iOS 自定义视图 - 使用 CGRect.zero 初始化 - 约束警告

Question

我有一个自定义视图，两个标签位于彼此下方。视图初始化方法如下所示

self.locationView = LocationView(frame: CGRect.zero)

为了在主视图中定位子视图，我使用了以下约束：

        self.gMapsView.addConstraints(
        NSLayoutConstraint.constraints(
            withVisualFormat: "H:|-[locationView]-|",
            options: NSLayoutFormatOptions(rawValue: UInt(0)),
            metrics: nil,
            views: views
        )
    )

    self.gMapsView.addConstraints(
        NSLayoutConstraint.constraints(
            withVisualFormat: "V:[locationView]-(paddingBottom)-|",
            options: NSLayoutFormatOptions(rawValue: UInt(0)),
            metrics: [
                "paddingBottom": LOCATION_VIEW_CONFIG.paddingBottom
            ],
            views: views
        )
    )

为了在位置视图中定位标签，我使用以下约束：

        self.addConstraints(
        NSLayoutConstraint.constraints(
            withVisualFormat: "H:|[streetLabel]|",
            options: NSLayoutFormatOptions(rawValue: UInt(0)),
            metrics: nil,
            views: views
        )
    )

    self.addConstraints(
        NSLayoutConstraint.constraints(
            withVisualFormat: "H:|[cityLabel]|",
            options: NSLayoutFormatOptions(rawValue: UInt(0)),
            metrics: nil,
            views: views
        )
    )

    self.addConstraints(
        NSLayoutConstraint.constraints(
            withVisualFormat: "V:|-[streetLabel]-[cityLabel]-|",
            options: NSLayoutFormatOptions(rawValue: UInt(0)),
            metrics: nil,
            views: views
        )
    )

不幸的是，我收到了约束警告：

(
"<NSAutoresizingMaskLayoutConstraint:0x608000280820 h=--& v=--& Test.LocationView:0x7fdc40f0c780.height == 0   (active)>",
"<NSLayoutConstraint:0x608000280190 UILabel:0x7fdc40f0cb40.top == Test.LocationView:0x7fdc40f0c780.topMargin   (active)>",
"<NSLayoutConstraint:0x608000280320 V:[UILabel:0x7fdc40f0cb40]-(NSSpace(8))-[UILabel:0x7fdc40d155e0]   (active)>",
"<NSLayoutConstraint:0x6080002802d0 Test.LocationView:0x7fdc40f0c780.bottomMargin == UILabel:0x7fdc40d155e0.bottom   (active)>"
)

Will attempt to recover by breaking constraint 
<NSLayoutConstraint:0x608000280320 V:[UILabel:0x7fdc40f0cb40]-(NSSpace(8))-[UILabel:0x7fdc40d155e0]   (active)>

我该如何修复它们？非常感谢:)

Answer 1

您需要关闭 Autoresizing Mask，这是此处列出的第一个约束 (NSAutoresizingMaskLayoutConstraint)，它与您稍后创建的约束冲突。您可以看到它正在将高度设置为 0。添加：

self.locationView.translatesAutoresizingMaskIntoConstraints = 否；

您的布局可能还有其他问题，但这应该可以解决冲突。

iOS 自定义视图 - 使用 CGRect.zero 初始化 - 约束警告

iOS Custom View - init with CGRect.zero - Constraint warning

warnings

constraints

ios

autolayout