（iOS）带占位符的TextView

• 因为在项目中有需要多行输入，并且带占位符的输入文本，UITextField并不能满足的我们的需求，所以下面自定义了一个带占位符的TextView.
  • 下面是使用

   LTTextView  *textView = [[ LTTextView alloc]initWithFrame:CGRectMake(LTMargin, LTMarginBig, ScreenWidth - 2*LTMargin , 200)];
    textView.placeholderTextView.text = @"这个是占位符，请输入....";
    [self.view addSubview:textView];


    LTTextView *textView1 = [LTTextView placeholderTextView];
    textView1.frame = CGRectMake(LTMargin, 240, ScreenWidth - 2*LTMargin , 200);
    textView1.placeholderTextView.text = @"这个是测试的，请输入....";
    [self.view addSubview:textView1];

• 下面是实现的代码

  //
//  LTTextView.h
//  LTTextvViewDemo
//
//  Created by WJX on 16/7/8.
//  Copyright © 2016年 wjx. All rights reserved.
//

#import <UIKit/UIKit.h>

@interface LTTextView : UIView

/**  */
@property (nonatomic, strong, nullable) UITextView  *textView;

/** 占位*/
@property (nonatomic, strong, nullable) UITextView  *placeholderTextView;

+ (instancetype )placeholderTextView;
@end

//
//  LTTextView.m
//  LTTextvViewDemo
//
//  Created by WJX on 16/7/8.
//  Copyright © 2016年 wjx. All rights reserved.
//

#import "LTTextView.h"

//这里是限制字数
#define MAX_WORD_LIMIT 200


@interface LTTextView ()<UITextViewDelegate,UITextFieldDelegate>



@end
@implementation LTTextView

#pragma mark - --- init 视图初始化 ---

+ (instancetype )placeholderTextView{
//    init方法内部会自动调用initWithFrame:方法
    return [[self alloc]init];
}
- (instancetype)initWithFrame:(CGRect)frame
{
    self = [super initWithFrame:frame];
    if (self) {
        [self setupUI];

    }
    return self;
}
- (void)setupUI{
    [self addSubview:self.placeholderTextView];
    [self addSubview:self.textView];

}
#pragma mark - --- delegate 视图委托 ---

/**
 * 这个方法专门用来布局子控件，一般在这里设置子控件的frame
 * 当控件本身的尺寸发生改变的时候，系统会自动调用这个方法
 *
 */
- (void)layoutSubviews{
    [super layoutSubviews];

    CGFloat textViewW = self.frame.size.width;
    CGFloat textViewH = self.frame.size.height;
    self.textView.frame = CGRectMake(0, 0, textViewW, textViewH );
    self.placeholderTextView.frame  = CGRectMake(0, 0, textViewW, textViewH );

}
//点击return 按钮 去掉
-(BOOL)textFieldShouldReturn:(UITextField *)textField
{
    [textField resignFirstResponder];
    return YES;
}
-(BOOL)textView:(UITextView *)textView shouldChangeTextInRange:(NSRange)range replacementText:(NSString *)text{
    if (text.length == 0 && range.location == 0) {
        self.placeholderTextView.hidden = NO;
    }else{
        self.placeholderTextView.hidden =YES;
    }

    if ([text isEqualToString:@"\n"]) {
        [textView resignFirstResponder];
        return NO;
    }
    return YES;
}

/*由于联想输入的时候，函数textView:shouldChangeTextInRange:replacementText:无法判断字数，
 因此使用textViewDidChange对TextView里面的字数进行判断
 */
- (void)textViewDidChange:(UITextView *)textView
{
    if (textView.text.length == 0) {
        self.placeholderTextView.hidden = NO;


    }else{
        self.placeholderTextView.hidden =YES;

    }

    //该判断用于联想输入
    if (textView.text.length > MAX_WORD_LIMIT)
    {
        textView.text = [textView.text substringToIndex:MAX_WORD_LIMIT];
    }
}


#pragma mark - --- event response 事件相应 ---

#pragma mark - --- private methods 私有方法 ---

#pragma mark - --- setters 属性 ---

#pragma mark - --- getters 属性 —--
- (UITextView *)textView{
    if (!_textView) {
        _textView = [[UITextView alloc]init];
        _textView.backgroundColor = [UIColor clearColor];
        _textView.layer.borderColor = [UIColor lightGrayColor].CGColor;
        _textView.layer.borderWidth = 0.5;
        _textView.font = [UIFont systemFontOfSize:13];
        _textView.delegate = self;
    }

    return _textView;
}
- (UITextView *)placeholderTextView{
    if (!_placeholderTextView) {
        _placeholderTextView = [[UITextView alloc]init];
        _placeholderTextView.font = [UIFont systemFontOfSize:13];
        _placeholderTextView.textColor = [UIColor colorWithRed:133/255 green:136/255 blue:140/255 alpha:0.2];
    }
    return _placeholderTextView;
}

@end

• git上的demo地址 https://github.com/wjxlogo/LTTextView