JSQMessagesViewController/JSMessagesViewController/Classes/JSMessageTextView.m

//
//  Created by Jesse Squires
//  http://www.hexedbits.com
//
//
//  Documentation
//  http://cocoadocs.org/docsets/JSMessagesViewController
//
//
//  The MIT License
//  Copyright (c) 2013 Jesse Squires
//  http://opensource.org/licenses/MIT
//

#import "JSMessageTextView.h"
#import "JSBubbleView.h"
#import "NSString+JSMessagesView.h"

@interface JSMessageTextView ()

- (void)setup;

- (void)addTextViewNotificationObservers;
- (void)removeTextViewNotificationObservers;
- (void)didReceiveTextViewNotification:(NSNotification *)notification;

@end



@implementation JSMessageTextView

#pragma mark - Initialization

- (void)setup
{
    _placeHolderTextColor = [UIColor lightGrayColor];
    
    self.autoresizingMask = UIViewAutoresizingFlexibleWidth;
    self.scrollIndicatorInsets = UIEdgeInsetsMake(10.0f, 0.0f, 10.0f, 8.0f);
    self.contentInset = UIEdgeInsetsZero;
    self.scrollEnabled = YES;
    self.scrollsToTop = NO;
    self.userInteractionEnabled = YES;
    self.font = [UIFont systemFontOfSize:16.0f];
    self.textColor = [UIColor blackColor];
    self.backgroundColor = [UIColor whiteColor];
    self.keyboardAppearance = UIKeyboardAppearanceDefault;
    self.keyboardType = UIKeyboardTypeDefault;
    self.returnKeyType = UIReturnKeyDefault;
    self.textAlignment = NSTextAlignmentLeft;
    
    [self addTextViewNotificationObservers];
}

- (instancetype)initWithFrame:(CGRect)frame
{
    self = [super initWithFrame:frame];
    if (self) {
        [self setup];
    }
    return self;
}

- (instancetype)initWithCoder:(NSCoder *)aDecoder
{
    self = [super initWithCoder:aDecoder];
    if (self) {
        [self setup];
    }
    return self;
}

- (void)dealloc
{
    [self removeTextViewNotificationObservers];
    _placeHolder = nil;
    _placeHolderTextColor = nil;
}

#pragma mark - Setters

- (void)setPlaceHolder:(NSString *)placeHolder
{
    if ([placeHolder isEqualToString:_placeHolder]) {
        return;
    }
    
    NSUInteger maxChars = [JSMessageTextView maxCharactersPerLine];
    if ([placeHolder length] > maxChars) {
        placeHolder = [placeHolder substringToIndex:maxChars - 8];
        placeHolder = [[placeHolder js_stringByTrimingWhitespace] stringByAppendingFormat:@"..."];
    }
    
    _placeHolder = placeHolder;
    [self setNeedsDisplay];
}

- (void)setPlaceHolderTextColor:(UIColor *)placeHolderTextColor
{
    if ([placeHolderTextColor isEqual:_placeHolderTextColor]) {
        return;
    }
    
    _placeHolderTextColor = placeHolderTextColor;
    [self setNeedsDisplay];
}

#pragma mark - Message text view

- (NSUInteger)numberOfLinesOfText
{
    return [JSMessageTextView numberOfLinesForMessage:self.text];
}

+ (NSUInteger)maxCharactersPerLine
{
    return ([UIDevice currentDevice].userInterfaceIdiom == UIUserInterfaceIdiomPhone) ? 33 : 109;
}

+ (NSUInteger)numberOfLinesForMessage:(NSString *)text
{
    return (text.length / [JSMessageTextView maxCharactersPerLine]) + 1;
}

#pragma mark - Text view overrides

- (void)setText:(NSString *)text
{
    [super setText:text];
    [self setNeedsDisplay];
}

- (void)setAttributedText:(NSAttributedString *)attributedText
{
    [super setAttributedText:attributedText];
    [self setNeedsDisplay];
}

- (void)setFont:(UIFont *)font
{
    [super setFont:font];
    [self setNeedsDisplay];
}

- (void)setTextAlignment:(NSTextAlignment)textAlignment
{
    [super setTextAlignment:textAlignment];
    [self setNeedsDisplay];
}

#pragma mark - Drawing

- (void)drawRect:(CGRect)rect
{
    [super drawRect:rect];
    
    if ([self.text length] == 0 && self.placeHolder) {
        CGRect placeHolderRect = CGRectMake(10.0f,
                                            7.0f,
                                            rect.size.width,
                                            rect.size.height);
        
        [self.placeHolderTextColor set];
        
        if (NSFoundationVersionNumber > NSFoundationVersionNumber_iOS_6_0) {
            NSMutableParagraphStyle *paragraphStyle = [[NSMutableParagraphStyle alloc] init];
            paragraphStyle.lineBreakMode = NSLineBreakByTruncatingTail;
            paragraphStyle.alignment = self.textAlignment;
            
            [self.placeHolder drawInRect:placeHolderRect
                          withAttributes:@{ NSFontAttributeName : self.font,
                                            NSForegroundColorAttributeName : self.placeHolderTextColor,
                                            NSParagraphStyleAttributeName : paragraphStyle }];
        }
        else {
            [self.placeHolder drawInRect:placeHolderRect
                                withFont:self.font
                           lineBreakMode:NSLineBreakByTruncatingTail
                               alignment:self.textAlignment];
        }
    }
}

#pragma mark - Notifications

- (void)addTextViewNotificationObservers
{
    [[NSNotificationCenter defaultCenter] addObserver:self
                                             selector:@selector(didReceiveTextViewNotification:)
                                                 name:UITextViewTextDidChangeNotification
                                               object:self];
    
    [[NSNotificationCenter defaultCenter] addObserver:self
                                             selector:@selector(didReceiveTextViewNotification:)
                                                 name:UITextViewTextDidBeginEditingNotification
                                               object:self];
    
    [[NSNotificationCenter defaultCenter] addObserver:self
                                             selector:@selector(didReceiveTextViewNotification:)
                                                 name:UITextViewTextDidEndEditingNotification
                                               object:self];
}

- (void)removeTextViewNotificationObservers
{
    [[NSNotificationCenter defaultCenter] removeObserver:self
                                                    name:UITextViewTextDidChangeNotification
                                                  object:self];
    
    [[NSNotificationCenter defaultCenter] removeObserver:self
                                                    name:UITextViewTextDidBeginEditingNotification
                                                  object:self];
    
    [[NSNotificationCenter defaultCenter] removeObserver:self
                                                    name:UITextViewTextDidEndEditingNotification
                                                  object:self];
}

- (void)didReceiveTextViewNotification:(NSNotification *)notification
{
    [self setNeedsDisplay];
}

@end