UITextView(占位字符，限制字数)

textView.png textNumber.png

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自定义带占位符的TextView

设置占位符方式千奇百怪，可以添加Label，添加等属性TextView，把text属性当placeholder使用...
在此利用的是系统的_placeholdeLabel

DDYTextView.h

#import <UIKit/UIKit.h>

@interface DDYTextView : UITextView

@property (nonatomic, strong) NSString *placeholder;

@property (nonatomic, strong) UIColor *placeholderTextColor;

+ (instancetype)textView;

+ (instancetype)textViewPlaceholder:(NSString *)placeholder font:(UIFont *)font;

+ (instancetype)textViewPlaceholder:(NSString *)placeholder font:(UIFont *)font frame:(CGRect)frame;

@end

DDYTextView.m

#import "DDYTextView.h"
#import <objc/runtime.h>
#import <objc/message.h>

@interface DDYTextView ()

@property (nonatomic, strong) UILabel *placeHolderLabel;

@end


@implementation DDYTextView

@synthesize placeholder = _placeholder;
@synthesize placeholderTextColor = _placeholderTextColor;

+ (instancetype)textView
{
    return [[self alloc] init];
}

+ (instancetype)textViewPlaceholder:(NSString *)placeholder font:(UIFont *)font
{
    return [[self alloc] initWithPlaceholder:placeholder font:font frame:CGRectZero];
}

+ (instancetype)textViewPlaceholder:(NSString *)placeholder font:(UIFont *)font frame:(CGRect)frame
{
    return [[self alloc] initWithPlaceholder:placeholder font:font frame:frame];
}

- (instancetype)initWithPlaceholder:(NSString *)placeholder font:(UIFont *)font frame:(CGRect)frame
{
    if (self = [super initWithFrame:frame])
    {
        self.placeholder = placeholder;
        self.font = font;
    }
    return self;
}

- (instancetype)initWithFrame:(CGRect)frame
{
    if (self = [super initWithFrame:frame])
    {
        // layoutManager(NSLayoutManager)的是否非连续布局属性，默认YES，设置为NO就不会再自己重置滑动了。
        self.layoutManager.allowsNonContiguousLayout = NO;
        // 如果存在占位字符则默认浅灰色
        self.placeholderTextColor = [UIColor lightGrayColor];
        // 手拖拽退键盘（输入造成滚动不退键盘）
        self.keyboardDismissMode = UIScrollViewKeyboardDismissModeOnDrag;
    }
    return self;
}

- (UILabel *)placeHolderLabel
{
    if (!_placeHolderLabel)
    {
        _placeHolderLabel = [[UILabel alloc] init];
        
        unsigned int count = 0;
        Ivar *ivars = class_copyIvarList(NSClassFromString(@"UITextView"), &count);
        for(int i =0; i < count; i ++)
        {
            NSString *ivarName = [NSString stringWithCString:ivar_getName(ivars[i]) encoding:NSUTF8StringEncoding];
            if ([ivarName isEqualToString:@"_placeholderLabel"])
            {
                _placeHolderLabel.numberOfLines = 0;
                _placeHolderLabel.font = self.font;
                _placeHolderLabel.ddy_x = 5;
                _placeHolderLabel.ddy_y = 8;
                _placeHolderLabel.textAlignment = self.textAlignment;
                [self addSubview:_placeHolderLabel];
                [self setValue:_placeHolderLabel forKey:@"_placeholderLabel"];
            }
        }
    }
    return _placeHolderLabel;
}

- (void)setPlaceholder:(NSString *)placeholder
{
    _placeholder = placeholder;
    self.placeHolderLabel.text = placeholder;
    [self setNeedsDisplay];
}

- (void)setPlaceholderTextColor:(UIColor *)placeholderTextColor
{
    _placeholderTextColor = placeholderTextColor;
    [self setNeedsDisplay];
}

- (void)setTextContainerInset:(UIEdgeInsets)textContainerInset
{
    [super setTextContainerInset:textContainerInset];
    [self setNeedsDisplay];
}

