Customizing Predefined Dialog Boxes
This section shows you how to program modifications to a predefined dialog box to fit the needs of an application.
IlvFileChooser
There are 2 options for customizing the IlvFileChooser Dialog Box:
-
Use the IlvFileChooserOptions class to specify options of the IlvFileChooser dialog. This class enables you to make changes easily, for example, changing a label or the size of a button.
The following code fragment shows how to add file filters to the Filter list of the IlvFileChooser dialog:
if (filename && filename[0] && IlvFileExists(filename)) ...
IlvFileChooserOptions* opt = new IlvFileChooserOptions(IlvFileChooserOpen);
opt->addFilter("All files (*.*)","*");
opt->addFilter("Ilv files (*.ilv)","ilv");
opt->addFilter("Iva files (*.iva)","iva");
opt->addFilter("Views files (*.iva,*.ilv)","iva|ilv");
dlg = new IlvFileChooser(getDisplay(),0,0,opt);
if (dlg->get() > 0) {
IlString filename = dlg->getResult(0);
if ((filename. getLength() > 0) && IlvFileExists((const char*)filename)) {
...
}
}
delete dlg;
-
Use a subclass of the IlvFileChooserOptions class to provide a specific implementation for virtual functions.
The following code fragment shows how to change the width of labels File name and Filter and to hide the Up directory button:
class MyOptionsClass : public IlvFileChooserOptions
{
public:
MyOptionsClass(IlvFileChooserType typ = IlvFileChooserOpen,
IlvFileChooserSelection sel
= IlvFileChooserFileSelection):
IlvFileChooserOptions(typ, sel) {
}
virtual IlInt getLabelWidth() const { return 100; }
virtual IlBoolean isUpDirectoryButtonShown() const { return IlFalse; }
};
MyOptionsClass* opt = new MyOptionsClass();
dlg = new IlvFileChooser(getDisplay(), 0, 0, opt);
if (dlg->get() > 0) {
IlString filename = dlg->getResult(0);
if ((filename.getLength() > 0) && IlvFileExists((const char*)filename))
{
...
}
}
delete dlg;
With either option, if you want to provide your own Apply button or sheet, you need to create a subclass of the IlvFileChooser class itself. You are also responsible for the connection between your created gadgets and the IlvFileChooser methods which manage events. For example, call the processApply method when the Apply button is clicked.
The following code fragment creates a subclass of IlvFileChooser where:
-
The label of the Apply button is Validate
-
The Apply button is represented by a bitmap image
-
The sheet is always single selection
class MyFileChooser : public IlvFileChooser
{
public:
MyFileChooser(IlvDisplay* display,
const char* dir = 0,
const char* title = 0,
IlvFileChooserOptions* options = 0,
IlvSystemView transientFor = 0,
IlUInt properties = 0)
: IlvFileChooser(display, dir, title, options, transientFor, properties) {}
virtual IlvButton* createApplyButton(const IlvRect& rect,
const IlString& label) const;
virtual IlvFileChooserSheet* createSheet(const IlvRect& rect) const;
};
// Set Apply button characteristics
static void
MyApplyCB(IlvGraphic*, IlAny arg)
{
MyFileChooser* dlg = (MyFileChooser*)arg;
if (dlg)
dlg->processApply();
}
IlvButton*
MyFileChooser::createApplyButton(const IlvRect& rect,
const IlString& label) const
{
// Read the bitmap
IlvBitmap* bmp = getDisplay()->readBitmap("my bitmap file name");
// Create a button
IlvButton* btn = new IlvButton(getDisplay(), "Validate", rect);
btn->setBitmap(bmp);
// Connect the button to a callback to manage the click events
btn->addCallback(btn->CallbackSymbol(), MyApplyCB, (IlAny)this);
return btn;
}
// Set sheet to single selection mode
static void
MySheetSelectionCB(IlvGraphic*, IlAny arg)
{
MyFileChooser* dlg = (MyFileChooser*)arg;
if (dlg)
dlg->selectionChanged();
}
IlvFileChooserSheet*
MyFileChooser::createSheet(const IlvRect& rect) const
{
IlvFileChooserSheet* sheet =
new IlvFileChooserSheet(getDisplay(), rect, (IlvFileChooser*)this);
// Disable multi selection
sheet->setExclusive(IlTrue);
// Disable edition
sheet->allowEdit(IlFalse);
// Connect the sheet with the dialog to manage the selection changes
sheet->setCallback(sheet->CallbackSymbol(), MySheetSelectionCB, (IlAny)this);
return sheet;
}
Note
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