技術內容：分別讀取相簿以及調取相機,將圖片顯示到imageView上

佈局：

1.建立imageView 和 button 併為button一個關聯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:@"選擇影象" forState:(UIControlStateNormal)];
    
    [self.view addSubview:self.aButton];
    [self.view addSubview:self.aImageView];
    [self.aButton release];
    [self.aImageView release];
    
    
    [self addTapGestureOnImageView];
 

2.因為有的場景需要直接點選圖片更換別的圖片，所以在imageView上新增輕拍動作

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

3.實現輕拍動作中方法

- (void)pickerImage:(UIButton *)button{
    //新增ActionSheet控制元件，提示選項框，調出相機或拍攝圖片
    //第一個引數：是行為列表的標題 一般為空
    //第二個引數：遵循代理
    //第三個引數：取消這個操作按鈕上 顯示的文字
    //第四個引數：destructive 破壞性的, 毀滅性的 自己理解吧 反正我寫的是拍照，執行操作的意思
    //第五個引數：從相簿選取圖片
    UIActionSheet *actionSheet = [[UIActionSheet alloc]initWithTitle:nil delegate:self cancelButtonTitle:@"取消" destructiveButtonTitle:@"拍照" otherButtonTitles:@"從相簿選擇圖片", nil];
    //在當前介面顯示actionSheet物件
    [actionSheet showInView:self.view];
    [actionSheet release];
}
 

4.實現action代理協議中的方法

- (void)actionSheet:(UIActionSheet *)actionSheet clickedButtonAtIndex:(NSInteger)buttonIndex{
    switch (buttonIndex) {
        case 0:
            //呼叫系統相機，拍照
            [self pickerPictureFromCamera];
            break;
        case 1:
            [self pickerPictureFromPhotosAlbum];
        default:
            break;
    }
}
 

4.1從攝像頭獲取圖片

- (void)pickerPictureFromCamera{
    
    //判斷前攝像頭是否可用，如果不可用的話，用後攝像頭。如果後攝像頭也不可用的話用手機圖片庫
    //判斷前置攝像頭是否可用
    if ([UIImagePickerController isCameraDeviceAvailable:UIImagePickerControllerCameraDeviceFront]) {
        NSLog(@"用前置攝像頭");
        
        self.imagePC = [[UIImagePickerController alloc]init];
        self.imagePC.cameraDevice = UIImagePickerControllerCameraDeviceFront;
        [self.imagePC release];
        //判斷後置攝像頭是否可用
    }else if ([UIImagePickerController isCameraDeviceAvailable:UIImagePickerControllerCameraDeviceRear]){
        NSLog(@"用後置攝像頭");
        
        self.imagePC = [[UIImagePickerController alloc]init];
        self.imagePC.cameraDevice = UIImagePickerControllerCameraDeviceRear;
        [self.imagePC release];
        //兩者都不行的話，從手機相簿調取照片
    }else{
        UIAlertView *alertView = [[UIAlertView alloc]initWithTitle:@"呼叫攝像頭失敗" message:@"請從手機相簿中選取照片" delegate:self cancelButtonTitle:@"確定" otherButtonTitles:nil, nil];
        [alertView show];
        [alertView release];
    }
    
    //初始化圖片控制器物件
    UIImagePickerController *imagePicker = [[UIImagePickerController alloc]init];
    //sourceType資源樣式
    //設定圖片選擇器選擇圖片的樣式
    imagePicker.sourceType = UIImagePickerControllerSourceTypePhotoLibrary;
    //設定圖片是否允許編輯
    imagePicker.allowsEditing = YES;
    //設定圖片選擇器代理物件為這個檢視控制器
    imagePicker.delegate = self;
    //把相機推出來 模態
    [self presentViewController:imagePicker animated:YES completion:nil];
    //釋放
    [imagePicker release];
    
}

4.2從手機的圖片庫獲取圖片

- (void)pickerPictureFromPhotosAlbum{
    //初始化圖片控制器物件
    UIImagePickerController *imagePicker = [[UIImagePickerController alloc]init];
    //sourceType資源樣式
    //設定圖片選擇器選擇圖片的樣式
    imagePicker.sourceType = UIImagePickerControllerSourceTypePhotoLibrary;
    //設定圖片是否允許編輯
    imagePicker.allowsEditing = YES;
    //設定圖片選擇器代理物件為這個檢視控制器
    imagePicker.delegate = self;
    //把選擇控制器推出來 模態
    [self presentViewController:imagePicker animated:YES completion:nil];
    //釋放
    [imagePicker release];
}

5.將選取好的照片儲存到詳情頁的方法

- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info{
    //以相簿作為字典，從中取出照片
    self.aImageView.image = [info objectForKey:UIImagePickerControllerEditedImage];
    //把選取框模態回去
    [self dismissViewControllerAnimated:YES completion:nil];
}