代码我用自己写的demo代码，效果是我的项目效果

#RootViewController.h中
//  Copyright © 2016年 糖糖. All rights reserved.
//

#import "ViewController.h"

#import "ShareController.h"

@interface ViewController ()

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    self.navigationItem.title = @"测试";
    
    self.navigationItem.rightBarButtonItem = [[UIBarButtonItem alloc] initWithTitle:@"模态弹出全屏" style:UIBarButtonItemStyleDone target:self action:@selector(ActionShare)];
}


- (void)ActionShare{
    
    ShareController *lagerPicVC = [[ShareController alloc]init];
    
// 这里面有很多枚举值，你可以去试试    lagerPicVC.modalPresentationStyle=UIModalPresentationOverFullScreen;;//关键语句，必须有
    
    [self presentViewController:lagerPicVC animated:YES completion:nil];
}

- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

@end

ShareController.m中

//  Copyright © 2016年 糖糖. All rights reserved.
//

#import "ShareController.h"

@interface ShareController ()

@end

@implementation ShareController

- (void)viewDidLoad {
    [super viewDidLoad];
    self.view.backgroundColor = [[UIColor grayColor] colorWithAlphaComponent:0.5];
}

- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

@end