zebra barcode printer in vb.net The Library in More Depth in Objective-C

Encoder DataMatrix in Objective-C The Library in More Depth

The Library window holds the template components that you will use in your application. Let s take a quick tour.

The Library window shows a list of components with a detailed description of the currently selected component (see Figure 3 11).

You can choose the amount of information displayed in the Item pane: Icons, Icons and Labels, or Icons and Descriptions. (Right-click in this pane or choose the Action menu at the bottom of the Library window.) The Library popup at the top of the window shows an

outline list of components; you can make this view persistent by dragging down the little splitter bar below the popup. Drag it back up to turn it back into a popup list. You can filter the display by typing into the filter text field at the bottom of the Library window: type rounded and you will see only Rounded Rect Button and Rounded Textured Button. Finally, you can create Smart Groups. These work in the same way as Smart Folders in other Mac applications and allow you to specify criteria such as recently used components.

In the first part of this chapter, you saw how to create and customize the user interface components of your application. For these components to be anything more than just eye candy, you will need to make these components the visual machinery that drives your application. They need to interact with you as the user and with each other. For anything beyond the most simple application, you will be writing code (probably large amounts of it), and somehow that code needs to communicate with these components. This will be our focus for the remainder of this chapter.

Let s look at the Document window now. You can see different views of this window in Figures 3 2 and 3 12. The Document window contains objects that represent the different objects in your application. Some represent the visible objects that you have been working with already in this chapter. You can also show the Document window in Outline view mode. Figure 3 12 shows this view with the application s window object open to show the Categories Table Column. You can then set attributes in the Inspector for this selection, which gives you an alternate way to configure the objects in your user interface. This can be useful in complex hierarchies of contained objects, allowing you to select precisely the object you want. Other objects in the Document window are less obvious. File s Owner, First Responder, and Application are invisible objects, because they don t have a visible user interface component. These are called proxy objects because they represent or connect objects outside of the NIB file (created purely in code in Xcode Workspace, for example) to objects in the NIB. The current document (or NIB file) is quite an unusual NIB, since you created it in a vacuum that is, without reference to any Xcode project. Normally a NIB file is instantiated as part of the creation of an Xcode project rather than standalone as you have created it here. You will see an indicator in the status bar showing the project that owns this NIB, and you can see that for the current Document window there is no project. In fact, this NIB file has served its purpose, so close this file; you may save it for future reference in XML format (XIB) or binary format (NIB). From this point onward you will be creating your NIB files by the more conventional route.

You re going to create a couple of real applications now to illustrate exactly how the objects in the NIB connect to each other and to your code.