代表無法正常工作

Question

我想通過委託在導航堆棧上的子視圖和父視圖之間傳遞一些信息。

但是，由於某種原因，當我從子視圖執行委託，然後從導航控制器彈出子視圖它永遠不會進入在父視圖中設置的委託方法..我已經嘗試NSLogs &斷點線程是在主視圖中明確地沒有采用這種代表方法，所以我希望你能幫助我。

首先，我會告訴你我是如何設置我的代表的，我在子視圖中調用它，然後在主視圖中設置它，希望你們能夠看到我目前還沒有的東西。

Subview.h //我已經離開了不相關的委託東西

#import <UIKit/UIKit.h> 

//Delegate - Protocol stuff for passing data from this view to the parent view 
@protocol PassSearchData <NSObject> 
@required 
- (void) setManufactureSearchFields:(NSArray *)arrayValues withIndexPath:(NSIndexPath *)myIndexPath; 
@end 

@interface SecondViewController : UITableViewController <UITableViewDataSource> { 
//Delegate (Used to pass information back to parent view) 
    id <PassSearchData> delegate; 
} 
//Delegate (Used to pass information back to parent view) 
@property (strong) id delegate; 
@end 

SecondView.m

#import "SecondViewController.h" 
#import "FirstViewController.h" 

@implementation SecondViewController 

//.. 

//Delegate (Used to pass information back to parent view) 
@synthesize delegate; 

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath 
{  
    //Access selected cells content (cell.textLabel.text) 
    UITableViewCell *cell = [tableView cellForRowAtIndexPath:indexPath]; 

    //Parent view logic (sends info back to the correct cell in parent view) 
    if (parentViewSelectedIndexPath.section == 0) 
    { 
     if (parentViewSelectedIndexPath.row == 0) 
     { 
      //Predicates restrict the values that will be returned from the query 
      NSPredicate *predicate = [NSPredicate predicateWithFormat:@"%K like %@",@"MANUFACTURER",cell.textLabel.text]; 
      filterArray = [parsedDataArrayOfDictionaries filteredArrayUsingPredicate:predicate]; 

      [[self delegate]setManufactureSearchFields:filterArray withIndexPath:indexPath]; 

//   NSLog(@"Filtered Array = %@", filterArray); 
     } 
    } 
    [self.navigationController popViewControllerAnimated:YES]; //pops current view from the navigatoin stack 

}//... 

那麼這就是我如何設置它的FirstViewController

內

FirstViewController.h

#import <UIKit/UIKit.h> 
#import "VehicleResultViewController.h" //With this included I can now use the PassSearchData delegates of this view for passing data 

@interface VehicleSearchViewController : UITableViewController <PassSearchData> { 
//.. 

FirstViewController.m

#import "VehicleSearchViewController.h" 
#import "VehicleResultViewController.h" //Subview 

//.. 

#pragma mark - Received data from Sub view delegates 

//These are the delegate method for passing data from the child to the parent view (parent being this view, with the delegate being declared in the subview) 

- (void) setManufactureSearchFields:(NSArray *)arrayValues withIndexPath:(NSIndexPath *)myIndexPath 
{ 
    manufactureSearchObjectString = [[arrayValues valueForKey:@"MANUFACTURER"] objectAtIndex:0]; 
    manufactureIdString = [[arrayValues valueForKey:@"MANUFACTURERID"] objectAtIndex:0]; //Restricts Models dataset 
    manufactureResultIndexPath = myIndexPath; 
} 

如果有人知道我缺少/做錯了任何幫助將是真的真的heapful什麼

任何問題，讓我知道。

解決方案

在當我去加載內 的tableView的secondviewcontroller的firstviewcontroller：didSelectRowAtIndexPath方法：我忘了設定secondviewcontrollers委託之前，我推的視圖導航堆棧..所以遺漏碼是這個。

FirstView.m

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath 
{ 
//Get the subview ready for use 
     VehicleResultViewController *vehicleResultViewController = [[VehicleResultViewController alloc] initWithNibName:@"VehicleResultViewController" bundle:nil]; 

     //Pass the selected object to the new view controller. 
     [self.navigationController pushViewController:vehicleResultViewController animated:YES]; 

     [vehicleResultViewController setDelegate:self]; 

//etc 

感謝你們。

Answer 1

好的，首先，你的代表應該是一個弱引用來避免保留週期。但我懷疑也許代表沒有被設置。你可以在SecondViewController被實例化並且委託被設置的地方顯示代碼嗎？你可以在委託調用中設置一個斷點並確認它不是零嗎？

Answer 2

我想你不是在設置委託。 創建SecondViewController的Instanace（對象）後，您必須設置Delegate。

即

SecondViewController *secondObj=[[SecondViewController alloc]initWithNibName:@"SecondViewController"> bundle:nil]; 

[secondObj setDelegate:self];