table view disappears when I add a constraint - ios

Question

I have a container view:
and I have a table view that I add to the container programmatically:
self.searchResultsSourcesTVC = [storyboard instantiateViewControllerWithIdentifier:#"searchResultsSourcesTVC"];
[self.searchResultsContainer addSubview:self.searchResultsSourcesTVC.view];
The result here is that the table view is not automatically sized to fit in the container; it seems to extend south of the screen quite a bit, to the extent that the scroll bar can completely disappear south of the screen. But it does display the table and search results.
So I attempted to add a constraint (I am using auto layout) to make the vertical bounds of the table view match those of the container view:
UITableView *tableView = self.searchResultsSourcesTVC.tableView;
NSDictionary *views = NSDictionaryOfVariableBindings(tableView);
tableView.translatesAutoresizingMaskIntoConstraints = NO; // without this line there are conflicts
[self.searchResultsContainer addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:#"V:|[tableView]|" options:0 metrics:Nil views:views]];
[self.view layoutIfNeeded]; // not sure whether this line is necessary
Now there is no table at all. Just a blank view.
What am I doing wrong? What's the best way to add a table view to a container view programmatically and make the bounds of the table view coextensive with those of the container view? Thanks

Answer 1

It seems like you don't have enough constraints to fully describe what the size you need is. For example it seems like you don't have horizontal constraints. You generally need 4 constraints to fully express the size of the view you want to layout; specifically you need a center X, center Y, width, and height.
For example:
NSLayoutConstraint *con1 = [NSLayoutConstraint constraintWithItem:self attribute:NSLayoutAttributeCenterX relatedBy:0 toItem:view attribute:NSLayoutAttributeCenterX multiplier:1 constant:0];
NSLayoutConstraint *con2 = [NSLayoutConstraint constraintWithItem:self attribute:NSLayoutAttributeCenterY relatedBy:0 toItem:view attribute:NSLayoutAttributeCenterY multiplier:1 constant:0];
NSLayoutConstraint *con3 = [NSLayoutConstraint constraintWithItem:self attribute:NSLayoutAttributeWidth relatedBy:0 toItem:view attribute:NSLayoutAttributeWidth multiplier:1 constant:0];
NSLayoutConstraint *con4 = [NSLayoutConstraint constraintWithItem:self attribute:NSLayoutAttributeHeight relatedBy:0 toItem:view attribute:NSLayoutAttributeHeight multiplier:1 constant:0];
NSArray *constraints = #[con1, con2, con3, con4];
[self.searchResultsController addConstraints:constraints];