字符串每4个一个空格

NSNumber *number = [NSNumber numberWithLongLong:1234567890098765];

NSNumberFormatter *formatter = [NSNumberFormatter new];

[formatter setUsesGroupingSeparator:YES];设置用组分隔

[formatter setGroupingSize:4];//四个一组

[formatter setGroupingSeparator:@" "];组间用空格隔开

NSString *string = [formatter stringFromNumber:number];

string : 1234 5678 9009 8765

- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string {

if (textField == bankCardNumTextField) {

// 四位加一个空格

if ([string isEqualToString:@""]) { // 删除字符

if ((textField.text.length - 2) % 5 == 0) {

textField.text = [textField.text substringToIndex:textField.text.length - 1];

}

return YES;

} else {

if (textField.text.length % 5 == 0) {

textField.text = [NSString stringWithFormat:@"%@ ", textField.text];

}

}

return YES;

}

return YES;

}