UIImagePickerController

前言

• iOS 获取图片有三种方法：
  • 直接调用摄像头拍照；
  • 从相册中选择；
  • 从图库中选择。
• UIImagePickerController 是系统提供的用来获取图片和视频的接口。用 UIImagePickerController 类来获取图片视频，大体分为以下几个步骤：
  • 初始化 UIImagePickerController 类；
  • 设置 UIImagePickerController 实例的数据来源类型；
  • 设置代理；
  • 如果需要做图片修改的话设置 allowsEditing = YES。

1、imagePickerController 的创建

• 需遵守协议 UIImagePickerControllerDelegate, UINavigationControllerDelegate

// 实例化 UIImagePickerController 对象

UIImagePickerController *imagePickerController = [[UIImagePickerController alloc] init];

// 设置代理
imagePickerController.delegate = self;

// 设置是否需要做图片编辑，default NO
imagePickerController.allowsEditing = YES;

// 判断数据来源是否可用
if([UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypePhotoLibrary]) {

	// 设置数据来源
	imagePickerController.sourceType = UIImagePickerControllerSourceTypePhotoLibrary;

	// 打开相机/相册/图库
	[self presentViewController:imagePickerController animated:YES completion:nil];
}

// UIImagePickerControllerDelegate 协议方法

// 取消选择
- (void)imagePickerControllerDidCancel:(UIImagePickerController *)picker {

	// 退出当前界面
	[picker dismissViewControllerAnimated:YES completion:nil];
}

// 选择完成
- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info {

	UIImageView *imageView = [[UIImageView alloc] initWithFrame:CGRectMake(0, 20, self.view.frame.size.width, self.view.frame.size.height - 20)];
	[self.view addSubview:imageView];

	// 获取点击的图片
	imageView.image = [info objectForKey:UIImagePickerControllerOriginalImage];

	[picker dismissViewControllerAnimated:YES completion:nil];
}

2、imagePickerController 的设置

// 设置代理，需遵守 UIImagePickerControllerDelegate, UINavigationControllerDelegate 协议
imagePickerController.delegate = self;

// 设置是否需要做图片编辑
imagePickerController.allowsEditing = YES;

// 判断设备数据来源是否支持
/*
UIImagePickerControllerSourceTypePhotoLibrary,      // 来自图库
UIImagePickerControllerSourceTypeCamera,            // 来自相机
UIImagePickerControllerSourceTypeSavedPhotosAlbum   // 来自相册
*/
if ([UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypePhotoLibrary]) {

}

// 判断摄像头是否支持
/*
UIImagePickerControllerCameraDeviceRear,     // 后置摄像头
UIImagePickerControllerCameraDeviceFront     // 前置摄像头
*/
if ([UIImagePickerController isCameraDeviceAvailable:UIImagePickerControllerCameraDeviceRear]) {

}

// 判断闪光灯是否支持
if ([UIImagePickerController isFlashAvailableForCameraDevice:UIImagePickerControllerCameraDeviceFront]) {

}

// 获取数据来源支持的媒体类型
/*
UIImagePickerControllerSourceTypePhotoLibrary,      // 来自图库
"public.image",
"public.movie"

UIImagePickerControllerSourceTypeCamera,            // 来自相机
...

UIImagePickerControllerSourceTypeSavedPhotosAlbum   // 来自相册
"public.image",
"public.movie"
*/
NSArray *mediaTypesArray = [UIImagePickerController availableMediaTypesForSourceType:UIImagePickerControllerSourceTypeSavedPhotosAlbum];

// 获取相机拥有的模式
/*
UIImagePickerControllerCameraDeviceRear,   // 后置摄像头
...

UIImagePickerControllerCameraDeviceFront   // 前置摄像头
...
*/
NSArray *captureModesArray = [UIImagePickerController availableCaptureModesForCameraDevice:UIImagePickerControllerCameraDeviceFront];

// 设置数据来源
/*
UIImagePickerControllerSourceTypePhotoLibrary,     // 来自图库，默认
UIImagePickerControllerSourceTypeCamera,           // 来自相机
UIImagePickerControllerSourceTypeSavedPhotosAlbum  // 来自相册
*/
imagePickerController.sourceType = UIImagePickerControllerSourceTypePhotoLibrary;

// 设置媒体类型
/*
kUTTypeImage 包含：

kUTTypeImage;                // 抽象的图片类型
kUTTypeJPEG;
kUTTypeJPEG2000;
kUTTypeTIFF;
kUTTypePICT;
kUTTypeGIF;
kUTTypePNG;
kUTTypeQuickTimeImage;
kUTTypeAppleICNS;
kUTTypeBMP;
kUTTypeICO

kUTTypeMovie 包含：

kUTTypeAudiovisualContent;   // 抽象的声音视频
kUTTypeMovie;                // 抽象的媒体格式（声音和视频）
kUTTypeVideo;                // 只有视频没有声音
kUTTypeAudio;                // 只有声音没有视频
kUTTypeQuickTimeMovie;
kUTTypeMPEG;
kUTTypeMPEG4;
kUTTypeMP3;
kUTTypeMPEG4Audio;
kUTTypeAppleProtectedMPEG4Audio

需要 #import <MobileCoreServices/MobileCoreServices.h> 才能用 kUTTypeImage 和 KUTTypeMovie 。

default value is an array containing kUTTypeImage.
*/
imagePickerController.mediaTypes = @[(NSString *)kUTTypeImage, (NSString *)kUTTypeMovie];

// 设置摄像头
/*
UIImagePickerControllerCameraDeviceRear,   // 后置摄像头，默认
UIImagePickerControllerCameraDeviceFront   // 前置摄像头
*/
imagePickerController.cameraDevice = UIImagePickerControllerCameraDeviceFront;

// 设置相机模式
/*
UIImagePickerControllerCameraCaptureModePhoto,  // 照相模式，默认
UIImagePickerControllerCameraCaptureModeVideo   // 录像模式
*/
imagePickerController.cameraCaptureMode = UIImagePickerControllerCameraCaptureModePhoto;

// 设置闪光灯模式
/*
UIImagePickerControllerCameraFlashModeOff  = -1,  // 关
UIImagePickerControllerCameraFlashModeAuto = 0,   // 自动，默认
UIImagePickerControllerCameraFlashModeOn   = 1    // 开
*/
imagePickerController.cameraFlashMode = UIImagePickerControllerCameraFlashModeOn;

// 设置录像质量
/*
UIImagePickerControllerQualityTypeHigh = 0,     // 高质量，highest quality
UIImagePickerControllerQualityTypeMedium = 1,   // 中质量，默认，Wi-Fi
UIImagePickerControllerQualityTypeLow = 2,      // 低质量，cellular network
UIImagePickerControllerQualityType640x480 = 3,  // VGA 质量，VGA quality

UIImagePickerControllerQualityTypeIFrame1280x720 = 4,
UIImagePickerControllerQualityTypeIFrame960x540 = 5

apply only if mediaTypes includes kUTTypeMovie
*/
imagePickerController.videoQuality = UIImagePickerControllerQualityTypeHigh;

// 设置录像时间长度
/*
default is 10 minutes. apply only mediaTypes includes kUTTypeMovie
*/
imagePickerController.videoMaximumDuration = 600;

// 设置是否显示相机原生 UI
/*
set to NO to hide all standard camera UI. default is YES. available sourceType is Camera.
*/
imagePickerController.showsCameraControls = YES;

// 自定义相机视图
/*
set a view to overlay the preview view. default is YES. available sourceType is Camera.
*/
imagePickerController.cameraOverlayView = myView;

// 改变相机视图
/*
set the transform of the preview view. default is YES. available sourceType is Camera.

