I have a method called creatcomponents() where I am creating few text fields and buttons in a composite. Now I want to write listeners to the button which calls a method and in this method I have get the values of the text fields. The problem I am facing is I am unable to access textfields from the method called in the listeners. Can someone help me on how to acheive this?
One way is to save the controls are fields in your class:
public class MyClass
{
private Text text1;
private Text text2;
public void createComponents(Composite parent)
{
Composite composite = new Composite(parent, SWT.None);
text1 = new Text(composite, SWT.SINGLE);
text2 = new Text(composite, SWT.SINGLE);
text1.addModifyListener(new ModifyListener()
{
#Override
public void modifyText(ModifyEvent event)
{
// Access field
String text = text1.getText();
}
});
}
}
Also note that many of the event classes passed to listeners have a widget field which refers to the current control which you can also use:
text1.addModifyListener(new ModifyListener()
{
#Override
public void modifyText(ModifyEvent event)
{
Text control = (Text)event.widget;
String text = control.getText();
}
});
Related
I have an ObservableList of model items. The model item is enabled for property binding (the setter fires a property changed event). The list is the content provider to a TableViewer which allows cell editing. I also intend to add a way of adding new rows (model items) via the TableViewer so the number of items in the list may vary with time.
So far, so good.
As this is all within an eclipse editor, I would like to know when the model gets changed. I just need one changed event from any changed model item in order to set the editor 'dirty'. I guess I could attach some kind of listener to each individual list item object but I wonder if there is a clever way to do it.
I think that I might have a solution. The following class is an inline Text editor. Changes to the model bean (all instances) are picked up using the listener added in doCreateElementObservable. My eclipse editor just needs to add its' own change listener to be kept informed.
public class InlineEditingSupport extends ObservableValueEditingSupport
{
private CellEditor cellEditor;
private String property;
private DataBindingContext dbc;
IChangeListener changeListener = new IChangeListener()
{
#Override
public void handleChange(ChangeEvent event)
{
for (ITableEditorChangeListener listener : listenersChange)
{
listener.changed();
}
}
};
public InlineEditingSupport(ColumnViewer viewer, DataBindingContext dbc, String property)
{
super(viewer, dbc);
cellEditor = new TextCellEditor((Composite) viewer.getControl());
this.property = property;
this.dbc = dbc;
}
protected CellEditor getCellEditor(Object element)
{
return cellEditor;
}
#Override
protected IObservableValue doCreateCellEditorObservable(CellEditor cellEditor)
{
return SWTObservables.observeText(cellEditor.getControl(), SWT.Modify);
}
#Override
protected IObservableValue doCreateElementObservable(Object element, ViewerCell cell)
{
IObservableValue value = BeansObservables.observeValue(element, property);
value.addChangeListener(changeListener); // ADD THIS LINE TO GET CHANGE EVENTS
return value;
}
private List<ITableEditorChangeListener> listenersChange = new ArrayList<ITableEditorChangeListener>();
public void addChangeListener(ITableEditorChangeListener listener)
{
listenersChange.remove(listener);
listenersChange.add(listener);
}
public void removeChangeListener(ITableEditorChangeListener listener)
{
listenersChange.remove(listener);
}
}
I have a for loop that displays a list of text fields and radio buttons.
What is the best way to reference the widgets so that I can read the text fields and aslo find which radio button is checked.
Here is my loop
for(int x = 0; x<getLoopCount(); x++)
{
answerTable.setWidget(x,0, new Label("Answer:"));
answerTable.setWidget(x,1, new TextBox());
answerTable.setWidget(x,2, new RadioButton(""));
}
Is there a way to ID each widget so I can reference it?
I would recommend grouping the three widgets together in a composite widget like this:
class AnswerComposite extends Composite {
private final Label label;
private final TextBox textBox;
private final RadioButton radioButton;
public AnswerComposite() {
label = new Label("Answer:");
textBox = new TextBox();
radioButton = new RadioButton("answerGroup");
HorizontalPanel contentPanel = new HorizontalPanel();
contentPanel.add(label);
contentPanel.add(textBox);
contentPanel.add(radioButton);
initWidget(contentPanel);
}
public String getText() {
return textBox.getValue();
}
public boolean isSelected() {
return radioButton.getValue();
}
}
You can then add them to a panel and/or put them in a list like this:
VerticalPanel answersPanel = new VerticalPanel();
List<AnswerComposite> answerComposites = new ArrayList<AnswerComposite>();
for (int i = 0; i < getLoopCount(); i++) {
AnswerComposite answerComposite = new AnswerComposite();
answersPanel.add(answerComposite);
answerComposites.add(answersComposite);
}
Checking your widgets then becomes very easy:
answerComposites.get(i).getText();
answerComposites.get(i).isSelected();
It will probably also be convenient to add a ValueChangeHandler to your RadioButtons (see enrybo's answer).
