应用内购买在 [[SKPaymentQueue defaultQueue] addPayment: payment] 上崩溃

Question

我的应用内购买有效。我展示了一个带有“Buy”UIButton 的 ModalView。您单击该按钮，应用程序内购买就会完成该过程。你甚至可以连续做几次。

如果您打开模态视图，然后关闭模态视图（使用 UITabBarButtonItem），然后重新打开模态视图并点击“购买”按钮，则会出现此问题。应用程序崩溃了，我得到一个 NSZombie，上面写着

*** -[InAppPurchaseManager respondsToSelector:]：消息发送至 已释放实例 0x1c7ad0

NSZombie 指向 .m 文件中的第 160 行。我已经用注释标记了。

我从此页面获得原始代码： http:// /troybrant.net/blog/2010/01/in-app-purchases-a-full-walkthrough/

我已经为此苦苦挣扎很多天了......任何帮助都会很棒。

这是.h

//
//  InAppPurchaseManager.h
//  Copyright 2010 __MyCompanyName__. All rights reserved.


#import <UIKit/UIKit.h>
#import <StoreKit/StoreKit.h>

#define kInAppPurchaseManagerProductsFetchedNotification @"kInAppPurchaseManagerProductsFetchedNotification"
#define kInAppPurchaseManagerTransactionFailedNotification @"kInAppPurchaseManagerTransactionFailedNotification"
#define kInAppPurchaseManagerTransactionSucceededNotification @"kInAppPurchaseManagerTransactionSucceededNotification"

#define kInAppPurchaseCreditProductId @"com.myname.app.iap"

@interface InAppPurchaseManager : UIViewController <SKProductsRequestDelegate, SKPaymentTransactionObserver>
{
    SKProduct *productID;
    SKProductsRequest *productsRequest;

 IBOutlet UIBarButtonItem *closeButton;
 IBOutlet UIButton *buyButton;
 IBOutlet UILabel *testLabel;

}

@property (retain, nonatomic) SKProduct *productID;
@property (retain, nonatomic) SKProductsRequest *productsRequest;

@property (retain, nonatomic) IBOutlet UIBarButtonItem *closeButton;
@property (retain, nonatomic) IBOutlet UIButton *buyButton;
@property (retain, nonatomic) IBOutlet UILabel *testLabel;


// public methods
-(void)loadStore;
-(BOOL)canMakePurchases;
-(void)purchaseCredit;

-(void)requestInAppPurchaseData;
-(void)buyButtonAction:(id)sender;
-(void)closeButtonAction:(id)sender;
-(void)updateButtonStatus:(NSString *)status;

@end

这是.m

// InAppPurchaseManager.m

#import "InAppPurchaseManager.h"

@implementation InAppPurchaseManager

@synthesize productID;
@synthesize productsRequest;

@synthesize closeButton;
@synthesize buyButton;
@synthesize testLabel;


- (void)dealloc {

 [productID release];
 //[productsRequest release];

 [closeButton release];
 [buyButton release];
 [testLabel release];

    [super dealloc];
}


- (void)viewDidLoad {
    [super viewDidLoad];

 [closeButton release];
 closeButton = [[UIBarButtonItem alloc] initWithTitle:@"Close" style:UIBarButtonItemStyleBordered target:self action:@selector(closeButtonAction:)];
 self.navigationItem.leftBarButtonItem = closeButton;

 [self loadStore];

 self.navigationItem.title = @"Credits";


}

-(void)closeButtonAction:(id)sender { 
 [self dismissModalViewControllerAnimated:YES];
}


-(void)buyButtonAction:(id)sender {

 if([self canMakePurchases]) {
  [self updateButtonStatus:@"OFF"];

  [self performSelectorOnMainThread:@selector(requestInAppPurchaseData) withObject:nil waitUntilDone:NO];

 } else {
  UIAlertView *alertView = [[UIAlertView alloc] initWithTitle:nil message:[NSString stringWithString:@"Your account settings do not allow for In App Purchases."] delegate:self cancelButtonTitle:@"OK" otherButtonTitles:nil];
  [alertView show];
  [alertView release];  
 }

