UIImagePickerController换头像

LoginViewController.h中@interface LoginViewController : UIViewController<UINavigationControllerDelegate, UIImagePickerControllerDelegate> //协议第四步 签订协议//UIImagePickerController用法-(void)click{    self.imagePicker = [[UIImagePickerController alloc] init];    //  选择类型 （照片库模式， 相机模式， 相机胶片模式）    self.imagePicker.sourceType = UIImagePickerControllerSourceTypePhotoLibrary;    //是否允许编辑    self.imagePicker.allowsEditing = YES;    //协议第五步 指定代理人    self.imagePicker.delegate = self;    //模态 显示本地相册    [self presentViewController:self.imagePicker animated:YES completion:^{    }];    [_imagePicker release];}//协议第六步 实现协议方法#pragma mark -- UIImagePickerController协议方法//当用户选择相册中的某个图片时触发这个方法//该方法可以获取到选中的图片-(void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info{    NSLog(@"info = %@",info);//打印是一个字典    //根据字典中key为UIImagePickerControllerOriginalImage来获取图片    UIImage *image = [info objectForKey:@"UIImagePickerControllerOriginalImage"];    //按钮背景图片设为获取到的图片    [self.portraitsButton setBackgroundImage:image forState:UIControlStateNormal];    //模态消失    [self.imagePicker dismissViewControllerAnimated:YES completion:^{    }];}self.imagePicker = [[UIImagePickerController alloc] init];            self.imagePicker.sourceType = UIImagePickerControllerSourceTypeCamera;//相机            self.imagePicker.allowsEditing = YES;//设置当拍照完或在相册选完照片后，是否跳到编辑模式进行图片剪裁            self.imagePicker.cameraDevice = UIImagePickerControllerCameraDeviceRear;//设置使用后置摄像头，可以使用前置摄像头            self.imagePicker.delegate = self;            //模态 调用相机            [self presentViewController:self.imagePicker animated:YES completion:^{}];