Iphone 在TabBar应用程序中从一个视图更改为另一个视图时无法显示警报？_Iphone_Objective C

Iphone 在TabBar应用程序中从一个视图更改为另一个视图时无法显示警报？

iphone objective-c

Iphone 在TabBar应用程序中从一个视图更改为另一个视图时无法显示警报？,iphone,objective-c,Iphone,Objective C,我正在应用程序中使用选项卡栏控制器我可以通过单击选项卡上的按钮来更改视图，但当我单击选项卡按钮时，它会显示一个警报，供最终用户确认，如：“您应该离开此页面” 如果“是”，则导航，否则应保持在同一页面上不过，警报不会显示。试试这个 UIAlertView *alert = [[UIAlertView alloc]initWithTitle:@"title" message:@"myMSg" delegate:self cancelButtonTitle:@"Ok" otherButt

我正在应用程序中使用选项卡栏控制器

我可以通过单击选项卡上的按钮来更改视图，但当我单击选项卡按钮时，它会显示一个警报，供最终用户确认，如：“您应该离开此页面”

如果“是”，则导航，否则应保持在同一页面上

不过，警报不会显示。

试试这个

     UIAlertView *alert = [[UIAlertView alloc]initWithTitle:@"title" message:@"myMSg" delegate:self cancelButtonTitle:@"Ok" otherButtonTitles:@"cancel"];
     [alert show];
     [alert release];

   -(void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex
    {
      if (buttonIndex == 0)
      {
          //Code for OK button i.e go to the next tab bar
      }
       if (buttonIndex == 1)
        {
           //Code for cancel button i.e dont load the next tab bar.
         }
    }

试试这个

     UIAlertView *alert = [[UIAlertView alloc]initWithTitle:@"title" message:@"myMSg" delegate:self cancelButtonTitle:@"Ok" otherButtonTitles:@"cancel"];
     [alert show];
     [alert release];

   -(void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex
    {
      if (buttonIndex == 0)
      {
          //Code for OK button i.e go to the next tab bar
      }
       if (buttonIndex == 1)
        {
           //Code for cancel button i.e dont load the next tab bar.
         }
    }

这是alertview的代码，在单击tab按钮后调用的方法中调用它…并添加UIAlertView委托

     UIAlertView *myAlert=[[UIAlertView alloc]initWithTitle:@"Alert" message:@"You should leave this page" delegate:self cancelButtonTitle:@"ok" otherButtonTitles:nil,nil];
     [myAlert show];
     [myAlert release];

也重写该方法

       - (void)alertView:(UIAlertView *)actionSheet clickedButtonAtIndex:(NSInteger)buttonIndex {
             if(actionSheet==myAlert){
                if (buttonIndex == 0)
                {
                //here call the corresponding page
                 }
                 }
         else
         {
                    //Do nothing
        NSLog(@"cancel");
         }

      }

这是alertview的代码，在单击tab按钮后调用的方法中调用它…并添加UIAlertView委托

     UIAlertView *myAlert=[[UIAlertView alloc]initWithTitle:@"Alert" message:@"You should leave this page" delegate:self cancelButtonTitle:@"ok" otherButtonTitles:nil,nil];
     [myAlert show];
     [myAlert release];

也重写该方法

       - (void)alertView:(UIAlertView *)actionSheet clickedButtonAtIndex:(NSInteger)buttonIndex {
             if(actionSheet==myAlert){
                if (buttonIndex == 0)
                {
                //here call the corresponding page
                 }
                 }
         else
         {
                    //Do nothing
        NSLog(@"cancel");
         }

      }

您可以通过编程方式创建选项卡栏控制器，而不是在xib文件中创建它们，如下所示

- (void)applicationDidFinishLaunching:(UIApplication *)application { 
    // set up a local nav controller which we will reuse for each view controller
    UINavigationController *localNavigationController;
    // create tab bar controller and array to hold the view controllers
    tabBarController = [[UITabBarController alloc] init];
    NSMutableArray *localControllersArray = [[NSMutableArray alloc] initWithCapacity:4];

