vb.net barcode font 10: Windows and Menus and Sheets in Java

Creator Data Matrix 2d barcode in Java 10: Windows and Menus and Sheets

CHAPTER 10: Windows and Menus and Sheets
Make Data Matrix ECC200 In Java
Using Barcode generator for Android Control to generate, create DataMatrix image in Android applications.
www.OnBarcode.com
Code 128 Code Set A Encoder In Java
Using Barcode drawer for Android Control to generate, create Code 128 Code Set A image in Android applications.
www.OnBarcode.com
Figure 10 8. How the menu system decides whether a menu item should be enabled or not
EAN-13 Supplement 5 Encoder In Java
Using Barcode drawer for Android Control to generate, create EAN-13 Supplement 5 image in Android applications.
www.OnBarcode.com
Barcode Generation In Java
Using Barcode creator for Android Control to generate, create Barcode image in Android applications.
www.OnBarcode.com
The upshot of all this is that the menu item s target object, whether configured explicitly or found in the responder chain, is the one that decides whether the menu item should be enabled (at the current time) or not. This means that you have complete dynamic control over each menu item. By implementing validateUserInterfaceItem: in each of your classes containing methods that are called by menu items, whether directly or through the responder chain, you can define some logic that the menu system calls at the right time, and automatically enables or disables each menu item based on what you return. Let s illustrate this with an example. We ll create a new window in our nib file, matched by a new delegate class just for that window, which will implement validateUserInterfaceItem: to handle the state of a menu item. In a real application, you would probably base it on the content of a model object, but for simplicity s sake, we ll enable or disable a menu item based on what s selected in the window. Start by creating a new class in Xcode, just a plain NSObject subclass called ListWindowDelegate. In its header, define an integer property called selectedTag, which we ll later bind to a GUI object (add the lines that are shown in bold):
Create UCC-128 In Java
Using Barcode encoder for Android Control to generate, create EAN / UCC - 14 image in Android applications.
www.OnBarcode.com
Paint UPCA In Java
Using Barcode generation for Android Control to generate, create UPC-A Supplement 2 image in Android applications.
www.OnBarcode.com
#import <Cocoa/Cocoa.h> @interface ListWindowDelegate : NSObject {
Print PDF 417 In Java
Using Barcode drawer for Android Control to generate, create PDF-417 2d barcode image in Android applications.
www.OnBarcode.com
Print 2/5 Industrial In Java
Using Barcode creation for Android Control to generate, create 2 of 5 Industrial image in Android applications.
www.OnBarcode.com
CHAPTER 10: Windows and Menus and Sheets
Encoding Data Matrix 2d Barcode In None
Using Barcode creation for Excel Control to generate, create ECC200 image in Office Excel applications.
www.OnBarcode.com
DataMatrix Reader In Visual Studio .NET
Using Barcode scanner for .NET Control to read, scan read, scan image in VS .NET applications.
www.OnBarcode.com
NSInteger selectedTag; } @property (assign) NSInteger selectedTag; @end
Painting QR In Objective-C
Using Barcode generator for iPhone Control to generate, create Quick Response Code image in iPhone applications.
www.OnBarcode.com
Draw Code 128C In Objective-C
Using Barcode creation for iPhone Control to generate, create ANSI/AIM Code 128 image in iPhone applications.
www.OnBarcode.com
In the matching .m file, we re going to synthesize the accessors for the selectedTag property, implement the specialAction: method that a menu item will be connected to with target/action via the First Responder proxy, and implement the validateUserInterfaceItem: method.
UPC Code Printer In None
Using Barcode creator for Online Control to generate, create GS1 - 12 image in Online applications.
www.OnBarcode.com
Paint Matrix Barcode In Visual Basic .NET
Using Barcode maker for .NET framework Control to generate, create 2D Barcode image in Visual Studio .NET applications.
www.OnBarcode.com
#import "ListWindowDelegate.h" @implementation ListWindowDelegate @synthesize selectedTag; - (BOOL)validateUserInterfaceItem: (id <NSValidatedUserInterfaceItem>)anItem { SEL theAction = [anItem action]; if (theAction == @selector(specialAction:) ) { if (self.selectedTag == 13013) { return YES; } else { return NO; } } // default, in case it's not the action we care about return YES; } - (void)specialAction:(id)sender { NSRunAlertPanel(@"Boy Howdy!", @"That's some mighty special action you got there!", nil, nil, nil); } @end
EAN 128 Scanner In VB.NET
Using Barcode reader for .NET Control to read, scan read, scan image in .NET applications.
www.OnBarcode.com
Code-39 Decoder In VS .NET
Using Barcode scanner for VS .NET Control to read, scan read, scan image in Visual Studio .NET applications.
www.OnBarcode.com
We should point out a thing or two about the validateUserInterfaceItem: method. First, you ll see that we re using the item s action to determine what method it would call if clicked. In code, an action (or any kind of method for that matter) can be referred to by the Objective-C SEL type. Technically, a SEL is not a method, but a selector : a sort of hash of the method s name, somewhat modified for performance considerations, which the Objective-C runtime can use to look up the method s actual implementation. Besides looking up a method, a SEL can be compared to another SEL, such as that returned by the @selector(specialAction:) construct shown in the code. In our method, we test to see whether the menu item in question is targeted at the action method we care about, in which case we go deeper (if not, we fall through to the end of the method, where we just return YES, assuming the menu item is calling some other action method that we re not going to worry about validating for now). If the actions match up, we then do a simple check against some internal state, in the form of the selectedTag property, to see if we want to allow this menu item to be enabled or not. Now let s create a GUI to put this code to work. Back in MainMenu.xib in Interface Builder, drag a plain NSObject from the Library to the nib window, and use the Identity Inspector to change its class to ListWindowDelegate. Then drag out a new window from the Library, and connect its delegate outlet to the ListWindowDelegate object you ve
EAN / UCC - 13 Creation In Objective-C
Using Barcode drawer for iPhone Control to generate, create EAN / UCC - 13 image in iPhone applications.
www.OnBarcode.com
Code 39 Full ASCII Encoder In VS .NET
Using Barcode drawer for .NET framework Control to generate, create Code-39 image in Visual Studio .NET applications.
www.OnBarcode.com
Code 128 Code Set B Recognizer In None
Using Barcode scanner for Software Control to read, scan read, scan image in Software applications.
www.OnBarcode.com
ANSI/AIM Code 128 Printer In None
Using Barcode generation for Software Control to generate, create Code 128B image in Software applications.
www.OnBarcode.com
Copyright © OnBarcode.com . All rights reserved.