iOS 开发之应用内弹出 App Store 应用界面

　　在APP内给其他APP做推广，经常用到在应用内弹出应用的APP

　　#import <StoreKit/SKStoreProductViewController.h>

　　设置代理：<SKStoreProductViewControllerDelegate>

- (void)buttonDidClick:(id)sender
{
    //首先实例化一个VC
    SKStoreProductViewController *storeVC = [[SKStoreProductViewController alloc] init];
    //然后设置代理，注意这很重要，不如弹出就没法dismiss了
    storeVC.delegate = self;
    //接着弹出VC
    [self presentViewController:storeVC animated:YES completion:nil];
    //最后加载应用数据
    [storeVC loadProductWithParameters:@{SKStoreProductParameterITunesItemIdentifier:@""} completionBlock:^(BOOL result, NSError * _Nullable error) {
        if (error) {
            //handle the error
        }
    }];
}

#pragma mark - SKStoreProductViewControllerDelegate
- (void)productViewControllerDidFinish:(SKStoreProductViewController *)viewController {
    //在代理方法里dismiss这个VC
    [viewController dismissViewControllerAnimated:YES completion:nil];
}