Showing Edit / Delete buttons for each row in a GWT CellTable? - java

I have a cell table showing some data. For each row, I want to have two columns which contain edit / delete buttons. When each button is clicked, it should be able to notify a listener which button was clicked (and preferably also be able to pass in the object that row is associated with).
How can I do this? Specifically, I know how to render a button, but how can I process the on-click event and pass in the object which the user clicked to edit or delete?

This is the standard approach:
myTable.addCellPreviewHandler(new Handler<MyObject>() {
#Override
public void onCellPreview(CellPreviewEvent<MyObject> event) {
if ("click".equals(event.getNativeEvent().getType())) {
if (event.getColumn() == 0 || event.getColumn() == 1) {
MyObject object = event.getValue();
Window.alert("Column clicked: " + event.getColumn());
}
}
}
});
This is a more efficient solution, because you only have one handler attached to a table, instead of trying to attach a handler to each button in each row.

I think you can make a foreach through all the rows in the celltable (I never worked with celltables)
And then you can add your own ClickHandler to the Button.
Something like that (not tested):
final int row = myrow; // add the row value or a object identifier or similar
Button delete_button = new Button("delete");
delete_button.addClickHandler(new ClickHandler(){
#Override
public void onClick(ClickEvent event) {
// Insert your delete funciton
delete(row);
}
});
You mentioned a Listener, Listener are depreciated, use Handler instead.

Related

Mouse Event not working when clicking JTable

I created a simple mouse event. When the user clicks the JTable it will fetch the records in the JTable and display them in the JTextField. In this case I am trying to display the ID from the Table into the Text Field.
public void fetchRec() {
xtable.addMouseListener(new MouseAdapter() {
public void rowClicked(MouseEvent evt){
xtable =(JTable) evt.getSource();
int row = xtable.rowAtPoint( evt.getPoint() );
int column = xtable.columnAtPoint( evt.getPoint() );
String s=xtable.getModel().getValueAt(row, column)+"";
idLabelField.setText(s);
}
});
}
I am calling the method here but it keeps telling me that rowClicked method is unused. I don't understand how its unused? Everything else I am calling is working except this.
public void bookDimensions() throws Exception {
addTextLabels();
addTextFields();
addPanelButtons();
addRecord();
addTable();
fetchRec();
}
Turn on cell selection and listen to the selection model instead of mouse events. See java: how to select only one cell in a jtable and not the whole row

SWT selection event after deleting selection

I'm making a simple menu to delete items on a tree. However, after deleting the items, the tree does not receive a selection event, therefore, the code in the listener does not execute (the listener, in the full code, updates a part of the UI).
I have simplified the code below, leaving out details. It is something like this:
tree.addListener (SWT.Selection, new Listener(){
public void handleEvent(Event e) {
(....)
}
}
I also tried this:
tree.addSelectionListener (new SelectionListener(){
public void widgetDefaultSelected(SelectionEvent e){
(...)
}
public void widgetSelected(SelectionEvent e) {
(...)
}
}
On my menu action (delete selection), there is this:
TreeItem [] selected = tree.getSelection();
tree.deselectAll();
if (selected.length > 0)
{
for( TreeItem i : selected){
i.dispose();
}
}
After deleting the selection, my selection listener does not fire. It does fire if I deselect all itens using the ctrl+click combination.
What should I do? Is there a way to fire the SWT.Selection event to the tree after deleting the itens or should I isolate the code inside the listener to call it again? Shouldn't the tree.deselectAll() fire a Selection event?
You can send a selection event programmatically with:
Event event = new Event();
event.widget = tree;
event.display = tree.getDisplay();
event.type = SWT.Selection;
tree.notifyListeners(SWT.Selection, event);
Have same situation and found
this link mentioning, that programmatically setSelection may never send this event due to design, so always send it (if needed) programmatically after setting too

Add change listner to ComboBox when value remains unchanged

I have a ComboBox (JavaFX) that displays info from a database according to the selected String.
For eg: the values in the ComboBox are as follows:
Table 1
Table 2
When I have Table 1 selected, and I then select Table 2, the value change is detected and the code is run.
But when I have Table 1 selected, and I re-select Table 1, no value change is detected. Instead I want code to reload Table 1 from the source database.
The current code:
myComboBox.valueProperty().addListener(new ChangeListener<String>() {
#Override
public void changed(ObservableValue ov, String t, String t1) {
myComboBoxValue = t1;
if (t1 != null) {
displayTable(t1)
}
}
});
The listener will not be triggered if the old selected value is equal to the new value. However, if this is what you want, you can clear the selected value once the comboBox is clicked.
myComboBox.valueProperty().addListener(new ChangeListener<String>() {
#Override
public void changed(ObservableValue ov, String t, String t1) {
myComboBoxValue = t1;
if (t1 != null) {
displayTable(t1)
}
}
});
myComboBox.setOnAction(new EventHandler<ActionEvent>() {
#Override
public void handle(ActionEvent event) {
myComboBox.getSelectionModel().clearSelection();
}
});
A working approach to react to item selection in ComboBox irrespective if a new item was selected or not can be found here: https://stackoverflow.com/a/25704438/4749209
Basing on this solution, your sample code would stay like this:
myComboBox.showingProperty().addListener((ov, old_show_state, new_show_state) ->
{
// checks if the combobox popup menu was closed
if (new_show_state == false)
{
myComboBoxValue = myComboBox.getValue();
if (myComboBoxValue != null)
{
displayTable(myComboBoxValue)
}
}
});
The only problem to mention is that the reload operation you mentioned will happen if the user clicks outside the combobox popup menu area, as it will close too.
You don't change a value when it remains the same, so no event gets fired. Depending on what you are trying to do you could e. g. add a listener to onHidden. It's ugly and doesn't cover e. g. when you set the same value programmatically, but would work for changes via mouse click.

