在IB中仅更改iPhone 4的约束值

Question

如何只在一个设备上更改约束的值.例如,我想为iPhone 4以外的所有iPhone显示400px高度的按钮,我将用300px显示它？

Answer 1

最好的解决方案是从NSLayoutConstraint类创建新的类继承并添加下面的属性,就像您可以更改常量,乘数以及停用每个设备的约束以及界面构建器中的所有这些:

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
            }
        }
    }
}