iOS中UITextFiled只能输入数字和小数点

#define NUMBERS @"0123456789."

 _contentTextFiled.delegate = self;

#pragma mark ---textfiled代理方法- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string {        NSCharacterSet*cs;        cs = [[NSCharacterSet characterSetWithCharactersInString:NUMBERS] invertedSet];        NSString *filtered = [[string componentsSeparatedByCharactersInSet:cs] componentsJoinedByString:@""];        BOOL basicTest = [string isEqualToString:filtered];        if (!basicTest) {            return NO;        }else {            return YES;        }}

用以上代理方法可实现只能输入数字和小数点