一、实现的逻辑很简单且代码量不多，直接贴出源码供方便快速使用。
@property (nonatomic, strong) UITextView *textView;
@property (nonatomic, strong) UILabel *limitLabel;
_textView = [[UITextView alloc] initWithFrame:CGRectMake(5,5, MAIN_WIDTH-10,130.3)];
_textView.placeHolder = @"请描述您的问题...";
_textView.returnKeyType = UIReturnKeyDone;
_textView.delegate = self;
_textView.textColor = UIColorFromRGB(0xBEBDBD);
_textView.font = [UIFont systemFontOfSize:15];
[self addSubview:_textView];
_limitLabel = [[UILabel alloc] initWithFrame:CGRectMake(MAIN_WIDTH/4*3,130.3, MAIN_WIDTH/4-10,20)];
_limitLabel.text = @"0/500";
_limitLabel.font = [UIFont systemFontOfSize:12];
_limitLabel.textAlignment = NSTextAlignmentRight;
_limitLabel.textColor = UIColorFromRGB(0x999999);
_limitLabel.backgroundColor = [UIColor clearColor];
二、实现TextView代理方法
实时监听TextView输入框的return键，当点击return键时结束编辑的实现思路：判断输入的字是否为\n回车，即按下return键
- (void)textViewDidChange:(UITextView *)textView {
_limitLabel.text = [NSString stringWithFormat:@"%ld/500",textView.text.length ];
}
- (BOOL)textView:(UITextView *)textView shouldChangeTextInRange:(NSRange)range replacementText:(NSString *)text{
NSLog(@"textLength == %ld",textView.text.length);
if([text isEqualToString:@"\n"]){//判断输入的字是否是回车，即按下return
[self.textView resignFirstResponder];
returnNO;
}
if([self stringContainsEmoji:text] == YES) {
[PubllicMaskViewHelper showTipViewWith:@"不支持输入Emoji表情符号"inSuperView:self withDuration:1];
returnNO;
}
if(textView.text.length + text.length >500) {
NSString *allText = [NSString stringWithFormat:@"%@%@",textView.text,text];
textView.text = [allText substringToIndex:500];
[PubllicMaskViewHelper showTipViewWith:@"输入不能超过500个字"inSuperView:self withDuration:1];
returnNO;
}
returnYES;
}
三、过滤所有Emoji表情符号
// 过滤所有表情
- (BOOL)stringContainsEmoji:(NSString *)string {
__block BOOL returnValue = NO;
[string enumerateSubstringsInRange:NSMakeRange(0, [string length]) options:NSStringEnumerationByComposedCharacterSequences usingBlock:
^(NSString *substring, NSRange substringRange, NSRange enclosingRange, BOOL *stop) {
constunichar hs = [substring characterAtIndex:0];
// surrogate pair
if(0xd800<= hs && hs1) {
constunichar ls = [substring characterAtIndex:1];
constintuc = ((hs -0xd800) *0x400) + (ls -0xdc00) +0x10000;
if(0x1d000<= uc && uc1) {
constunichar ls = [substring characterAtIndex:1];
if(ls ==0x20e3) {
returnValue = YES;
}
}else{
// non surrogate
if(0x2100<= hs && hs <=0x27ff) {
returnValue = YES;
}elseif(0x2B05<= hs && hs <=0x2b07) {
returnValue = YES;
}elseif(0x2934<= hs && hs <=0x2935) {
returnValue = YES;
}elseif(0x3297<= hs && hs <=0x3299) {
returnValue = YES;
}elseif(hs ==0xa9|| hs ==0xae|| hs ==0x303d|| hs ==0x3030|| hs ==0x2b55|| hs ==0x2b1c|| hs ==0x2b1b|| hs ==0x2b50) {
returnValue = YES;
}
}
}];
returnreturnValue;
}