Auto-resizing NSTokenField with constraint-based layout

问题

Is there any way to automatically resize the height of a NSTokenField (keeping the width constant) using constraints?

-sizeToFit should work, but it doesn't. If I set a constraint to keep the width constant and call this method it ignores the constraints and resizes the width only (when what I want is to resize the height only).

回答1:

The cellSizeForBounds method of the token field does return the correct size, so you can implement it like this (custom subclass, in Swift):

class TagsTokenField: NSTokenField {

    override func textDidChange(notification: NSNotification) {
        super.textDidChange(notification)
        self.invalidateIntrinsicContentSize()
    }

    override var intrinsicContentSize: NSSize {
        let size = self.cell!.cellSizeForBounds(NSMakeRect(0, 0, self.bounds.size.width, 1000))
        return NSMakeSize(CGFloat(FLT_MAX), size.height)
    }

}

回答2:

Based on How to let NSTextField grow with the text in auto layout?

Also don't set size contraints, just let it be.

The method intrinsicContentSize in NSView returns what the view itself thinks of as its intrinsic content size.

NSTextField calculates this without considering the wraps property of its cell, so it will report the dimensions of the text if laid out in on a single line.

Hence, a custom subclass of NSTokenField can override this method to return a better value, such as the one provided by the cell's cellSizeForBounds: method:

-(NSSize)intrinsicContentSize
{
    if ( ![self.cell wraps] ) {
        return [super intrinsicContentSize];
    }

    NSRect frame = [self frame];

    CGFloat width = frame.size.width;

    // Make the frame very high, while keeping the width
    frame.size.height = CGFLOAT_MAX;

    // Calculate new height within the frame
    // with practically infinite height.
    CGFloat height = [self.cell cellSizeForBounds: frame].height;

    return NSMakeSize(width, height);
}

来源：https://stackoverflow.com/questions/17147366/auto-resizing-nstokenfield-with-constraint-based-layout