This chapter is from the book
This chapter is from the book
This chapter is from the book
This chapter is from the book
Exercises
After reading this chapter, test your knowledge with these exercises:
- A label is constrained with 8-point offsets from its superview’s leading and trailing edges. It is 22 points high. Is this label’s layout ambiguous? If so, how can you remove the ambiguity?
- You create a system-style button and assign it the title Continue. The button’s center is constrained to a point (150, 150) from its superview’s top and leading edges. Is this view’s layout ambiguous? If so, how can you remove the ambiguity?
In viewWillAppear: you create a new test view and add it to your view controller:
UIView *testView = [[UIView alloc] initWithFrame:CGRectMake(50, 50, 100, 30)]; view.backgroundColor = [UIColor blueColor]; [self.view addSubview:view]; view.translatesAutoresizingMaskIntoConstraints = NO;After these lines, you add constraints that center the test view within its superview. What size will the view be when the app runs? Why?
- A 54-by-54-point image consists of a 50-by-50-point square, with a drop shadow offset 4 points to the right and 4 points down. (a) Show code that assigns alignment insets to this image. (b) When the image is added to an image view and center-aligned to its superview on both axes, what geometric point within the image lies at the center of the superview?
- You add a button to your view and constrain it to stretch from side to side at a priority of 500. Will it stretch? Why or why not?