給界面上任何控件截圖並保存為PNG的方法

 UIView *view = [[[[[UIApplication sharedApplication] windows] objectAtIndex:1] subviews] lastObject];//獲得某個window的某個subView
 
    NSInteger index = 0;//用來給保存的png命名
    for (UIView *subView in [view subviews]) {//遍歷這個view的subViews
        if ([subView isKindOfClass:NSClassFromString(@"UIImageView")] || [subView isKindOfClass:NSClassFromString(@"UIThreePartButton")]) {//找到自己需要的subView
           
            if(UIGraphicsBeginImageContextWithOptions != NULL)
            {
                UIGraphicsBeginImageContextWithOptions(subView.frame.size, NO, 0.0);
            } else {
                UIGraphicsBeginImageContext(subView.frame.size);
            }            
 
            //獲取圖像
            [subView.layer renderInContext:UIGraphicsGetCurrentContext()];
            UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
            UIGraphicsEndImageContext();
 
            //保存圖像
            NSString *path = [NSHomeDirectory() stringByAppendingFormat:@"/%d.png",index];
            if ([UIImagePNGRepresentation(image) writeToFile:path atomically:YES]) {
                index += 1;
                NSLog(@"Succeeded!");
            }
            else {

附：截屏代碼

 UIGraphicsBeginImageContext(self.view.bounds.size);

 [self.view.layer renderInContext:UIGraphicsGetCurrentContext()];

 UIImage *image= UIGraphicsGetImageFromCurrentImageContext();

 UIGraphicsEndImageContext();

 UIImageWriteToSavedPhotosAlbum(image, self, nil, nil);

    在91助手上常見iPhone屏幕截圖的功能，於是就開始想辦法，看能不能手動把屏幕截圖做出來。下面這個函數的代碼，就是根據UIView上的 顯示內容生成一張屏幕截圖。值得注意的是，其中引用了Quartz2D中的函數，所以要使用的話要在文件頭部增加一個引用。
#import QuartzCore/QuartzCore.h
-(UIImage *)getImageFromView:(UIView *)orgView{
UIGraphicsBeginImageContext(orgView.bounds.size); 
[orgView.layer renderInContext:UIGraphicsGetCurrentContext()]; 
UIImage *image = UIGraphicsGetImageFromCurrentImageContext(); 
UIGraphicsEndImageContext(); return image;
}