iOS UITextView 和 UITextField 字数限制

- (BOOL)textView:(UITextView *)textView shouldChangeTextInRange:(NSRange)range replacementText:(NSString *)text{
    NSInteger maxLength = 200;
    
    
    NSString *appendStr = [textView.text stringByReplacingCharactersInRange:range withString:text];
    
    NSInteger restNum = maxLength -[appendStr length];
    
    //
    if(restNum >= 0){
        return YES;
    }
    else{
        NSRange rg = {0,[text length]+restNum};
        if (rg.length>0) {
            NSString *s = [text substringWithRange:rg];
            [textView setText:[textView.text stringByReplacingCharactersInRange:range withString:s]];
        }
        
        [self textViewDidChange:textView];
        
        return NO;
    }
}


- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)text
{
    NSInteger maxLength = 100;
    NSString *appendStr = [textField.text stringByReplacingCharactersInRange:range withString:text];
    NSInteger restNum = maxLength -[appendStr length];
    
    if(restNum >= 0){
        return YES;
    }
    else{
        NSRange rg = {0,[text length]+restNum};
        if (rg.length>0) {
            NSString *s = [text substringWithRange:rg];
            [textField setText:[textField.text stringByReplacingCharactersInRange:range withString:s]];
        }
        
        [self TextFieldChangeAction:nil];
        
        return NO;
    }
}