获取能用于显示的baseview，排除警告框

baseview.m

- (void)baseView
{
    BOOL hasAlertView = FALSE;
    UIView* baseView = [UIApplication sharedApplication].keyWindow;
    for (UIWindow* w in [UIApplication sharedApplication].windows) {
        for (UIView *o in w.subviews)
        {
            [self dismissAlertView:o didDismiss:&hasAlertView];
        }
    }
    if (hasAlertView) {
        baseView = [[UIApplication sharedApplication].windows objectAtIndex:0];
    }
    return baseView;
}

- (void)dismissAlertView:(UIView *)w didDismiss:(BOOL*)hasAlertView
{
    if ([w respondsToSelector:@selector(dismissWithClickedButtonIndex:animated:)] && [w respondsToSelector:@selector(cancelButtonIndex)])
    {
        [(UIAlertView *)w dismissWithClickedButtonIndex:[(UIAlertView *)w cancelButtonIndex] animated:NO];
        *hasAlertView = YES;
        return;
    }
    for (UIView *o in w.subviews) {
        [self dismissAlertView:o didDismiss:hasAlertView];
    }
}