代码如下：
HDTextView.h
#import <UIKit/UIKit.h>
NS_ASSUME_NONNULL_BEGIN
@class HDTextView;
@interface HDTextView : UITextView<UITextViewDelegate>
@property (strong, nonatomic) UILabel *placeholderLabel;//占位label
@property (copy, nonatomic) NSString *placeholder; //占位字
@property (assign, nonatomic) NSInteger maxLength;//最大长度
@property (strong, nonatomic) UILabel *wordNumLabel;//计算字数label
///是否允许输入emoji 默认不允许
@property (nonatomic, assign) BOOL allowEmoji;
///文字输入
@property (copy, nonatomic) void(^didChangeText)(HDTextView *textView);
- (void)didChangeText:(void(^)(HDTextView *textView))block;
@end
NS_ASSUME_NONNULL_END
HDTextView.m
#import "HDTextView.h"
@interface HDTextView()
@property (strong, nonatomic) NSString *currentText;
@end
@implementation HDTextView
-(id)initWithFrame:(CGRect)frame{
self = [super initWithFrame:frame];
if (self) {
[self addObserver];
[self setView];
//设置文字偏移量
self.textContainerInset = UIEdgeInsetsMake(16, 15, 16, 15);
}
return self;
}
-(id)initWithCoder:(NSCoder *)aDecoder{
self = [super initWithCoder:aDecoder];
if (self) {
[self addObserver];
[self setView];
//设置文字偏移量
self.textContainerInset = UIEdgeInsetsMake(16, 15, 16, 15);
}
return self;
}
-(id)init{
self = [super init];
if (self) {
[self addObserver];
[self setView];
//设置文字偏移量
self.textContainerInset = UIEdgeInsetsMake(16, 15, 16, 15);
}
return self;
}
-(void)setView{
if (!self.placeholderLabel) {
self.placeholderLabel = [[UILabel alloc]initWithFrame:CGRectMake(16, 16, self.frame.size.width-16, self.frame.size.height)];
self.placeholderLabel.textColor = [UIColor lightGrayColor];
self.placeholderLabel.numberOfLines = 0;
self.placeholderLabel.font = [self font];
[self addSubview:self.placeholderLabel];
super.delegate = self;
}
if (!self.wordNumLabel) {
self.wordNumLabel = [[UILabel alloc]initWithFrame:CGRectZero];
self.wordNumLabel.font = [UIFont systemFontOfSize:13];
self.wordNumLabel.textColor = [UIColor lightGrayColor];
self.wordNumLabel.textAlignment = NSTextAlignmentRight;
[self addSubview:self.wordNumLabel];
}
self.allowEmoji = NO;//不允许输入emoji
}
-(void)layoutSubviews{
self.placeholderLabel.frame = CGRectMake(16, 16, self.frame.size.width-16, self.frame.size.height);
[self.placeholderLabel sizeToFit];
[self.wordNumLabel sizeToFit];
[self refreshFram];
}
-(void)addObserver
{
[[NSNotificationCenter defaultCenter]removeObserver:self name:UITextViewTextDidChangeNotification object:self];
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(placeholderTextViewdidChange:) name:UITextViewTextDidChangeNotification object:self];
}
-(void)setPlaceholder:(NSString *)placeholder{
_placeholder = placeholder;
self.placeholderLabel.text = _placeholder;
[self.placeholderLabel sizeToFit];
[self endEditing:NO];
}
-(void)setMaxLength:(NSInteger)maxLength{
_maxLength = maxLength;
self.wordNumLabel.text = [NSString stringWithFormat:@"0/%ld",(long)_maxLength];
}
-(void)placeholderTextViewdidChange:(NSNotification *)notificat{
HDTextView *textView = (HDTextView *)notificat.object;
if ([self.text length]>0) {
[self.placeholderLabel setHidden:YES];
}else{
[self.placeholderLabel setHidden:NO];
}
if ([textView.text length]>self.maxLength&&self.maxLength!=0&&textView.markedTextRange == nil) {
textView.text = [textView.text substringToIndex:self.maxLength];
}
self.wordNumLabel.text = [NSString stringWithFormat:@"%ld/%ld",(long)[textView.text length],(long)_maxLength];
if (self.didChangeText) {
self.didChangeText(textView);
}
[self refreshFram];
_currentText = textView.text;
}
- (void)didChangeText:(void (^)(HDTextView *))block{
self.didChangeText = block;
}
- (void)setText:(NSString *)text{
[super setText:text];
if (text.length>0) {
[self.placeholderLabel setHidden:YES];
self.wordNumLabel.text = [NSString stringWithFormat:@"%ld/%ld",(long)[text length],(long)_maxLength];
[self.wordNumLabel sizeToFit];
[self refreshFram];
}
}
-(void)placeholderTextViewEndEditing{
if ([self.text length]>0) {
[self.placeholderLabel setHidden:YES];
}else{
[self.placeholderLabel setHidden:NO];
}
}
- (void)refreshFram{
[self.wordNumLabel sizeToFit];
if (self.contentSize.height>self.frame.size.height-self.wordNumLabel.frame.size.height-5) {
self.wordNumLabel.frame = CGRectMake(self.frame.size.width - self.wordNumLabel.frame.size.width-5, self.contentSize.height+self.contentInset.bottom-self.wordNumLabel.frame.size.height-5, self.wordNumLabel.frame.size.width, self.wordNumLabel.frame.size.height);
self.contentInset = UIEdgeInsetsMake(0, 0, self.wordNumLabel.frame.size.height, 0);
}else{
self.wordNumLabel.frame = CGRectMake(self.frame.size.width - self.wordNumLabel.frame.size.width-5, self.frame.size.height + self.contentInset.bottom-self.wordNumLabel.frame.size.height-5, self.wordNumLabel.frame.size.width, self.wordNumLabel.frame.size.height);
self.contentInset = UIEdgeInsetsMake(0, 0, 0, 0);
}
}
-(void)dealloc{
[[NSNotificationCenter defaultCenter] removeObserver:self];
}
//判断是否输入的是emoji表情
- (BOOL)stringContainsEmoji:(NSString *)string{
NSUInteger stringUtf8Length = [string lengthOfBytesUsingEncoding:NSUTF8StringEncoding];
if(stringUtf8Length >= 4 && (stringUtf8Length / string.length != 3)){
return YES;
}else{
return NO;
}
}
- (BOOL)textView:(UITextView *)textView shouldChangeTextInRange:(NSRange)range replacementText:(NSString *)text{
if (self.allowEmoji) {
return YES;
}else {
if ([self stringContainsEmoji:text]) {
NSLog(@"输入的是表情...");
return NO;
}else{
NSLog(@"输入的不是表情...");
return YES;
}
}
}
