UILabel的尺寸是否会恢复其高度？

Question

我正在尝试在我的应用中实现以下内容:

themeLabel = [[UILabel alloc] init];
themeLabel.backgroundColor = [UIColor redColor];
themeLabel.text = themeString;
[themeLabel sizeThatFits:CGSizeMake(274, 274)];
themeLabel.numberOfLines = 0;
[topThemeView addSubview:themeLabel];

NSLog(@"Height is %f ", themeLabel.frame.size.height);

[themeLabel setFrame:CGRectMake(leftMargin, mainScrollView.frame.origin.y + topPadding, 274, themeLabel.frame.size.height)];

而我最终得到的Label's高度0.0.有什么想法吗？

Answer 1

themeLabel = [[UILabel alloc] init];
themeLabel.backgroundColor = [UIColor redColor];
themeLabel.text = themeString;
themeLabel.numberOfLines = 0;

CGRect labelFrame = CGRectMake(leftMargin, mainScrollView.frame.origin.y + topPadding, 0.0, 0.0);
labelFrame.size = [themeLabel sizeThatFits:CGSizeMake(274, 274)];

[themeLabel setFrame:labelFrame];
[topThemeView addSubview:themeLabel];