测试环境：Xcode 6.2，iOS 6.0以上


- (id) initWithTitle:(NSString *)title delegate:(id)delegate cancelButtonTitle:(NSString *)cancelButtonTitle otherButtonTitles:(NSString *)otherButtonTitles, ... {
    if (self = [super initWithFrame:[UIScreen mainScreen].bounds]) {
        _title = title;
        _delegate = delegate;
        _cancelButtonTitle = cancelButtonTitle;
        _otherButtonArray = [NSMutableArray array];
        va_list args;
        va_start(args, otherButtonTitles);
        if (otherButtonTitles) {
            [_otherButtonArray addObject:otherButtonTitles];
            while (1) {
                NSString *otherButtonTitle = va_arg(args, NSString *);
                if (otherButtonTitle == nil) {
                    break;
                } else {
                    [_otherButtonArray addObject:otherButtonTitle];
                }
            }
        }
        va_end(args);
        
        self.backgroundColor = [UIColor clearColor];
        
        UITapGestureRecognizer *tapGestureRecognizer = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(hide)];
        _backgroundView = [[UIView alloc] initWithFrame:self.frame];
        _backgroundView.alpha = 0;
        _backgroundView.backgroundColor = [UIColor blackColor];
        [_backgroundView addGestureRecognizer:tapGestureRecognizer];
        [self addSubview:_backgroundView];
        
        [self initContentView];
    }
    return self;
}