iOS之给TextView增加placeholder

利用两个UITextView非常简单的实现给TextView增加placeholder的功能

.h

#import <UIKit/UIKit.h>

@interface ZCTextView : UIView

@property (nonatomic, strong) UITextView *placeholderTextView;
@property (nonatomic, strong) UITextView *textView;

@end

.m

#import "ZCTextView.h"

@interface ZCTextView()<UITextViewDelegate>

@end

@implementation ZCTextView

- (instancetype)initWithFrame:(CGRect)frame
{
    self = [super initWithFrame:frame];
    if (self) {
        [self addSubview:self.placeholderTextView];
        [self addSubview:self.textView];
    }
    return self;
}

- (UITextView *)placeholderTextView
{
    if (!_placeholderTextView) {
        _placeholderTextView = [[UITextView alloc] initWithFrame:CGRectMake(10, 0, self.width-20, self.height)];
        _placeholderTextView.font = [UIFont systemFontOfSize:15];
        _placeholderTextView.textColor = UIColorFromRGB(0xcdcdcd);
        _placeholderTextView.backgroundColor = [UIColor clearColor];
    }
    return _placeholderTextView;
}

- (UITextView *)textView
{
    if (!_textView) {
        _textView = [[UITextView alloc] initWithFrame:CGRectMake(10, 0, self.width-20, self.height)];
        _textView.font = [UIFont systemFontOfSize:15];
        _textView.textColor = UIColorFromRGB(0x595959);
        _textView.backgroundColor = [UIColor clearColor];
        _textView.delegate = self;
    }
    return _textView;
}

- (void)textViewDidBeginEditing:(UITextView *)textView
{
    _placeholderTextView.hidden = YES;
}

- (void)textViewDidChangeSelection:(UITextView *)textView
{
    if (STR_IS_NOT_EMPTY(self.textView.text)) {
        _placeholderTextView.hidden = YES;
    }else{
        _placeholderTextView.hidden = NO;
    }
}

- (void)textViewDidEndEditing:(UITextView *)textView
{
    if (STR_IS_NOT_EMPTY(self.textView.text)) {
        _placeholderTextView.hidden = YES;
    }else{
        _placeholderTextView.hidden = NO;
    }
}

@end

举例

@property (nonatomic, strong) ZCTextView *ContentTextView;

- (ZCTextView *)ContentTextView
{
    if (!_ContentTextView) {
        _ContentTextView = [[ZCTextView alloc] initWithFrame:CGRectMake(0, 0, SCREEN_WIDTH, 150)];
        _ContentTextView.placeholderTextView.text = @"这是默认提示文字";
        _ContentTextView.backgroundColor = [UIColor whiteColor];
    }
    return _ContentTextView;
}