Legacy Document

Important: The information in this document is obsolete and should not be used for new development.

NSToolbarItem.ItemValidation

(informal protocol)

Package	com.apple.cocoa.application
Companion guide	Toolbar Programming Topics for Cocoa

Overview

A toolbar item with a valid target and action is enabled by default. To allow a toolbar item to be disabled in certain situations, a toolbar item’s target can implement the validateToolbarItem method.

Note: NSToolbarItem’s validate method calls this method only if the item’s target has a valid action defined on its target and if the item is not a custom view item. If you want to validate a custom view item, then you have to subclass NSToolbarItem and override validate.

Tasks

Validating Toolbar Items

Instance Methods

validateToolbarItem

If this method is implemented and returns false, NSToolbar will disable theItem; returning true causes theItem to be enabled.

public abstract boolean validateToolbarItem(NSToolbarItem theItem)

Discussion

NSToolbar only calls this method for image items.

Note: validateToolbarItem is called very frequently, so it must be efficient.

If the receiver is the target for the actions of multiple toolbar items, it’s necessary to determine which toolbar item theItem refers to by testing the itemIdentifier.

public boolean validateToolbarItem (NSToolbarItem toolbarItem) {

    boolean enable = false;

    if (toolbarItem.itemIdentifier().equals(SaveDocToolbarItemIdentifier)) {

        // We will return true (save item is enabled)

        // only when the document is dirty and needs saving.

        enable = this.isDocumentEdited();

    } else if (toolbarItem.itemIdentifier().equals(NSToolbarItem.PrintItemIdentifier)) {

        enable = true;

    return enable;