根据字符串长度更改UILabel中的字体大小

Question

Let's say I have a UILabel which covers the entire window of the app. In this label is displayed random text with different lengths. Is it possible to change the text font size dependant on the text length?

Answer 1

Yes, UILabel can do that for you, just do:

theLabel.adjustsFontSizeToFitWidth = YES;
theLabel.minimumFontSize = MIN_FONT_SIZE;

Attention to this (from the documentation):

This property is effective only when the numberOfLines property is set to 1.

Answer 2

I created a category method at one point. You basically feed it a rectangle and it will return a font that fits. Maybe you can glean something from the following crude example:

- (UIFont *)fontSizeForRect:(CGRect)rect withFont:(UIFont *)font lineBreakMode:(UILineBreakMode)lineBreakMode minFontSize:(CGFloat)minFontSize 
    {

            CGFloat fontSize = [font pointSize];
            UIFont *tempFont = [UIFont fontWithName:[font fontName] size:[font pointSize]];
            CGFloat acceptableFontSize = fontSize;
            while (fontSize > minFontSize) 
            {
               UIFont *testFont = [UIFont fontWithName:[tempFont fontName] size:fontSize];
               CGSize sizeWithTestFont = [self sizeWithFont:testFont constrainedToSize:CGSizeMake(rect.size.width, 99999.0) lineBreakMode:lineBreakMode];
                if (sizeWithTestFont.height > rect.size.height)
                    fontSize -= 1.0f; //Shrink the font size by a point
                else 
                {
                    //Fits.  Use it.  
                    acceptableFontSize = fontSize;
                    break;
                }
            }

            return [UIFont fontWithName:[font fontName] size:acceptableFontSize];
        }