Ios UILabel在Objective-C中不显示任何内容

UILabel上可以显示的字数和字符数是否有任何限制。我正在尝试为Label lblUsername分配近10000个字符，如果少于1000个字符，它将显示标签上的文本，但在接近10000个字符时，它不会显示任何内容。这是我的objective-c代码

 UILabel *lblUsername=[[UILabel alloc] initWithFrame:CGRectMake(100,100,100,20)];
        lblUsername.numberOfLines = 0;
       lblUsername.text=@"Username sdfsdfsdfsdfsdfdsfsd  sdfsdfsdfsdf sdfsdfsdf sdjkskdfksdfkjsdkjfsdjfksjdkskdjfkdsjfkjsdjfkjjdsfkdskjfjskd sd sdfjsjkjksdkfjksdfjksdfjjsdkfjksdfjksdjfkjsdkfjsdjfkjsdkfjUsername sdfsdfsdfsdfsdfdsfsd  sdfsdfsdfsdf sdfsdfsdf sdjkskdfksdfkjsdkjfsdjfksjdkskdjfkdsjfkjsdjfkjjdsfkdskjfjskd sd sdfjsjkjksdkfjksdfjksdfjjsdkfjksdfjksdjfkjsdkfjsdjfkjsdkfjUsername sdfsdfsdfsdfsdfdsfsd  sdfsdfsdfsdf sdfsdfsdf sdjkskdfksdfkjsdkjfsdjfksjdkskdjfkdsjfkjsdjfkjjdsfkdskjfjskd sd sdfjsjkjksdkfjksdfjksdfjjsdkfjksdfjksdjfkjsdkfjsdjfkjsdkfjUsername sdfsdfsdfsdfsdfdsfsd  sdfsdfsdfsdf sdfsdfsdf sdjkskdfksdfkjsdkjfsdjfksjdkskdjfkdsjfkjsdjfkjjdsfkdskjfjskd sd sdfjsjkjksdkfjksdfjksdfjjsdkfjksdfjksdjfkjsdkfjsdjfkjsdkfjUsername sdfsdfsdfsdfsdfdsfsd  sdfsdfsdfsdf sdfsdfsdf sdjkskdfksdfkjsdkjfsdjfksjdkskdjfkdsjfkjsdjfkjjdsfkdskjfjskd sd sdfjsjkjksdkfjksdfjksdfjjsdkfjksdfjksdjfkjsdkfjsdjfkjsdkfjUsername sdfsdfsdfsdfsdfdsfsd  sdfsdfsdfsdf sdfsdfsdf sdjkskdfksdfkjsdkjfsdjfksjdkskdjfkdsjfkjsdjfkjjdsfkdskjfjskd sd sdfjsjkjksdkfjksdfjksdfjjsdkfjksdfjksdjfkjsdkfjsdjfkjsdkfjUsername sdfsdfsdfsdfsdfdsfsd  sdfsdfsdfsdf sdfsdfsdf sdjkskdfksdfkjsdkjfsdjfksjdkskdjfkdsjfkjsdjfkjjdsfkdskjfjskd sd sdfjsjkjksdkfjksdfjksdfjjsdkfjksdfjksdjfkjsdkfjsdjfkjsdkfjUsername sdfsdfsdfsdfsdfdsfsd  sdfsdfsdfsdf sdfsdfsdf