tederen_ios/smartRhino/Project/Other/Third/UIPlaceHolderTextView/UIPlaceHolderTextView.m

//
//  UIPlaceHolderTextView.m
//  xbxm
//
//  Created by Scott Su on 14-12-6.
//  Copyright (c) 2014年 tongxueplus. All rights reserved.
//

#import "UIPlaceHolderTextView.h"

@interface UIPlaceHolderTextView ()



@end


@implementation UIPlaceHolderTextView
CGFloat const UI_PLACEHOLDER_TEXT_CHANGED_ANIMATION_DURATION = 0.25;
- (instancetype)init{
    self = [super init];
    if (self) {
        if (!self.placeholder) {
                [self setPlaceholder:@""];
            }
            
            if (!self.placeholderColor) {
                [self setPlaceholderColor:UIColorHex(#999999)];
            }
            
            [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(textChanged:) name:UITextViewTextDidChangeNotification object:nil];
            
            if (_placeHolderLabel == nil )
            {
                _placeHolderLabel = [[UILabel alloc] init];
                _placeHolderLabel.lineBreakMode = NSLineBreakByWordWrapping;
                _placeHolderLabel.numberOfLines = 0;
                _placeHolderLabel.font = self.font;
                _placeHolderLabel.backgroundColor = [UIColor clearColor];
                _placeHolderLabel.textColor = self.placeholderColor;
                _placeHolderLabel.alpha = 0;
                _placeHolderLabel.tag = 999;
                [self addSubview:_placeHolderLabel];
            }
            
            _placeHolderLabel.text = self.placeholder;
            [_placeHolderLabel mas_makeConstraints:^(MASConstraintMaker *make) {
                make.left.top.mas_offset(8);
                make.right.mas_offset(-8);
                make.height.mas_greaterThanOrEqualTo(20);
            }];
            [self sendSubviewToBack:_placeHolderLabel];
    }
    return self;
}
- (void)awakeFromNib
{
    [super awakeFromNib];
    
    // Use Interface Builder User Defined Runtime Attributes to set
    // placeholder and placeholderColor in Interface Builder.
    if (!self.placeholder) {
        [self setPlaceholder:@""];
    }
    
    if (!self.placeholderColor) {
        [self setPlaceholderColor:UIColorHex(#999999)];
    }
    
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(textChanged:) name:UITextViewTextDidChangeNotification object:nil];
    
    if (_placeHolderLabel == nil )
    {
//        _placeHolderLabel = [[UILabel alloc] initWithFrame:CGRectMake(8,8,self.bounds.size.width - 16,0)];
        _placeHolderLabel = [[UILabel alloc] init];
        _placeHolderLabel.lineBreakMode = NSLineBreakByWordWrapping;
        _placeHolderLabel.numberOfLines = 0;
        _placeHolderLabel.font = self.font;
        _placeHolderLabel.backgroundColor = [UIColor clearColor];
        _placeHolderLabel.textColor = self.placeholderColor;
        _placeHolderLabel.alpha = 0;
        _placeHolderLabel.tag = 999;
        //            _placeHolderLabel.backgroundColor = RGB(51, 51, 51);
        [self addSubview:_placeHolderLabel];
    }
    
    _placeHolderLabel.text = self.placeholder;
    //        [_placeHolderLabel sizeToFit];
//    CGFloat H = [self.placeholder sizeWithFont:self.font byWidth:self.bounds.size.width - 16].height;
    [_placeHolderLabel mas_makeConstraints:^(MASConstraintMaker *make) {
        make.left.top.mas_offset(8);
        make.right.mas_offset(-8);
        make.height.mas_greaterThanOrEqualTo(20);
    }];
//    _placeHolderLabel.frame = CGRectMake(8, 8, self.bounds.size.width - 16, [self.placeholder sizeWithFont:self.font byWidth:self.bounds.size.width - 16].height);
    [self sendSubviewToBack:_placeHolderLabel];
}
- (void)setPlaceholder:(NSString *)placeholder
{
    _placeholder = placeholder;
    _placeHolderLabel.text = _placeholder;
}
- (id)initWithFrame:(CGRect)frame
{
    if( (self = [super initWithFrame:frame]) )
    {
        [self setPlaceholder:@""];
        [self setPlaceholderColor:[UIColor lightGrayColor]];
        [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(textChanged:) name:UITextViewTextDidChangeNotification object:nil];
    }
    return self;
}

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

- (void)textChanged:(NSNotification *)notification
{
    if([[self placeholder] length] == 0)
    {
        return;
    }
    
    [self.placeHolderLabel setText:self.placeholder];
    
    [UIView animateWithDuration:0.2 animations:^{
        if([[self text] length] == 0)
        {
            [(UILabel *)[self viewWithTag:999] setAlpha:1];
        }
        else
        {
            [(UILabel *)[self viewWithTag:999] setAlpha:0];
        }
    }];
}

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

- (void)drawRect:(CGRect)rect
{
    if( [[self placeholder] length] > 0 )
    {
    
    }
    
    if( [[self text] length] == 0 && [[self placeholder] length] > 0 )
    {
        [(UILabel *)[self viewWithTag:999] setAlpha:1];
    }
    
    [super drawRect:rect];
}
@end