}


-(void)updateButtonStatus:(NSString *)status {

 if ([status isEqual:@"OFF"]) {
  closeButton.enabled = NO;
  buyButton.enabled = NO;
  buyButton.titleLabel.textColor = [UIColor grayColor];
 } else {
  closeButton.enabled = YES;
  buyButton.enabled = YES;
  buyButton.titleLabel.textColor = [UIColor blueColor];
 }

}

#pragma mark -
#pragma mark SKProductsRequestDelegate methods


//
// call this method once on startup
//
- (void)loadStore
{

    // restarts any purchases if they were interrupted last time the app was open
    [[SKPaymentQueue defaultQueue] addTransactionObserver:self];

}


- (void)requestInAppPurchaseData
{
 NSSet *productIdentifiers = [NSSet setWithObject:kInAppPurchaseCreditProductId];

    productsRequest = [[SKProductsRequest alloc] initWithProductIdentifiers:productIdentifiers];
    productsRequest.delegate = self;
    [productsRequest start];

    // we will release the request object in the delegate callback
}



- (void)productsRequest:(SKProductsRequest *)request didReceiveResponse:(SKProductsResponse *)response
{

    NSArray *products = response.products;


    productID = [products count] == 1 ? [[products objectAtIndex:0] retain] : nil;
    if (productID)
    {
  /*
   NSLog(@"Product title: %@" , productID.localizedTitle);
   NSLog(@"Product description: %@" , productID.localizedDescription);
   NSLog(@"Product price: %@" , productID.price);
   NSLog(@"Product id: %@" , productID.productIdentifier);
   */

  NSUserDefaults *standardUserDefaults = [NSUserDefaults standardUserDefaults];
  NSString *currentCredits = ([standardUserDefaults objectForKey:@"currentCredits"]) ? [standardUserDefaults objectForKey:@"currentCredits"] : @"0";

  testLabel.text = [NSString stringWithFormat:@"%@", currentCredits];
    }

    for (NSString *invalidProductId in response.invalidProductIdentifiers)
    {
        //NSLog(@"Invalid product id: %@" , invalidProductId);
  testLabel.text = @"Try Again Later.";
    }

    // finally release the reqest we alloc/init’ed in requestProUpgradeProductData
    [productsRequest release];

    [[NSNotificationCenter defaultCenter] postNotificationName:kInAppPurchaseManagerProductsFetchedNotification object:self userInfo:nil];

 [self performSelectorOnMainThread:@selector(purchaseCredit) withObject:nil waitUntilDone:NO];
}


//
// call this before making a purchase
//
- (BOOL)canMakePurchases
{
    return [SKPaymentQueue canMakePayments];
}

//
// kick off the upgrade transaction
//
- (void)purchaseCredit
{

    SKPayment *payment = [SKPayment paymentWithProductIdentifier:kInAppPurchaseCreditProductId];

 // *********************************************************************************************************
 [[SKPaymentQueue defaultQueue] addPayment:payment]; // <--- This is where the NSZombie Appears *************
 // *********************************************************************************************************

}

#pragma -
#pragma Purchase helpers

//
// saves a record of the transaction by storing the receipt to disk
//
- (void)recordTransaction:(SKPaymentTransaction *)transaction
{
 if ([transaction.payment.productIdentifier isEqualToString:kInAppPurchaseCreditProductId])
    {
        // save the transaction receipt to disk
        [[NSUserDefaults standardUserDefaults] setValue:transaction.transactionReceipt forKey:@"InAppPurchaseTransactionReceipt" ];
        [[NSUserDefaults standardUserDefaults] synchronize];
    }

}

//
// enable pro features
//
- (void)provideContent:(NSString *)productId
{
 if ([productId isEqualToString:kInAppPurchaseCreditProductId])
    {        
  // Increment currentCredits
  NSUserDefaults *standardUserDefaults = [NSUserDefaults standardUserDefaults];
  NSString *currentCredits = [standardUserDefaults objectForKey:@"currentCredits"];
  int newCreditCount = [currentCredits intValue] + 1;
  [standardUserDefaults setObject:[NSString stringWithFormat:@"%d", newCreditCount] forKey:@"currentCredits"];

  testLabel.text = [NSString stringWithFormat:@"%d", newCreditCount];

