UIAlertview让取消按钮消失

注意：cancelButton的index == 0

- (void)PWtypeClicked:(UIButton *)btn {
    NSLog(@"点击选择类型密码按钮");
    UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"选择密码类型" message:nil delegate:self cancelButtonTitle:@"一级密码" otherButtonTitles:@"二级密码", nil];
    [alert show];
}

pragma mark -- alertDelegate

- (void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex {
    UITextField *tmpField = (UITextField *)[self.view viewWithTag:100];
    if (buttonIndex == 0) {
        tmpField.text = @"一级密码";
    } else if(buttonIndex == 1){
        tmpField.text = @"二级密码";
    }
}