Making Menus with wxPerl
by Roberto Alamos
|
Pages: 1, 2, 3, 4, 5, 6
Using Wx::Menu
Creating a menu with Wx::Menu is as easy as:
my $menu = Wx::Menu->new();Now $menu is a Wx::Menu object. WxPerl has five types of items. The first is the normal item, upon which you can click to get a response (a dialog or something else). The second is the check item, which has the Boolean property of being checked or not (independent of another check items). The third item is the radio item, which is an "exclusive check item;" if you check a particular radio item, other radio items in its radio group get unchecked instantly. The fourth type of item is the separator, which is just a straight line that acts as a barrier that separates groups of similar items inside of a menu. The fifth type is the submenu, an item that expands another menu when the mouse cursor is over it.
Setting Up Menu Items
To create a normal item for your menu, write:
$menu->Append($id, $label, $helpstr);where $id is an unique integer that identifies this item, $label is the text to display on the menu, and $helpstr is a string to display in the status bar. (This last argument is optional.) Note that every menu item must have an unique identifier number in order to be able to operate with this item during the rest of the program. (From now on, $id will denote the unique identifier number of a menu item.)
To create a check or radio item, the methods are analogous to Append--AppendCheckItem and AppendRadioItem, respectively. Add a separator with the AppendSeparator method; it does not expect arguments. Create a submenu with the AppendSubMenu method:
$menu->AppendSubMenu($id, $label, $submenu, $helpstr);where $submenu is an instance to another Wx::Menu object. (Don't try to make that a submenu be a submenu of itself, because the Universe will crash or, in the best case, your program won't execute at all.)
While append methods add menu items in the last position of your menus, Wx::Menu gives you methods to add menu items at any position you want. For instance, to add a normal item at some position in a menu:
$menu->Insert($pos, $id, $label, $helpstr);where $pos is the position of the item, starting at 0. To add a radio item, check item, or separator, use the InsertRadioItem, InsertCheckItem, or InsertSeparator methods. As usual, the latter takes no arguments. To insert a submenu, use the InsertSubMenu method:
$menu->InsertSubMenu($pos, $id, $label, $submenu, $helpstr);You can also insert an item at the first position by using the Prepend method:
$menu->Prepend($id, $label, $helpstr);
PrependRadioItem, PrependCheckItem, and PrependSeparator methods are also available. As you might expect, there's a PrependSubMenu method that works like this:
$menu->PrependSubMenu($id, $label, $submenu, $helpstr);
Sometimes, a menu grows to include too many menu items, and then it's impractical to show them all. For this problem, Wx::Menu has the Break method. When called, it causes Wx to place subsequently appended items into another column. Call this method like so:
$menu->Break();Menu Item Methods
Once you have created your items, you need some way to operate on them, such as finding information about them through their identifier numbers, getting or setting their labels or help strings, enabling or disabling them, checking or unchecking them, or removing them. For example, you may want to retrieve some specific menu item in some point of your program. To do this, use the FindItem method in either of two ways:
my $menuitem_with_the_given_id = $menu->FindItem($id);
my ($menuitem, $submenu) = $menu->FindItem($id);where $menuitem is the corresponding Wx::MenuItem object with the identifier $id, and $submenu is the (sub)menu to which $menuitem belongs. You can also retrieve a menu item through the FindItemByPosition method (but remember that positions start at 0):
my $menuitem = $menu->FindItemByPosition($pos);Wx::Menu provides methods to get or set properties of menu items. To set a property, there are two methods: SetLabel and SetHelpString. A SetLabel call might be:
$menu->SetLabel($id, $newlabel);SetHelpString works similarly:
$menu->SetHelpString($id, $newhelpstr);