旋转 45 度，需要输入的参数为弧度，45/180 * M_PI，1 度 ＝ PI/180 弧度
*/
imagePickerController.cameraViewTransform = CGAffineTransformMakeRotation(0.25 * M_PI);

// 打开相机/相册/图库
/*
访问设置的数据来源界面
*/
[self presentViewController:imagePickerController animated:YES completion:nil];

// 拍照
/*
拍摄照片
*/
[imagePickerController takePicture];

// 录像

// 开始录像
[imagePickerController startVideoCapture];

// 停止录像
[imagePickerController stopVideoCapture];

// 退出当前界面（相机/相册/图库）
/*
在 UIImagePickerControllerDelegate 协议方法中调用
*/
[picker dismissViewControllerAnimated:YES completion:nil];

// 获取选取媒体类型（图片或者视频）
/*
选取的信息都在 info 中，info 是一个字典。字典中的键：

UIImagePickerControllerMediaType;     // 指定用户选择的媒体类型，包含着 kUTTypeImage 和 kUTTypeMovie
UIImagePickerControllerOriginalImage; // 原始图片
UIImagePickerControllerEditedImage;   // 修改后的图片，只有打开编辑模式 info 里才有此键值对
UIImagePickerControllerCropRect;      // 裁剪尺寸，只有打开编辑模式 info 里才有此键值对
UIImagePickerControllerMediaURL;      // 媒体的 URL
UIImagePickerControllerReferenceURL;  // 原件的 URL
UIImagePickerControllerMediaMetadata  // 当数据来源是照相机的时候这个值才有效

kUTTypeImage 包含：

kUTTypeImage;               // 抽象的图片类型
kUTTypeJPEG;
kUTTypeJPEG2000;
kUTTypeTIFF;
kUTTypePICT;
kUTTypeGIF;
kUTTypePNG;
kUTTypeQuickTimeImage;
kUTTypeAppleICNS;
kUTTypeBMP;
kUTTypeICO

kUTTypeMovie 包含：

kUTTypeAudiovisualContent;  // 抽象的声音视频
kUTTypeMovie;               // 抽象的媒体格式（声音和视频）
kUTTypeVideo;               // 只有视频没有声音
kUTTypeAudio;               // 只有声音没有视频
kUTTypeQuickTimeMovie;
kUTTypeMPEG;
kUTTypeMPEG4;
kUTTypeMP3;
kUTTypeMPEG4Audio;
kUTTypeAppleProtectedMPEG4Audio

需要 #import <MobileCoreServices/MobileCoreServices.h> 才能用 kUTTypeImage 和 KUTTypeMovie 。
*/

// 直接处理点击的媒体资源

UIImageView *imageView = [[UIImageView alloc] initWithFrame:CGRectMake(0, 20, self.view.frame.size.width, self.view.frame.size.height - 20)];
[self.view addSubview:imageView];

// 获取点击的图片
imageView.image = [info objectForKey:UIImagePickerControllerOriginalImage];

// 先判断点击的资源类型再处理

// 判断点击的媒体资源类型
if ([[info objectForKey:UIImagePickerControllerMediaType] isEqualToString:(NSString *)kUTTypeImage]) {

	UIImageView *headerImageView = [[UIImageView alloc] initWithFrame:CGRectMake(20, 40, 100, 100)];
	headerImageView.layer.borderColor = [[UIColor greenColor] CGColor];
	headerImageView.layer.borderWidth = 3;
	[self.view addSubview:headerImageView];

	// 获取点击的图片
	headerImageView.image = [info objectForKey:UIImagePickerControllerEditedImage];
}

3、UIImagePickerControllerDelegate 协议方法

// 取消选择，点击界面中的取消（Cancel）按钮时触发
- (void)imagePickerControllerDidCancel:(UIImagePickerController *)picker {

}

// 选择完成，点击界面中的某个图片或者选择（Choose）按钮时触发
- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info {

}