ios - 如何在 TableViewController B 中选择行时在 ViewController A 中启用 UI 按钮

Question

我在选项卡栏 Controller 中有两个 View Controller (都嵌入在导航 Controller 中)。 ViewControllerA 有两个按钮(MybuttonA 和 MybuttonB，在 Storyboard 中未选中启用框)。 ViewControllerB 是一个 TableViewController。我想在 ViewControllerB 表中选择特定行后启用 ViewControllerA 中的按钮。每个按钮在启用时预计会插入不同的 View Controller 。

我目前的代码仅在 ViewControllersA 和 ViewControllersB 未嵌入导航 Controller 时有效。但是如果没有嵌入导航 Controller ，启用的按钮不会推送 ViewControllers。

ViewControllerA.h

#import <UIKit/UIKit.h>
@interface  ViewControllerA : UIViewController {
IBOutlet UIButton * MybuttonA;
IBOutlet UIButton * MybuttonB;

}
-(IBAction)mybuttonaction:(id)sender;
@property(strong,nonatomic)UIButton *MybuttonA;
 @property(strong,nonatomic)UIButton *MybuttonB;

 @end

ViewControllerA.m

#import "ViewControllerA.h"
@interface ViewControllerA ()
@end

@implementation ViewControllerA
@synthesize MybuttonA;
@synthesize MybuttonB;



- (void)viewDidLoad
{
 [super viewDidLoad];
 // Do any additional setup after loading the view.

 }


-(IBAction)mybuttonaction:(id)sender{
     //write code to push view controller
}

ViewControllerB.h

#import <UIKit/UIKit.h>
#import "ViewControllerA.h"
@interface ViewControllerB : UITableViewController{

ViewControllerA *viewcontrollerA;
}
@property (nonatomic, retain) ViewControllerA *viewcontrollerA;
@end

ViewControllerB.m

#import "ViewControllerB.h"
 #import "ViewControllerA.h"

@interface ViewControllerB () {

}

@end

@implementation ViewControllerB
@synthesize  viewcontrollerA;

- (void)viewDidLoad
{
[super viewDidLoad];

   self.title = @"CONTENTS";

     self.refreshControl = [[UIRefreshControl alloc] init];

  [self.refreshControl addTarget:self action:@selector(reload)        forControlEvents:UIControlEventValueChanged];
 [self reload];
 [self.refreshControl beginRefreshing];

  viewcontrollerA = [self.tabBarController.viewControllers objectAtIndex:0];


 }

#pragma mark - Table View

  - (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
 {return 1;}

 - (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
 {
  {return 5;}
 }

   - (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:   (NSIndexPath *)indexPath
 {
 UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:@"Cell"    forIndexPath:indexPath];
  cell.textLabel.text = [NSString stringWithFormat: @"Cell #%d", indexPath.row];

 }

 return cell;
 }

  - (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {

   UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:@"Cell" forIndexPath:indexPath];
NSString* value = [tableView cellForRowAtIndexPath:indexPath].textLabel.text;

   if ([value isEqual:@"1"]){
   viewcontrollerA.MybuttonA.enabled=YES;
   }
   else if ([value isEqual:@"2"])
   {
            viewcontrollerA.MybuttonB.enabled=YES;
   }

    }

  else {
   [tableView deselectRowAtIndexPath:indexPath animated:NO];
   }
   }
  @end

Answer 1

使用这个:

viewcontrollerA = ((UINavigationController*)[self.tabBarController.viewControllers objectAtIndex:0] ).topViewController

取而代之的是:

  viewcontrollerA = [self.tabBarController.viewControllers objectAtIndex:0];