How to color text in UITextView - ios

Question

I've got four buttons on the view controller and a text view. These five buttons has colors, for example red, yellow, green, blue and black.
When the user started to type without pressing those buttons the color of the text view being typed should have black color text. If user press red button then the color of the text from that point should be red until the user press any other colored button.
How to do this ? Ive followed this tutorial https://www.objc.io/issues/5-ios7/getting-to-know-textkit/
But do not know how to customized it to what I want to achieve.

Answer 1

Here is how I proceed if it can helps you:
1- add one property to retain current Color and initialize it with black color
#property (nonatomic, retain) UIColor *curColor;//in your interface declaration
self.curColor = [UIColor blackColor];//Init it in Viewdidload for example
2- implements UITextViewDelegate
- (BOOL)textView:(UITextView *)textView shouldChangeTextInRange:(NSRange)range replacementText:(NSString *)text
{
NSAttributedString *currentText = self.Textview.attributedText;//To store current text and its attributs
NSAttributedString *newOneText = [[NSAttributedString alloc] initWithString:text attributes:#{NSForegroundColorAttributeName:self.curColor}];//for the new text with selected color
NSMutableAttributedString *shouldDisplayText = [[NSMutableAttributedString alloc] initWithAttributedString: currentText];
[shouldDisplayText appendAttributedString: newOneText];// add old and new text
self.Textview.attributedText = shouldDisplayText;//set it ton control
return NO;
}
3- Add IBAction for changing color
=>
- (IBAction) redColorClicked
{
self.curColor = [UIColor colorWithRed:1.0f green: 0.0f blue:0.0f alpha:1.0f];
}
- (IBAction) blueColorClicked
{
self.curColor = [UIColor colorWithRed:0.0f green: 0.0f blue:1.0f alpha:1.0f];
}

Answer 2

You need to use NSAttributedString class.
let defaultAttributes = [NSFontAttributeName: UIFont.systemFontOfSize(UIFont.systemFontSize()),
NSForegroundColorAttributeName: UIColor.blackColor()]
let text = "this text is red and yellow"
let str = NSMutableAttributedString(string: text, attributes: defaultAttributes)
str.setAttributes([NSForegroundColorAttributeName: UIColor.redColor()], range: (text as NSString).rangeOfString("red"))
str.setAttributes([NSForegroundColorAttributeName: UIColor.yellowColor()], range: (text as NSString).rangeOfString("yellow"))
textView.attributedText = str

Answer 3

You can use NSMutableAttributedString to achieve that. The idea is the following (I didn't tested it, just wrote it here by hand):
NSString *str = #"stackoverflow";
NSMutableAttributedString *attributedString = [[NSMutableAttributedString alloc] initWithString:str];
// Set foreground color of "stack" substring in our string to red
[attributedString addAttribute:NSForegroundColorAttributeName
value:[UIColor redColor];
range:NSMakeRange(0, 5)];
Using this method you can achieve what you want applying color to ranges you want in the text.
You can set the attributed text to you UILabel like that:
yourLabel.attributedText = attributedString