sdjkskdfksdfkjsdkjfsdjfksjdkskdjfkdsjfkjsdjfkjjdsfkdskjfjskd sd sdfjsjkjksdkfjksdfjksdfjjsdkfjksdfjksdjfkjsdkfjsdjfkjsdkfjUsername sdfsdfsdfsdfsdfdsfsd  sdfsdfsdfsdf sdfsdfsdf sdjkskdfksdfkjsdkjfsdjfksjdkskdjfkdsjfkjsdjfkjjdsfkdskjfjskd sd sdfjsjkjksdkfjksdfjksdfjjsdkfjksdfjksdjfkjsdkfjsdjfkjsdkfjUsername sdfsdfsdfsdfsdfdsfsd  sdfsdfsdfsdf sdfsdfsdf sdjkskdfksdfkjsdkjfsdjfksjdkskdjfkdsjfkjsdjfkjjdsfkdskjfjskd sd sdfjsjkjksdkfjksdfjksdfjjsdkfjksdfjksdjfkjsdkfjsdjfkjsdkfjUsername sdfsdfsdfsdfsdfdsfsd  sdfsdfsdfsdf sdfsdfsdf sdjkskdfksdfkjsdkjfsdjfksjdkskdjfkdsjfkjsdjfkjjdsfkdskjfjskd sd sdfjsjkjksdkfjksdfjksdfjjsdkfjksdfjksdjfkjsdkfjsdjfkjsdkfjUsername sdfsdfsdfsdfsdfdsfsd  sdfsdfsdfsdf sdfsdfsdf sdjkskdfksdfkjsdkjfsdjfksjdkskdjfkdsjfkjsdjfkjjdsfkdskjfjskd sd sdfjsjkjksdkfjksdfjksdfjjsdkfjksdfjksdjfkjsdkfjsdjfkjsdkfjUsername sdfsdfsdfsdfsdfdsfsd  sdfsdfsdfsdf sdfsdfsdf sdjkskdfksdfkjsdkjfsdjfksjdkskdjfkdsjfkjsdjfkjjdsfkdskjfjskd sd sdfjsjkjksdkfjksdfjksdfjjsdkfjksdfjksdjfkjsdkfjsdjfkjsdkfjUsername sdfsdfsdfsdfsdfdsfsd  sdfsdfsdfsdf sdfsdfsdf sdjkskdfksdfkjsdkjfsdjfksjdkskdjfkdsjfkjsdjfkjjdsfkdskjfjskd sd sdfjsjkjksdkfjksdfjksdfjjsdkfjksdfjksdjfkjsdkfjsdjfkjsdkfjUsername sdfsdfsdfsdfsdfdsfsd  sdfsdfsdfsdf sdfsdfsdf sdjkskdfksdfkjsdkjfsdjfksjdkskdjfkdsjfkjsdjfkjjdsfkdskjfjskd sd sdfjsjkjksdkfjksdfjksdfjjsdkfjksdfjksdjfkjsdkfjsdjfkjsdkfj";
        [lblUsername sizeToFit];
      // lblUsername.tag=i;
       lblUsername.textColor=[UIColor blueColor];
        lblUsername.backgroundColor=[UIColor yellowColor];
       lblUsername.font=[UIFont fontWithName:@"Helvetica" size:12];

