Question

如果我在界面构建器中创建标签并通过不符合其当前大小的代码设置字符串，则标签将垂直增长以适合其大小，非常棒！除了x＆amp;约束，Xcode创建一个包含拥抱和压缩阻力的NSContentSizeLayoutConstraint。

这是约束

的日志输出

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

问题是，如何以编程方式执行此操作？我还没有找到办法。无法创建NSContentSizeLayoutConstraint，并且设置NSTextField的contentCompressionResistance似乎没有任何效果。

这是我的代码：

 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preferredMaxLayoutWidth。我认为你不想要或不需要明确的宽度约束。

在我的测试中，我发现这有效：

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，与您的主要区别在于我将editable设置为NO。我也省略了宽度和高度限制并设置了抗压性。

Answer 2

我认为一种更好的方法是覆盖NSTextField并更新internalContentSize。

public class DynamicTextField: NSTextField {
   public override var intrinsicContentSize: NSSize {
      if cell!.wraps {
         let fictionalBounds = NSRect(x: bounds.minX, y: bounds.minY, width: bounds.width, height: CGFloat.greatestFiniteMagnitude)
         return cell!.cellSize(forBounds: fictionalBounds)
      } else {
         return super.intrinsicContentSize
      }
   }

   public override func textDidChange(_ notification: Notification) {
      super.textDidChange(notification)

      if cell!.wraps {
         validatingEditing()
         invalidateIntrinsicContentSize()
      }
   }
}

之后，约束将按预期工作。请注意，仅当您在Interface Builder或代码中将Layout设置为Wraps时，它才有效。

NSTextField和AutoLayout：自动增长高度 - ＆gt;编程

2 个答案: