iPhone app startup zoom effect

I've noticed when starting apps on the iPhone, they first appear as small windows gradually getting bigger and bigger, 开发者_开发问答until filling the entire screen. These small windows look like the applications. However, when running my applications on my iPhone, the zooming windows are always black. Why is that?

You can add a picture to your project, name it Default.png, with the dimensions 320x480, and that will cause it to show when you start up the application.

http://iosdevelopertips.com/cocoa/defaultpng-the-secret-of-the-load-screen.html

It's because they are using a launch image. It's scaled to look like a window filling the screen.

You need to create a Default.png file in your application bundle. See Application Icon and Launch Images:

The file for the application’s launch image is named Default.png. This image should closely resemble the application’s initial user interface; the system displays the launch image before an application is ready to display its user interface, giving users the impression of a quick launch. The launch image should also be a PNG image file, located in the top level of the application bundle. If the application is launched through a URL, the system looks for a launch image named Default-scheme.png, where scheme is the scheme of the URL. If that file is not present, it chooses Default.png instead.