UILabel multi-line extension

UILabel , , , - .

UITextView, .

, UIView coverView UILabel. UILabel , , coverView , coverView origin.y size.height , UILabel. UILabel , coverView origin.y size.height , UILabel. UILabel .

UIView : AnimatedLabel. . , .

( IB ):

// Init
AnimatedLabel *animLabel = [[AnimatedLabel alloc] initWithFrame:/*desired CGRect*/];

// Set the surroundingBackgroundColor, this color will be used for the coverView
// you should set it to the container view backgroundColor
// IMPORTANT: transparency is not supported! (if its transparent you'll see the UILabel)
animLabel.surroundingBackgroundColor = self.view.backgroundColor;

// Set the text
animLabel.label.text = /*text text text ...*/;

// Call sizeToFit to modify the label size to fit the text perfectly
// so that the text is not moved after the label is expanded (UILabel always
// centers the text vertically and if the label
// is not resized you will see that the text is repositioned after the animation)
[animLabel sizeToFit];

// Open the label
[animLabel open];

// Close the label
[animLabel close];

// You can resize the animLabel and the subviews will be correctly resized
animLabel.frame = /*CGRect*/;

AnimatedLabel.h

//
//  AnimatedLabel.h
//  labeltest
//
//  Created by Alpar Szotyori on 20/06/2012.
//  Use it, modify it, improve it, share it!
//

#import <UIKit/UIKit.h>

@interface AnimatedLabel : UIView

@property (nonatomic, strong) UILabel *label;
@property (nonatomic, strong) UIColor *surroundingBackgroundColor;
@property (nonatomic) BOOL isOpen;

// Public methods

- (void)open;
- (void)close;

@end

AnimatedLabel.m:

//
//  AnimatedLabel.m
//  labeltest
//
//  Created by Alpar Szotyori on 20/06/2012.
//  Use it, modify it, improve it, share it!
//

#import "AnimatedLabel.h"

@interface NSString (visibleText)

- (NSString*)stringVisibleInRect:(CGRect)rect withFont:(UIFont*)font constrainedToSize:(CGSize)size;

@end

@implementation NSString (visibleText)

- (NSString*)stringVisibleInRect:(CGRect)rect withFont:(UIFont*)font constrainedToSize:(CGSize)size
{
    BOOL addEllipse = NO;
    NSString *visibleString = @"";
    for (int i = 2; i <= self.length; i++)
    {
        NSString *testString = [self substringToIndex:i];
        CGSize stringSize = [testString sizeWithFont:font constrainedToSize:size];
        if (stringSize.height > rect.size.height || stringSize.width > rect.size.width) {
            addEllipse = YES;
            break;
        }

        visibleString = testString;
    }

    if (addEllipse) {
        if (visibleString.length >= 3) {
            visibleString = [[visibleString substringToIndex:visibleString.length - 3] stringByAppendingString:@"…"];
        }
    }

    return visibleString;
}

@end


@interface AnimatedLabel()

@property (nonatomic, strong) UIView *coverView;
@property (nonatomic, strong) UIColor *backgrndColor;
@property (nonatomic) CGFloat origLabelHeight;
@property (nonatomic, strong) NSString *origLabelText;
@property (nonatomic) BOOL animating;
@property (nonatomic) BOOL labelKVOSet;

- (void)changeHeight:(CGFloat)height animated:(BOOL)animated;
- (void)addKVOToLabel;
- (void)removeKVOFromLabel;

@end


@implementation AnimatedLabel

#pragma mark - Properties

@synthesize label;
@synthesize surroundingBackgroundColor = i_surroundingBackgroundColor;
@synthesize isOpen;

- (void)setSurroundingBackgroundColor:(UIColor *)surroundingBackgroundColor {
    i_surroundingBackgroundColor = surroundingBackgroundColor;
    self.coverView.backgroundColor = i_surroundingBackgroundColor;
}

#pragma mark - Initialization

- (id)initWithCoder:(NSCoder *)aDecoder {
    self = [super initWithCoder:aDecoder];
    if (self) {
        self.label = [[UILabel alloc] initWithFrame:CGRectMake(0.0, 0.0, self.frame.size.width, self.frame.size.height)];
        self.label.numberOfLines = 0;
        self.label.backgroundColor = self.backgrndColor;
        self.origLabelHeight = self.label.frame.size.height;
        [self addKVOToLabel];

        self.coverView = [[UIView alloc] initWithFrame:CGRectZero];
        self.coverView.backgroundColor = [UIColor whiteColor];

        [self addSubview:self.label];
        [self addSubview:self.coverView];

        self.animating = NO;
        self.isOpen = NO;
    }
    return self;
}

- (id)initWithFrame:(CGRect)frame
{
    self = [super initWithFrame:frame];
    if (self) {
        self.label = [[UILabel alloc] initWithFrame:CGRectMake(0.0, 0.0, frame.size.width, frame.size.height)];
        self.label.numberOfLines = 0;
        self.label.backgroundColor = self.backgrndColor;
        self.origLabelHeight = self.label.frame.size.height;
        [self addKVOToLabel];

        self.coverView = [[UIView alloc] initWithFrame:CGRectZero];
        self.coverView.backgroundColor = [UIColor whiteColor];