---

您的框架太小，无法显示其大小，因此会进一步减小它。这是您的代码的工作示例：

我刚刚添加了一个属性：

@property (nonatomic) UILabel *lblUsername;

然后我设置了所有与视图相关的内容：

_lblUsername=[[UILabel alloc] initWithFrame:CGRectZero];
_lblUsername.numberOfLines = 0;
_lblUsername.text=@"Username sdfsdfsdfsdfsdfdsfsd  sdfsdfsdfsdf sdfsdfsdf sdjkskdfksdfkjsdkjfsdjfksjdkskdjfkdsjfkjsdjfkjjdsfkdskjfjskd sd sdfjsjkjksdkfjksdfjksdfjjsdkfjksdfjksdjfkjsdkfjsdjfkjsdkfjUsername sdfsdfsdfsdfsdfdsfsd  sdfsdfsdfsdf sdfsdfsdf sdjkskdfksdfkjsdkjfsdjfksjdkskdjfkdsjfkjsdjfkjjdsfkdskjfjskd sd sdfjsjkjksdkfjksdfjksdfjjsdkfjksdfjksdjfkjsdkfjsdjfkjsdkfjUsername sdfsdfsdfsdfsdfdsfsd  sdfsdfsdfsdf sdfsdfsdf sdjkskdfksdfkjsdkjfsdjfksjdkskdjfkdsjfkjsdjfkjjdsfkdskjfjskd sd sdfjsjkjksdkfjksdfjksdfjjsdkfjksdfjksdjfkjsdkfjsdjfkjsdkfjUsername sdfsdfsdfsdfsdfdsfsd  sdfsdfsdfsdf sdfsdfsdf sdjkskdfksdfkjsdkjfsdjfksjdkskdjfkdsjfkjsdjfkjjdsfkdskjfjskd sd sdfjsjkjksdkfjksdfjksdfjjsdkfjksdfjksdjfkjsdkfjsdjfkjsdkfjUsername sdfsdfsdfsdfsdfdsfsd  sdfsdfsdfsdf sdfsdfsdf sdjkskdfksdfkjsdkjfsdjfksjdkskdjfkdsjfkjsdjfkjjdsfkdskjfjskd sd sdfjsjkjksdkfjksdfjksdfjjsdkfjksdfjksdjfkjsdkfjsdjfkjsdkfjUsername sdfsdfsdfsdfsdfdsfsd  sdfsdfsdfsdf sdfsdfsdf sdjkskdfksdfkjsdkjfsdjfksjdkskdjfkdsjfkjsdjfkjjdsfkdskjfjskd sd sdfjsjkjksdkfjksdfjksdfjjsdkfjksdfjksdjfkjsdkfjsdjfkjsdkfjUsername sdfsdfsdfsdfsdfdsfsd  sdfsdfsdfsdf sdfsdfsdf sdjkskdfksdfkjsdkjfsdjfksjdkskdjfkdsjfkjsdjfkjjdsfkdskjfjskd sd sdfjsjkjksdkfjksdfjksdfjjsdkfjksdfjksdjfkjsdkfjsdjfkjsdkfjUsername sdfsdfsdfsdfsdfdsfsd  sdfsdfsdfsdf sdfsdfsdf sdjkskdfksdfkjsdkjfsdjfksjdkskdjfkdsjfkjsdjfkjjdsfkdskjfjskd sd sdfjsjkjksdkfjksdfjksdfjjsdkfjksdfjksdjfkjsdkfjsdjfkjsdkfjUsername sdfsdfsdfsdfsdfdsfsd  sdfsdfsdfsdf sdfsdfsdf sdjkskdfksdfkjsdkjfsdjfksjdkskdjfkdsjfkjs sdfsdfsdfsdfsdfdsfsd  sdfsdfsdfsdf sdfsdfsdf sdjkskdfksdfkjsdkjfsdjfksjdkskdjfkdsjfkjsdjfkjjdsfkdskjfjskd sd sdfjsjkjksdkfjksdfjksdfjjsdkfjksdfjksdjfkjsdkfjsdjfkjsdkfjUsername sdfsdfsdfsdfsdfdsfsd  sdfsdfsdfsdf sdfsdfsdf sdjkskdfksdfkjsdkjfsdjfksjdkskdjfkdsjfkjsdjfkjjdsfkdskjfjskd sd sdfjsjkjksdkfjksdfjksdfjjsdkfjksdfjksdjfkjsdkfjsdjfkjsdkfj jsdkfjUsername sdfsdfsdfsdfsdfdsfsd  sdfsdfsdfsdf sdfsdfsdf sdjkskdfksdfkjsdkjfsdjfksjdkskdjfkdsjfkjsdjfkjjdsfkdskjfjskd sd sdfjsjkjksdkfjksdfjksdfjjsdkfjksdfjksdjfkjsdkfjsdjfkjsdkfjUsername sdfsdfsdfsdfsdfdsfsd  sdfsdfsdfsdf sdfsdfsdf sdjkskdfksdfkjsdkjfsdjfksjdkskdjfkdsjfkjs sdfsdfsdfsdfsdfdsfsd  sdfsdfsdfsdf sdfsdfsdf sdjkskdfksdfkjsdkjfsdjfksjdkskdjfkdsjfkjsdjfkjjdsfkdskjfjskd sd sdfjsjkjksdkfjksdfjksdfjjsdkfjksdfjksdjfkjsdkfjsdjfkjsdkfjUsername sdfsdfsdfsdfsdfdsfsd  sdfsdfsdfsdf sdfsdfsdf sdjkskdfksdfkjsdkjfsdjfksjdkskdjfkdsjfkjsdjfkjjdsfkdskjfjskd sd sdfjsjkjksdkfjksdfjksdfjjsdkfjksdfjksdjfkjsdkfjsdjfkjsdkfj";
// lblUsername.tag=i;
_lblUsername.textColor=[UIColor blueColor];
_lblUsername.backgroundColor=[UIColor yellowColor];
_lblUsername.font=[UIFont fontWithName:@"Helvetica" size:12];
[self.view addSubview:_lblUsername];

