I'm having a problem using a GWT listbox. I have a case where the user selects a value from a listBox, but it can become invalidated if they change data in a related field. To validate the listBox, the user has to either select a new value, or confirm their old selection by selecting the same value again. I can't figure out how to determine if they have selected the same value so that I can restyle the listBox to look validated.
The valueChanged handler only detects if a new value is selected. The clickHandler and focusHandler fire too often because they fire when the user isn't selecting a value. Any ideas?
You can improve the clickHandler with something like this :
ignoreClick = true;
lastSelection = -1 ;
....
listBox.addClickHandler(new ClickHandler() {
#Override
public void onClick(ClickEvent event) {
if (!ignoreClick) {
lastSelection = listBox.getSelectedIndex();
}
ignoreClick = !ignoreClick;
}
});
I tried it and the event was only fired if you selected an item. But you should rethink your user interface , like said above.
Related
I'm probably doing something else wrong but I've followed examples given here:
How to remove a row from the Cell Table
and
GWT get CellTable contents for printing or export
to accomplish my goal and the result is close but not quite right.
I have a page with two widgets. The first wiget contains a CellTable that uses an aSync ListDataProvider to pull results and populate a table. The table has a selection change event handler associated with it that loads further details about the selected item into the second widget below it.
public OrderAdminTable() {
selectionModel.addSelectionChangeHandler(new SelectionChangeEvent.Handler() {
#Override
public void onSelectionChange(SelectionChangeEvent event) {
OrderAdminListProxy selected = selectionModel.getSelectedObject();
if (selected != null && orderSnapShot != null) {
orderSnapShot.loadSnapShot(selected);
}
}
});
initTable();
this.addStyleName("order-list fixed_headers BOM");
this.setSelectionModel(selectionModel);
}
Once the second widget has loaded the details about the selected item, the user can remove the item from the table/list by clicking a button in the RootPanel that is the parent of both widgets.
searchView.getCmdReview().addClickHandler(new ClickHandler() {
#Override public void onClick(ClickEvent event) {
searchView.getOrderAdminSnapshot().reviewOrder();//this line calls a web service that deletes the item from the server data
dataProvider.getList().remove(searchView.getOrderAdminSnapshot().getSelectedOrder());
for(int i=0;i<table.getRowCount();i++){
TableRowElement row = table.getRowElement(i);
for(int j=0;j<row.getCells().getLength();j++){
if(row.getCells().getItem(j).getInnerText().contains(searchView.getOrderAdminSnapshot().getSelectedOrder().getSalesOrderNumber())){
row.setAttribute("removed", "true");
row.addClassName("hidden");
}
}
}
}
});
This all works fine until you select another item in the table. When that happens, the selection change event seems to redraw the table and remove my custom attribute and class from the previously selected item. This makes it appear in the list again.
The ultimate goal here is to avoid a round trip to the server to pull new results when you remove an item from the list. The line "searchView.getOrderAdminSnapshot().reviewOrder();" makes a web service call that removes the item from the data on the server side so it does not appear in subsequent reloads.
Is there some way to force the selection change event to maintain the state of the table row that was previously selected? Is there a better way to remove the selected item from the list? Any advice would be appreciated.
Once you remove the object from the list dataProvider.getList().remove, it should disappear from the table. There is no need to hide the row - this row should be gone. So your loop should never find it.
I'm using UploadItem, RadioGroupItem and some other widgets. RadioButton is having onChangeHandler which will decide what all other components need to be displayed. I've uploaded some file using UploadItem. Then I changed the radio button selection. On changing the radio button, required widgets are getting displayed properly but whatever file I'd selected using UploadItem is going away. Fresh UploadItem widget is getting displayed. In other words page is getting refreshed.
My requirement is whenever I change radio button option, required widget should displayed along with that whatever file I had selected using UploadItem should remain same.
My Code is something like this:
UploadItem upload = new UploadItem();
RadioGroupItem radioGroup = new RadioGroupItem();
HashMap map = new HashMap();
map.put("option1","option1");
map.put("option2","option2");
radioGroup.setValueMap(map);
TextItem textbox = new TextItem();
radioGroup.addChangeHandler(new ChangeHandler(){
public void onChanged(ChangedEvent event) {
String radioValue =((String)event.getValue());
if(radioValue.equalsIgnoreCase("option2")){
textbox.show();
}else{
textbox.hide();
}
}
});
Add all created widgets to DynamicForm object using dynamicForm.setFields(all created widgets)
Changing the radio button should hide and show the textBox. But while doing that page is getting refreshed and whatever file we had selected using UploadItem is lost.
