1.首先创建一个继承与UITextView的ZDTextView
2.在#import "ZDTextView.h"文件里面创建
@property(nonatomic,copy) NSString *myPlaceholder; //文字
@property(nonatomic,strong) UIColor *myPlaceholderColor; //文字颜色
@property UILabel *placeholderLabel;
3.#import "ZDTextView.m"
//重写初始化方法
- (instancetype)initWithFrame:(CGRect)frame{
self = [super initWithFrame:frame];
if(self) {
self.backgroundColor= [UIColor clearColor];
UILabel *placeholderLabell = [[UILabel alloc]init];//占位label
placeholderLabell.backgroundColor= [UIColor clearColor];
placeholderLabell.numberOfLines=0; //多行显示
[self addSubview:placeholderLabell];
self.placeholderLabel= placeholderLabell; //赋值
self.myPlaceholderColor= [UIColor lightGrayColor]; //字体颜色
self.font= [UIFont systemFontOfSize:15]; //给定一个默认字体大小
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(textDidChange) name:UITextViewTextDidChangeNotification object:self]; //通知:监听文字的改变的状态
}
return self;
}
//实现监听方法
#pragma mark -监听文字改变
- (void)textDidChange {
self.placeholderLabel.hidden = self.hasText;
}
/**
//设置lable的显示位置
*/
- (void)layoutSubviews{
[super layoutSubviews];
self.placeholderLabel.mj_y=8;
self.placeholderLabel.mj_x=5;
self.placeholderLabel.mj_w=self.mj_w-self.placeholderLabel.mj_x*2.0;
CGSize maxSize =CGSizeMake(self.placeholderLabel.mj_w,MAXFLOAT);
self.placeholderLabel.mj_h= [self.myPlaceholder boundingRectWithSize:maxSize options:NSStringDrawingUsesFontLeading | NSStringDrawingUsesLineFragmentOrigin attributes:@{NSFontAttributeName : self.placeholderLabel.font} context:nil].size.height;
}
/**
重新赋值
@param myPlaceholder 重新赋值
*/
- (void)setMyPlaceholder:(NSString*)myPlaceholder{
_myPlaceholder= [myPlaceholder copy];
//设置文字
self.placeholderLabel.text= myPlaceholder;
//重新计算子控件frame
[self setNeedsLayout];
}
- (void)setMyPlaceholderColor:(UIColor*)myPlaceholderColor{
_myPlaceholderColor= myPlaceholderColor;
//设置颜色
self.placeholderLabel.textColor= myPlaceholderColor;
}
//重写这个set方法保持font一致
- (void)setFont:(UIFont*)font{
[super setFont:font];
self.placeholderLabel.font= font;
//重新计算子控件frame的大小位置
[self setNeedsLayout];
}
- (void)setText:(NSString*)text{
[super setText:text];
[self textDidChange]; // UITextViewTextDidChangeNotification 通知的回调方法
}
- (void)setAttributedText:(NSAttributedString*)attributedText{
[super setAttributedText:attributedText];
[self textDidChange]; //这里调用的就是UITextViewTextDidChangeNotification 通知的回调
}
//操作完成销毁通知
- (void)dealloc{
[[NSNotificationCenter defaultCenter]removeObserver:UITextViewTextDidChangeNotification];
}
最后我们在使用的时候直接导入#import "ZDTextView.h"
ZDTextView *sugesttextview=[[ZDTextView alloc]initWithFrame:CGRectMake(ScaleX(15), suglable.frame.origin.y+suglable.frame.size.height, SIZE_WIDTH-ScaleX(30), ScaleX(140))];//适配ZDTextView，这里你可以使用自己的方式
sugesttextview.backgroundColor=[UIColor colorWithHexString:@"#efefef"];//改变背景颜色
sugesttextview.myPlaceholder=@"请输入您的建议或意见";
sugesttextview.editable=YES;
sugesttextview.myPlaceholderColor=[UIColor colorWithHexString:@"#999999"];//改变字体颜色
sugesttextview.placeholderLabel.font=[UIFont systemFontOfSize:mytextfont];//设置字体大小
[self addSubview:sugesttextview];