ios 跳轉AppStore的兩種方法，應用內和直接跳轉

#import "ViewController.h"
#import <StoreKit/StoreKit.h>
@interface ViewController ()<SKStoreProductViewControllerDelegate>
 
@end
 
@implementation ViewController
 
- (void)viewDidLoad {
    [super viewDidLoad];
    //第一種方法  直接跳轉
    UIButton *btn = [[UIButton alloc]initWithFrame:CGRectMake(100, 100, 100, 50)];
    btn.backgroundColor = [UIColor redColor];
    [btn setTitle:@"直接跳轉" forState:UIControlStateNormal];
    btn.tag = 1;
    [btn addTarget:self action:@selector(btn:) forControlEvents:UIControlEventTouchUpInside];
    //第二中方法  應用內跳轉
    UIButton *btnT = [[UIButton alloc]initWithFrame:CGRectMake(100, 300, 100, 50)];
    btnT.backgroundColor = [UIColor purpleColor];
    btnT.tag = 2;
    [btnT setTitle:@"應用內跳轉" forState:UIControlStateNormal];
    [btnT addTarget:self action:@selector(btn:) forControlEvents:UIControlEventTouchUpInside];
    [self.view addSubview:btn];
    [self.view addSubview:btnT];
}
- (void)btn:(UIButton *)btn{
    if (btn.tag == 1) {
        //第一種方法  直接跳轉
        [[UIApplication sharedApplication] openURL:[NSURL URLWithString:@"itms-apps://itunes.apple.com/app/id1018221712"]];
    }else{
        //第二中方法  應用內跳轉
        //1:導入StoreKit.framework,控制器裏面添加框架#import <StoreKit/StoreKit.h>
        //2:實現代理SKStoreProductViewControllerDelegate
        SKStoreProductViewController *storeProductViewContorller = [[SKStoreProductViewController alloc] init];
        storeProductViewContorller.delegate = self;
//        ViewController *viewc = [[ViewController alloc]init];
//        __weak typeof(viewc) weakViewController = viewc;
         
        //加載一個新的視圖展現
        [storeProductViewContorller loadProductWithParameters:
         //appId
         @{SKStoreProductParameterITunesItemIdentifier : @"1018221712"} completionBlock:^(BOOL result, NSError *error) {
             //回調
             if(error){
                 NSLog(@"錯誤%@",error);
             }else{
                 //AS應用界面
                 [self presentViewController:storeProductViewContorller animated:YES completion:nil];
             }
         }];
    }
     
}
#pragma mark - 評分取消按鈕監聽
//取消按鈕監聽
- (void)productViewControllerDidFinish:(SKStoreProductViewController *)viewController{
    [self dismissViewControllerAnimated:YES completion:nil];
}