share(textToShare: String, url: String, image: UIImage, sourceView: UIView)
/// 在app内以子视图方式打开其他app预览，仅支持6.0以上
 private func openAppWithIdentifier(appId: String) {
 if let _ = NSClassFromString("SKStoreProductViewController") {
  let storeProductViewController = SKStoreProductViewController()
  storeProductViewController.delegate = self
  let dict = NSDictionary(object:appId, forKey:SKStoreProductParameterITunesItemIdentifier) as! [String : AnyObject]
  storeProductViewController.loadProductWithParameters(dict, completionBlock: { (result, error) -> Void in
//  self.presentViewController(storeProductViewController, animated: true, completion: nil)
  })
  self.presentViewController(storeProductViewController, animated: true, completion: nil)
 }else {
  UIApplication.sharedApplication().openURL(NSURL(string: "itms-apps://itunes.apple.com/app/id\(appId)")!)
 }
 }
 /// 分享文字图片信息，ipad上会以sourceView为焦点弹出选择视图
 private func share(textToShare: String, url: String, image: UIImage, sourceView: UIView) {
 let objectsToShare = [textToShare, url, image]
 let activityViewController = UIActivityViewController(activityItems: objectsToShare, applicationActivities: nil)
 if UIDevice.currentDevice().userInterfaceIdiom == UIUserInterfaceIdiom.Phone {
  self.presentViewController(activityViewController, animated: true, completion: nil)
 }else {
  let popover = activityViewController.popoverPresentationController
  if (popover != nil){
  popover?.sourceView = sourceView
  popover?.sourceRect = sourceView.frame
  popover?.permittedArrowDirections = UIPopoverArrowDirection.Any
  self.presentViewController(activityViewController, animated: true, completion: nil)
  }
 }
 }