Vaadin Table Item removal by click of button

I am using Vaadin 7.1.7.
I have a Table which has a few TextFields and a Button called "delete".
On click of the delete button, that particular row is to be deleted.
As i understand, I could remove table item as follows:
table.removeItem(itemID);
Unfortunately, I am unable to fetch the itemID of the row to remove it from the table.
Since, I used table.addItem(o, null); to addItems to it, how could I get the rowID/itemID on the click of the button inside buttonClickListener?
My trys so far have been:
#Override
public void buttonClick(ClickEvent event) {
Table t = (Table) event.getButton().getParent();
}
This has got me to the parent table but not to that particular item.
Thanks in advance
.
You could for example use setData(rowID) when you create the buttons.
The onClick you retrieve the associated data of the button and have the correct row id.
Provide a row id, override Button.ClickListener, and use the id in the click listener.
Object rowId = new Object();
Button button = new Button("Delete");
button.addClickListener(new RowDeleteListener(rowId));
//populate cells in the row, add the button & whatever
table.addItem(row, rowId);
public class RowDeleteListener implements Button.ClickListener {
Object rowId;
public RowDeleteListener(Object rowId) {
this.rowId = rowId;
}
public void buttonClick(ClickEvent event) {
table.removeItem(rowId);
}
}
Or André Schild’s solution, which is to use setData(rowId) on the button.
Button button = new Button("Delete");
button.addClickListener(new Button.ClickListener() {
public void buttonClick(ClickEvent event) {
table.removeItem(getData());
}
});
//Populate row stuff.
button.setData(table.addItem(row, null));
I like the first solution slightly better because it's more obvious what's going on, and also because the button has the correct row id before it gets added to the table instead of after.
Or, if you feel like creating something obnoxious: you could use the Button object as the id for the row.
Button button = new Button("Delete");
button.addClickListener(new Button.ClickListener() {
public void buttonClick(ClickEvent event) {
table.removeItem(this);
}
});
//populate row stuff, including adding the button to the row.
table.addItem(row, button);
I didn't test or compile any of these so... you know...

Show TableViewer not in line, but in matrix order

I use the TableViewer to show informations in a table. The user can select one of the shown options by selecting one line of the table.
I want to create a table in matrix form, in which the user can not only select the line. It should be possible to select every item of the table, like row 2 column 3. For every item selection an action is called to handle this item as it is in the TableViewer.
As far as i now, i can add CellModifier and CellEditors to the line of Columns of the table, but the reference for the action is always the line object and not the selected TableItem.
Does somebody have an example how to create such a matrix inside a Composite?
I can create it by setting a GridLayout and adding the components in a for-loop, but than i get issues, when i want to redraw the Composite with new childrens. The TableViewer does already have this handling, so i dont want to implement it again.
I had the same problem a while ago and the only way I found to solve it was to register a mouse listener on the SWT table widget associated to the table viewer.
MouseListener columnSelectionMouseListener = new ColumnSelectionMouseListener();
getViewer().getTable().addMouseListener(columnSelectionMouseListener);
public class ColumnSelectionMouseListener implements MouseListener {
private TableColumn selectedColumn;
#Override
public void mouseDoubleClick(MouseEvent e) {
// Nothing to do here
}
#Override
public void mouseDown(MouseEvent e) {
table = (Table) e.widget;
TableItem item = table.getItem(new Point(e.x, e.y));
for (int i = 0; i < table.getColumnCount(); i++) {
TableColumn column = table.getColumn(i);
Rectangle bounds = item.getBounds(i);
if (bounds.contains(e.x, e.y)) {
selectedColumn = column;
}
}
}
#Override
public void mouseUp(MouseEvent e) {
// Nothing to do here
}
public TableColumn getSelectedField() {
return selectedColumn;
}
}
Then, for example in the viewer's selection listener, you can ask to the mouse listener which column was selected when the mouse has been pressed and combine that with the selected line coming from the viewer's selection to perform the appropriate action.
Hope this can help.
Manu
Maybe the following JFace snippet will help:
Snippet058CellNavigationIn34
Ingo

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