        [self addSubview:self.label];
        [self addSubview:self.coverView];

        self.animating = NO;
        self.isOpen = NO;
    }
    return self;
}

#pragma mark - Overriden methods

- (void)setFrame:(CGRect)frame {
    if (!self.animating && self.isOpen) {
        self.isOpen = NO;
        [self changeHeight:self.origLabelHeight animated:NO];
        frame.size.height = self.origLabelHeight;
    }

    [super setFrame:frame];

    if (!self.animating) {        
        self.label.frame= CGRectMake(0.0, 0.0, frame.size.width, frame.size.height);
        self.origLabelHeight = self.label.frame.size.height;

        [self removeKVOFromLabel];

        NSString *visibleText = [self.origLabelText stringVisibleInRect:self.label.frame withFont:self.label.font constrainedToSize:CGSizeMake(frame.size.width, LONG_MAX)];
        self.label.text = visibleText;
        [self.label sizeToFit];

        [self addKVOToLabel];
    }
}

- (void)setBackgroundColor:(UIColor *)backgroundColor {
    [super setBackgroundColor:[UIColor clearColor]];

    self.backgrndColor = backgroundColor;

    self.label.backgroundColor = self.backgrndColor;
}

- (UIColor *)backgroundColor {
    return self.backgrndColor;
}

- (void)sizeToFit {
    [self removeKVOFromLabel];

    NSString *visibleText = [self.origLabelText stringVisibleInRect:self.label.frame withFont:self.label.font constrainedToSize:CGSizeMake(self.frame.size.width, LONG_MAX)];
    self.label.text = visibleText;
    [self.label sizeToFit];
    self.origLabelHeight = self.label.frame.size.height;

    [self addKVOToLabel];

    self.frame = CGRectMake(self.frame.origin.x, self.frame.origin.y, self.label.frame.size.width, self.label.frame.size.height);
}

#pragma mark - KVO methods

- (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context {
     if ([keyPath isEqualToString:@"text"]) {
         self.origLabelText = [change objectForKey:NSKeyValueChangeNewKey];
     }
}

#pragma mark - Public methods

- (void)open {
    self.origLabelHeight = self.label.frame.size.height;
    [self removeKVOFromLabel];
    self.label.text = self.origLabelText;
    [self addKVOToLabel];
    [self.label sizeToFit];

    if (self.origLabelHeight == self.label.frame.size.height) {
        return;
    }

    [self changeHeight:self.label.frame.size.height animated:YES];
    self.isOpen = YES;
}

- (void)close {
    if (self.frame.size.height == self.origLabelHeight) {
        return;
    }

    [self changeHeight:self.origLabelHeight animated:YES];
    self.isOpen = NO;
}

#pragma mark - Private methods

#pragma mark - Properties

@synthesize coverView, backgrndColor, origLabelHeight, origLabelText, animating, labelKVOSet;

#pragma mark - Methods

- (void)changeHeight:(CGFloat)height animated:(BOOL)animated {
    if (self.frame.size.height == height) {
        return;
    }

    if (height > self.frame.size.height) {
        self.animating = YES;

        [self.label sizeToFit];
        height = self.label.frame.size.height;

        self.coverView.frame = CGRectMake(0.0, self.frame.size.height, self.frame.size.width, height - self.frame.size.height);
        self.frame = CGRectMake(self.frame.origin.x, self.frame.origin.y, self.frame.size.width, height);
        self.label.frame = CGRectMake(0.0, 0.0, self.frame.size.width, self.frame.size.height);

        if (animated) {
            [UIView animateWithDuration:0.5 animations:^(){
                self.coverView.frame = CGRectMake(0.0, self.frame.size.height, self.frame.size.width, 0.0); 
            } completion:^(BOOL completed){
                self.animating = NO;
            }];
        } else {
            self.coverView.frame = CGRectMake(0.0, self.frame.size.height, self.frame.size.width, 0.0); 
            self.animating = NO;
        }
    } else {
        self.animating = YES;

        if (animated) {
            [UIView animateWithDuration:0.5 animations:^(){
                self.coverView.frame = CGRectMake(0.0, height, self.frame.size.width, self.frame.size.height - height);
            } completion:^(BOOL completed){
                self.frame = CGRectMake(self.frame.origin.x, self.frame.origin.y, self.frame.size.width, height);
                self.coverView.frame = CGRectMake(0.0, height, self.frame.size.width, 0.0);
                self.label.frame = CGRectMake(0.0, 0.0, self.frame.size.width, height);
                self.animating = NO;
            }];
        } else {
            self.frame = CGRectMake(self.frame.origin.x, self.frame.origin.y, self.frame.size.width, height);
            self.coverView.frame = CGRectMake(0.0, height, self.frame.size.width, 0.0);
            self.label.frame = CGRectMake(0.0, 0.0, self.frame.size.width, height);
            self.animating = NO;            
        }
    }
}

- (void)addKVOToLabel {
    if (self.label == nil) {
        return;
    }

    if (!self.labelKVOSet) {
        self.labelKVOSet = YES;
        [self.label addObserver:self forKeyPath:@"text" options:NSKeyValueObservingOptionNew context:nil];
    }
}

- (void)removeKVOFromLabel {
    if (self.label == nil) {
        return;
    }

    if (self.labelKVOSet) {
        self.labelKVOSet = NO;
        [self.label removeObserver:self forKeyPath:@"text"];
    }
}

@end