UITableViewCell中的宽高比NSLayoutConstraint中断 [英] Aspect ratio NSLayoutConstraint in UITableViewCell is breaks
问题描述
我正在尝试为UITableViewCell中的UIImageView设置适当的NSLayoutConstraint.所需的约束如下:
I'm trying to set appropriate NSLayoutConstraints for a UIImageView in a UITableViewCell. The desired constraints are as follows:
- 16:9的宽高比
- 0位领先
- 0尾随
- 11个热门
- 11个底部
UIImageView是单元格contentView的唯一子视图.我已经设置了tableView.rowHeight = UITableViewAutomaticDimension和tableView.estimatedRowHeight = 80
The UIImageView is the sole subview of the cell's contentView. I have set tableView.rowHeight = UITableViewAutomaticDimension and tableView.estimatedRowHeight = 80
2018-03-28 15:52:30.454688-0400 TestApp[28844:694668] [LayoutConstraints] Unable to simultaneously satisfy constraints.
Probably at least one of the constraints in the following list is one you don't want.
Try this:
(1) look at each constraint and try to figure out which you don't expect;
(2) find the code that added the unwanted constraint or constraints and fix it.
(
"<NSLayoutConstraint:0x604000486cc0 UIImageView:0x7f91cf670470.width == 1.77778*UIImageView:0x7f91cf670470.height (active)>",
"<NSLayoutConstraint:0x604000486e50 H:|-(0)-[UIImageView:0x7f91cf670470] (active, names: '|':UITableViewCellContentView:0x7f91cf66f7e0 )>",
"<NSLayoutConstraint:0x604000486ef0 H:[UIImageView:0x7f91cf670470]-(0)-| (active, names: '|':UITableViewCellContentView:0x7f91cf66f7e0 )>",
"<NSLayoutConstraint:0x604000486f40 V:|-(11)-[UIImageView:0x7f91cf670470] (active, names: '|':UITableViewCellContentView:0x7f91cf66f7e0 )>",
"<NSLayoutConstraint:0x604000486ea0 V:[UIImageView:0x7f91cf670470]-(11)-| (active, names: '|':UITableViewCellContentView:0x7f91cf66f7e0 )>",
"<NSLayoutConstraint:0x604000487530 'UIView-Encapsulated-Layout-Height' UITableViewCellContentView:0x7f91cf66f7e0.height == 233 (active)>",
"<NSLayoutConstraint:0x6040004874e0 'UIView-Encapsulated-Layout-Width' UITableViewCellContentView:0x7f91cf66f7e0.width == 375 (active)>"
)
Will attempt to recover by breaking constraint
<NSLayoutConstraint:0x604000486cc0 UIImageView:0x7f91cf670470.width == 1.77778*UIImageView:0x7f91cf670470.height (active)>
Make a symbolic breakpoint at UIViewAlertForUnsatisfiableConstraints to catch this in the debugger.
The methods in the UIConstraintBasedLayoutDebugging category on UIView listed in <UIKit/UIView.h> may also be helpful.
点击按钮添加缺少的约束"不会添加任何新的约束.值1.77778是我的宽高比的正确十进制表示形式.我不确定为什么运行时需要打破此约束.
Hitting the button "Add Missing Constraints" doesn't add any new constraints. The value 1.77778 is the correct decimal representation for my aspect ratio. I'm not sure why the runtime needs this constraint to be broken.
我也尝试过使用动作->调试器命令expr -l objc++ -O -- [[UIWindow keyWindow] _autolayoutTrace]为UIViewAlertForUnsatisfiableConstraints创建一个符号断点，但是由于打印整个视图层次结构，我发现打印输出没有帮助.我不确定"UILayoutGuide的布局不确定"与我的UITableView或单元格有什么关系.
I have also tried creating a symbolic breakpoint for UIViewAlertForUnsatisfiableConstraints with Action -> Debugger Command expr -l objc++ -O -- [[UIWindow keyWindow] _autolayoutTrace] and I'm not finding the print-out helpful as it's printing the whole view hierarchy. I'm not sure what a "AMBIGUOUS LAYOUT for UILayoutGuide" has to do with my UITableView or cell...
