IOS9 KeyWindow为空的问题

 建议写一个全局的宏

IOS9的[UIApplication sharedApplication].keyWindow 建议用代理的

+(UIWindow *)getKeyWindow{

    if ([[[UIDevice currentDevice] systemVersion] floatValue] >= 9.0f){

        return [[[UIApplication sharedApplication] delegate] window];

    }else{

        UIWindow *window = [UIApplication sharedApplication].keyWindow;

        if (!window) {

            return [[[UIApplication sharedApplication] delegate] window];

        }

        return window;

    }

}