iOS从相册和照相机读取图片(UIImagePickerCont

2016-05-13 本文已影响4755人 JerryLMJ

前言

UIKit框架提供了一个图像选择器UIImagePickerController，我们不仅可以从相册中选择图像资源，还可以从照相机中直接获取拍摄的图像。

UIImagePickerController的创建

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

UIImagePickerController继承于UINavigationController，所以我们可以在当前通过以下方法调出：

[self presentViewController:imagePicker animated:YES completion:nil];

sourceType属性

sourceType属性是设置UIImagePickerController的图片选择源的，我们通过 sourceType来设置将要从相册、相机还是相机胶卷选择图片。

@property(nonatomic) UIImagePickerControllerSourceType sourceType; // default value is UIImagePickerControllerSourceTypePhotoLibrary.

typedef NS_ENUM(NSInteger, UIImagePickerControllerSourceType) {
    // 相册
    UIImagePickerControllerSourceTypePhotoLibrary,
    // 相机
    UIImagePickerControllerSourceTypeCamera,
    // 相机胶卷
    UIImagePickerControllerSourceTypeSavedPhotosAlbum
} __TVOS_PROHIBITED;

相机胶卷是相册下的一个分类，该文件夹下的图片均是相机拍摄产生的图片

其他属性

// 是否可以编辑

@property(nonatomic) BOOL allowsEditing NS_AVAILABLE_IOS(3_1); // replacement for -allowsImageEditing; default value is NO.

// 是否可以编辑图像

@property(nonatomic) BOOL allowsImageEditing NS_DEPRECATED_IOS(2_0, 3_1);

// 图像类型

@property(nonatomic,copy) NSArray<NSString *> *mediaTypes;
// default value is an array containing kUTTypeImage.

// 视频类型图像最大时长

// video properties apply only if mediaTypes includes kUTTypeMovie
@property(nonatomic) NSTimeInterval videoMaximumDuration NS_AVAILABLE_IOS(3_1); 
// default value is 10 minutes.

// 图像质量类型

@property(nonatomic) UIImagePickerControllerQualityType videoQuality NS_AVAILABLE_IOS(3_1);         
// default value is UIImagePickerControllerQualityTypeMedium. If the cameraDevice does not support the videoQuality, it will use the default value.

typedef NS_ENUM(NSInteger, UIImagePickerControllerQualityType) {
    UIImagePickerControllerQualityTypeHigh = 0,       // highest quality
    UIImagePickerControllerQualityTypeMedium = 1,     // medium quality, suitable for transmission via Wi-Fi 
    UIImagePickerControllerQualityTypeLow = 2,         // lowest quality, suitable for tranmission via cellular network
    UIImagePickerControllerQualityType640x480 NS_ENUM_AVAILABLE_IOS(4_0) = 3,    // VGA quality
    UIImagePickerControllerQualityTypeIFrame1280x720 NS_ENUM_AVAILABLE_IOS(5_0) = 4,
    UIImagePickerControllerQualityTypeIFrame960x540 NS_ENUM_AVAILABLE_IOS(5_0) = 5,
} __TVOS_PROHIBITED;

// 是否显示相机操作控件

// camera additions available only if sourceType is UIImagePickerControllerSourceTypeCamera.
@property(nonatomic) BOOL showsCameraControls NS_AVAILABLE_IOS(3_1);   
// set to NO to hide all standard camera UI. default is YES

// 预览视图

@property(nullable, nonatomic,strong) __kindof UIView *cameraOverlayView  NS_AVAILABLE_IOS(3_1);   
// set a view to overlay the preview view.

// 预览视图的转换

@property(nonatomic) CGAffineTransform cameraViewTransform NS_AVAILABLE_IOS(3_1);
// set the transform of the preview view.

关于相机设备的属性

// 相机捕获类型
@property(nonatomic) UIImagePickerControllerCameraCaptureMode cameraCaptureMode NS_AVAILABLE_IOS(4_0); // default is UIImagePickerControllerCameraCaptureModePhoto
// 相机设备
@property(nonatomic) UIImagePickerControllerCameraDevice      cameraDevice      NS_AVAILABLE_IOS(4_0); // default is UIImagePickerControllerCameraDeviceRear
// 相机闪光类型
@property(nonatomic) UIImagePickerControllerCameraFlashMode   cameraFlashMode   NS_AVAILABLE_IOS(4_0); // default is UIImagePickerControllerCameraFlashModeAuto. 
// cameraFlashMode controls the still-image flash when cameraCaptureMode is Photo. cameraFlashMode controls the video torch when cameraCaptureMode is Video.

typedef NS_ENUM(NSInteger, UIImagePickerControllerCameraCaptureMode) {
    UIImagePickerControllerCameraCaptureModePhoto,
    UIImagePickerControllerCameraCaptureModeVideo
} __TVOS_PROHIBITED;

typedef NS_ENUM(NSInteger, UIImagePickerControllerCameraDevice) {
    UIImagePickerControllerCameraDeviceRear,
    UIImagePickerControllerCameraDeviceFront
} __TVOS_PROHIBITED;

typedef NS_ENUM(NSInteger, UIImagePickerControllerCameraFlashMode) {
    UIImagePickerControllerCameraFlashModeOff  = -1,
    UIImagePickerControllerCameraFlashModeAuto = 0,
    UIImagePickerControllerCameraFlashModeOn   = 1
} __TVOS_PROHIBITED;