然后我设置了一个合适的框架，你的框架太小了：

- (void)viewDidLayoutSubviews {
    [super viewDidLayoutSubviews];
    [_lblUsername setFrame:CGRectMake(10, 10, CGRectGetWidth(self.view.bounds) - 20, CGRectGetHeight(self.view.bounds) - 20)];
}

一切正常，我可以看到整个文本。长度没有限制，但您可能需要稍后滚动，因为文本对于您的视图来说太长了

---

您应该比我在这里使用viewDidLoad和ViewDidLayoutSubView的快速示例做得更好。您应该创建单独的视图，将其指定为self.view，在initWithFrame:method中创建标签和视图中的其他内容，并在layoutSubviews方法中布局所有内容。

在视图层次检查器中，您可以看到实际上显示了文本，但标签的开头是额外的空间

rmaddy的评论是对的，我觉得自己很愚蠢，没有早点看到它：因为字体和大小会影响文本需要的大小，所以你必须在设置好所有内容后调用它。因此，只要做：

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    UILabel *lblUsername=[[UILabel alloc] initWithFrame:CGRectMake(100,100,100,20)];
    lblUsername.numberOfLines = 0;
    lblUsername.text=@"Username sdfsdfsdfsdfsdfdsfsd  sdfsdfsdfsdf sdfsdfsdf sdjkskdfksdfkjsdkjfsdjfksjdkskdjfkdsjfkjsdjfkjjdsfkdskjfjskd sd sdfjsjkjksdkfjksdfjksdfjjsdkfjksdfjksdjfkjsdkfjsdjfkjsdkfjUsername sdfsdfsdfsdfsdfdsfsd  sdfsdfsdfsdf sdfsdfsdf sdjkskdfksdfkjsdkjfsdjfksjdkskdjfkdsjfkjsdjfkjjdsfkdskjfjskd sd sdfjsjkjksdkfjksdfjksdfjjsdkfjksdfjksdjfkjsdkfjsdjfkjsdkfjUsername sdfsdfsdfsdfsdfdsfsd  sdfsdfsdfsdf sdfsdfsdf sdjkskdfksdfkjsdkjfsdjfksjdkskdjfkdsjfkjsdjfkjjdsfkdskjfjskd sd sdfjsjkjksdkfjksdfjksdfjjsdkfjksdfjksdjfkjsdkfjsdjfkjsdkfjUsername sdfsdfsdfsdfsdfdsfsd  sdfsdfsdfsdf sdfsdfsdf sdjkskdfksdfkjsdkjfsdjfksjdkskdjfkdsjfkjsdjfkjjdsfkdskjfjskd sd sdfjsjkjksdkfjksdfjksdfjjsdkfjksdfjksdjfkjsdkfjsdjfkjsdkfjUsername sdfsdfsdfsdfsdfdsfsd  sdfsdfsdfsdf sdfsdfsdf sdjkskdfksdfkjsdkjfsdjfksjdkskdjfkdsjfkjsdjfkjjdsfkdskjfjskd sd sdfjsjkjksdkfjksdfjksdfjjsdkfjksdfjksdjfkjsdkfjsdjfkjsdkfjUsername sdfsdfsdfsdfsdfdsfsd  sdfsdfsdfsdf sdfsdfsdf sdjkskdfksdfkjsdkjfsdjfksjdkskdjfkdsjfkjsdjfkjjdsfkdskjfjskd sd sdfjsjkjksdkfjksdfjksdfjjsdkfjksdfjksdjfkjsdkfjsdjfkjsdkfjUsername sdfsdfsdfsdfsdfdsfsd  sdfsdfsdfsdf sdfsdfsdf sdjkskdfksdfkjsdkjfsdjfksjdkskdjfkdsjfkjsdjfkjjdsfkdskjfjskd sd sdfjsjkjksdkfjksdfjksdfjjsdkfjksdfjksdjfkjsdkfjsdjfkjsdkfjUsername sdfsdfsdfsdfsdfdsfsd  sdfsdfsdfsdf sdfsdfsdf sdjkskdfksdfkjsdkjfsdjfksjdkskdjfkdsjfkjsdjfkjjdsfkdskjfjskd sd sdfjsjkjksdkfjksdfjksdfjjsdkfjksdfjksdjfkjsdkfjsdjfkjsdkfjUsername sdfsdfsdfsdfsdfdsfsd  sdfsdfsdfsdf sdfsdfsdf sdjkskdfksdfkjsdkjfsdjfksjdkskdjfkdsjfkjsdjfkjjdsfkdskjfjskd sd sdfjsjkjksdkfjksdfjksdfjjsdkfjksdfjksdjfkjsdkfjsdjfkjsdkfjUsername sdfsdfsdfsdfsdfdsfsd  sdfsdfsdfsdf sdfsdfsdf sdjkskdfksdfkjsdkjfsdjfksjdkskdjfkdsjfkjsdjfkjjdsfkdskjfjskd sd sdfjsjkjksdkfjksdfjksdfjjsdkfjksdfjksdjfkjsdkfjsdjfkjsdkfjUsername sdfsdfsdfsdfsdfdsfsd  sdfsdfsdfsdf sdfsdfsdf sdjkskdfksdfkjsdkjfsdjfksjdkskdjfkdsjfkjsdjfkjjdsfkdskjfjskd sd sdfjsjkjksdkfjksdfjksdfjjsdkfjksdfjksdjfkjsdkfjsdjfkjsdkfjUsername sdfsdfsdfsdfsdfdsfsd  sdfsdfsdfsdf sdfsdfsdf sdjkskdfksdfkjsdkjfsdjfksjdkskdjfkdsjfkjsdjfkjjdsfkdskjfjskd sd sdfjsjkjksdkfjksdfjksdfjjsdkfjksdfjksdjfkjsdkfjsdjfkjsdkfjUsername sdfsdfsdfsdfsdfdsfsd  sdfsdfsdfsdf sdfsdfsdf sdjkskdfksdfkjsdkjfsdjfksjdkskdjfkdsjfkjsdjfkjjdsfkdskjfjskd sd sdfjsjkjksdkfjksdfjksdfjjsdkfjksdfjksdjfkjsdkfjsdjfkjsdkfjUsername sdfsdfsdfsdfsdfdsfsd  sdfsdfsdfsdf sdfsdfsdf sdjkskdfksdfkjsdkjfsdjfksjdkskdjfkdsjfkjsdjfkjjdsfkdskjfjskd sd sdfjsjkjksdkfjksdfjksdfjjsdkfjksdfjksdjfkjsdkfjsdjfkjsdkfjUsername sdfsdfsdfsdfsdfdsfsd  sdfsdfsdfsdf sdfsdfsdf sdjkskdfksdfkjsdkjfsdjfksjdkskdjfkdsjfkjsdjfkjjdsfkdskjfjskd sd sdfjsjkjksdkfjksdfjksdfjjsdkfjksdfjksdjfkjsdkfjsdjfkjsdkfj";
    // lblUsername.tag=i;
    lblUsername.textColor=[UIColor blueColor];
    lblUsername.backgroundColor=[UIColor yellowColor];
    lblUsername.font=[UIFont fontWithName:@"Helvetica" size:12];
    [lblUsername sizeToFit];
    [self.view addSubview:lblUsername];
}


