iOS啓動時設置豎屏

在- (BOOL)application:(UIApplication )application didFinishLaunchingWithOptions:(NSDictionary )launchOptions 第一句加上

    if ([[UIApplication sharedApplication] respondsToSelector:@selector(setStatusBarOrientation:)]){
        SEL selector = NSSelectorFromString(@"setStatusBarOrientation:");
        NSInvocation *invocation = [NSInvocation invocationWithMethodSignature:[UIApplication instanceMethodSignatureForSelector:selector]];
        UIDeviceOrientation orentation = UIDeviceOrientationPortrait;
        [invocation setSelector:selector];
        [invocation setTarget:[UIApplication sharedApplication]];
        [invocation setArgument:&orentation atIndex:2];
        [invocation invoke];
    }