使用方法：
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
// Override point for customization after application launch.
self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
self.window.backgroundColor =[UIColor whiteColor];
LXLeftController *leftVc =[[LXLeftController alloc]init];
LXTabbarController *mainVc =[[LXTabbarController alloc]init];
LXQQSlideController *qqSlideVc =[LXQQSlideController initWithLeftVC:leftVc mainVc:mainVc];
self.window.rootViewController = qqSlideVc;
self.qqSlideVc = qqSlideVc;
self.window.backgroundColor =[UIColor whiteColor];
return YES;
}