    }

}

//
// removes the transaction from the queue and posts a notification with the transaction result
//
- (void)finishTransaction:(SKPaymentTransaction *)transaction wasSuccessful:(BOOL)wasSuccessful
{

    // remove the transaction from the payment queue.
    [[SKPaymentQueue defaultQueue] finishTransaction:transaction];

    NSDictionary *userInfo = [NSDictionary dictionaryWithObjectsAndKeys:transaction, @"transaction" , nil];
    if (wasSuccessful)
    {
        // send out a notification that we’ve finished the transaction
        [[NSNotificationCenter defaultCenter] postNotificationName:kInAppPurchaseManagerTransactionSucceededNotification object:self userInfo:userInfo];
    }
    else
    {
        // send out a notification for the failed transaction
        [[NSNotificationCenter defaultCenter] postNotificationName:kInAppPurchaseManagerTransactionFailedNotification object:self userInfo:userInfo];
    }


 [self updateButtonStatus:@"ON"];

}

//
// called when the transaction was successful
//
- (void)completeTransaction:(SKPaymentTransaction *)transaction
{

 [self updateButtonStatus:@"OFF"];

 [self recordTransaction:transaction];
    [self provideContent:transaction.payment.productIdentifier];
 [self finishTransaction:transaction wasSuccessful:YES];

}

//
// called when a transaction has been restored and and successfully completed
//
- (void)restoreTransaction:(SKPaymentTransaction *)transaction
{
    [self recordTransaction:transaction.originalTransaction];
    [self provideContent:transaction.originalTransaction.payment.productIdentifier];
    [self finishTransaction:transaction wasSuccessful:YES];
}

//
// called when a transaction has failed
//
- (void)failedTransaction:(SKPaymentTransaction *)transaction
{

    if (transaction.error.code != SKErrorPaymentCancelled)
    {
   // error!
        [self finishTransaction:transaction wasSuccessful:NO];
    }
    else
    {
   // this is fine, the user just cancelled, so don’t notify
        [[SKPaymentQueue defaultQueue] finishTransaction:transaction];
    }

 [self updateButtonStatus:@"ON"];

}

#pragma mark -
#pragma mark SKPaymentTransactionObserver methods

//
// called when the transaction status is updated
//
- (void)paymentQueue:(SKPaymentQueue *)queue updatedTransactions:(NSArray *)transactions
{

    for (SKPaymentTransaction *transaction in transactions)
    {
        switch (transaction.transactionState)
        {
            case SKPaymentTransactionStatePurchased:
                [self completeTransaction:transaction];
                break;
            case SKPaymentTransactionStateFailed:
                [self failedTransaction:transaction];
                break;
            case SKPaymentTransactionStateRestored:
                [self restoreTransaction:transaction];
                break;
            default:
                break;
        }
    }
}


@end

Answer 1

该错误消息表明一条消息正在发送到已释放的 InAppPurchaseManager 实例（您的类）。它发生在您打开视图（创建实例），关闭视图（释放实例），然后再次打开视图（创建第二个实例）之后。问题发生在 addPayment: 调用中。这表明框架仍然拥有旧的已发布实例的句柄，并且正在尝试向其发送消息。

您为框架提供了 loadStore 中对象的句柄，当您调用时，

[[SKPaymentQueue defaultQueue] addTransactionObserver:self];

我看不到您在任何地方删除 self 作为观察者。发送通知的对象通常不会保留其观察者，因为这样做可能会造成保留周期和/或内存泄漏。

在您的 dealloc 代码中，您需要清理并调用 removeTransactionObserver:。那应该可以解决你的问题。

Answer 2

我认为使用 addTransactionObserver 添加的观察者显然是弱引用 - 而不是强引用，这可以解释这一点。我做了一个简单的测试：

// bad code below:
// the reference is weak so the observer is immediately destroyed
addTransactionObserver([[MyObserver alloc] init]);
...
[[SKPaymentQueue defaultQueue] addPayment:payment]; // crash

即使没有调用removeTransactionObserver，也会发生同样的崩溃。
我的例子的解决方案是简单地保留对观察者的强引用：

@property (strong) MyObserver* observer;
....
self.observer = [[MyObserver alloc] init];
addTransactionObserver(observer);