Question

我的应用程序循环遍历图像路径数组，并将所有这些图像合并为一个。代码如下。但是，当我在控制台中打印出（gdb）图像时，应用程序崩溃了。如果我删除图像释放行，那么它工作正常，但这可能会导致内存泄漏。请查看此代码并解释为什么会发生这种情况以及可以改进的内容。谢谢。

UIGraphicsBeginImageContextWithOptions(CGSizeMake(width*len+padding*len+padding,
                                                  height+padding*2), 
                                       YES, 0.0);
do{

        //draw image
        path = (NSString*)[_imageData objectAtIndex:i];
        UIImage * img = [[[UIImage alloc] initWithContentsOfFile:path]
                           cropCenterAndScaleImageToSize:CGSizeMake(width, height)];
        [img drawAtPoint: CGPointMake(width*i+padding*i+padding,padding) blendMode:kCGBlendModeNormal alpha:1];
        [img release]; //APP CRASHES HERE BUT WORKS IF THIS LINE REMOVED
        i++;
    }while (i<len);
    UIImage *result = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    UIImageWriteToSavedPhotosAlbum(result, self,
                                   @selector(image:didFinishSavingWithError:contextInfo:),
                                   nil);

Answer 1

问题是您没有释放分配的图像。您正在释放自动释放的裁剪图像并泄漏分配的图像。

改变这个：

UIImage * img = [[[UIImage alloc] initWithContentsOfFile:path]
                   cropCenterAndScaleImageToSize:CGSizeMake(width, height)];
[img drawAtPoint: CGPointMake(width*i+padding*i+padding,padding) blendMode:kCGBlendModeNormal alpha:1];
[img release];

为：

UIImage *original = [[UIImage alloc] initWithContentsOfFile:path];
UIImage *cropped = [original cropCenterAndScaleImageToSize:CGSizeMake(width, height)];
[cropped drawAtPoint:CGPointMake(width * i + padding * i + padding, padding) blendMode:kCGBlendModeNormal alpha:1];
[original release];

我假设cropCenterAndScaleImageToSize:是一种返回自动释放的UIImage引用的类别方法。

释放UIImage会崩溃应用程序

1 个答案: