NSTextField和AutoLayout：自动增长高度 - >以编程方式

Question

如果我在界面构建器中创建一个标签并通过代码设置字符串不符合其当前大小，则标签将垂直增长以适合其大小，太棒了！ 除了x约束，Xcode还创建了一个NSContentSizeLayoutConstraint，它包含拥抱和压缩阻力。

这里是约束

<NSContentSizeLayoutConstraint:0x6080000a11a0 V:[NSTextField:0x600000180c30(17)] Hug:750 CompressionResistance:750> 

的问题是一个日志输出，如何以编程方式做到这一点？我还没有找到方法。没有办法创建一个NSContentSizeLayoutConstraint，并且设置NSTextField的contentCompressionResistance似乎没有任何作用。

这里是我的代码：

self.label = [[NSTextField alloc]initWithFrame:NSMakeRect(0, 0, 100, 20)]; 
[self.label setTranslatesAutoresizingMaskIntoConstraints:NO]; 
[self.label setBordered:YES]; 
[[self.label cell] setLineBreakMode:NSLineBreakByWordWrapping]; 
[self.window.contentView addSubview:self.label]; 
self.label.stringValue = @"Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum."; 

NSDictionary *dict = @{@"label" : self.label}; 
[self.label.superview addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"H:|-[label]"options:0 metrics:nil views:dict]]; 
[self.label.superview addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"V:|-[label]" options:0 metrics:nil views:dict]]; 

NSLayoutConstraint *constraint = [NSLayoutConstraint constraintWithItem:self.label attribute:NSLayoutAttributeWidth relatedBy:NSLayoutRelationEqual toItem:nil attribute:0 multiplier:0 constant:40]; 
constraint.priority = 1; 
[self.label addConstraint:constraint]; 
constraint = [NSLayoutConstraint constraintWithItem:self.label attribute:NSLayoutAttributeHeight relatedBy:NSLayoutRelationEqual toItem:nil attribute:0 multiplier:0 constant:18]; 
constraint.priority = 1; 
[self.label addConstraint:constraint]; 

[self.label setContentCompressionResistancePriority:1000 forOrientation:NSLayoutConstraintOrientationHorizontal]; 
[self.label setContentCompressionResistancePriority:1000 forOrientation:NSLayoutConstraintOrientationVertical]; 

Answer 1

设置文本字段的preferredMaxLayoutWidth。我认为你不想要或不需要显式宽度约束。

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在我的测试中，我发现这个工程：

self.label = [[NSTextField alloc] initWithFrame:NSMakeRect(0, 0, 100, 18)]; 
self.label.translatesAutoresizingMaskIntoConstraints = NO; 
[self.label.cell setLineBreakMode:NSLineBreakByWordWrapping]; 
self.label.stringValue = @"Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum."; 
self.label.preferredMaxLayoutWidth = 100; 
self.label.editable = NO; 

[self.window.contentView addSubview:self.label]; 

NSDictionary* views = @{ @"label" : self.label }; 
[self.label.superview addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"H:|-[label]" options:0 metrics:nil views:views]]; 
[self.label.superview addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"V:|-[label]" options:0 metrics:nil views:views]]; 

基本上，从你的主要区别是，我设置editable到NO。我也忽略了宽度和高度的限制，并设置了抗压强度。