iOS 关于限制字数输入的效果,so seay

h文件
//输入文字的textview
@property(nonatomic,strong)UITextView *textView;
//计算字数的laebl
@property(nonatomic,strong)UILabel *zishuLabel;
记得添加textview的代理: UITextViewDelegate

m文件
分别定义 textview 和 label
//textview
self.textView = [[UITextView alloc] initWithFrame:CGRectMake(10, 60, self.view.bounds.size.width - 20, 200)];
self.textView.layer.cornerRadius = 5;
self.textView.layer.borderColor = [UIColor blackColor].CGColor;
self.textView.layer.borderWidth = 1;
self.textView.delegate = self;
[self.view addSubview:_textView];

//label
self.zishuLabel = [[UILabel alloc] initWithFrame:CGRectMake(self.view.bounds.size.width - 110, 230, 100, 30)];
self.zishuLabel.text = @"0/100";
[self.view addSubview:_zishuLabel];

写关于textview的代理方法
-(void)textViewDidChange:(nonnull UITextView *)textView
{
self.zishuLabel.text = [NSString stringWithFormat:@"%ld/100",textView.text.length];

NSInteger res = 100-textView.text.length;
if(res >= 0){
    
}else{
    self.textView.text = [self.textView.text substringToIndex:100];
    self.zishuLabel.text = @"100/100";
}

}
-(BOOL)textView:(UITextView )textView shouldChangeTextInRange:(NSRange)range replacementText:(NSString)text
{
if ([text isEqualToString:@"\n"]) {
[self.textView resignFirstResponder];
return NO;
}
return YES;
}

-(BOOL)textFieldShouldReturn:(UITextField *)textField
{

[self.textView resignFirstResponder];

return YES;

}

好了,完成了!