Understanding the UI Components Available in iOS
Mobile devices are powerful computing platforms and can accommodate a wide range of hardware capabilities. New iOS devices often have high-performance cameras, as well as a built-in GPS and one or more sensors.
Now that Apple has made the iOS platform developer-friendly by opening up the platform to outside developers, you can design apps that can control a camera and take photographs, make phone calls and send text messages, and record and play audio and video. Also, your device can sense movement and rotation through its sensors. You can use these capabilities to detect orientation, acceleration, and rotation. ios app development course
In this section, I describe what iOS provides in terms of user-interface components. Figure 9-5 shows you a varied set of UI elements on an iOS screen and the typical location of each element on the screen of a device. As you can see, the window is the background screen, and an instance of a Navigation Bar component is at the top. Also, a view consisting of the Date Picker control and the Text Field control overlays the window. Finally, an instance of the Tab Bar component, composed of bar items, is at the bottom of the screen.
iOS UI elements in a tree-like hierarchy. As shown in this figure, a window is the root of three view hierarchies. The first is the Navigation bar at the top, along with the elements it contains. The second is the Tab bar at the bottom, with its contained elements. The last view on the screen (which is between the Navigation bar and the Tab bar) is the app-specific view hierarchy that is, in a sense, the main view hierarchy of the app. Learn UI Design Course
For more on the iOS view hierarchies, go to www.dummies.com/go/ iosprogramminglinks and check out the iOS View Hierarchy link.
Each element on the screen is a view. That is, the navigation bar is a view as are its components, so are the tab bar and its components, and finally so are the window, the overlaid view, the date picker, and the text field. iOS provides classes that you use to create these views. I discuss these classes next and provide examples of code with their use, starting with the simpler classes (Text Field, Label, and Button), moving on to the more complex ones
(Alert and Picker), and then to the even more complex ones that come with their view controllers. These include the Navigation view, the Tab Bar view, and so on.
For a detailed reference on iOS views, go to www.dummies.com/go/ iosprogramminglinks and check out the iOS Views link.