You can add a ValueChangeHandler to your RadioButton when you are creating them.
for(int x = 0; x<getLoopCount(); x++){
answerTable.setWidget(x,0, new Label("Answer:"));
answerTable.setWidget(x,1, new TextBox());
RadioButton rb = new RadioButton("");
rb.addValueChangeHandler(new ValueChangeHandler(){
#Override
void onValueChange(ValueChangeEvent<Boolean> event){
// Do something
}
});
answerTable.setWidget(x,2, rb);
}
The ValueChangeEvent will only be fired when the RadioButton is checked. It will not fire if another RadioButton in the same group is checked.
Since you're adding the ValueChangeHandler as you're creating your RadioButton you should know what is to be done with it without having to create an ID for it.
Let me give you an adhoc answer, so don't care about the syntax but the algorithmic idea.
Extend GWT button.
abstract class MyButton
extends Button{
// provide the appropriate constructor in impl class,
// especially if using uibinder
abstract public void helloDolly(... args ...);
}
Instantiate all those buttons using MyButton.
MyButton[] buttons = {
new MyButton(){
public void helloDolly(... args ...){
Window.alert("allo allo #1");
}
},
new MyButton(){
public void helloDolly(... args ...){
Window.alert("allo allo #2");
}
},
// blah blah black sheep ....
}
Use clickEvent.getSource() when defining handler.
buttons[i].addEventHandler(
new ClickHandler(ClickEvent click){
Object src = click.getSource();
if (src !instanceOf MyButton){
throw new MyAngryException("For goodness' sake, pls use MyButton");
// or ignore
return;
}
((MyButton)src).helloDolly(... args ...);
}
)
I have a user form with a lot of gwt listbox. The form is like an excel form with named list.
It's ugly and the arrows take place.
I would like the cells were like in excel. The arrow appears only when you click in the cell.
I start to program my own widget with a textbox and a listbox embedded into a DeckPanel, switching when you click on the textbox or when the value change. But with this solution, it is necessary to click again to open the listbox.
Now, it will be great, if when you click on the textbox, the listbox will be displayed already open.
In the code below, I try to do this into the method onClick wih this line:
DomEvent.fireNativeEvent(event.getNativeEvent(), listBox);
But it has no effects.
public class CustomListBox extends Composite implements ClickHandler,
ChangeHandler, HasChangeHandlers {
private final StringListBox listBox;
private final TextBox textBox;
private final DeckPanel panel;
public CustomListBox() {
textBox = new TextBox();
textBox.addClickHandler(this);
textBox.setReadOnly(true);
listBox = new StringListBox();
listBox.addChangeHandler(this);
panel = new DeckPanel();
panel.add(textBox);
panel.add(listBox);
panel.showWidget(0);
// All composites must call initWidget() in their constructors.
initWidget(panel);
}
#Override
public void onClick(ClickEvent event) {
Object sender = event.getSource();
if (sender == textBox) {
panel.showWidget(1);
DomEvent.fireNativeEvent(event.getNativeEvent(), listBox);
}
}
public void addItem(String item) {
listBox.addItem(item);
}
public int getSelectedIndex() {
return listBox.getSelectedIndex();
}
public String getItemText(int selectedIndex) {
return listBox.getItemText(selectedIndex);
}
#Override
public HandlerRegistration addChangeHandler(ChangeHandler handler) {
return listBox.addChangeHandler(handler);
}
#Override
public void onChange(ChangeEvent event) {
Object sender = event.getSource();
if (sender == listBox) {
textBox.setText(getItemText(getSelectedIndex()));
panel.showWidget(0);
}
}
}
Since you are already programming your own widget, why don't you go all the way. Don't swap out the text box for a list box widget. Instead of a textbox use a label. Add an arrow to your label background when you mouse over, then use a popupPanel for the list itself. In the popupPanel you can make the list items whatever you like, just make sure when you click on it, it sets the text in your original label.
I'd like a way to easily tie a widget back to the business object it is rendering. So when the user interacts with a widget I can easily determine the business object holding the data for that widget.
For example, if we imagine a calendar widget that we're going to implement with an AbsolutePanel. For each appt object we'll add a label to the calendar. Then when a user clicks on a label he can update the appt. So I need to know which appt object that label refers to.