// setup the first view controller (Root view controller)
RootViewController *myViewController;
myViewController = [[RootViewController alloc] initWithTabBar];

// create the nav controller and add the root view controller as its first view
localNavigationController = [[UINavigationController alloc] initWithRootViewController:myViewController];

// add the new nav controller (with the root view controller inside it)
// to the array of controllers
[localControllersArray addObject:localNavigationController];

// release since we are done with this for now
[localNavigationController release];
[myViewController release];

// setup the first view controller just like the first 
ResortsListViewController *resortsListViewController;
resortsListViewController = [[ResortsListViewController alloc] initWithNibName:@"ResortsListView" bundle:nil];
resortsListViewController.title = @"Category1";
resortsListViewController.tabBarItem.image = [UIImage imageNamed:@"image1.png"];
resortsListViewController.navigationItem.title=@"a1";
localNavigationController = [[UINavigationController alloc] initWithRootViewController:resortsListViewController];
[localControllersArray addObject:localNavigationController]; 
[localNavigationController release];

// setup the second view controller just like the first 
RootViewController *rootViewController;
rootViewController = [[RootViewController alloc] initWithNibName:@"RootViewController" bundle:nil];
rootViewController.title = @"a2";
rootViewController.tabBarItem.image = [UIImage imageNamed:@"image2.png"];
resortsListViewController.navigationItem.title=@"a2";
localNavigationController = [[UINavigationController alloc] initWithRootViewController:rootViewController];
[localControllersArray addObject:localNavigationController]; 
[localNavigationController release];

// setup the third view controller just like the first 
RootViewController *rootViewController;
rootViewController = [[RootViewController alloc] initWithNibName:@"RootViewController" bundle:nil];
rootViewController.title = @"a3";
rootViewController.tabBarItem.image = [UIImage imageNamed:@"image3.png"];
rootViewController.navigationItem.title=@"ay3";
localNavigationController = [[UINavigationController alloc] initWithRootViewController:rootViewController];
[localControllersArray addObject:localNavigationController]; 
[localNavigationController release];

[rootViewController release];

// load up our tab bar controller with the view controllers
tabBarController.viewControllers = localControllersArray;

// release the array because the tab bar controller now has it
[localControllersArray release];

// add the tabBarController as a subview in the window
[window addSubview:tabBarController.view];

// need this last line to display the window (and tab bar controller)
[window makeKeyAndVisible];

}

&之后，为每个按钮使用警报视图：

UIAlertView *Alert=[[UIAlertView alloc]initWithTitle:@"Alert" message:@"Do you want to leave this page1" delegate:self cancelButtonTitle:@"ok" otherButtonTitles:nil,nil];
     [Alert show];
     [Alert release];
     [Alert setTag:1];

UIAlertView*Alert=[[UIAlertView alloc]initWithTitle:@“Alert”消息：@“您想离开此页面吗2”委托：自取消按钮：@“确定”其他按钮：无，无]； [警报显示]； [警报发布]； [警报设置标签：2]

&检查按下了哪个按钮：

   -(void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex
    {
     if ([alertView tag] == 1) 
      if (buttonIndex == 0)
      {
          //Code for OK button i.e go to the next tab bar
      }
       if (buttonIndex == 1)
        {
           //Code for cancel button i.e dont load the next tab bar.
         }
    }

您可以通过编程方式创建选项卡栏控制器，而不是在xib文件中创建它们，如下所示

- (void)applicationDidFinishLaunching:(UIApplication *)application { 
    // set up a local nav controller which we will reuse for each view controller
    UINavigationController *localNavigationController;
    // create tab bar controller and array to hold the view controllers
    tabBarController = [[UITabBarController alloc] init];
    NSMutableArray *localControllersArray = [[NSMutableArray alloc] initWithCapacity:4];

// setup the first view controller (Root view controller)
RootViewController *myViewController;
myViewController = [[RootViewController alloc] initWithTabBar];

