How can I (un)hide a SWT TableItem? - java

I am trying to allow my user to search through a table of information, dynamically hiding/showing results that contain the search. I have the hiding part down, and it works well, but I'm having trouble showing the table item again once the search criteria is changed.
Here is my hide code:
searchField.addModifyListener(new ModifyListener() {
#Override
public void modifyText(ModifyEvent arg0) {
modified = true;
for (int i = 0; i < table.getItems().length; i++) {
if (!(table.getItem(i).getText(2)
.contains(searchField.getText()))) {
table.getItem(i).dispose();
}
}
if ("".equals(searchField.getText())) {
modified = false;
//where I would want to un-hide items
}
}
});

Looking at your code, it seems you try to hide the item by calling dispose(). If you dispose a widget, it is gone for good. You cannot get it back.
If you want to unhide it again, will have to create a new item at the position of the previously hidden one with the same content.

Isn't it better to actually operate with some kind of a table model and JFace bindings, rather, then do it like that? And yes, disposing is not hiding. You should probably remove the item from the table.

You have probably to save the data from TableItem into collection before you call dispose. Then when you search again you could check that collection and if matches are found, then insert back into Table by creating new TableItem.

Related

Java - adding existing objects to view iterating through an array list

what I want to do is press a button to add previously declared TableRow objects (refers to TableRow objects already created in XML file) that I have hidden using table.removeView(row1) etc on program start.
Then I want to be able to click a button to add each TableRow back to the view one at a time until all the rows are visible again. I have tried a few different ways without any luck and the last method I tried was creating an array list in my onCreate method like so:
final ArrayList<TableRow> rowlist = new ArrayList<TableRow>();
rowlist.add(row4);
rowlist.add(row5);
rowlist.add(row6);
rowlist.add(row7);
rowlist.add(row8);
rowlist.add(row9);
rowlist.add(row10);
Then trying to iterate through like this:
public void onClick(View v) {
Iterator<TableRow> rowiterator = rowlist.iterator();
while (rowiterator.hasNext()) {
table.addView(rowiterator.next());
}
}
What I get now is when I press my button it just adds all the rows back in at once, when I want it to iterate through the list adding rows one at a time.
Can anyone help me resolve this problem, or tell me if I'm being a complete idiot and suggest an entirely new and better method of achieving what I want to achieve?
Note: I'm pretty new to Java programming and on this problem I am absolutely stumped!
You're iterating over the entire array when you click the button and adding them all back in. Something like this is probably more like what you want:
public void onClick(View v) {
if(rowlist.size() > 0)
{
table.addView(rowlist.get(0));
rowlist.remove(0);
}
}

Null error when attempting to add custom row to CellTable in gwt

I have a Cell Table that I am using to output some search results. The cell table uses a list data provider to update info. I want to separate different sections so I am attempting to add a custom row in between different sections that has one cell that spans all of the columns. I am extending AbstractCellTableBuilder to do this, but my issue comes when I use TableRowBuilder and startRow(), calling startRow() returns a null pointer exception, to AbstractCellTableBuilder.java:243, which refers to tbody. So this is leading me to believe that my cell table is not getting passed into AbstractCellTableBuilder properly. My understanding of gwt and java is pretty basic, so I might just not be understanding how exactly this is supposed to work, and the showcase example is pretty complicated for me to understand. If anyone can tell where I'm messing up or has any simpler examples of this that might help me I would appreciate it!
I had found a similar answer and tried to implement it, and that is how I came up with what I have, but it answer wasn't quite detailed enough for me to fully understand how it works. Here is what I referenced:
Building a custom row on demand with GWT CellTableBuilder
EDITED:
Basic format of how I add normal rows to the cell table
searchProvider = new ListDataProvider<SearchColumn>();
cellTable_2 = new CellTable<SearchColumn>();
//Add columns to the cellTable
searchProvider.addDataDisplay(cellTable_2);
//What I call when adding a row to the cellTable using the ListDataProvider
searchProvider.getList().add(new SearchColumn("",label,"","","","","","",""));
Adding the CustomCellTableBuilder to the cell table:
//Passing the CustomCellTableBuilder to the cell table
CustomCellTableBuilder buildRow = new CustomCellTableBuilder();
cellTable_2.setTableBuilder(buildRow);
The CustomCellTableBuilder for adding custom rows:
public class CustomCellTableBuilder extends AbstractCellTableBuilder<SearchColumn>{
public CustomCellTableBuilder() {
super(cellTable_2);
}
#Override
protected void buildRowImpl(SearchColumn rowValue, int absRowIndex){
//building main rows logic
if (labelrow == 1){
System.out.println("Going to build extra row if");
buildExtraRow(absRowIndex, rowValue);
}
else {
System.out.println("Getting into normal buildRow");
buildRow(rowValue,absRowIndex);
}
}
private void buildExtraRow(int absRowIndex, SearchColumn rowValue){
start(true);
TableRowBuilder row = startRow();
TableCellBuilder td = row.startTD().colSpan(getColumns().size());
td.text("Testing this out").endTD();
row.endTR();
}}
I think you should call start(true) before calling startRow() because tbody is initialized to null. Start() call will initialize tbody to HtmlBuilderFactory.get().createTBodyBuilder().
The source doesn't lie.
Just like that:
private void buildExtraRow(int absRowIndex, SearchColumn rowValue) {
start(true); // true makes builder to rebuild all rows
TableRowBuilder row = startRow();
// whatever
}