For instance, if we look at the following code; if the label for an appointment receives a click, how can I find out to which appt it represented ? The only solution I can see is to create a ApptLabel sub-class for Label which would hold a reference to its appt. This is fine, but the example illustrates a more general need which is to associate widgets with data objects; however this would mean that every object that has a presence in a view needs to subclass a widget. that seems heavy - I expected to find something in the framework e.g. a string property in a widget that I can set to an object key
other approaches I tried; maintaining a map of Map -- this didnt work as the label object I create doesnt appear to be the same (in terms of the Object.equals which I guess is what HashMap uses)
class WidgetCalendar extends Composite {
AbsolutePanel m_panel = new AbsolutePanel();
m_panel.setStylePrimaryName("calendar");
m_panel.setPixelSize(width, height);
public WidgetCalendar(ArrayList<BomAppt> appts) {
initWidget(m_panel);
for (BomAppt a : appts) {
Label l = new Label();
l.addClickHandler(new ClickHandler() {
public void onClick(ClickEvent event) {
// how do I know my BomAppt in here ?
}
m_panel.add(l, someX, someY);
}
}
}
Ideally I can do something like this
class WidgetCalendar extends Composite {
AbsolutePanel m_panel = new AbsolutePanel();
m_panel.setStylePrimaryName("calendar");
m_panel.setPixelSize(width, height);
public WidgetCalendar(ArrayList<BomAppt> appts) {
initWidget(m_panel);
for (BomAppt a : appts) {
Label l = new Label();
l.setItemData(a.getUniqueId());
l.addClickHandler(new ClickHandler() {
public void onClick(ClickEvent event) {
BomAppt a = BomAppt.getApptWithId(e.getItemData())
}
}
m_panel.add(l, someX, someY);
}
}
}
This is the solution where I create a subclass, this seems heavy to me and I'd prefer something simpler
class ApptLabel extends Label {
public ApptLabel(BomAppt a) {
m_a = a;
this.addClickHandler(new ClickHandler() {
public void onClick(ClickEvent event) {
m_a.doSomething();
});
}
BomAppt m_a;
}
class WidgetCalendar extends Composite {
AbsolutePanel m_panel = new AbsolutePanel();
m_panel.setStylePrimaryName("calendar");
m_panel.setPixelSize(width, height);
public WidgetCalendar(ArrayList<BomAppt> appts) {
initWidget(m_panel);
for (BomAppt a : appts) {
BomLabel l = new BomLabel();
l.addClickHandler(new ClickHandler() {
public void onClick(ClickEvent event) {
// how do I know my BomAppt in here ?
}
m_panel.add(l, someX, someY);
}
}
}
For instance, if we look at the following code; if the label for an
appointment receives a click, how can I find out to which appt it
represented ?
By using Composite pattern you can find out which widget was clicked, initially you should create your own custom Appointment widget which is responsible for drawing one appointment. And in you Appointment widget you can have a set of other widgets, in your case, for Label add click handler. Once user clicks that label, you can execute business logic with its data and you can represent data.
public class Appointment extends Composite {
private AppointmentDetails data;
public Appointment(AppointmentDetails data){
draw(data);
}
private void draw(AppointmentDetails data){
Label label = new Label();
label.addClickHandler(new ClickHandler() {
public void onClick(ClickEvent event) {
// do your business logic with this AppointmentDetails
}
});
}
}
After that you should have one Calendar widget which contains several Appointments.
Keep in your mind: your classes each serve a single, very clearly defined purpose, separated from other classes with other clearly defined purposes.
I have a gwt form which has about 70-100 widgets (textboxes,listboxes,custom widgets etc)
I am trying to implement the features of CUT ,COPY in this form .For this i have 2 buttons right on top of the form.
Now the problem i have is that when i click on the copy button , the widget that was focused in the form looses focus and i dont know which text to copy(or which widget was last focused before the focus getting to the copy button)
I was planning to implement blur handlers on all the widgets but i feel is a very laborious and not a good solution.
How can i get around this issue?
Thanks
Perhaps someone with a deeper insight might provide a better approach but I beleive adding blur handlers is perfectly valid. I do not quite see why you think it would be laborious, after all you don't need a different handler for each of your widgets, you can get away with only one(at most a couple for a variety of controls..), here is a very simple example,
public class CustomBlurHandler implements BlurHandler{
Object lastSource;
String text;
#Override
public void onBlur(BlurEvent event) {
if (event.getSource() instanceof TextBox) {
lastSource = event.getSource();
text = textBox.getSelectedText();
}
}
public Object getLastSource() {
return lastSource;
}
public String getText() {
return text;
}
}
and onModuleLoad :
public class Test implements EntryPoint {
CustomBlurHandler handler = new CustomBlurHandler();
public void onModuleLoad() {
TextBox text1 = new TextBox();
TextBox text2 = new TextBox();
text1.addBlurHandler(handler);
text2.addBlurHandler(handler);
Button b = new Button("Get last selected text");
b.addClickHandler(new ClickHandler() {
#Override
public void onClick(ClickEvent event) {
Window.alert(handler.getLastSource()+ " " + handler.getText());
}
});
RootPanel.get().add(text1);
RootPanel.get().add(text2);
RootPanel.get().add(b);
}
}