方法

类方法

/*是否是可用的读取源*/ 
+ (BOOL)isSourceTypeAvailable:(UIImagePickerControllerSourceType)sourceType; 
// returns YES if source is available (i.e. camera present)

/*可用的读取源都有哪些*/
+ (nullable NSArray<NSString *> *)availableMediaTypesForSourceType:(UIImagePickerControllerSourceType)sourceType; 
// returns array of available media types (i.e. kUTTypeImage)

/*相机是否可用*/
+ (BOOL)isCameraDeviceAvailable:(UIImagePickerControllerCameraDevice)cameraDevice                   NS_AVAILABLE_IOS(4_0); 
// returns YES if camera device is available 

/*相机闪光是否可用*/
+ (BOOL)isFlashAvailableForCameraDevice:(UIImagePickerControllerCameraDevice)cameraDevice           NS_AVAILABLE_IOS(4_0); 
// returns YES if camera device supports flash and torch.

/*可用的捕获类型都有哪些*/
+ (nullable NSArray<NSNumber *> *)availableCaptureModesForCameraDevice:(UIImagePickerControllerCameraDevice)cameraDevice NS_AVAILABLE_IOS(4_0); 
// returns array of NSNumbers (UIImagePickerControllerCameraCaptureMode)

实例方法

/*开始视频捕获*/
-(BOOL)startVideoCapture NS_AVAILABLE_IOS(4_0);

/*停止视频捕获*/
-(void)stopVideoCapture  NS_AVAILABLE_IOS(4_0);

代理函数

@property(nullable,nonatomic,weak) id<UINavigationControllerDelegate, UIImagePickerControllerDelegate> delegate;

@optional
// The picker does not dismiss itself; the client dismisses it in these callbacks.
// The delegate will receive one or the other, but not both, depending whether the user
// confirms or cancels.

/*选择图片完成回调*/
- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingImage:(UIImage *)image editingInfo:(nullable NSDictionary<NSString *,id> *)editingInfo NS_DEPRECATED_IOS(2_0, 3_0);

/*选择图像完成回调*/
- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary<NSString *,id> *)info;

/*点击‘取消’按钮回调*/
- (void)imagePickerControllerDidCancel:(UIImagePickerController *)picker;

回调函数中的infoDictionary的key(我们可以通过这些key在回调函数的info字典中获得我们想要的内容)：

// info dictionary keys
/*图像类型【NSString】*/
UIKIT_EXTERN NSString *const UIImagePickerControllerMediaType __TVOS_PROHIBITED;      // an NSString (UTI, i.e. kUTTypeImage)
/*原始图片【UIImage】*/
UIKIT_EXTERN NSString *const UIImagePickerControllerOriginalImage __TVOS_PROHIBITED;  // a UIImage
/*编辑后的图片【UIImage】*/
UIKIT_EXTERN NSString *const UIImagePickerControllerEditedImage __TVOS_PROHIBITED;    // a UIImage
/*剪裁大小【NSValue（CGRect）】*/
UIKIT_EXTERN NSString *const UIImagePickerControllerCropRect __TVOS_PROHIBITED;       // an NSValue (CGRect)
/*图像url【NSURL】*/
UIKIT_EXTERN NSString *const UIImagePickerControllerMediaURL __TVOS_PROHIBITED;       // an NSURL
/*相关url【NSURL】*/
UIKIT_EXTERN NSString *const UIImagePickerControllerReferenceURL        NS_AVAILABLE_IOS(4_1) __TVOS_PROHIBITED;  // an NSURL that references an asset in the AssetsLibrary framework
/*媒体元数据【NSDictionary】*/
UIKIT_EXTERN NSString *const UIImagePickerControllerMediaMetadata       NS_AVAILABLE_IOS(4_1) __TVOS_PROHIBITED;  // an NSDictionary containing metadata from a captured photo
/*PHLivePhoto类型的数据，【PHLivePhoto】是iOS9以后添加的一个新的图片类型，它不仅仅是一张静态的图片，它会抓取拍摄时的声音和更多帧的图像*/
UIKIT_EXTERN NSString *const UIImagePickerControllerLivePhoto NS_AVAILABLE_IOS(9_1) __TVOS_PROHIBITED;  // a PHLivePhoto

应用

LMJImageChooseControl是我自己自定义的一个图片选择控件，这个控件实现了相册、相机选择获取图片的功能。
托管地址：https://github.com/MajorLMJ/LMJImageChooseControl
欢迎下载体验，同时理解UIImagePickerController的使用。

有关相册、相机的访问权限

关于相册、相机的权限请阅读：iOS访问相册、相机权限