Iphone 设置UILabel背景色会导致应用程序崩溃

我有以下代码：

UIImageView *photo = [[[UIImageView alloc] initWithFrame:CGRectMake(title_bar.titleView.frame.origin.x+130, title_bar.titleView.frame.origin.y-12, 22.0, 22.0)] autorelease];
UIImage *theImage = [UIImage imageNamed:@"question mark icon"];
photo.image = theImage;
UIView *new_view = [[UIView alloc] init];
[new_view addSubview:photo];
UILabel *new_label = [[UILabel alloc] initWithFrame:CGRectMake(title_bar.titleView.frame.origin.x-145, title_bar.titleView.frame.origin.y-12, 268.0, 22.0)];
[new_label setText:@"gregrgtg"];
[new_label setBackgroundColor:[UIColor clearColor]]; //COMMENTING THIS LINE OUT MAKES IT WORK
[new_view addSubview:new_label];
title_bar.titleView = new_view;

当背景色设置为“清除”时，程序会发出信号。如果我注释掉那一行，除了标签的背景是白色外，效果很好。另外，如果我只是初始化标签而不是用框架初始化它，程序不会崩溃，但是我的标签看不见

UIImageView *photo = [[[UIImageView alloc] initWithFrame:CGRectMake(title_bar.titleView.frame.origin.x+130, title_bar.titleView.frame.origin.y-12, 22.0, 22.0)] autorelease];
UIImage *theImage = [UIImage imageNamed:@"question mark icon"];
photo.image = theImage;
UIView *new_view = [[UIView alloc] init];
[new_view addSubview:photo];

title_bar.titleView = new_view;//this line by madhu

UILabel *new_label = [[UILabel alloc] initWithFrame:CGRectMake(title_bar.titleView.frame.origin.x-145, title_bar.titleView.frame.origin.y-12, 268.0, 22.0)];
[new_label setText:@"gregrgtg"];
[new_label setBackgroundColor:[UIColor clearColor]]; //COMMENTING THIS LINE OUT MAKES IT WORK
[new_view addSubview:new_label];

原因:

你至少已经添加了你的标题栏的标题视图，但之前已经将其引用

原因:

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您至少添加了标题栏的标题视图，但之前已将其转介。

谢谢，效果不错！如果你不介意的话，你知道它为什么有效吗？我不认为这会有什么不同。谢谢，这很有效！如果你不介意的话，你知道它为什么有效吗？我认为这不会有什么不同。