如何将屏幕截图保存到相册

Cocos2d-x
#1 
CCRenderTexture *renderTexture = CCRenderTexture::create(size.width , size.height , kCCTexture2DPixelFormat_RGBA8888);    renderTexture->setPosition(ccp(size.width / 2, size.height / 2));
    renderTexture->begin();
    this->visit();
    renderTexture->end();
    renderTexture->saveToFile("test.png", kCCImageFormatPNG);

环境：cocos2d-x2.1.5 xcode
上述代码是截屏并保存的方法，但是并不能保存到 ipad 相册里
求教各位！不知道谁接触过关于将图片保存到 iPad/Android 相册里的问题。

#2

#import <QuartzCore/QuartzCore.h>

-(void)viewDidAppear:(BOOL)animated

{

;



    self.view.backgroundColor = ;

    UIWindow *screenWindow =  keyWindow];

    UIGraphicsBeginImageContext(screenWindow.frame.size);

    ;

    UIImage * viewImage = UIGraphicsGetImageFromCurrentImageContext();

    UIGraphicsEndImageContext();

    UIImageWriteToSavedPhotosAlbum(viewImage, nil, nil, nil);

}

http://www.cnblogs.com/X-Code/archive/2013/02/14/2912615.html

#3

cocos2d-x3.7 怎么写呢？