在 IB 中仅更改 iPhone 4 的约束值

Question

如何仅在一台设备上更改约束值。 例如，我想为除 iPhone 4 之外的所有 iPhone 显示一个高度为 400px 的按钮，我会以 300px 显示它？

Answer 1

最好的解决方案是创建一个继承自 NSLayoutConstraint 类的新类并添加下面的属性，这样您就可以更改常量、乘数以及停用每个设备的约束以及所有这些在界面构建器中：

import UIKit

/**
 * This class used to modify easly the constraint for each device iPhone 4, iPhone 5, iPhone 6 or iPhone 6 Plus
 * You can modify the constant, the multiplier and also active / deactive the constraint for each device
 * You should modify this properties only in the storyboard
 */
@IBDesignable
public class LayoutConstraint: NSLayoutConstraint {

    // MARK: ?3¨5

    /**
     * The constant for device with 3.5 insh size
     * The default value is the value of the constant of the constraint.
     */
    @IBInspectable
    public var ?3¨5_const: CGFloat = 0 {
        didSet {
            if CGRectGetMaxY(UIScreen.mainScreen().bounds) == 480 {
                constant = ?3¨5_const
            }
        }
    }

    /**
     * The multiplier for device with 3.5 insh size
     * The default value is the value of the constant of the constraint.
     */
    @IBInspectable
    public var ?3¨5_multip: CGFloat = 0 {
        didSet {
            if CGRectGetMaxY(UIScreen.mainScreen().bounds) == 480 {
                self.setValue(?3¨5_multip, forKey: "multiplier")
            }
        }
    }

    /**
     * The boolean to active deative constraint for device with 3.5 insh size
     * The default value is true.
     */
    @IBInspectable
    public var ?3¨5_active: Bool = true {
        didSet {
            if CGRectGetMaxY(UIScreen.mainScreen().bounds) == 480 {
                active = ?3¨5_active
            }
        }
    }

    // MARK: ?4¨0

    /**
     * The constant for device with 4.0 insh size
     * The default value is the value of the constant of the constraint.
     */
    @IBInspectable
    public var ?4¨0_const: CGFloat = 0 {
        didSet {
            if CGRectGetMaxY(UIScreen.mainScreen().bounds) == 568 {
                constant = ?4¨0_const
            }
        }
    }

    /**
     * The multiplier for device with 4.0 insh size
     * The default value is the value of the constant of the constraint.
     */
    @IBInspectable
    public var ?4¨0_multip: CGFloat = 0 {
        didSet {
            if CGRectGetMaxY(UIScreen.mainScreen().bounds) == 568 {
                self.setValue(?4¨0_multip, forKey: "multiplier")
            }
        }
    }

    /**
     * The boolean to active deative constraint for device with 4.0 insh size
     * The default value is true.
     */
    @IBInspectable
    public var ?4¨0_active: Bool = true {
        didSet {
            if CGRectGetMaxY(UIScreen.mainScreen().bounds) == 568 {
                active = ?4¨0_active
            }
        }
    }

    // MARK: ?4¨7

    /**
     * The constant for device with 4.7 insh size
     * The default value is the value of the constant of the constraint.
     */
    @IBInspectable
    public var ?4¨7_const: CGFloat = 0 {
        didSet {
            if CGRectGetMaxY(UIScreen.mainScreen().bounds) == 667 {
                constant = ?4¨7_const
            }
        }
    }

    /**
     * The multiplier for device with 4.7 insh size
     * The default value is the value of the constant of the constraint.
     */
    @IBInspectable
    public var ?4¨7_multip: CGFloat = 0 {
        didSet {
            if CGRectGetMaxY(UIScreen.mainScreen().bounds) == 667 {
                self.setValue(?4¨7_multip, forKey: "multiplier")
            }
        }
    }

    /**
     * The boolean to active deative constraint for device with 4.7 insh size
     * The default value is true.
     */
    @IBInspectable
    public var ?4¨7_active: Bool = true {
        didSet {
            if CGRectGetMaxY(UIScreen.mainScreen().bounds) == 667 {
                active = ?4¨7_active
            }
        }
    }
    // MARK: ?5¨5

    /**
     * The constant for device with 5.5 insh size
     * The default value is the value of the constant of the constraint.
     */
    @IBInspectable
    public var ?5¨5_const: CGFloat = 0 {
        didSet {
            if CGRectGetMaxY(UIScreen.mainScreen().bounds) == 736 {
                constant = ?5¨5_const
            }
        }
    }

    /**
     * The multiplier for device with 5.5 insh size
     * The default value is the value of the constant of the constraint.
     */
    @IBInspectable
    public var ?5¨5_multip: CGFloat = 0 {
        didSet {
            if CGRectGetMaxY(UIScreen.mainScreen().bounds) == 736 {
                self.setValue(?5¨5_multip, forKey: "multiplier")
            }
        }
    }

    /**
     * The boolean to active / deactive constraint for device with 5.5 insh size
     * The default value is true.
     */
    @IBInspectable
    public var ?5¨5_active: Bool = true {
        didSet {
            if CGRectGetMaxY(UIScreen.mainScreen().bounds) == 736 {
                active = ?5¨5_active
            }
        }
    }
}

