ios点击链接直接跳转到 App Store 指定应用下载页面

//跳转到应用页面
NSString*str = [NSStringstringWithFormat:
@"http://itunes.apple.com/us/app/id%d",appid]; 
[[UIApplicationsharedApplication]openURL:[NSURLurlWithString:str]];
 

//跳转到评价页面
NSString*str = [NSStringstringWithFormat:@"itms-a
p ps://ax.itunes.apple.com/WebObjects/MZStore.woa/wa/viewContentsUserReviews?type=Purple+Software&id;=%d",   
                         appid];   
[[UIApplicationsharedApplication]openURL:[NSURLurlWithString:str]];