iOS 获得屏幕正在显示的Controller（自定义的控制器）的实用方法

项目有点紧张，好久没有写点东西了。后面我会抽更多时间学习和分享学习的一些总结，分享给各位，请持续关注。

具体场景我都不说了。直接上代码

- (void)needShowLogin
{
YPJGLoginViewController * login = [[YPJGLoginViewController alloc] init];
login.hidesBottomBarWhenPushed = YES;
UIViewController * VC = [self currentViewController];
YPJGLog(@"当前显示的控制器%@",VC);
//判断是否已经显示登录窗口，没有显示则push显示
if (![[NSString stringWithUTF8String:object_getClassName(VC)] isEqual:[NSString stringWithUTF8String:object_getClassName(login)]])
{
[VC.navigationController pushViewController:login animated:YES];
}
}
//获取Window当前显示的ViewController
- (UIViewController*)currentViewController{
//获得当前活动窗口的根视图
UIViewController* vc = [UIApplication sharedApplication].keyWindow.rootViewController;
while (1)
{
//根据不同的页面切换方式，逐步取得最上层的viewController
if ([vc isKindOfClass:[UITabBarController class]]) {
vc = ((UITabBarController*)vc).selectedViewController;
}
if ([vc isKindOfClass:[UINavigationController class]]) {
vc = ((UINavigationController*)vc).visibleViewController;
}
if (vc.presentedViewController) {
vc = vc.presentedViewController;
}else{
break;
}
}
return vc;
}

网上还有另外一种方法 (经测试只拿到当前 活活动窗口的根视图 不推荐)

- (UIViewController *)getCurrentVC
{
UIViewController *result = nil;
UIWindow * window = [[UIApplication sharedApplication] keyWindow];
if (window.windowLevel != UIWindowLevelNormal)
{
NSArray *windows = [[UIApplication sharedApplication] windows];
for(UIWindow * tmpWin in windows)
{
if (tmpWin.windowLevel == UIWindowLevelNormal)
{
window = tmpWin;
break;
}
}
}
UIView *frontView = [[window subviews] objectAtIndex:0];
id nextResponder = [frontView nextResponder];
if ([nextResponder isKindOfClass:[UIViewController class]])
result = nextResponder;
else
result = window.rootViewController;
return result;
}

顺便分享一个 字符串为空判断的宏定义 很高效

#define IsNOTNullOrEmptyOfNSString(string) !((![string isKindOfClass:[NSString class]])||[string isEqualToString:@""] || (string == nil) || [string isEqualToString:@"<null>"]|| [string isEqualToString:@"(null)"]|| [string isEqualToString:@"null"]|| [string isEqualToString:@"nil"] || [string isKindOfClass:[NSNull class]]||[[string stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceCharacterSet]] length]==0)

本期暂时到这里，需要什么新的ios相关知识，也可以给我留言哦，我们一起学习研究