方法一：（截图较清晰）

-(UIImage*) imageByCaptureScreen  {
    if(&UIGraphicsBeginImageContextWithOptions!=NULL)
    {
//        UIGraphicsBeginImageContextWithOptions([UIScreen mainScreen].bounds.size,NO,0);
        
        UIGraphicsBeginImageContextWithOptions(CGSizeMake(kScreenWidth, kScreenHeight - 64 - 50),NO,0);
        
    }
    else
    {
        UIGraphicsBeginImageContext(CGSizeMake(kScreenWidth, kScreenHeight - 64 - 50));
    }
    CGContextRef context = UIGraphicsGetCurrentContext();
    for(UIWindow*window in[[UIApplication sharedApplication]windows])
    {
        if(![window respondsToSelector:@selector(screen)] || [window screen] == [UIScreen mainScreen])
        {
            CGContextSaveGState(context);
            CGContextTranslateCTM(context, [window center].x, [window center].y);
            CGContextConcatCTM(context, [window transform]);
//            if(IOS7_OR_LATER)
//            {
//                CGContextTranslateCTM(context,
//                                      -[window bounds].size.width* [[window layer]anchorPoint].x,
//                                      -[window bounds].size.height* [[window layer]anchorPoint].y);
//            }
//            else
//            {
                CGContextTranslateCTM(context,
                                      -[window bounds].size.width* [[window layer]anchorPoint].x,
                                      -([window bounds].size.height)* [[window layer]anchorPoint].y-64);
//            }
            [[window layer]renderInContext:context];
            
            CGContextRestoreGState(context);
            
        }
        
    }
    
    UIImage*image = UIGraphicsGetImageFromCurrentImageContext();
    
    UIGraphicsEndImageContext();
    
    return image;
    
}

方法二：（截取的图片清晰度不如方法一）

-(UIImage *)fullScreenshots{

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

    UIGraphicsBeginImageContext(screenWindow.frame.size);//全屏截图，包括window

    [screenWindow.layer renderInContext:UIGraphicsGetCurrentContext()];

    UIImage *viewImage =UIGraphicsGetImageFromCurrentImageContext();

    UIGraphicsEndImageContext();

    CGRect rect1 =CGRectMake(0 , 64 , kScreenWidth , kScreenHeight - 64 - 50);

    UIImage * imgeee = [UIImage imageWithCGImage:CGImageCreateWithImageInRect([viewImage CGImage], rect1)];

    return imgeee;
    
}