iphone - 在iPhone中创建图像的缩略图？

Question

我正在尝试使用使用UIImagePickerController创建从照片库或相机导入的图像的缩略图-(void)imagePickerController:(UIImagePickerController *)picker didFinishPickingImage:(UIImage *)selectedImage editInfo:(NSDictionary *)editingInfo 使用相机可以轻松创建单击图像的缩略图，但是通过从照片库中选择图像来完成缩略图后，我的应用程序将崩溃。.当我在应用程序中启用NSZombie时，它会显示 f- [UIImage drawInRect:]:已发送消息在myThumbnail变量上释放实例0x5abc140 。

我可能做错了什么？

 - (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingImage:(UIImage *)selectedImage editingInfo:(NSDictionary *)editingInfo
{
     [self saveImage:selectedImage];
}
- (void)saveImage:(UIImage *)img
{
    myThumbNail = img;

    UIGraphicsBeginImageContext(CGSizeMake(60.0,60.0));

    [myThumbNail drawInRect:CGRectMake(0.0, 0.0, 60.0, 60.0)];// gets killed here
}

Answer 1

您的saveImage:方法中的图像是什么？我认为应该是img。
希望这可以帮助

- (void)saveImage:(UIImage *)img
{
    [img retain];
    //alloc your myThumbNail before this
    myThumbNail = img;
    [img release];
    UIGraphicsBeginImageContext(CGSizeMake(60.0,60.0));

    [myThumbNail drawInRect:CGRectMake(0.0, 0.0, 60.0, 60.0)];// gets killed here

}