// create the nav controller and add the root view controller as its first view
localNavigationController = [[UINavigationController alloc] initWithRootViewController:myViewController];

// add the new nav controller (with the root view controller inside it)
// to the array of controllers
[localControllersArray addObject:localNavigationController];

// release since we are done with this for now
[localNavigationController release];
[myViewController release];

// setup the first view controller just like the first 
ResortsListViewController *resortsListViewController;
resortsListViewController = [[ResortsListViewController alloc] initWithNibName:@"ResortsListView" bundle:nil];
resortsListViewController.title = @"Category1";
resortsListViewController.tabBarItem.image = [UIImage imageNamed:@"image1.png"];
resortsListViewController.navigationItem.title=@"a1";
localNavigationController = [[UINavigationController alloc] initWithRootViewController:resortsListViewController];
[localControllersArray addObject:localNavigationController]; 
[localNavigationController release];

// setup the second view controller just like the first 
RootViewController *rootViewController;
rootViewController = [[RootViewController alloc] initWithNibName:@"RootViewController" bundle:nil];
rootViewController.title = @"a2";
rootViewController.tabBarItem.image = [UIImage imageNamed:@"image2.png"];
resortsListViewController.navigationItem.title=@"a2";
localNavigationController = [[UINavigationController alloc] initWithRootViewController:rootViewController];
[localControllersArray addObject:localNavigationController]; 
[localNavigationController release];

// setup the third view controller just like the first 
RootViewController *rootViewController;
rootViewController = [[RootViewController alloc] initWithNibName:@"RootViewController" bundle:nil];
rootViewController.title = @"a3";
rootViewController.tabBarItem.image = [UIImage imageNamed:@"image3.png"];
rootViewController.navigationItem.title=@"ay3";
localNavigationController = [[UINavigationController alloc] initWithRootViewController:rootViewController];
[localControllersArray addObject:localNavigationController]; 
[localNavigationController release];

[rootViewController release];

// load up our tab bar controller with the view controllers
tabBarController.viewControllers = localControllersArray;

// release the array because the tab bar controller now has it
[localControllersArray release];

// add the tabBarController as a subview in the window
[window addSubview:tabBarController.view];

// need this last line to display the window (and tab bar controller)
[window makeKeyAndVisible];

}

&之后，为每个按钮使用警报视图：

UIAlertView *Alert=[[UIAlertView alloc]initWithTitle:@"Alert" message:@"Do you want to leave this page1" delegate:self cancelButtonTitle:@"ok" otherButtonTitles:nil,nil];
     [Alert show];
     [Alert release];
     [Alert setTag:1];

&检查按下了哪个按钮：

   -(void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex
    {
     if ([alertView tag] == 1) 
      if (buttonIndex == 0)
      {
          //Code for OK button i.e go to the next tab bar
      }
       if (buttonIndex == 1)
        {
           //Code for cancel button i.e dont load the next tab bar.
         }
    }

我只想在某些特定视图上使用此警报。在我的应用程序中有5个选项卡，在所有选项卡中，我添加了1个导航控制器…我不需要每次在某些重要视图上单击tabbaritem时都发出警报…谢谢！！然后在该函数中，只需检查调用了哪个视图，并相应地显示警报……获取数组中的所有控制器，如以下数组=[[self-tabBarController]ViewController]；然后检查要推送的控制器[[array objectAtIndex:0]sKindOfClass:[YourClassName class]]如果满足，则显示警报。我只希望在某些特定视图上显示此警报。在我的应用程序中，有5个选项卡，在所有选项卡中，我添加了1个导航控制器…我不需要每次在某些重要视图上单击tabbaritem时都发出警报…谢谢！！然后在该函数中，只需检查调用了哪个视图，并相应地显示警报……获取数组中的所有控制器，如以下数组=[[self-tabBarController]ViewController]；然后检查要推送的控制器[[array objectAtIndex:0]sKindOfClass:[YourClassName class]]是否满足，然后显示警报。。