CODEWITHSUNDEEP
iphoneiosobjective-canimationuiview
schlow
schlow

Reputation: 154

How to make a method that rotates a UIView work many times

I have a view that slides up from the bottom of the screen when the user swipes up and when this happen a little arrow is supposed to rotate so that it is now pointing downwards. In a similar fashion, when the view is slid away to the bottom of the screen, the arrow should rotate again so that it points upwards. Ideally, I would like to call the same method every time the view slides in or out to rotate the arrow 180 degrees. Right now I am using:

[UIView animateWithDuration:.5 animations:^{
    viewToBeRotated.transform = CGAffineTransformMakeRotation(M_PI);
}];

This works fine the first time but then doesn't do anything on further method calls, any pointers on how to do do this correctly?

Upvotes: 0

Views: 113

Answers (1)

Marcio
Marcio

Reputation: 2107

When you set a transform on a view you erase previous transform. To have multiple transforms applied to one view at the same time you must "add" them. Each CGAffineTransformMake{Rotation/Scale/etc} has an equivalent which allows you to "add" a transform to another one.

To resolve your issue you can use the following :

self.iv.transform = CGAffineTransformRotate(self.iv.transform, M_PI);

Upvotes: 3

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