At first I've found a workaround which was like this:
for (Iterator it_IDS = combobox.getItemIds().iterator(); it_IDS.hasNext();) {
Object id = (Object) it_IDS.next();
if(id.toString().equals(cookie.getValue().toString())){
combo2.select(id);
break;
}
}
However, I couldn't believe that this was working since it doesn't change anything at the core problem. So I've investigated, that the RowID is built via a BigDecimal and voilà:
if(cookie != null) {
combobox.select(new RowId(new BigDecimal(cookie.getValue())));
}
I'm so happy right now :) Thanks for your patience kukis.

In case you came here because you're experiencing the same issue using a BeanItemContainer as datasource, bear in mind that you must implement both equals()and hashCode() methods on the underlying class for ComboBox's select() or setValue() methods to work.
You have plenty examples on Vaadin Forum on how to implement these methods:
ComboBox select value problem
Select or ComboBox does not Show Selected Property
Combobox select/setValue

How to listen on save button or assign an event after it was clicked in Vaadin 7

When I am editing grid inline I can save or cancel my grid row changes. I want to update my database entries after button 'save' will be pushed(Data base mechanism has already done) How can I implement it?
My container:
BeanItemContainer<CategoryOfService> beansContainer;
Editing view:
All what I need it know which listeners I have to use. I found some CommitHandler which I can add by EditorFieldGroup class but I can't implement it properly maybe there is have to be another way to resolve problem.

There's kind of a way to capture inline Save click on the grid.
grid.getEditorFieldGroup().addCommitHandler(new FieldGroup.CommitHandler() {
#Override
public void preCommit(FieldGroup.CommitEvent commitEvent) throws FieldGroup.CommitException {
//...
}
#Override
public void postCommit(FieldGroup.CommitEvent commitEvent) throws FieldGroup.CommitException {
//...
}
});
After clicking Save both methods preCommit and postCommit get called.
Hope it helps :)

Grid does not currently give you any direct way of adding listeners to the save and cancel buttons for the inline editor, although that is something that might change in Vaadin 7.6.
As a workaround before that happens, the CommitHandler approach that you already mentioned is still supposed to work. You can find a basic example here. The contents of your BeanItemContainer should be fully updated in the postCommit phase.

grid.getEditor().addSaveListener((EditorSaveListener<Product>) event -> {
//your stuf
HibernateDataSource.updateProduct(event.getBean());
});

Showing combo box when a specific selection occurs

I am coding a bookshop in Java and have a problem with when a new book is ordered I want the user to select whether it is a ebook or paper book. If it is an ebook I want another combo box to show on the page with called cboFormat. I have some code but it doesn't seem to work.
This is in the constructor.
if("Ebook".equals(cboBookType.getSelectedItem()))
{
cboFormat.enable();
}
else
{
cboFormat.disable();
}
Why doesn't this work? I have also previously set the format input to disabled.

This could be that you do not have a actionlistener on your combo box ? As Andrew suggested, there could be more reasons why your block does not work. If you pasted more code it would be easier to determine what the problem is. If however you are missing action listener on your combo box, code below.
public void actionPerformed(ActionEvent e) {
JComboBox cboBookType = (JComboBox)e.getSource();
String bookType= (String)cboBookType.getSelectedItem();
//and paste your ifs here
if("Ebook".equals.....){
...
}
... rest of code
}
And if you don't know what action listener is, its basically interface used by other classes to listen for an action event. i.e. user clicking button, or user selecting checkbox etc.

Dont use enable and disable try this and dont put it in the constructor because then it wont get updated you have to make a new event like itemchanged or itemstatechanged i dont know it exactly
if("Ebook".equals(cboBookType.getSelectedItem()))
{
cboFormat.setvisible(true);
}
else
{
cboFormat.setvisible(false);
}

Create subclasses of parent class from file

I'm trying to create a menu screen, and I want to be able to create it, and any further permutations of it dynamically. I've created a MenuItem helper class to handle the menu items that show up, and it reads the name, image, and set the next state (something that is handled later). What I want to know is, how can I create the specific following Screens (they'll all be some subclass of my Screen class)?
What is the most efficient method to pass specific objects into the menuItems? Do I need to pre-create each possible Screen and then just read back in the serialized form of it, or can I create them dynamically. I'd hoped to be able to do something as simple as reading in a literal string "new SubClass(...)" and act off that, but I don't know how to go about that. Any other suggestions would be great!

If I understand correctly, what you want is a mechanism that reads a String command from a text file, and based on this command, displays a screen.
So, extract the interface of the "display screen" command into an interface. For example:
public interface ScreenDisplayer {
void displayScreen(Screen mainScreen);
}
Then build a Map<String, ScreenDisplayer>:
map.put("screen1", new ScreenDisplayer() {
#Override
void displayScreen(Screen mainScreen) {
// TODO display screen 1
});
// same for all the other commands
And when a "menu item" is clicked, get the DisplayScreen from the map and call it:
String command = selectedMenuItem.getCommand();
ScreenDisplayer displayer = map.get(command);
displayer.displayScreen(mainScreen);

text in text box

i am pretty new to the gwt framework and i am using it for building the ui of my web site,
i would like to make the text box have a text in it that once the user clicks on it for the first time, the text disappears. and in the rest of the time it behaves like a normal text box
any ideas on how to do it?

When you create the textbox, set the default text and add a keyboard listener:
TextBox box = new TextBox();
box.setText("Default Text");
box.addKeyboardListener(this);
defaultValue = true; // this is a global boolean value
Then have your class implement KeyboardListener leaving them all blank except:
public void onKeyPress(Widget arg0, char arg1, int arg2)
{
if(defaultValue)
{
box.setText = "";
defaultValue = false;
}
}

you can add a clickHandler to the box.
Within the handler you do something as easy as:
if(text==DEFAULT_TEXT)
{
text==""
}
If someone is going to write again the same DEFAULT_TEXT it would get wiped out again.
If you want to avoid that add boolean variable in the check expression.

Can't tell it for GWT, but a general approach could be:
use a variable to flag, whether the text box is 'initialized' or 'in use'
add a listener to the text widget (I'd use a KeyboardListener and make the text disappear when the user starts entering text and not on the first - maybe accidental - mouse click)
When the listener receives the first event for the widget (flag = 'initialized'), clear the flag and replace the text inside the text field with the actual keystroke.
(for a click listener: upon the first click on the widget clear the flag and the text box.)