Building web apps with Dashcode in Objective-C

Generate QR in Objective-C Building web apps with Dashcode

Once you ve started up Dashcode, you ll need to begin a project by selecting a template. Each of these templates comes partially filled in with different starting objects intended to make your development experience quicker and simpler. The various possibilities are summarized in table 7.1.

Table 7.1 Dashcode templates get you started quickly Summary A navigation controller that is list-based A totally blank application An application that displays and plays podcasts An application that reads and displays an RSS feed A flipside controller with two screens SDK equivalent Navigation-based application Window-based application N/A N/A Utility application

Note that for each template we ve listed an SDK equivalent template. Apple has used many common techniques for both SDK and Dashcode development, and if you re transitioning from one to another, these equivalents will help guide you; otherwise, you can ignore them. Generally, you should be able to easily decide which template you want to use based on the needs of your web app. If you re linking to podcasts or RSS feeds, you ll use those specific templates. The Utility template should be used whenever you want a simple one-page application with information or preferences of some sort on a second page, and the Browser template should be used whenever you want to build hierarchies of lists. If none of the templates applies, the Custom template is the right place to start.

When you start a Dashcode project, the main screen will display what your project currently looks like, and it ll also feature a huge variety of buttons and other controls that can be used to build it up. For example, the starting screen for a project based on the RSS template is shown in figure 7.1. The Dashcode screen is broadly divided into three parts. Above is the top bar, which features a few useful buttons. Below and to the right is the canvas. This is area where you can see what your web app looks like. To the left is the navigator, which gives you access to the entirety of your program (and to some helpful advice). There are three additional screens that aren t initially visible, but which are each quite important: the source code panel, the inspector and the Library. We ll talk about each of these in turn.

Figure 7.1 Dashcode includes a top bar (top) for important buttons, a navigator (left) for getting around your web page, and a canvas (right) to show off your content. ABOUT THE TOP BAR

The top bar provides you with buttons to get to a few important pages inside Dashcode. It s how you call up the inspector and the Library. The View menu lets you replace the canvas and source code panels with some of the subsidiary panels that we re not going to dig into in this overview. Finally, the Run button lets you test out web apps as you write them. The top bar doesn t bear much additional discussion, but it s a great navigational tool inside Dashcode.

Dashcode s development canvas is the right panel of the main page. It s simple and easy to use. You can manipulate graphical objects there by dragging them around, and the canvas will try to help you keep things aligned by showing clear blue lines when objects align to the middle or edges of the screen. It ll also sometimes limit where your object can go. For example, if you drag around some of the locations for the article listings in the existing template, you will see limits on positioning based on

whether you re using absolute or document-flow positioning for an individual object. This can be adjusted using the inspector for the object, a topic we ll return to shortly. Resizing items is equally simple. Besides that, you can also change the textual content of most objects within the canvas. For example, double-clicking on My RSS Feed in the RSS example will allow you to change that title on the page. Just keep in mind that the canvas is a graphical user interface. You can use it to eyeball the placement of objects in your web app and to make quick and easy changes to the content.