Question

I have a weird problem with a simple NSScrollView on the Mac. I just started programming in Cocoa, but I had previous experience with UIKit on iOS. I added an NSScrollView to my xib file and subclassed the NSView that was automatically generated by Xcode when I dropped the scroll view in my window. The subclass simply adds content views to the scrollview and draws a background. Here it is:

#import "TweetsView.h"

@implementation TweetsView

- (id)initWithFrame:(NSRect)frame
{
    self = [super initWithFrame:frame];
    if (self) {
        // Initialization code here.
    }

    return self;
}

- (void)awakeFromNib {

    [self reload];

}

- (void)reload {

    //Retrieve tweets
    ACAccount *account = [[TwitterModel retrieveTwitterAccounts] objectAtIndex:1];
    TwitterModel *model = [[TwitterModel alloc] init];
    NSArray *timeline = [model retrieveMainTimelineWithAccount:account];

    //Display the tweets
    int stackHeight = 0;
    for (NSDictionary *tweetDictionary in timeline) {

        TweetView *tweetView = [[TweetView alloc] initWithFrame:NSMakeRect(0, stackHeight, self.frame.size.width, 60)];
        [tweetView setMainText:[tweetDictionary objectForKey:@"text"]];
        [self addSubview:tweetView];

        stackHeight += (int)tweetView.frame.size.height;
    }
    self.frame = NSMakeRect(self.frame.origin.x, self.frame.origin.y, self.frame.size.width, stackHeight);

}

- (void)drawRect:(NSRect)dirtyRect
{

    [[NSColor colorWithCalibratedRed:0.96 green:0.96 blue:0.96 alpha:1.0] setFill];
    NSRectFill(dirtyRect);

    [super drawRect:dirtyRect];

}

- (void)setTweets:(NSArray *)tweets {
    _tweets = tweets;
}

- (NSArray *)tweets {
    return _tweets;
}

@end

When I run this program the scroll view will display just normal but I can’t scroll it with my trackpad. The scrollbars don’t appear either. When I resize the window the scrollbars appear for a second just like they normally do in a Cocoa application, and if I’m quick I can scroll by dragging the scroll bars then. So I think the Scroll View does exist, but it doesn’t respond to my mouse and gestures.

What am I doing wrong here? I’m running Mountain Lion and Xcode 4.4 and there are no views in front of the scroll view.
Thanks in advance!

Answer 1

Apparently the document view of my scroll view was a subclass of NSScrollView which is obviously wrong. I changed it to a subclass of NSView and now the problem is fixed.