CODEWITHSUNDEEP
iosuiviewdrawrectlayoutsubviews
Sunil Rao
Sunil Rao

Reputation: 850

How to invoke drawRect: when layoutSubviews invokes in ios

I am using drawRect: to draw shapes. I have to invoke this method and redraw the shapes when orientation changes, so i thought if there is a way to invoke drawRect: automatically when layoutSubviews() been called.

Thank you.

Upvotes: 1

Views: 472

Answers (3)

Hamish
Hamish

Reputation: 80901

You can set the view's contentMode to .redraw.

This will invoke setNeedsDisplay (and therefore drawRect) whenever the view's bounds change, and will therefore also be invoked upon rotation (provided you've setup your autoresizingMask so that the view's bounds change on rotation).

Upvotes: 6

mkhoshpour
mkhoshpour

Reputation: 855

In viewDidLoad() function put:

NSNotificationCenter.defaultCenter().addObserver(self, selector: "rotated", name: UIDeviceOrientationDidChangeNotification, object: nil)

and then add the following function: 

func rotated()
{
    if(UIDeviceOrientationIsLandscape(UIDevice.currentDevice().orientation))
    {            
        print("landscape")
        // Your drawRect function here
    }

    if(UIDeviceOrientationIsPortrait(UIDevice.currentDevice().orientation))
    {
        print("Portrait")
        // Your drawRect function here

    }

}

Upvotes: 0

Tristan Burnside
Tristan Burnside

Reputation: 2566

From the UIView class reference https://developer.apple.com/library/ios/documentation/UIKit/Reference/UIView_Class/#//apple_ref/occ/instm/UIView/drawRect:

This method is called when a view is first displayed or when an event occurs that invalidates a visible part of the view. You should never call this method directly yourself. To invalidate part of your view, and thus cause that portion to be redrawn, call the setNeedsDisplay or setNeedsDisplayInRect: method instead.

That's it. Just call setNeedsDisplay on the appropriate view.

Upvotes: 2

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