Question

我在我的应用程序中使用UITabBarItem和UIButton时遇到问题。我的按钮位于UITabBarItem内。当我按下它时，我想被推到另一个控制器以显示PDF。

以下是一段适用于其他情况的代码：

- (void)viewDidLoad {
   UIImage* imageButton = [UIImage imageNamed:@"pdf-button.png"];
   UIButton *buttonPDF = [UIButton buttonWithType:UIButtonTypeCustom];
   buttonPDF.frame = CGRectMake(SCREEN_WIDTH/2 - 100, 100, 200, 36);
   [buttonPDF setImage:imageButton forState:UIControlStateNormal];
   buttonPDF.contentMode = UIViewContentModeScaleAspectFit;
   buttonPDF.contentHorizontalAlignment = UIControlContentHorizontalAlignmentFill;
   [buttonPDF addTarget:self action:@selector(displayPDFParams:) forControlEvents:UIControlEventTouchUpInside];
   [self.view addSubview:buttonPDF];
}

-(void)displayPDFParams:(UIButton *)sender {
    PDFProduitController *pdfController = [[PDFProduitController alloc] init];
    pdfController.pdf = documentParametres;
    [self.navigationController pushViewController:pdfController animated:YES];
}

displayPDFParams被调用，但它并没有让我感动pdfController。我认为这是因为我无法定位我的应用程序的父导航控制器... 任何帮助将不胜感激。提前谢谢！

Answer 1

您需要使用导航控制器初始化根视图控制器。这是代码。

在 AppDelegate.h

中

#import <UIKit/UIKit.h>
#import "HomeViewController.h"
@class HomeViewController;
@interface IDSAppDelegate : UIResponder <UIApplicationDelegate>{
    UINavigationController *nav;
}
@property (strong, nonatomic) HomeViewController *homeViewController;
@end

在 AppDelegate.m

中

#import "IDSAppDelegate.h"
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
    self.homeViewController = [[HomeViewController alloc] initWithNibName:@"HomeViewController" bundle:nil];
    nav=[[UINavigationController alloc]initWithRootViewController:self.homeViewController];
    self.window.rootViewController = nav;
    [self.window makeKeyAndVisible];  
    return YES;
}

Answer 2

通过在我的UIViewController中定义属性（如UITabBarItem）解决问题，如下所示：

@property (nonatomic, retain) UINavigationController *superNavController;

并在我的UITabBarController中设置：

self.myViewController.superNavController = self.navigationController;

最后我修改了displayPDFParams方法：

-(void)displayPDFParams:(UIButton *)sender {

   PDFProduitController *pdfController = [[PDFProduitController alloc] init];
   pdfController.pdf = self.documentParametres;

   [self.superNavController pushViewController:pdfController animated:YES];

}

完美无缺！

从UITabBarItem推送到UIViewController

2 个答案: