TTImageView problem - objective-c

Question

I want to display some TTImageView in a TTScrollView.
- (UIView*)scrollView:(TTScrollView*)scrollView pageAtIndex:(NSInteger)pageIndex {
TTView* pageView = nil;
if (!pageView) {
pageView = [[[TTView alloc] init] autorelease];
pageView.backgroundColor = [UIColor clearColor];
pageView.userInteractionEnabled = NO;
}
NSString *imagePath = [self.screenShotImgPath objectAtIndex:pageIndex];
TTImageView *imageView = [[[TTImageView alloc] initWithFrame:CGRectZero] autorelease];
imageView.autoresizesToImage = YES;
imageView.urlPath = imagePath;
imageView.backgroundColor = [UIColor clearColor];
imageView.delegate = self;
//here I need to rotate image
if (imageView.width > imageView.height){
CGAffineTransform tran = CGAffineTransformIdentity;
CGSize bnds = imageView.size;
CGSize bnds2 = imageView.size;
bnds = [self swapWidthAndHeight:bnds];
tran = CGAffineTransformMakeTranslation(0.0,bnds2.width);
tran = CGAffineTransformRotate(tran, [self degreesToRadians:-90.0]);
imageView.transform = tran;
}
//here I need to scale image view frame to fit image actual scale
CGFloat scale = imageView.width/imageView.height;
CGFloat scaledWidth = (scrollView.height - 20.f) * scale;
imageView.frame = CGRectMake((scrollView.width - scaledWidth)/2, 10.f, scaledWidth, scrollView.height - 20.f);
[pageView addSubview:imageView];
return pageView;
}
but there is a problem: TTImageView download image asynchronously. So it is quit possible that when code go to
if (imageView.width > imageView.height){
this line the image is not loaded. So a exception is thrown.
Since the image view is added in
- (UIView*)scrollView:(TTScrollView*)scrollView pageAtIndex:(NSInteger)pageIndex {
so I can't move the below rotate code out of this method
if (imageView.width > imageView.height){
CGAffineTransform tran = CGAffineTransformIdentity;
CGSize bnds = imageView.size;
CGSize bnds2 = imageView.size;
bnds = [self swapWidthAndHeight:bnds];
tran = CGAffineTransformMakeTranslation(0.0,bnds2.width);
tran = CGAffineTransformRotate(tran, [self degreesToRadians:-90.0]);
imageView.transform = tran;
}
What I can do to solove this problem?

Answer 1

You can add a <TTImageViewDelegate> in your .h file
and this function in the .m:
#pragma mark TTImageViewDelegate
-(void) imageView:(TTImageView *)imageView didLoadImage:(UIImage *)image{
if (image){
//do your logic
}
}
This function will be triggered when the image is finished loading.