UIPlaceholderTextView

UIPlaceholderTextView.h

//
//  UIPlaceholderTextView.h
//  
//  Created by Nicolas Manzini on 27.10.14.
//  Free under MIT
//

#import <UIKit/UIKit.h>

@interface UIPlaceholderTextView : UITextView

@property (strong, nonatomic) NSAttributedString * attributedPlaceholder;
@property (assign, nonatomic) CGPoint placeholderOffset;

@end

UIPlaceholderTextView.m

//
//  UIPlaceholderTextView.m
//
//  Created by Nicolas Manzini on 27.10.14.
//  Free under MIT
//

#import "UIPlaceholderTextView.h"

const CGPoint defaultPlaceholderOffset = {5.f,7.f};

@interface UIPlaceholderTextView ()

@property (strong, nonatomic) UILabel * labelPlaceholder;
- (void)textDidChange:(NSNotification *)note;
- (void)initLabelPlaceholder;

@end

@implementation UIPlaceholderTextView

- (id)initWithCoder:(NSCoder *)aDecoder {
    self = [super initWithCoder:aDecoder];
    if (self) {
        _placeholderOffset = defaultPlaceholderOffset;
        [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(textDidChange:) name:UITextViewTextDidChangeNotification object:nil];
        [self initLabelPlaceholder];
    }
    return self;
}

- (instancetype)init {
    self = [super init];
    if (self) {
        _placeholderOffset = defaultPlaceholderOffset;
        [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(textDidChange:) name:UITextViewTextDidChangeNotification object:nil];
        [self initLabelPlaceholder];
    }
    return self;
}

- (instancetype)initWithFrame:(CGRect)frame {
    self = [super initWithFrame:frame];
    if (self) {
        _placeholderOffset = defaultPlaceholderOffset;
        [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(textDidChange:) name:UITextViewTextDidChangeNotification object:nil];
        [self initLabelPlaceholder];
    }
    return self;
}

- (instancetype)initWithFrame:(CGRect)frame textContainer:(NSTextContainer *)textContainer {
    self = [super initWithFrame:frame textContainer:textContainer];
    if (self) {
        _placeholderOffset = defaultPlaceholderOffset;
        [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(textDidChange:) name:UITextViewTextDidChangeNotification object:nil];
        [self initLabelPlaceholder];
    }
    return self;
}

- (void)initLabelPlaceholder {
    UIEdgeInsets insets   = self.contentInset;
    CGPoint      offset   = self.contentOffset;
    CGPoint      pOffset  = self.placeholderOffset;

    UILabel * label       = [[UILabel alloc] initWithFrame:CGRectMake(insets.left+offset.x+pOffset.x, insets.top+ offset.y+pOffset.y, 0.f, 0.f)];
    label.backgroundColor = [UIColor clearColor];
    label.userInteractionEnabled = NO;
    [self addSubview:label];
    self.labelPlaceholder = label;
}

- (void)setPlaceholderOffset:(CGPoint)placeholderOffset {
    CGPoint previousOffset = _placeholderOffset;
    _placeholderOffset = placeholderOffset;
    CGRect frame = self.labelPlaceholder.frame;
    frame.origin.x -= previousOffset.x;
    frame.origin.x += placeholderOffset.x;
    frame.origin.y -= previousOffset.y;
    frame.origin.x += placeholderOffset.y;
    self.labelPlaceholder.frame = frame;
}

- (void)textDidChange:(NSNotification *)note {
    if (note.object == self) {
        self.labelPlaceholder.hidden = self.text.length;
    }
}

- (void)setAttributedPlaceholder:(NSAttributedString *)attributedPlaceholder {
    _attributedPlaceholder = attributedPlaceholder;
    self.labelPlaceholder.attributedText = attributedPlaceholder;
    if (attributedPlaceholder) {
        [self resizeLabelPlaceholder];
    }
}

- (void)resizeLabelPlaceholder {
    NSStringDrawingContext * context = [NSStringDrawingContext new];
    context.minimumScaleFactor       = 0.f;
    CGRect bounds =
    [self.labelPlaceholder.attributedText boundingRectWithSize:self.bounds.size
                                                       options:NSStringDrawingUsesLineFragmentOrigin
                                                       context:context];
    CGRect frame      = self.labelPlaceholder.frame;
    frame.size.height = bounds.size.height;
    frame.size.width  = bounds.size.width;
    self.labelPlaceholder.frame = frame;
}

- (void)setFrame:(CGRect)frame {
    [super setFrame:frame];
    [self resizeLabelPlaceholder];
}

- (void)setBounds:(CGRect)bounds {
    [super setBounds:bounds];
    [self resizeLabelPlaceholder];
}

- (void)dealloc {
    [[NSNotificationCenter defaultCenter] removeObserver:self];
}

@end