•UIWindow:0x7f94bd466e60
| UITransitionView:0x7f94bd64b860
| | •UIView:0x7f94bd468e70
| | | *<UILayoutGuide: 0x6000007bdb20 - "UIViewSafeAreaLayoutGuide", layoutFrame = {{0, 44}, {375, 734}}, owningView = <UIView: 0x7f94bd468e70; frame = (0 0; 375 812); autoresize = W+H; layer = <CALayer: 0x600000822ec0>>>
| | | *UILabel:0x7f94bd469050'Test App'
| | UILayoutContainerView:0x7f94bd610f50
| | | UINavigationTransitionView:0x7f94bd488fa0
| | | | UIViewControllerWrapperView:0x7f94bd6129d0
| | | | | •UIView:0x7f94bd61cea0
| | | | | | *<UILayoutGuide: 0x6040001b7840 - "UIViewSafeAreaLayoutGuide", layoutFrame = {{0, 0}, {375, 690}}, owningView = <UIView: 0x7f94bd61cea0; frame = (0 88; 375 724); autoresize = W+H; layer = <CALayer: 0x6040002370a0>>>
| | | | | | *UITableView:0x7f94be080800
| | | | | | | FancySDK.ImageCell:0x7f94bf025600'5EC2187C-4839-47A3-83E9-C...'
| | | | | | | | •UITableViewCellContentView:0x7f94bd749410
| | | | | | | | | *UIImageView:0x7f94bd749810
| | | | | | | | _UITableViewCellSeparatorView:0x7f94bd749a40
| | | | | | | FancySDK.ArticleCell:0x7f94bd8d9600'18CCDA82-E137-496E-AB0C-5...'
| | | | | | | | •UITableViewCellContentView:0x7f94bd49a0a0
| | | | | | | | | *UIView:0x7f94bd48cfa0
| | | | | | | | | | *UIImageView:0x7f94bd48d180
| | | | | | | | | | *ic_expand:0x7f94bd48d3b0
| | | | | | | | | | *UILabel:0x7f94bd49c210'Apple will unveil the nex...'
| | | | | | | | | | *UILabel:0x7f94bd4a20d0'Apple’s annual Worldwide ...'
| | | | | | | | | | *UILabel:0x7f94bd49ccd0'https://www.theverge.com/...'
| | | | | | | | _UITableViewCellSeparatorView:0x7f94bd4a3990
| | | | | | | UIImageView:0x7f94bd62f410
| | | | | | | UIImageView:0x7f94bd62fbf0
| | | | | | *UIView:0x7f94bd61ccc0
| | | •Recommended for You:0x7f94bd611580
| | | | _UIBarBackground:0x7f94bd614750
| | | | | UIImageView:0x7f94bd615000
| | | | _UINavigationBarLargeTitleView:0x7f94bd50ff60'Recommended for You'
| | | | | UILabel:0x7f94bd4822f0
| | | | •_UINavigationBarContentView:0x7f94bd60ad60'Recommended for You'
| | | | | *<UILayoutGuide: 0x6040001b7e60 - "BackButtonGuide(0x7f94bd60aa00)", layoutFrame = {{0, 0}, {16, 44}}, owningView = <_UINavigationBarContentView: 0x7f94bd60ad60; frame = (0 0; 375 44); layer = <CALayer: 0x604000235ee0>>>
| | | | | *<UILayoutGuide: 0x6040001b7d80 - "LeadingBarGuide(0x7f94bd60aa00)", layoutFrame = {{16, 0}, {24, 44}}, owningView = <_UINavigationBarContentView: 0x7f94bd60ad60; frame = (0 0; 375 44); layer = <CALayer: 0x604000235ee0>>>
| | | | | *<UILayoutGuide: 0x6040001b7ca0 - "TitleView(0x7f94bd60aa00)", layoutFrame = {{46, 0}, {321, 44}}, owningView = <_UINavigationBarContentView: 0x7f94bd60ad60; frame = (0 0; 375 44); layer = <CALayer: 0x604000235ee0>>>
| | | | | *<UILayoutGuide: 0x6040001b7bc0 - "TrailingBarGuide(0x7f94bd60aa00)", layoutFrame = {{367, 0}, {0, 44}}, owningView = <_UINavigationBarContentView: 0x7f94bd60ad60; frame = (0 0; 375 44); layer = <CALayer: 0x604000235ee0>>>
| | | | | *<UILayoutGuide: 0x6040001b7ae0 - "UIViewLayoutMarginsGuide", layoutFrame = {{16, 0}, {343, 44}}, owningView = <_UINavigationBarContentView: 0x7f94bd60ad60; frame = (0 0; 375 44); layer = <CALayer: 0x604000235ee0>>>
| | | | | *_UIButtonBarStackView:0x7f94bd62d8d0