my jComboBox does not react to my keyListener and actionPerform performs weired stuff

I am trying to search for UserName and return values onto jComboBox, here is the code
public void actionPerformed(java.awt.event.ActionEvent e) {
sr = new Search(((String) jComboBoxReceiver.getSelectedItem()));
usrList = sr.searchUser();
String[] userList = new String[usrList.size()] ;
for(int i=0;i<usrList.size();i++){
userList[i]= usrList.get(i).getUserName();
}
model = new DefaultComboBoxModel(userList);
jComboBoxReceiver.setModel(model);
}
after you click to somewhere else or click enter,it will conduct the search, however, it will go search for the first item again, which is very confusing... then i tried using key Pressed
if(e.getKeyCode()==13){
sr = new Search(((String) jComboBoxReceiver.getSelectedItem()));
usrList = sr.searchUser();
String[] userList = new String[usrList.size()] ;
for(int i=0;i<usrList.size();i++){
userList[i]= usrList.get(i).getUserName();
}
model = new DefaultComboBoxModel(userList);
jComboBoxReceiver.setModel(model);
}
And this one does not react at all.
You need to set the listener(s) on the Editor not the ComboBox itself. See the answer here:
Detecting when user presses enter in Java
Wow, you're rebuilding a ComboBoxModel each time ? Isn't it a little expensive ? You know there is a MutableComboBoxModel, also implemented by DefaultComboBoxModel that would allow you to add/remove elements from you combobox without rebuilding its model each time ?
Concerning your question, I don't understand the statement
However, if i do that, it does perform correctly, however, it will go search for the first item again
Do you mean your JComboBox starts to blink with content being modified each time ?
if so, maybe is it because your ActionListener is linked to JComboBox, which content changes continuously.
Anyway, i suggest you add some logs, like
sr = new Search(((String) jComboBoxReceiver.getSelectedItem()));
DefaultComboBoxModel model = (DefaultComboBoxModel) jComboBoxReceiver.getModel();
model.remvoeAllElements();
usrList = sr.searchUser();
String[] userList = new String[usrList.size()] ;
for(int i=0;i<usrList.size();i++){
String username = usrList.get(i).getUserName();
System.out.println(username); // feel free to instead use one loger
model.addElement(username);
}
Besides, i would tend to suggest you an other approach, in which combo box model don't contain simple Strings, but rather User objects, with a ListCellRenderer displaying only the user name.
IMO, what will really be confusing for your users is to have the content and selection of a combo box changed as soon as they select one of its options.
Anyway, if you really want to do that, then you should remove the action listener (or deactivate it) before changing its content, and re-add it (or reactivate it) after :
public void actionPerformed(java.awt.event.ActionEvent e) {
sr = new Search(((String) jComboBoxReceiver.getSelectedItem()));
usrList = sr.searchUser();
String[] userList = new String[usrList.size()] ;
for(int i=0;i<usrList.size();i++){
userList[i]= usrList.get(i).getUserName();
}
model = new DefaultComboBoxModel(userList);
jComboBoxReceiver.removeActionListener(this);
jComboBoxReceiver.setModel(model);
jComboBoxReceiver.addActionListener(this);
}

problem when implementing a selection listener in a JTable

I am developing a JTable with different rows. I would like to associate an event to the selection of a row in this table. I have used the following selection class to provide behaviour to the table selection:
public class TableSelectionListener implements ListSelectionListener{
public Integer item;
public TableSelectionListener(Integer item){
this.dialog = item;
}
public void valueChanged(ListSelectionEvent e) {
System.out.println("The row clicked is "+item);
}
}
When I create an instance of this table, sai tabletest, I have added the following piece of code:
tabletest.getSelectionModel().addListSelectionListener(new TableSelectionListener(tabletest.getSelectedRow());
The problem is that when I click on one row once, instead of retrieving the related message once, I retrieve the same message several times, suggesting that the actions repeated several times. For example:
The row clicked is 0
The row clicked is 0
The row clicked is 0
The row clicked is 0
Does anyone know where the problem may be?
Well, that's just normal.
Your selection listener is created with the value of tabletest.getSelectedRow() at its creation table (which is zero). And, as you never change the value of item in your listener, this listener fcan only display 0as a result.
If I were you, I wouold replace the valueChanged() method by something like (although it's untested and I remember strange things happens sometimes when mixing view and model row values) this :
public void valueChanged(ListSelectionEvent e) {
if(!e.getValueIsAdjusting()) // added as sometimes, multiple events are fired while selection changes
System.out.println("The row clicked is "+e.getFirstIndex());
}
Firstly, it's perfectly normal to get multiple ListSelectionEvents, while the selection is being changed. You can use the getValueIsAdjusting method to determine when selection has ended (it will return false).
Secondly, there's no need to construct your TableSelectionListener with a row number. When your valueChanged method is called, you can get the index of the first/last selected row (remember it's possibly to select multiple rows in the table, unless you disable that) using e.getFirstIndex() and e.getLastIndex() respectively.
An easier way of doing it, is as follows:
table.getSelectionModel().addListSelectionListener(new ListSelectionListener() {
#Override
public void valueChanged(ListSelectionEvent e) {
System.out.println("e...."+table.getSelectedRow());
}
});

CheckboxCellEditor shows text and not a check box

I'm using the following
org.eclipse.jface.viewers.CheckboxCellEditor.CheckboxCellEditor(Composite parent)
I'm creating a table viewer with cellEditors and doing the following
CellEditor[] editors = new CellEditor[columnNames.length];
editors[7] = new CheckboxCellEditor(table);
I have a CellModifier that has the following
public Object getValue(Object element, String property) {
Object result = null;
...
result = Boolean.valueOf(task.isDfRequested());
return result;
}
public void modify(Object element, String property, Object value) {
item.isSelected(((Boolean)value).booleanValue());
}
Finally I have a LabelProvider that has the following
public String getColumnText(Object element, int columnIndex) {
String result = "";
try {
result = Boolean.toString(item.isSelected());
} catch (Exception ex) { }
break;
However, in my UI instead of having a check box I have the word true or false && clicking it results in switching state to false or true. Any ideas on why I don't have a checkbox??
I've searched in the source code of CheckboxCellEditor class and in the constructor the control associated to the CellEditor is created in the createControl(Composite parent) method. This method is abstract in CellEditor class and it's implemented like this in CheckboxCellEditor:
protected Control createControl(Composite parent) {
return null;
}
So a control is not created, that's why you don't see the checkbox. In the documentation of the Class you can read:
Note that this implementation simply
fakes it and does does not create any
new controls. The mere activation of
this editor means that the value of
the check box is being toggled by the
end users; the listener method
applyEditorValue is immediately called
to signal the change.
I solved this using a ComboBoxCellEditor with yes and no items.
Regards.
Well, I have no idea how SWT works or what component you are even talking about.
But I do know that when using Swing you can have custom editors for a column in a JTable. If you don't tell the table the class of data for the column then the toString() method of the data is invoked. But if you tell the table that Boolean data is displayed in the column then the table will use the check box editor.
Sounds like a similiar symptom, but I don't know your particular solution.
What I've decided to do is to just implement a dirty hack others have been using.
Create two images of check boxes, one checked the other not checked. Switch the state between the two based on the boolean.
It's not perfect, but for now it gets the job done

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