+ (UIImage *)getSharedScreenView{

    UIWindow *screenWindow = [[UIApplication sharedApplication]keyWindow];

    ScreenView *currentView = [[[self class] alloc] init];

    currentView.frame = screenWindow.bounds;

    [screenWindow addSubview:currentView];

//UIGraphicsBeginImageContext() 图片会失真模糊

    UIGraphicsBeginImageContextWithOptions(screenWindow.frame.size, NO, 0.0);//图片不模糊

    [screenWindow.layer renderInContext:UIGraphicsGetCurrentContext()];

    UIImage* viewImage =UIGraphicsGetImageFromCurrentImageContext();

    UIGraphicsEndImageContext();

    [currentView removeFromSuperview];

    //UIImageWriteToSavedPhotosAlbum(viewImage,nil,nil,nil); //写入到相册

    return viewImage;

}