Ios 实施应用内购买时遇到问题

我一直在学习本教程，了解如何实现应用内购买-

但是，我在行中遇到错误：

productsRequest.delegate = self;

"Assigning to 'id <SKProductsRequestDelegate> from incompatible type "ViewController *const___strong'

---

这些不是错误而是警告，您应该在类声明中添加协议一致性

@interface ViewController : UIViewController < SKPaymentTransactionObserver, SKProductsRequestDelegate >

@interface ViewController:UIViewController

---

确保实现这两个协议所需的每一种方法。

谁甚至在没有说明原因的情况下贬低了这一点？我只是寻求帮助，这样做没有错。

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

@interface ViewController : UIViewController
{
     IBOutlet UIButton *removeAdsButton;
}

- (IBAction)purchase;
- (IBAction)restore;
- (IBAction)tapsRemoveAdsButton;

@end

BOOL areAdsRemoved;

#import "ViewController.h"

@interface ViewController ()

@end

@implementation ViewController

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

//Removal of ads
areAdsRemoved = [[NSUserDefaults standardUserDefaults] boolForKey:@"areAddsRemoved"];
[[NSUserDefaults standardUserDefaults] synchronize];
//this will load wether or not they bought the in-app purchase

if(areAdsRemoved){
    [self.view setBackgroundColor:[UIColor blueColor]];
    //if they did buy it, set the background to blue, if your using the code above to set the background to blue, if your removing ads, your going to have to make your own code here
}
}

- (void)didReceiveMemoryWarning
{
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}

#define kRemoveAdsProductIdentifier @"com.companyname.appname.removeads"

- (IBAction)tapsRemoveAdsButton {
NSLog(@"User requests to remove ads");

if([SKPaymentQueue canMakePayments]){
    NSLog(@"User can make payments");

    SKProductsRequest *productsRequest = [[SKProductsRequest alloc]     initWithProductIdentifiers:[NSSet setWithObject:kRemoveAdsProductIdentifier]];
    productsRequest.delegate  = self;
    [productsRequest start];

}
else{
    NSLog(@"User cannot make payments due to parental controls");
    //this is called the user cannot make payments, most likely due to parental controls
}
}

- (void)productsRequest:(SKProductsRequest *)request didReceiveResponse:(SKProductsResponse *)response{
SKProduct *validProduct = nil;
int count = [response.products count];
if(count > 0){
    validProduct = [response.products objectAtIndex:0];
    NSLog(@"Products Available!");
    [self purchase:validProduct];
}
else if(!validProduct){
    NSLog(@"No products available");
    //this is called if your product id is not valid, this shouldn't be called unless that happens.
}
}


- (IBAction)purchase:(SKProduct *)product{
SKPayment *payment = [SKPayment paymentWithProduct:product];
[[SKPaymentQueue defaultQueue] addTransactionObserver:self];
[[SKPaymentQueue defaultQueue] addPayment:payment];
}

- (IBAction) restore{
//this is called when the user restores purchases, you should hook this up to a button
[[SKPaymentQueue defaultQueue] restoreCompletedTransactions];
}

- (void) paymentQueueRestoreCompletedTransactionsFinished:(SKPaymentQueue *)queue
{
NSLog(@"received restored transactions: %i", queue.transactions.count);
for (SKPaymentTransaction *transaction in queue.transactions)
{
    if(SKPaymentTransactionStateRestored){
        NSLog(@"Transaction state -> Restored");
        //called when the user successfully restores a purchase
        [self doRemoveAds];
        [[SKPaymentQueue defaultQueue] finishTransaction:transaction];
        break;
    }

}

}

- (void)paymentQueue:(SKPaymentQueue *)queue updatedTransactions:(NSArray *)transactions{
for(SKPaymentTransaction *transaction in transactions){
    switch (transaction.transactionState){
        case SKPaymentTransactionStatePurchasing: NSLog(@"Transaction state -> Purchasing");
            //called when the user is in the process of purchasing, do not add any of your own code here.
            break;
        case SKPaymentTransactionStatePurchased:
            //this is called when the user has successfully purchased the package (Cha-Ching!)
            [self doRemoveAds]; //you can add your code for what you want to happen when the user buys the purchase here, for this tutorial we use removing ads
            [[SKPaymentQueue defaultQueue] finishTransaction:transaction];
            NSLog(@"Transaction state -> Purchased");
            break;
        case SKPaymentTransactionStateRestored:
            NSLog(@"Transaction state -> Restored");
            //add the same code as you did from SKPaymentTransactionStatePurchased here
            [[SKPaymentQueue defaultQueue] finishTransaction:transaction];
            break;
        case SKPaymentTransactionStateFailed:
            //called when the transaction does not finnish
            if(transaction.error.code != SKErrorPaymentCancelled){
                NSLog(@"Transaction state -> Cancelled");
                //the user cancelled the payment ;(
            }
            [[SKPaymentQueue defaultQueue] finishTransaction:transaction];
            break;
    }
}
}

- (void)doRemoveAds{
ADBannerView *banner;
[banner setAlpha:0];
areAdsRemoved = YES;
removeAdsButton.hidden = YES;
removeAdsButton.enabled = NO;
[[NSUserDefaults standardUserDefaults] setBool:areAdsRemoved forKey:@"areAdsRemoved"];
//use NSUserDefaults so that you can load wether or not they bought it
[[NSUserDefaults standardUserDefaults] synchronize];
}

@end

@interface ViewController : UIViewController < SKPaymentTransactionObserver, SKProductsRequestDelegate >