iOS-UITextView占位文字placeholder

自定义类,继承UITextView,实现类似于UITextField的占位文字效果,用户输入文本后占位文字消失.

使用方法仅需两行代码:

XWPlaceholderTextView *placholderTextView = [XWPlaceholderTextView shareWithFrame:CGRectMake(0, 0, kScreenWidth, kScreenHeight - 64) withPlaceholder:@"我们将根据您反馈的意见和问题, 提升产品的体验感!您的声音很重要"];    [self.view addSubview:placholderTextView];

.h

////  XWPlaceholderTextView.h//  Spread////  Created by 邱学伟 on 16/4/18.//  Copyright © 2016年 邱学伟. All rights reserved.//  有占位文字的UITextView#import <UIKit/UIKit.h>@interface XWPlaceholderTextView : UITextView/** *  占位文字 * 我们将根据您反馈的意见和问题, 提升产品的体验感! */@property (nonatomic, copy) NSString *placeholderStr;/** *  工厂方法 * *  @param frame          textView的尺寸 *  @param placeholderStr 占位文字 */+(instancetype)shareWithFrame:(CGRect)frame withPlaceholder:(NSString *)placeholderStr;/** *  初始化 */-(instancetype)initWithPlaceholder:(NSString *)placeholderStr;@end

.m

////  XWPlaceholderTextView.m//  Spread////  Created by 邱学伟 on 16/4/18.//  Copyright © 2016年 邱学伟. All rights reserved.//#import "XWPlaceholderTextView.h"//间隔#define kMargin 7//字体大小#define kFontSize 17@interface XWPlaceholderTextView ()<UITextViewDelegate>/** *  占位文本框 */@property (nonatomic, strong) UILabel *placeholderLB;@end@implementation XWPlaceholderTextView#pragma mark - 懒加载-(UILabel *)placeholderLB{    if (_placeholderLB == nil) {        _placeholderLB = [[UILabel alloc] init];        _placeholderLB.textColor = [UIColor lightGrayColor];        [_placeholderLB setNumberOfLines:0];    }    return _placeholderLB;}//初始化方法-(instancetype)initWithFrame:(CGRect)frame withPlaceholder:(NSString *)placeholderStr{    self = [super initWithFrame:frame];    if (self) {        //设置占位文本才会调用getter/setter方法        self.placeholderStr = placeholderStr;        self.delegate = self;//        self.layer.cornerRadius = kMargin;        self.font = [UIFont systemFontOfSize:kFontSize];    }    return self;}+(instancetype)shareWithFrame:(CGRect)frame withPlaceholder:(NSString *)placeholderStr{    XWPlaceholderTextView *XWText = [[XWPlaceholderTextView alloc] initWithFrame:frame withPlaceholder:placeholderStr];    return XWText;}#pragma mark - UITextViewDelegate- (void)textViewDidChange:(UITextView *)textView {    self.placeholderLB.hidden = textView.text.length;}#pragma mark - setter方法-(void)setPlaceholderStr:(NSString *)placeholderStr{    if (_placeholderStr != placeholderStr) {        _placeholderStr = placeholderStr;        //只有在设置占位文字时,才加载占位label        [self addSubview:self.placeholderLB];        //设置占位文本        [self.placeholderLB setText:_placeholderStr];        //占位文本Lable的尺寸        NSDictionary *attributes = @{                                     NSFontAttributeName:[UIFont systemFontOfSize:kFontSize]                                     };        //获取一段文本在规定长宽的尺寸        CGRect placeholderLBSize = [_placeholderStr boundingRectWithSize:CGSizeMake(self.frame.size.width - kMargin * 2, 0) options:NSStringDrawingUsesLineFragmentOrigin |NSStringDrawingUsesFontLeading attributes:attributes context:nil];        [self.placeholderLB setFrame:CGRectMake(kMargin, kMargin, placeholderLBSize.size.width, placeholderLBSize.size.height)];    }}/*// Only override drawRect: if you perform custom drawing.// An empty implementation adversely affects performance during animation.- (void)drawRect:(CGRect)rect {    // Drawing code}*/@end