iOS 应用内打开App Store下载页

1、导入framework#import
#import <StoreKit/StoreKit.h>

2、遵守协议，实现代理方法

@interface ViewController ()<SKStoreProductViewControllerDelegate>
/// 取消按钮点击
- (void)productViewControllerDidFinish:(SKStoreProductViewController *)viewController{
    [self dismissViewControllerAnimated:YES completion:nil];
}

3、配置SKStoreProductViewController

  NSString *APPID = @"app唯一标识";
  SKStoreProductViewController *storeProductVC = [[SKStoreProductViewController alloc] init];
  storeProductVC.delegate = self;
  NSDictionary *dic = [NSDictionary dictionaryWithObject:APPID forKey:SKStoreProductParameterITunesItemIdentifier];
  [storeProductVC loadProductWithParameters:dic completionBlock:^(BOOL result, NSError * _Nullable error) {
       if (!error) {
            [self presentViewController:storeProductVC animated:YES completion:nil];
       } else {
             NSLog(@"ERROR:%@",error);
       }
  }];