| | | | | | *<UILayoutGuide: 0x6040001b8020 - "UIButtonBar.flexibleSpaceEqualSizeLayoutGuide", layoutFrame = {{0, 0}, {8, 0}}, owningView = <_UIButtonBarStackView: 0x7f94bd62d8d0; frame = (16 0; 24 44); layer = <CALayer: 0x604000237f40>>>- AMBIGUOUS LAYOUT for UILayoutGuide:0x6040001b8020'UIButtonBar.flexibleSpaceEqualSizeLayoutGuide'.minX{id: 446}, UILayoutGuide:0x6040001b8020'UIButtonBar.flexibleSpaceEqualSizeLayoutGuide'.minY{id: 447}, UILayoutGuide:0x6040001b8020'UIButtonBar.flexibleSpaceEqualSizeLayoutGuide'.Width{id: 367}, UILayoutGuide:0x6040001b8020'UIButtonBar.flexibleSpaceEqualSizeLayoutGuide'.Height{id: 448}
| | | | | | *<UILayoutGuide: 0x6040001b81e0 - "UIButtonBar.minimumInterItemSpaceLayoutGuide", layoutFrame = {{0, 0}, {8, 0}}, owningView = <_UIButtonBarStackView: 0x7f94bd62d8d0; frame = (16 0; 24 44); layer = <CALayer: 0x604000237f40>>>- AMBIGUOUS LAYOUT for UILayoutGuide:0x6040001b81e0'UIButtonBar.minimumInterItemSpaceLayoutGuide'.minX{id: 449}, UILayoutGuide:0x6040001b81e0'UIButtonBar.minimumInterItemSpaceLayoutGuide'.minY{id: 450}, UILayoutGuide:0x6040001b81e0'UIButtonBar.minimumInterItemSpaceLayoutGuide'.Height{id: 451}
| | | | | | *<UILayoutGuide: 0x6040001b7a00 - "UIButtonBar.minimumInterGroupSpaceLayoutGuide", layoutFrame = {{0, 0}, {8, 0}}, owningView = <_UIButtonBarStackView: 0x7f94bd62d8d0; frame = (16 0; 24 44); layer = <CALayer: 0x604000237f40>>>- AMBIGUOUS LAYOUT for UILayoutGuide:0x6040001b7a00'UIButtonBar.minimumInterGroupSpaceLayoutGuide'.minX{id: 452}, UILayoutGuide:0x6040001b7a00'UIButtonBar.minimumInterGroupSpaceLayoutGuide'.minY{id: 453}, UILayoutGuide:0x6040001b7a00'UIButtonBar.minimumInterGroupSpaceLayoutGuide'.Height{id: 454}
| | | | | | *<UILayoutGuide: 0x6040001b74c0 - "UIViewLayoutMarginsGuide", layoutFrame = {{0, 0}, {24, 44}}, owningView = <_UIButtonBarStackView: 0x7f94bd62d8d0; frame = (16 0; 24 44); layer = <CALayer: 0x604000237f40>>>
| | | | | | *UIButton:0x7f94bd51de30
| | | | | | | UIImageView:0x7f94bd6210f0
| | | | | *UILabel:0x7f94bd6298a0'Recommended for You'
| | | | +_UINavigationBarModernPromptView:0x7f94bd488da0
| | | | | *UILabel:0x7f94bd4893d0
| | | UIActivityIndicatorView:0x7f94bd531500
| | | | UIImageView:0x7f94bd507950
Legend:
* - is laid out with auto layout
+ - is laid out manually, but is represented in the layout engine because translatesAutoresizingMaskIntoConstraints = YES
• - layout engine host
欢迎任何反馈.谢谢
推荐答案
此问题背后的主要原因是，最初的自动布局为单元格的contentView假定了一个固定的高度(直到正在计算动态高度)约束(必需)，该约束与您自己的约束，它出现在这里UIView-Encapsulated-Layout-Height，您可以通过将imageView的底部约束的优先级降低为999而不是1000(Required)来解决此问题
The main reason behind this problem is that initially autolayout assumes a fixed height (until dynamic height is being calculated ) constraint (Required) for the cell's contentView which conflicts with your own constraints and it appears here UIView-Encapsulated-Layout-Height , you can solve this by lowering the priority of the bottom constraint of the imageView to be 999 instead of 1000 ( Required )
说明
您当前的宽度= 375，宽高比= 16/9
your current width = 375 and aspect ratio = 16 / 9
然后imageView的高度将为(375 * 9)/16.0 = 210.9
then imageView height will = (375*9)/16.0 = 210.9
- 顶部11个，底部11个
总= 211 + 11 + 11 = 233> 80(估计的行高度)
total = 211 + 11 + 11 = 233 > 80 (estimatedRowHeight)
这篇关于UITableViewCell中的宽高比NSLayoutConstraint中断的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
