Question

我使用UITabBar显示两个viewControllers，firstViewController是一个uiview，secondViewController是一个表视图。当我点击第二个视图表格单元格时，我需要的是，该值应该在firstViewController的UILabel上更新。我的代码在这里，在secondviewcontroller.h

 @interface firstviewcontroller {
 NSMutableArray *stationnamestobepassed;
  }
 @property (nonatomic, retain) NSMutableArray *stationnamestobepassed;
 @end

在secondviewcontroller.m声明此

@implementation firstviewcontroller
@synthesize stationnamestobepassed;

 -(void) someaction{
  stationnamestobepassed = [NSMutableArray     
    arrayWithObjects:@"string1",@"string2",@"string3"];
  secondviewcontroller = [[secondviewcontroller alloc]initWithNibName:@"NIbName" 
Bundle:nil];
  secondviewcontroller.stationnamespassed = self.stationnamestobepassed;
  //i am not pushing the view controller.

 }

@end

在firstviewcontroller.h声明此

@interface secondviewcontroller {
 NSMutableArray *stationnamespassed;
}
@property (nonatomic, retain) NSMutableArray *stationnamespassed;


@end

在firstviewcontroller.m声明此

@implementation secondviewcontroller
@synthesize stationnamespassed;

  -(void)viewWillAppear:(BOOL)animated
   {
  //stationNameDisplay is a uilabel

stationNameDisplay.text=[stationnamespassed objectAtIndex:0];
NSLog(@"station name %@",[stationnamespassed objectAtIndex:0]);

 }
  -(void) dealloc{
  [stationnamespassed release];
   [super release];
 }
@end

问题是，值没有更新，它给出了NULL。但我尝试推动第一次竞争，它的工作原理。实际上我不想推动那个视图控制器因为我已经存在于选项卡上。

Answer 1

选择标签后，您的视图会显示出来。而此行生成该控制器的新对象，而不是制表符控制器的对象。

secondviewcontroller = [[secondviewcontroller alloc]initWithNibName:@"NIbName" 
Bundle:nil];

做你想做的事。你将不得不做这样的事情

UINavigationController* navController = [[self.tabBarController viewControllers] objectAtIndex:/*your tab index on which desiredControllerResides*/];
NSArray* viewControllers= [navController viewControllers];
for(UIViewController *theController in viewControllers)
{
if([theController isKindOfClass:[secondviewcontroller]])
{
   theController.stationnamespassed = self.stationnamestobepassed;
//i.e  this line of your code secondviewcontroller.stationnamespassed = self.stationnamestobepassed;
}
}

从UITabBar上的另一个视图控制器发送数据时，UI不会更新？

1 个答案: