更改仅IB中iPhone 4的约束值

Question

如何仅在一个设备上更改约束的值。 例如，除iPhone 4外，我想为所有iPhone显示一个高度为400px的按钮，而在iPhone 4上我该按钮的显示值为300px？

Answer 1

最好的解决方案是创建一个继承自NSLayoutConstraint类的新类并添加以下属性，这样您就可以更改常量，乘数，还可以在接口构建器中停用每个设备的约束以及所有这些约束：

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

您可以使用插座作为约束，并根据运行的设备更改其值。即，如果iphone4则为300px，否则为400px（使用插座的“ constant ”属性）

Answer 3

您可以选择该按钮的高度限制出口。 然后您可以检测设备是否为iphone 4，然后可以更改其约束的插座constant ，例如

   self.heightConstraint.constant = 300;

对于约束的连接出口，只需ctrl + drag from that constraint to class

您可以通过获取屏幕尺寸来检测设备。

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的答案的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
            }
        }
    }
}