Where to set translatesAutoresizingMaskIntoConstra

问题:

I need to set translatesAutoresizingMaskIntoConstraints to NO. By default it is set to YES (to assist with the majority of apps that are transitioning from struts and springs to the new Auto Layout).

Is there somewhere in Xcode where the default can be changed from YES to NO?

Or do I have to manually set it for every view?

回答1:

This is a great question - and one I've tried to find an answer to myself. Sadly, it looks like there is no "quick fix". Currently, Apple considers Constraint-based layout Opt-in - even naming a section of the UIView Class Reference:

Opting in to Constraint-Based Layout

But that Opt-in is not global. I presume this is because not everything looks good if you just turn Springs & Struts into Constraints. Some UI elements break, or you would get a ton of unsatisfiable constraints errors.

I can think of one possible solution - I have not tried it myself, but you could make a category on UIView that sets all UIView objects to return NO for - (BOOL)translatesAutoresizingMaskIntoConstraints. While I do not know what this would break, it would globally set translatesAutoresizingMaskIntoConstraints to NO.

Here is a good introduction to Categories if you want to learn more about them!

回答2:

I'm late to this question, but the mentioned option is still missing in Xcode 5 & 6, so the question is still meaningful.

Actually, we can always set a value to any property of a view/control/object by adding a User Defined Runtime Atribute in Storyboard (Interface Builder) like the following screenshot.

And it also works for translatesAutoresizingMaskIntoConstraints. So the question could be solved.

回答3:

When u have to change the size or position of your subview. Use (BOOL)translatesAutoresizingMaskIntoConstraints method before you set the frame of your subview.

[self.benchmarkButton removeFromSuperview];
[self.benchmarkButton setTranslatesAutoresizingMaskIntoConstraints:YES];
[self.benchmarkButton setFrame:CGRectMake(20, self.benchmarkButton.frame.origin.y+40, 260, 30)];
[self.benchmarksView addSubview:self.benchmarkButton];

Thats way your subview will not fight from constraints as it is default (AutoLayout) in Xcode 4.3 and later. Thanks

回答4:

According to the documentation, this property is automatically set to NO if the view is added through Interface Builder.

https://developer.apple.com/library/ios/documentation/UIKit/Reference/UIView_Class/#//apple_ref/occ/instp/UIView/translatesAutoresizingMaskIntoConstraints