ios-添加圖片到scrollveiw不成功

添加圖片到scrollveiw不成功

為什麼我用下面的代碼添加圖片到UIscrollView不成功？顯示的是一個空白屏幕。

UIImageView *imageView = [[UIImageView alloc] initWithFrame:CGRectMake(self.scrollView.frame.size.width * 1, 0, self.scrollView.frame.size.width, self.scrollView.frame.size.height)];
    imageView.backgroundColor = [UIColor redColor];
    [imageView setImage:[UIImage imageNamed:@"placeholder.png"]];
    [self.scrollView addSubview:imageView];
    self.scrollView.contentSize = CGSizeMake(self.scrollView.frame.size.width * self.urlArray.count, self.scrollView.frame.size.height);

最佳回答：

UIImageView *imageView = [[UIImageView alloc] initWithFrame:CGRectMake(0, 0, self.scrollView.frame.size.width, self.scrollView.frame.size.height)];

要給 UIScrollView 添加合適的 contentSize ，還有給 UIView 添加 UIScrollView