As per the documentation for hide() and show() of FormItem class, invocation of any of these methods, will cause the DynamicForm to be redrawn.
So it may cause the problem you're getting.
To overcome this issue, I would suggest you to put UploadItem in a separate DynamicForm.
fire an event on radio Selection change as
radioButton.addListener(Events.Change, new Listener<BaseEvent>() {
#Override
public void handleEvent(BaseEvent be) {
if(radioButton.getValue()){
//fire an event here for ur widget
}
}
});
I am using the following constructor to create a checkboxcell in an editable data grid.
CheckboxCell(false, true)
When I use this and click at any place in the row, selection change event does not fire and I am using single selection model .
When I use,
CheckboxCell();
Selection change event fires on the row but,
1) We have click twice to check or uncheck the cell.
2) if we check or uncheck in the checkboxcell, the value will reverted as soon as I click anywhere.
I am trying to figure out the solution, but not successful yet. Any help would be appreciated.
Am using GWT 2.4.0
The problem is because of selection if possible do not use selection model. and add field updater for the column of check box. I have used this:
Column< GridReportFields, Boolean > cb = new Column< GridReportFields, Boolean >(new CheckboxCell() ) {
#Override
public Boolean getValue(GridReportFields object) {
// TODO Auto-generated method stub
return object.getCheckb();
}
};
cb.setFieldUpdater(new FieldUpdater<GridReportFields, Boolean>() {
#Override
public void update(int index, GridReportFields object, Boolean value) {
// TODO Auto-generated method stub
object.setCheckb(value);
dataGrid.redraw();
}
});
here gridReport Field is my model class. and setCheckb is is setter for the boolean variable that holds the value of checkbox.
I want handle events on a Label when user holds down some key (Ctrl) and then clicks the mouse button together (Ctrl + mouse click), like open some window etc...
How could i do that in GWT? Should i get add two handlers or can do it with one?
thank you.
al
In your click handler you can check if the Ctrl key is pressed when the event was fired, see example below. You also might want to check for the specific mouse button the user clicked on. I've also added that to the example:
yourLabel.addClickHandler(new ClickHandler() {
if(NativeEvent.BUTTON_LEFT == event.getNativeButton() &&
event.isControlKeyDown()) {
//do what you want
}
});
Or for older version of GWT instead of event.isControlKeyDown use event.getNativeEvent().getCtrlKey(), which returns a boolean value true if the control key is pressed when this event is fired.
Edit: this code is buggy, please look at Hilbrand's answer
To be honest, I don't think you can do it with 1 or 2 handlers. I think you would need 3 handler.
A KeyDownHandler that sets a boolean you can later read form the MouseDownHandler
A MouseDownHandler that does what you want
A KeyUpHandler that resets the value of the boolean in the KeyDownHandler
boolean ctrlPressed;
yourLabel.addDomHandler(new KeyDownHandler() {
public void onKeyDown(KeyDownEvent event) {
if(event.getAssociatedType().equals(KeyCodes.KEY_CTRL))
ctrlPressed=true;
}
}, KeyDownEvent.getType());
yourLabel.addDomHandler(new KeyUpHandler() {
public void onKeyUp(KeyUpEvent event) {
if(event.getAssociatedType().equals(KeyCodes.KEY_CTRL))
ctrlPressed=false;
}
}, KeyUpEvent.getType());
yourLabel.addClickHandler(new ClickHandler() {
if(ctrlPressed) {
//do what you want
}
});
If i have a GWT composite widget with three text boxes like for SSN, and i need to fire change event only when focus is lost from the widget as a whole, not from individual text boxes how to go about doing that?
If you want just the event when your whole widget loses focus (not the text boxes), then make the top level of your widget be a FocusPanel, and expose the events that it gives you.
You need to implement the Observer Pattern on your composite, and trigger a new notification everytime:
the focus is lost on a specific text box AND
the focus was not transferred to any of the other text boxes.
Couldn't you use a timer? On lost focus from a text box, start a 5ms (or something small) timer that when it hits, will check focus on all 3 TextBox instances. If none have focus, then you manually notify your observers. If one has focus, do nothing.
Put this in your Composite class:
private Map<Widget, Boolean> m_hasFocus = new HashMap<Widget, Boolean>();
And then add this to each one of your TextBox instances:
new FocusListener() {
public void onFocus(Widget sender) {
m_hasFocus.put(sender, Boolean.TRUE);
}
public void onLostFocus(Widget sender) {
m_hasFocus.put(sender, Boolean.FALSE);
new Timer() {
public void run() {
for (Boolean bool : m_hasFocus.values()) {
if (bool) { return; }
}
notifyObservers();
}
};
}
};