Answer 2

您可以为您的约束设置插座并根据您正在运行的设备更改其值。即如果是 iphone4，则为 300 像素，否则为 400 像素，使用插座的“constant”属性

Answer 3

您可以取消该按钮的高度限制。然后你可以检测设备是否是 iphone 4 然后你可以改变它的约束插座的constant 之类的东西，

   self.heightConstraint.constant = 300;

仅用于连接约束出口ctrl + drag from that constraint to class

您可以通过获取屏幕大小来检测设备。

if ([ [ UIScreen mainScreen ] bounds ].size.height == 480.00) {

      NSLog(@"this is iphn 4");
      self.heightConstraint.constant = 300;
}

希望这会有所帮助:)

Answer 4

首先创建按钮高度约束的对象(btnConstHeight)

if ([ [ UIScreen mainScreen ] bounds ].size.height == 480.00) {
    self.btnConstHeight.constant = 300;
}
else{
    self.btnConstHeight.constant = 400;
}

Answer 5

@Hamza 答案的 Swift 4 版本

import Foundation

import UIKit

/**
 * This class used to modify easly the constraint for each device iPhone 4, iPhone 5, iPhone 6 or iPhone 6 Plus
 * You can modify the constant, the multiplier and also active / deactive the constraint for each device
 * You should modify this properties only in the storyboard
 */
@IBDesignable
public class LayoutConstraint: NSLayoutConstraint {

    // MARK: ?3¨5

    /**
     * The constant for device with 3.5 insh size
     * The default value is the value of the constant of the constraint.
     */
    @IBInspectable
    public var ?3¨5_const: CGFloat = 0 {
        didSet {

            if UIScreen.main.bounds.maxY == 480 {
                constant = ?3¨5_const
            }
        }
    }

    /**
     * The multiplier for device with 3.5 insh size
     * The default value is the value of the constant of the constraint.
     */
    @IBInspectable
    public var ?3¨5_multip: CGFloat = 0 {
        didSet {
            if UIScreen.main.bounds.maxY == 480 {
                self.setValue(?3¨5_multip, forKey: "multiplier")
            }
        }
    }

    /**
     * The boolean to active deative constraint for device with 3.5 insh size
     * The default value is true.
     */
    @IBInspectable
    public var ?3¨5_active: Bool = true {
        didSet {
            if UIScreen.main.bounds.maxY == 480 {
                isActive = ?3¨5_active
            }
        }
    }

    // MARK: ?4¨0

    /**
     * The constant for device with 4.0 insh size
     * The default value is the value of the constant of the constraint.
     */
    @IBInspectable
    public var ?4¨0_const: CGFloat = 0 {
        didSet {
            if UIScreen.main.bounds.maxY == 568 {
                constant = ?4¨0_const
            }
        }
    }

    /**
     * The multiplier for device with 4.0 insh size
     * The default value is the value of the constant of the constraint.
     */
    @IBInspectable
    public var ?4¨0_multip: CGFloat = 0 {
        didSet {
            if UIScreen.main.bounds.maxY == 568 {
                self.setValue(?4¨0_multip, forKey: "multiplier")
            }
        }
    }

    /**
     * The boolean to active deative constraint for device with 4.0 insh size
     * The default value is true.
     */
    @IBInspectable
    public var ?4¨0_active: Bool = true {
        didSet {
            if UIScreen.main.bounds.maxY == 568 {
                isActive = ?4¨0_active
            }
        }
    }

    // MARK: ?4¨7

    /**
     * The constant for device with 4.7 insh size
     * The default value is the value of the constant of the constraint.
     */
    @IBInspectable
    public var ?4¨7_const: CGFloat = 0 {
        didSet {
            if UIScreen.main.bounds.maxY == 667 {
                constant = ?4¨7_const
            }
        }
    }

    /**
     * The multiplier for device with 4.7 insh size
     * The default value is the value of the constant of the constraint.
     */
    @IBInspectable
    public var ?4¨7_multip: CGFloat = 0 {
        didSet {
            if UIScreen.main.bounds.maxY == 667 {
                self.setValue(?4¨7_multip, forKey: "multiplier")
            }
        }
    }

    /**
     * The boolean to active deative constraint for device with 4.7 insh size
     * The default value is true.
     */
    @IBInspectable
    public var ?4¨7_active: Bool = true {
        didSet {
            if UIScreen.main.bounds.maxY == 667 {
                isActive = ?4¨7_active
            }
        }
    }
    // MARK: ?5¨5

    /**
     * The constant for device with 5.5 insh size
     * The default value is the value of the constant of the constraint.
     */
    @IBInspectable
    public var ?5¨5_const: CGFloat = 0 {
        didSet {
            if UIScreen.main.bounds.maxY == 736 {
                constant = ?5¨5_const
            }
        }
    }

    /**
     * The multiplier for device with 5.5 insh size
     * The default value is the value of the constant of the constraint.
     */
    @IBInspectable
    public var ?5¨5_multip: CGFloat = 0 {
        didSet {
            if UIScreen.main.bounds.maxY == 736 {
                self.setValue(?5¨5_multip, forKey: "multiplier")
            }
        }
    }

    /**
     * The boolean to active / deactive constraint for device with 5.5 insh size
     * The default value is true.
     */
    @IBInspectable
    public var ?5¨5_active: Bool = true {
        didSet {
            if UIScreen.main.bounds.maxY == 736 {
                isActive = ?5¨5_active
            }
        }
    }
}