NSTextField width and autolayout - cocoa

Question

I am trying to create an NSTextField programmatically.
I want to use this NSTextField with auto layout, so its width will be defined automatically to display the entire line (there is only one line of text).
The problem is that textField.intrinsicContentSize and textField.fittingSize are both have -1 and 0 values for the horizontal coordinate, as the output of the code below is:
textField.intrinsicContentSize={-1, 21}
textField.fittingSize={0, 21}
The code:
NSTextField* textField = [[NSTextField alloc] initWithFrame:NSMakeRect(0, 0, 10, 24)];
NSString* str = #"One line of text here.";
[textField setStringValue: str];
[textField setTranslatesAutoresizingMaskIntoConstraints:NO];
[textField invalidateIntrinsicContentSize];
NSLog(#"textField.intrinsicContentSize=%#", NSStringFromSize(textField.intrinsicContentSize));
NSLog(#"textField.fittingSize=%#", NSStringFromSize(textField.fittingSize));
This makes the text field to have a zero width assigned by auto layout.
What should I do to get meaningful values for the fittingSize and intrinsicContentSize properties of the text field so they reflect the content of the text field?

Answer 1

Another way to compute the text field optimal width without using fittingSize is using the following code (replacing John Sauer's sizeTextFieldWidthToFit method):
- (void) sizeTextFieldWidthToFit {
[textField sizeToFit];
CGFloat newWidth = NSWidth(textField.frame);
textFieldWidthConstraint.constant = newWidth;
}
You can set the priority of textFieldWidthConstraint to be lower than the priority of another inequality constrain the represent your requirement to a minimal size of 25.

Answer 2

I can't explain why NSTextField's intrinsicContentSize's widths are -1, but I was able to calculate one based off its attributedString's size. Here's how I created the NSTextField:
// textField is an instance variable.
textField = [NSTextField new] ;
textField.translatesAutoresizingMaskIntoConstraints = NO ;
[view addSubview:textField] ;
NSDictionary* viewsDict = NSDictionaryOfVariableBindings(view, textField) ;
// textFieldWidthConstraint is an instance variable.
textFieldWidthConstraint = [NSLayoutConstraint constraintsWithVisualFormat:#"H:[textField(==0)]" options:0 metrics:nil views:viewsDict] [0] ;
[view addConstraint:textFieldWidthConstraint] ;
NSNumber* intrinsicHeight = #( textField.intrinsicContentSize.height ) ;
[view addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:#"V:[textField(==intrinsicHeight)]" options:0 metrics:NSDictionaryOfVariableBindings(intrinsicHeight) views:viewsDict]] ;
// Position textField however you like.
[view addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:#"H:|-[textField]" options:0 metrics:nil views:viewsDict]] ;
[view addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:#"V:|-[textField]" options:0 metrics:nil views:viewsDict]] ;
[self sizeTextFieldWidthToFit] ;
// set textField's delegate so that sizeTextFieldWidthToFit is called when textField's text changes.
textField.delegate = self ;
And here are the methods that resize it as its text changes:
- (void) controlTextDidChange:(NSNotification*)aNotification {
if ( aNotification.object == textField )
[self sizeTextFieldWidthToFit] ;
}
- (void) sizeTextFieldWidthToFit {
// I'd like the width to always be >= 25.
CGFloat newWidth = 25 ;
if ( ! [textField.stringValue isEqualToString:#""] ) {
NSDictionary* attributes = [textField.attributedStringValue attributesAtIndex:0 effectiveRange:nil] ;
NSSize size = [textField.stringValue sizeWithAttributes:attributes] ;
newWidth = MAX(newWidth, size.width + 10) ;
}
textFieldWidthConstraint.constant = newWidth ;
}

Answer 3

I'm adding this here because these answers are old and I couldn't find everything needed to get NSTextField to automatically wrap and play nice using autolayout and NSConstraints in a single answer.
With these settings the text will:
Remain in the horizontal boundaries set by the constraints.
Wrap automatically on word boundaries.
Automatically adjust its height as required.
Push down anything below (if attached by constraints).
This is the code to make it just work:
NSTextField *instructions = [NSTextField labelWithString:#"Some very long text..."];
instructions.translatesAutoresizingMaskIntoConstraints = NO;
instructions.autoresizesSubviews = YES;
instructions.usesSingleLineMode = NO;
instructions.lineBreakMode = NSLineBreakByWordWrapping;
[instructions cell].wraps = YES;
[instructions cell].scrollable = NO;
instructions.maximumNumberOfLines = 10;
instructions.preferredMaxLayoutWidth = 400.0;
[self addSubview:iCloudInstructions];
[self addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:#"H:|[instructions]|" options:0 metrics:nil views:NSDictionaryOfVariableBindings(instructions)]];
[self addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:#"V:|[instructions]-(20)-[button]" options:0 metrics:nil views:NSDictionaryOfVariableBindings(instructions, instructions)]];