下面是我的代码，可以直接拿来用
#import <UIKit/UIKit.h> @interface CustomTextView : UITextView
@property(nonatomic,strong)NSString *placeholder;
@end
#import "CustomTextView.h" @interface CustomTextView ()
@property(nonatomic,strong)UILabel *placeLab;
@end @implementation CustomTextView -(instancetype)initWithFrame:(CGRect)frame{
self = [super initWithFrame:frame];
if(self){ self.placeLab = [UILabel new];
self.placeLab.textColor = [ImageService colorWithHexString:GRAY_COLOR];
[self addSubview:self.placeLab];
self.placeLab.textAlignment = NSTextAlignmentRight;
[self.placeLab mas_makeConstraints:^(MASConstraintMaker *make) {
make.top.left.offset(5);
make.width.equalTo(self.mas_width).offset(-10);
}];
[[NSNotificationCenter defaultCenter]addObserver:self selector:@selector(beginChange) name:UITextViewTextDidBeginEditingNotification object:self];
[[NSNotificationCenter defaultCenter]addObserver:self selector:@selector(didChange) name:UITextViewTextDidChangeNotification object:self]; }
return self;
}
-(void)setFont:(UIFont *)font {
[super setFont:font];
self.placeLab.font = font;
}
-(void)setTextAlignment:(NSTextAlignment)textAlignment{
[super setTextAlignment:textAlignment];
self.placeLab.textAlignment = textAlignment;
} -(void)setPlaceholder:(NSString *)placeholder{
_placeholder = placeholder;
self.placeLab.text = placeholder;
} -(void)beginChange{
if([self.text isEqualToString:@""]){
self.placeLab.hidden = NO;
}else{
self.placeLab.hidden = YES;
}
}
-(void)didChange{
if([self.text isEqualToString:@""]){
self.placeLab.hidden = NO;
}else{
self.placeLab.hidden = YES;
}
}
-(void)setText:(NSString *)text{
[super setText:text];
[self beginChange];
} @end
-(void)dealloc{
[[NSNotificationCenter defaultCenter] removeObserver:self name:UITextViewTextDidBeginEditingNotification object:self];
[[NSNotificationCenter defaultCenter] removeObserver:self name:UITextViewTextDidChangeNotification object:self];
}