@end 

---

你添加到视图中了吗？[self.view addSubview:lblUsername]@格雷格，我猜他是这样做的，因为他说UILabel在少于1000个字符时会显示文本。你不使用UITextView而不是UILabel吗？用户名为10000个字符-我不会用我的iPhone键盘登录你的服务…调用sizeToFit后标签的框架是什么？这可能是因为有一些限制阻止你的标签变大吗？可能是因为sizeToFit停止在设备帧处吗？：在某些情况下，如果视图没有superview，它可能会根据屏幕边界调整自身大小。因此，如果希望给定视图根据其父视图调整自身大小，则应在调用此方法之前将其添加到父视图中。在UIViewDoc中，您应该始终键入视图弱属性，因为它们属于superview@vikingosegundo取决于您是否首先将它们添加到superview。我提出了这个解决方案，因为它可以更快地解释框架是如何工作的，这就是提问者的问题。我的解决方案不会产生任何内存泄漏，也不会保留周期。Ofc在这种情况下，它可能很弱，但在添加到视图后，您必须首先创建一个ivar并将其分配给属性-我认为这对于一篇文章来说解释太多了，特别是这里没有这个问题。我也觉得你的答案和我之前的答案有点一样；P、 尤其是与我的答案几乎相同的代码…我不是说你需要解释一切。但是如果我们提供代码，我们应该以无bug的方式来做。您的代码将导致泄漏。关于你的剽窃指控，请看我在你的回答下面留下的评论。称sizeToFit不会使标签变小。它调整标签的大小，使其足以容纳文本。但是对sizeToFit的要求应该在设置字体和其他所有东西之后。我的评论不是关于剽窃，而是发布了几乎相同的答案，这是什么感觉。。。关于泄密我已经说过了，没有泄密。保留2个强引用不会泄露。在这种情况下，没有泄漏。正如我在评论中指出的那样，您的代码不是无bug的非原子代码与原子代码，甚至比我的代码还要多，因为您的代码会降低执行速度，而我的代码不会。您应该使标签非原子，因为默认情况下它是原子代码。在这种情况下，不需要像在大多数情况下一样使用较慢的原子选项，尤其是在与UI连接的情况下。还有，为什么在viewDidLoad中调用sizeToFit？在这个代码中是多余的。我仍然觉得你编辑的答案非常好！在代码上与我之前的回答类似-很遗憾，尤其是在你没有代码之前。我的第一个版本已经包含了第一个屏幕截图。你觉得我在photoshop上画的东西怎么样？当然，我首先使用的是代码。此外，layoutSubview并不是真正的秘密方法。CoreGraphics函数也是如此。你完全改变了框架，而我只改变了高度。我从你那里偷的东西不多，我不认为你偷了什么。我只是说你的答案和我的几乎一样。我不反对你的第一个截图，因为它增加了讨论。后一个代码是+ -我的答案的重复。如果你认为2行和一个漏洞，你添加到代码中的问题是如此伟大和新颖的工作，你可以考虑考虑在IEEE提交一份文件。甚至结果也不一样。你制作了一个接近全屏的标签，而我尊重OPs标签的宽度尺寸和原点。泄漏在哪里？您甚至可能持有100个强引用，所有这些都将在视图 将在我显示的代码的情况下解除分配。这是个玩笑，这里没有漏洞。去IEEE，教他们如何思考泄漏问题。我已经告诉了我的意图以及为什么既没有泄漏也没有保留循环，所以我不会继续这个完全疯狂的讨论，除非有人告诉我为什么会有泄漏——如果是的话，我很乐意学习。我没看到有漏洞。尤其是您的代码也缺少一些要点。给我的。