Ios 如何使用NSLayoutConstraint限制UIButton高度

我有

UItoolbar

，其中添加了两项1<代码>UITextView和2<代码>ui按钮。

UITextview

的属性是根据输入的文本进行自动签名。 当

UITextview

高度增加时，我想限制

UIButton

高度，即

UIButton

高度不应增加

[_toolbar setItems:[NSArray arrayWithObjects:barButtonItemCommentText,barButtonItemSubmit,nil]];
submitBtn.translatesAutoresizingMaskIntoConstraints = NO;
textView.translatesAutoresizingMaskIntoConstraints = NO;
_toolbar.translatesAutoresizingMaskIntoConstraints = NO;

[_toolbar addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"H:|-8-[textView]-79-|" options:0 metrics:nil views:NSDictionaryOfVariableBindings(textView)]];

 [_toolbar addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"V:|-8-[textView]-8-|" options:0 metrics:nil views:NSDictionaryOfVariableBindings(textView)]];

[_toolbar addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"H:|-[submitBtn]-8-|" options:0 metrics:nil views:NSDictionaryOfVariableBindings(submitBtn)]];


[_toolbar addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"V:|-8-[submitBtn]-8-|" options:NSLayoutFormatAlignAllBaseline metrics:nil views:NSDictionaryOfVariableBindings(submitBtn)]];

[_toolbar addConstraint:[NSLayoutConstraint constraintWithItem:submitBtn
                                                 attribute:NSLayoutAttributeWidth
                                                 relatedBy:NSLayoutRelationEqual
                                                    toItem:nil
                                                 attribute:NSLayoutAttributeNotAnAttribute 
                                                multiplier:1.0 
                                                  constant:60]];
[textView setContentCompressionResistancePriority:UILayoutPriorityRequired forAxis:UILayoutConstraintAxisHorizontal];
[textView setContentCompressionResistancePriority:UILayoutPriorityRequired forAxis:UILayoutConstraintAxisVertical];

[_toolbar setContentCompressionResistancePriority:UILayoutPriorityRequired forAxis:UILayoutConstraintAxisVertical];


[_toolbar addConstraint:[NSLayoutConstraint constraintWithItem:_toolbar attribute:NSLayoutAttributeHeight relatedBy:NSLayoutRelationLessThanOrEqual toItem:nil attribute:NSLayoutAttributeNotAnAttribute multiplier:1.0f constant:MaxToolbarHeight]];

有关参考信息，请参见随附的屏幕截图：

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下面提到的约束使它在垂直方向上拉伸，因为它要求从顶部和底部始终为8像素

[_toolbar addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"V:|-8-[submitBtn]-8-|" options:NSLayoutFormatAlignAllBaseline metrics:nil views:NSDictionaryOfVariableBindings(submitBtn)]];

如果将其更改为“恒定高度”，则它将不会垂直增长，在这种情况下，高度始终为24

[_toolbar addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"V:[submitBtn(24)]-8-|" options:NSLayoutFormatAlignAllBaseline metrics:nil views:NSDictionaryOfVariableBindings(submitBtn)]];

---

可能会更改此行

[\u工具栏添加约束：[NSLayoutConstraint Constraints With VisualFormat:@“V:|-8-[submitBtn]-8-|”选项：NSLayoutFormatAlignAllBaseline度量：无视图：NSDictionaryOfVariableBindings（submitBtn）]

对此

[\u工具栏添加约束：[NSLayoutConstraint Constraints With VisualFormat:@“V:|->=8-[submitBtn]-8-|”选项：NSLayoutFormatAlignAllBaseline度量：无视图：NSDictionaryOfVariableBindings（submitBtn）]非常感谢@Dima，你让我开心。：）我发现我的问题评论中的答案和你的答案都是完美的。谢谢甘道夫和迪玛。