技术内容：分别读取相册以及调取相机,将图片显示到imageView上

布局：

1.创建imageView 和 button 并为button一个关联pickerImage的事件

<div style="text-align: left;"><span style="font-family: Helvetica; -webkit-text-stroke-width: initial;">    self.aImageView = [[UIImageView alloc]initWithFrame:CGRectMake(60, 100, 200, 200)];</span></div>    self.aImageView.backgroundColor = [UIColor redColor];
    self.aImageView.userInteractionEnabled = YES;

    self.aButton = [[UIButton alloc]initWithFrame:CGRectMake(98, 350, 125, 25)];
    self.aButton.backgroundColor = [UIColor blueColor];
    [self.aButton addTarget:self action:@selector(pickerImage:) forControlEvents:(UIControlEventTouchUpInside)];
    [self.aButton setTitle:@"选择图像" forState:(UIControlStateNormal)];

    [self.view addSubview:self.aButton];
    [self.view addSubview:self.aImageView];
    [self.aButton release];
    [self.aImageView release];

    [self addTapGestureOnImageView];

2.因为有的场景需要直接点击图片更换别的图片，所以在imageView上添加轻拍动作

- (void)addTapGestureOnImageView{
    UITapGestureRecognizer *tap = [[UITapGestureRecognizer alloc]initWithTarget:self action:@selector(pickerImage:)];
    [self.aImageView addGestureRecognizer:tap];
    [tap release];
}

3.实现轻拍动作中方法

- (void)pickerImage:(UIButton *)button{
    //添加ActionSheet控件，提示选项框，调出相机或拍摄图片
    //第一个参数：是行为列表的标题 一般为空
    //第二个参数：遵循代理
    //第三个参数：取消这个操作按钮上 显示的文字
    //第四个参数：destructive 破坏性的, 毁灭性的 自己理解吧 反正我写的是拍照，执行操作的意思
    //第五个参数：从相册选取图片
    UIActionSheet *actionSheet = [[UIActionSheet alloc]initWithTitle:nil delegate:self cancelButtonTitle:@"取消" destructiveButtonTitle:@"拍照" otherButtonTitles:@"从相册选择图片", nil];
    //在当前界面显示actionSheet对象
    [actionSheet showInView:self.view];
    [actionSheet release];
}

4.实现action代理协议中的方法

- (void)actionSheet:(UIActionSheet *)actionSheet clickedButtonAtIndex:(NSInteger)buttonIndex{
    switch (buttonIndex) {
        case 0:
            //调用系统相机，拍照
            [self pickerPictureFromCamera];
            break;
        case 1:
            [self pickerPictureFromPhotosAlbum];
        default:
            break;
    }
}

4.1从摄像头获取图片

- (void)pickerPictureFromCamera{

    //判断前摄像头是否可用，如果不可用的话，用后摄像头。如果后摄像头也不可用的话用手机图片库
    //判断前置摄像头是否可用
    if ([UIImagePickerController isCameraDeviceAvailable:UIImagePickerControllerCameraDeviceFront]) {
        NSLog(@"用前置摄像头");

        self.imagePC = [[UIImagePickerController alloc]init];
        self.imagePC.cameraDevice = UIImagePickerControllerCameraDeviceFront;
        [self.imagePC release];
        //判断后置摄像头是否可用
    }else if ([UIImagePickerController isCameraDeviceAvailable:UIImagePickerControllerCameraDeviceRear]){
        NSLog(@"用后置摄像头");

        self.imagePC = [[UIImagePickerController alloc]init];
        self.imagePC.cameraDevice = UIImagePickerControllerCameraDeviceRear;
        [self.imagePC release];
        //两者都不行的话，从手机相册调取照片
    }else{
        UIAlertView *alertView = [[UIAlertView alloc]initWithTitle:@"调用摄像头失败" message:@"请从手机相册中选取照片" delegate:self cancelButtonTitle:@"确定" otherButtonTitles:nil, nil];
        [alertView show];
        [alertView release];
    }

    //初始化图片控制器对象
    UIImagePickerController *imagePicker = [[UIImagePickerController alloc]init];
    //sourceType资源样式
    //设置图片选择器选择图片的样式
    imagePicker.sourceType = UIImagePickerControllerSourceTypePhotoLibrary;
    //设置图片是否允许编辑
    imagePicker.allowsEditing = YES;
    //设置图片选择器代理对象为这个视图控制器
    imagePicker.delegate = self;
    //把相机推出来 模态
    [self presentViewController:imagePicker animated:YES completion:nil];
    //释放
    [imagePicker release];

}

4.2从手机的图片库获取图片

- (void)pickerPictureFromPhotosAlbum{
    //初始化图片控制器对象
    UIImagePickerController *imagePicker = [[UIImagePickerController alloc]init];
    //sourceType资源样式
    //设置图片选择器选择图片的样式
    imagePicker.sourceType = UIImagePickerControllerSourceTypePhotoLibrary;
    //设置图片是否允许编辑
    imagePicker.allowsEditing = YES;
    //设置图片选择器代理对象为这个视图控制器
    imagePicker.delegate = self;
    //把选择控制器推出来 模态
    [self presentViewController:imagePicker animated:YES completion:nil];
    //释放
    [imagePicker release];
}

5.将选取好的照片保存到详情页的方法

- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info{
    //以相册作为字典，从中取出照片
    self.aImageView.image = [info objectForKey:UIImagePickerControllerEditedImage];
    //把选取框模态回去
    [self dismissViewControllerAnimated:YES completion:nil];
}

测试效果：（由于mac端虚拟机无前后摄像头所以直接跳转相册选取）