App第一次打开或者更新之后启动图片

NSString *str = [[NSBundle mainBundle] objectForInfoDictionaryKey:@"CFBundleShortVersionString"];

    NSString *isForst = [[NSUserDefaults standardUserDefaults] objectForKey:@"CFBundleShortVersionString"];

    NSUserDefaults *use = [NSUserDefaults standardUserDefaults];

    if (isForst.length == 0) {

        NSLog(@"第一次启动");

        [use setObject:str forKey:@"CFBundleShortVersionString"];

        [use synchronize];

    }

    else if ([str isEqualToString:isForst]) {

        NSLog(@"没有升级");

        

    } else {

            NSLog(@"升级");

            [use setObject:str forKey:@"CFBundleShortVersionString"];

            [use synchronize];

 

    }