- (void)setFrame:(CGRect)frame
{
    [super setFrame:frame];
    [self setNeedsDisplay];
}

- (void)changePlaceholderLocation
{
    if (!self.font) {
        DDYInfoLog(@"请先设置DDYTextView对象的font");
        self.font = DDYFont(12);
    }
    _placeHolderLabel.textColor = self.placeholderTextColor;
    _placeHolderLabel.font = self.font;
    _placeHolderLabel.ddy_x = self.textContainerInset.left;
    _placeHolderLabel.ddy_w = self.ddy_w - self.textContainerInset.left - self.textContainerInset.right;
    _placeHolderLabel.ddy_y = self.textContainerInset.top;
    _placeHolderLabel.ddy_h = self.ddy_h - self.textContainerInset.top - self.textContainerInset.bottom;
    [_placeHolderLabel sizeToFit];
}

- (void)drawRect:(CGRect)rect
{
    [super drawRect:rect];
    [self changePlaceholderLocation];
}

@end

使用

DDYTextView *textView2 = [DDYTextView textViewPlaceholder:@"我是占位的大哥" font:DDYFont(12) frame:CGRectMake(0, 120, DDYSCREENW, 100)];
    textView2.backgroundColor = [UIColor whiteColor];
    textView2.placeholderTextColor = [UIColor lightGrayColor];
    [self.view addSubview:textView2];

设置字数限制

#import "TextViewTestVC.h"
#import "DDYTextView.h"

@interface TextViewTestVC ()<UITextViewDelegate>

@property (nonatomic, strong) DDYTextView *textView;

@property (nonatomic, strong) UILabel *tipLabel;

@end

@implementation TextViewTestVC

- (void)viewDidLoad
{
    [super viewDidLoad];
    [self prepare];
    [self setupContentView];
}

- (void)prepare
{
    // 64当起点布局
    self.edgesForExtendedLayout = UIRectEdgeNone;
    self.automaticallyAdjustsScrollViewInsets = NO;
    self.extendedLayoutIncludesOpaqueBars = NO;
    self.view.backgroundColor = [UIColor whiteColor];
    self.view.backgroundColor = DDYColor(245, 245, 245, 1);
}

- (void)setupContentView
{
    UIView *bgView = [[UIView alloc] initWithFrame:CGRectMake(0, 10, DDYSCREENW, 140)];
    bgView.backgroundColor = [UIColor whiteColor];
    [self.view addSubview:bgView];
    
    _textView = [DDYTextView textView];
    _textView.font = DDYFont(14);
    _textView.placeholder = @"我是占位大哥";
    _textView.frame = CGRectMake(0, 0, DDYSCREENW, 110);
    _textView.textContainerInset = UIEdgeInsetsMake(10, 10, 10, 10);
    _textView.delegate = self;
    [bgView addSubview:_textView];
    
    _tipLabel = [[UILabel alloc] initWithFrame:CGRectMake(0, _textView.ddy_bottom + 10, DDYSCREENW-10, 20)];
    _tipLabel.textAlignment = NSTextAlignmentRight;
    _tipLabel.textColor = DDYColor(75, 222, 209, 1.0);
    _tipLabel.font = DDYFont(11);
    _tipLabel.text = @"0/250";
    [bgView addSubview:_tipLabel];
    
}

#pragma mark - UITextViewDelegate
#pragma mark 可以用来控制占位字符显隐，剩余字数计算等
- (void)textViewDidChange:(UITextView *)textView
{
    if (_textView.text.length > 250)
    {
        _textView.text = [_textView.text substringToIndex:250];
        _tipLabel.textColor = [UIColor redColor];
    }
    else
    {
        _tipLabel.textColor = (_textView.text.length == 250)?[UIColor redColor]:DDYColor(75, 222, 209, 1.0);
    }
    
    _tipLabel.text = [NSString stringWithFormat:@"%lu%@",(unsigned long)_textView.text.length,@"/250"];
    [_textView scrollRangeToVisible:NSMakeRange(_textView.text.length, 1)];
    
}

@end

Scan demoCode 仅参考