How do you put a normal control into an NSView?

Question

What I'm actually trying to do is put a WebKitView into a ScreenSaver (which inherits NSView). I'm totally new to MacOS X and Cocoa (but I'm very familiar with Objective-C and used some parts of GNUStep). Do I need some laying out? I want to show only one control in the whole NSView.

Answer 1

In your initWithFrame:isPreview: method, create a WebView in the usual way, then, send yourself an addSubview: message, passing the web view:

webView = [[WebView alloc] initWithFrame:frame];
[self addSubview:webView];

If you're wondering what rectangle you should pass as the WebView's frame, read the View Programming Guide. Also, don't forget to release the webView in dealloc (or autorelease it in initWithFrame:isPreview:).

Once you have your web view, you'll need to load a page into it. Set a suitably long animation interval (at least a couple of seconds), and load the page in animateOneFrame:

- (void) animateOneFrame {
    [[webView mainFrame] loadRequest:[NSURLRequest requestWithURL:[NSURL URLWithString:@"http://google.com/"]]];
}

You may also want to handle WebViewProgressFinishedNotification, and put off re-loading the web view until that happens (to compensate for slow or soaked connections). You'll do this with an instance variable, which you set to YES in both initWithFrame:isPreview: and your notification-handler method, and test and set to NO in animateOneFrame:

- (void) animateOneFrame {
    if (hasFinished) {
        [[webView mainFrame] loadRequest:[NSURLRequest requestWithURL:[NSURL URLWithString:@"http://google.com/"]]];
        hasFinished = NO;
    }
}

Answer 2

[aScreenSaverView addSubview:aWebKitView];

But why add a UIWebView into a screen saver view when you can just make the UIWebView take up the full screen on its own? Introducing view hierarchies where they are not needed is not a good idea because it increases the processing needed to display the interface.

Answer 3

You can also not worry too much about your animation interval by calling

[self stopAnimation];

at the end of your animateOneFrame method.