iOS different constraints for different devices

问题:

I have a ViewController designed for iPhone SE

As you can see I also have a constraint Align Top to: Safe Area Equals 75

The question is, is it possible to change this value for iPhone 8 and iPhone 8 Plus? For example:

• SE = 75
• 8 = 85
• 8 Plus = 105

回答1:

we were facing similar issue. We solved with helper class called scaled. Which basically just multiply size of something, which should appear larger on larger device.

extension CGFloat {
    public var scaled: CGFloat {
        switch UIDevice.type.getResolutionGroup()! {
        case .lr320x568:
            return self
        case .lr375x667:
            return self * 1.1
        case .lr414x736:
            return self * 1.2
        case .lr768x1024:
            return self * 1.3
        // For iPads
        case .lr1024x1366:
            return self * 1.3
        }
    }
}

And implementation of resolution group

public func getResolutionGroup() -> ResolutionGroup? {
        switch self {
        case .iPhone5, .iPhone5C, .iPhone5S, .iPhoneSE, .iPodTouch5, .iPodTouch6:
            return .lr320x568
        case .iPhone6, .iPhone6S, .iPhone7:
            return .lr375x667
        case .iPhone6Plus, .iPhone6SPlus, .iPhone7Plus:
            return .lr414x736
        case .iPadMini, .iPadMini2, .iPadMini3, .iPadMini4:
            return .lr768x1024
        case .iPad2, .iPad3, .iPad4, .iPadAir, .iPadAir2:
            return .lr768x1024
        case .iPadPro:
            return .lr1024x1366
        case .simulator:
            return isiPhone() ? .lr320x568 : .lr768x1024
        default:
            return .lr320x568
        }
    }

And usage in app

fileprivate let footerHeight = CGFloat(180).scaled

回答2:

Not using Interface Builder, no. Constraints, can only target Compact, Regular or Any sizes and all iPhone models have Compact width and Regular height when in portrait mode.

If you want that kind of granularity, you have to do it with code instead.

回答3:

This is not applicanle in IB , you can try in code by hooking the top constraint of the view as IBOutlet and in viewDidLayoutSubviews

override func viewDidLayoutSubviews()
{

   if(deviceWidthSE)
   {      
      self.viewTopCon.constant = 75
   }
   else
   if(deviceWidth8)
   {
      self.viewTopCon.constant = 85
   }
   else
   if(deviceWidth8Plus)
   {
      self.viewTopCon.constant = 105
   }

}