# 从 iOS 应用内消息进行购买
为了让您的用户可以直接从 iOS 应用中显示的应用内消息进行购买，您可以为 Rich Media 实现开箱即用的解决方案，并添加回调以获取有关应用内购买的更多信息。
## Rich Media JavaScript 实现
要在您的 Rich Media 中实现应用内购买，请使用简单的 **JavaScript 函数调用**：
```javascript
pushwooshImpl.makePurchaseWithIdentifier("Premium"); // product identifier specified in your App Store product information
```
## AppDelegate 回调方法
如果您需要在购买时执行回调，请按如下方式实现 **PWPurchaseDelegate 协议**：
1. 使您项目的 AppDelegate 符合 PWPurchaseDelegate 协议：
```objective-c
@interface AppDelegate : PWAppDelegate
```
2. 在您的 AppDelegate 中实现 PWPurchaseDelegate 的方法：
```objective-c
#pragma mark - Purchase delegate methods
- (void) onPWInAppPurchaseHelperPaymentComplete:(NSString*) identifier {
NSLog(@“Custom purchase delegate -- payment complete for identifier: %@“, identifier);
}
-(void)onPWInAppPurchaseHelperProducts:(NSArray* _Nullable)products {
NSLog(@“Custom purchase delegate -- retrieved list of products”);
}
-(void)onPWInAppPurchaseHelperPaymentFailedProductIdentifier:(NSString* _Nullable)identifier error:(NSError* _Nullable)error {
NSLog(@“Custom purchase delegate -- payment failed with identifier %@ and error %@“, identifier, error.description);
}
```
### 可用的 PWPurchaseDelegate 方法列表
#### 产品列表
```objective-c
@protocol PWPurchaseDelegate
// Detailed information about list of products in your app
-(void)onPWInAppPurchaseHelperProducts:(NSArray* _Nullable)products;
@end
```
#### 成功交易
```objective-c
@protocol PWPurchaseDelegate <NSObject>
// A successfully processed transaction
-(void)onPWInAppPurchaseHelperPaymentComplete:(NSString* _Nullable)identifier;
@end
```
#### 失败交易
```objective-c
@protocol PWPurchaseDelegate <NSObject>
// A failed transaction
-(void)onPWInAppPurchaseHelperPaymentFailedProductIdentifier:(NSString* _Nullable)identifier error:(NSError* _Nullable)error;
@end
```
#### 从 App Store 推广
```objective-c
@protocol PWPurchaseDelegate
// An in-app purchase is initiated from the App Store, and the transaction continues in your app.
-(void)onPWInAppPurchaseHelperCallPromotedPurchase:(NSString* _Nullable)identifier;
@end
```
#### 恢复已完成交易失败
```objective-c
@protocol PWPurchaseDelegate
// An error occurred while restoring transactions
-(void)onPWInAppPurchaseHelperRestoreCompletedTransactionsFailed:(NSError * _Nullable)error;
@end
```