对图库的操作

选择相册： UIImagePickerControllerSourceTypesourceType=UIImagePickerControllerSourceTypeCamera;
   if (![UIImagePickerControllerisSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera]) {
       sourceType=UIImagePickerControllerSourceTypePhotoLibrary;
   }
   UIImagePickerController * picker = [[UIImagePickerControlleralloc]init];
   picker.delegate = self;
   picker.allowsEditing=YES;
   picker.sourceType=sourceType;
   [self presentModalViewController:picker animated:YES];
选择完毕：  -(void)imagePickerController:(UIImagePickerController*)pickerdidFinishPickingMediaWithInfo:(NSDictionary *)info
{
   [picker dismissModalViewControllerAnimated:YES];
   UIImage * image=[info objectForKey:UIImagePickerControllerEditedImage];
   [self performSelector:@selector(selectPic:) withObject:imageafterDelay:0.1];
}
 -(void)selectPic:(UIImage*)image
{
   NSLog(@"image%@",image);
   imageView = [[UIImageView alloc] initWithImage:image];
   imageView.frame = CGRectMake(0, 0, image.size.width, image.size.height);
[self.viewaddSubview:imageView];
   [self performSelectorInBackground:@selector(detect:) withObject:nil];
}
detect 为自己定义的方法，编辑选取照片后要实现的效果 取消选择：  -(void)imagePickerControllerDIdCancel:(UIImagePickerController*)picker  

{
   [picker dismissModalViewControllerAnimated:YES];
}