iPhone 應用裡實現截屏功能的代碼

Phone 使用者同步選取 Home 和鎖屏鍵就能截屏，但在應用裡總不能跳出一行字讓使用者自己按截屏鍵，支援高清解析度：

UIView *view = [[[[[UIApplication sharedApplication] windows] objectAtIndex:1] subviews] lastObject];//獲得某個window的某個subView


    NSInteger index = 0;//用來給儲存的png命名

    for (UIView *subView in [view subviews]) {//遍曆這個view的subViews

        if ([subView isKindOfClass:NSClassFromString(@"UIImageView")] || [subView isKindOfClass:NSClassFromString(@"UIThreePartButton")]) {//找到自己需要的subView

            //支援retina高分的關鍵

            if(UIGraphicsBeginImageContextWithOptions != NULL)

            {

                UIGraphicsBeginImageContextWithOptions(subView.frame.size, NO, 0.0);

            } else {

                UIGraphicsBeginImageContext(subView.frame.size);

            }            


            //擷取映像

            [subView.layer renderInContext:UIGraphicsGetCurrentContext()];

            UIImage *image = UIGraphicsGetImageFromCurrentImageContext();

            UIGraphicsEndImageContext();


            //儲存映像

            NSString *path = [NSHomeDirectory() stringByAppendingFormat:@"/%d.png",index];

            if ([UIImagePNGRepresentation(image) writeToFile:path atomically:YES]) {

                index += 1;

                NSLog(@"Succeeded!");

            }

            else {

                NSLog(@"Failed!");

            }

        }

    }

第二種方式

UIImage* image = nil;#if TARGET_IPHONE_SIMULATOR    CGSize imageSize = [view bounds].size;    if (NULL != UIGraphicsBeginImageContextWithOptions)        UIGraphicsBeginImageContextWithOptions(imageSize, NO, 0);    else        UIGraphicsBeginImageContext(imageSize);    CGContextRef context = UIGraphicsGetCurrentContext();    [view.layer renderInContext:context];      image = UIGraphicsGetImageFromCurrentImageContext();    UIGraphicsEndImageContext();#else    CGImageRef screen = UIGetScreenImage();//
by smking, 使用這種方法前，需要在.m檔案開始處，加入extern "C" CGImageRef UIGetScreenImage();，
這樣才能使用UIGetScreenImage()；函數// by heqin, 本人測試過，在上傳代碼時，如果裡面使用了這個方法，則會被拒，蘋果認為這是個私人方法，2013.3.9    image = [UIImage imageWithCGImage:screen];  #endif// by heqin, 另一個問題是， 上面兩種方法都無法捕捉到當前螢幕中是用OpenGL繪製的情況，所以對於OpenGL的截屏，還需要進一步研究再補充一個儲存當前view到相簿的方法#import <QuartzCore/QuartzCore.h>    UIGraphicsBeginImageContext(currentView.bounds.size);     //currentView 當前的view
    [currentView.layer renderInContext:UIGraphicsGetCurrentContext()];
    UIImage *viewImage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    UIImageWriteToSavedPhotosAlbum(viewImage, nil, nil, nil);