IOS获取当前页面的UIViewController

在开发中我们经常需要在当前页面提示Tip信息或者Alert，那么比较通用的方法是通过通用的方法拿到当前页面的VC。在MBProgressHUD中我们也需要一个工具类来进行相应的提示。

/**
 获得当前页面

 @return 获得当前页面
 */
+(UIViewController *)getCurrentVC {
    UIViewController *result = nil;
    UIWindow * window = [[UIApplication sharedApplication] keyWindow];
    //app默认windowLevel是UIWindowLevelNormal，如果不是，找到UIWindowLevelNormal的
    if (window.windowLevel != UIWindowLevelNormal) {
        NSArray *windows = [[UIApplication sharedApplication] windows];
        for(UIWindow * tmpWin in windows) {
            if (tmpWin.windowLevel == UIWindowLevelNormal) {
                window = tmpWin;
                break;
            }
        }
    }
    id nextResponder = nil;
    UIViewController *appRootVC = window.rootViewController;
    //如果是present上来的appRootVC.presentedViewController不为nil
    if (appRootVC.presentedViewController) {
        nextResponder = appRootVC.presentedViewController;
    } else {
        UIView *frontView = [[window subviews] objectAtIndex:0];
        nextResponder = [frontView nextResponder];
    }
    
    if ([nextResponder isKindOfClass:[UITabBarController class]]) {
        
        UITabBarController * tabbar = (UITabBarController *)nextResponder;
        UINavigationController * nav = (UINavigationController *)tabbar.viewControllers[tabbar.selectedIndex];
        result = nav.childViewControllers.lastObject;
        
    } else if ([nextResponder isKindOfClass:[UINavigationController class]]){
        UIViewController * nav = (UIViewController *)nextResponder;
        result = nav.childViewControllers.lastObject;
    } else {
        result = nextResponder;
    }
    return result;
}

工具类简单封装

#import "HUDUtil.h"
#import "MBProgressHUD.h"
#import "UtilMacros.h"
#import "AppDelegate.h"
#import "StringMacros.h"

@implementation HUDUtil

/**
 显示alert
 */
+(void)showAlertWithTitle:(NSString *)title andContent:(NSString *)content {
    UIAlertController *alertController = [UIAlertController alertControllerWithTitle:title message:content preferredStyle:UIAlertControllerStyleAlert];
    UIAlertAction *okAction = [UIAlertAction actionWithTitle:@"确定" style:UIAlertActionStyleDefault handler:^(UIAlertAction *action) {}];
    [alertController addAction:okAction];
    [[HUDUtil getCurrentVC] presentViewController:alertController animated:YES completion:nil];
}

/**
 显示loading
 */
+(void)showLoading {
    MBProgressHUD *hud = [MBProgressHUD showHUDAddedTo:[HUDUtil getCurrentVC].view animated:YES];
    hud.label.text = Tip_Loading;
    hud.label.font = [UIFont systemFontOfSize:14.0f];
}

/**
 隐藏loading
 */
+(void)hiddenLoading {
    [MBProgressHUD hideHUDForView:[HUDUtil getCurrentVC].view animated:YES];
}

/**
 显示loading
 
 @param aView 目标显示层
 */
+(void)showLoadingWithView:(UIView *)aView {
    MBProgressHUD *hud = [MBProgressHUD showHUDAddedTo:aView animated:YES];
    hud.label.text = Tip_Loading;
    hud.label.font = [UIFont systemFontOfSize:14.0f];
}

/**
 隐藏loading
 
 @param aView 目标显示层
 */
+(void)hiddenLoadingWithView:(UIView *)aView {
    [MBProgressHUD hideHUDForView:aView animated:YES];
}

/**
 显示提示框

 @param message 提示信息
 */
+ (void)showTipWithHud:(NSString*)message{
    UIView *view = [UIApplication sharedApplication].keyWindow;
    MBProgressHUD *hud = [MBProgressHUD showHUDAddedTo:view animated:YES];
    [view bringSubviewToFront:hud];
    [hud setOffset:CGPointMake(hud.offset.x, SCREEN_HEIGHT/4)];
    hud.mode = MBProgressHUDModeText;
    hud.detailsLabel.text = message;
    hud.margin = 10.f;
    hud.removeFromSuperViewOnHide = YES;
    [hud hideAnimated:YES afterDelay:1];
}

/**
 获得当前页面

 @return 获得当前页面
 */
+(UIViewController *)getCurrentVC {
    UIViewController *result = nil;
    UIWindow * window = [[UIApplication sharedApplication] keyWindow];
    //app默认windowLevel是UIWindowLevelNormal，如果不是，找到UIWindowLevelNormal的
    if (window.windowLevel != UIWindowLevelNormal) {
        NSArray *windows = [[UIApplication sharedApplication] windows];
        for(UIWindow * tmpWin in windows) {
            if (tmpWin.windowLevel == UIWindowLevelNormal) {
                window = tmpWin;
                break;
            }
        }
    }
    id nextResponder = nil;
    UIViewController *appRootVC = window.rootViewController;
    //如果是present上来的appRootVC.presentedViewController不为nil
    if (appRootVC.presentedViewController) {
        nextResponder = appRootVC.presentedViewController;
    } else {
        UIView *frontView = [[window subviews] objectAtIndex:0];
        nextResponder = [frontView nextResponder];
    }
    
    if ([nextResponder isKindOfClass:[UITabBarController class]]) {
        
        UITabBarController * tabbar = (UITabBarController *)nextResponder;
        UINavigationController * nav = (UINavigationController *)tabbar.viewControllers[tabbar.selectedIndex];
        result = nav.childViewControllers.lastObject;
        
    } else if ([nextResponder isKindOfClass:[UINavigationController class]]){
        UIViewController * nav = (UIViewController *)nextResponder;
        result = nav.childViewControllers.lastObject;
    } else {
        result = nextResponder;
    }
    return result;
}

@end