UIImagePickerController

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本文详细介绍了UIImagePickerController的使用方法，包括如何从照片库、相机和保存的照片专辑中获取图片，以及如何设置不同属性来定制用户体验。

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UIImagePickerController

照片的来源UIImagePickerControllerSourceType包括：

照片库（不可删除）：UIImagePickerControllerSourceTypePhotoLibrary
照相机：UIImagePickerControllerSourceTypeCamera
保存的照片（可以删除）：UIImagePickerControllerSourceTypeSavedPhotosAlbum

代理类：UIImagePickerControllerDelegate, UINavigationControllerDelegate

//检查照片源是否可用
if ([UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera]) {
    UIImagePickerController *imagePicker = [[UIImagePickerController alloc]init];
    [imagePicker setSourceType:UIImagePickerControllerSourceTypePhotoLibrary];
    [imagePicker setAllowsEditing:YES]; 
    [imagePicker setDelegate:self]; 
    [self presentViewController:imagePicker animated:YES completion:nil];
 } else {
        NSLog(@"照片源不可用");
        }
代理方法：
    - (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info{ 
        NSLog(@"%@", info);
        UIImage *image = info[@"UIImagePickerControllerEditedImage"];
        [_imageView setImage:image]; 
    [self dismissViewControllerAnimated:YES completion:nil];
    //可以使用多线程序来保存
    }

//指定使用照相机模式,可以指定使用相册／照片库
    imagepicker.sourceType = UIImagePickerControllerSourceTypeCamera;
    //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。只有当showsCameraControls属性为true时才有效果
    imagepicker.allowsEditing = YES;
    //设置拍照时的下方的工具栏是否显示，如果需要自定义拍摄界面，则可把该工具栏隐藏
    imagepicker.showsCameraControls  = YES;
    //设置使用后置摄像头，可以使用前置摄像头
    imagepicker.cameraDevice = UIImagePickerControllerCameraDeviceRear;
    //设置闪光灯模式
    /*
     typedef NS_ENUM(NSInteger, UIImagePickerControllerCameraFlashMode) {
     UIImagePickerControllerCameraFlashModeOff  = -1,
     UIImagePickerControllerCameraFlashModeAuto = 0,
     UIImagePickerControllerCameraFlashModeOn   = 1
     };
     */
    imagepicker.cameraFlashMode = UIImagePickerControllerCameraFlashModeAuto;
    //设置相机支持的类型，拍照和录像
    imagepicker.mediaTypes = @[(NSString*)kUTTypeImage,(NSString*)kUTTypeMovie];
    //设置拍摄时屏幕的view的transform属性，可以实现旋转，缩放功能
   // imagepicker.cameraViewTransform = CGAffineTransformMakeRotation(M_PI*45/180);
   // imagepicker.cameraViewTransform = CGAffineTransformMakeScale(1.5, 1.5);
    //所有含有cameraXXX的属性都必须要sourceType是UIImagePickerControllerSourceTypeCamera时设置才有效果，否则会有异常
    //设置UIImagePickerController的代理
    imagepicker.delegate = self;
-(void)showCamera{
    //用模态方式呈现imagepicker
    [self presentModalViewController:imagepicker animated:YES];
}
使用 imagepicker.cameraViewTransform = CGAffineTransformMakeRotation(M_PI*45/180);旋转45度的效果：

使用imagepicker.cameraViewTransform = CGAffineTransformMakeScale(1.5, 1.5);全屏的效果，同时imagepicker.showsCameraControls  =NO;隐藏工具栏：

使用imagepicker.allowsEditing = YES;出现的图片编辑效果，只有当imagepicker.showsCameraControls  = YES;才有效果：

使用 imagepicker.mediaTypes = @[(NSString*)kUTTypeImage,(NSString*)kUTTypeMovie];支持拍照和视频的前后对比效果：

UIImagePickerController回调详解

//成功获得相片还是视频后的回调
- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info{
    //通过UIImagePickerControllerMediaType判断返回的是照片还是视频
    NSString* type = [info objectForKey:UIImagePickerControllerMediaType];
    //如果返回的type等于kUTTypeImage，代表返回的是照片,并且需要判断当前相机使用的sourcetype是拍照还是相册
    if ([type isEqualToString:(NSString*)kUTTypeImage]&&picker.sourceType==UIImagePickerControllerSourceTypeCamera) {
        //获取照片的原图
        UIImage* original = [info objectForKey:UIImagePickerControllerOriginalImage];
        //获取图片裁剪的图
        UIImage* edit = [info objectForKey:UIImagePickerControllerEditedImage];
        //获取图片裁剪后，剩下的图
        UIImage* crop = [info objectForKey:UIImagePickerControllerCropRect];
        //获取图片的url
        NSURL* url = [info objectForKey:UIImagePickerControllerMediaURL];
        //获取图片的metadata数据信息
        NSDictionary* metadata = [info objectForKey:UIImagePickerControllerMediaMetadata];
        //如果是拍照的照片，则需要手动保存到本地，系统不会自动保存拍照成功后的照片
        UIImageWriteToSavedPhotosAlbum(edit, self, @selector(image:didFinishSavingWithError:contextInfo:), nil);
    }else{

    }
    //模态方式退出uiimagepickercontroller
    [imagepicker dismissModalViewControllerAnimated:YES];
}
//取消照相机的回调
- (void)imagePickerControllerDidCancel:(UIImagePickerController *)picker{
    //模态方式退出uiimagepickercontroller
    [imagepicker dismissModalViewControllerAnimated:YES];
}
//保存照片成功后的回调
- (void)image:(UIImage *)image didFinishSavingWithError:(NSError *)error
  contextInfo:(void *)contextInfo{

    NSLog(@"saved..");
}

UIImagePickerController的静态方法

imagepicker = [[UIImagePickerController alloc]init];
    //UIImagePickerController静态方法判断设备是否支持照相机／图片库／相册功能
    /*
     typedef NS_ENUM(NSInteger, UIImagePickerControllerSourceType) {
     UIImagePickerControllerSourceTypePhotoLibrary,
     UIImagePickerControllerSourceTypeCamera,
     UIImagePickerControllerSourceTypeSavedPhotosAlbum
     };
     */
    BOOL isCameraSupport = [UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera];
    NSLog(@"support camera:%d",isCameraSupport);

    //UIImagePickerController静态方法判断设备是否支持前置摄像头／后置摄像头
    /*
     typedef NS_ENUM(NSInteger, UIImagePickerControllerCameraDevice) {
     UIImagePickerControllerCameraDeviceRear,
     UIImagePickerControllerCameraDeviceFront
     };
     */
    BOOL isRearSupport = [UIImagePickerController isCameraDeviceAvailable:UIImagePickerControllerCameraDeviceRear];
    NSLog(@"rear support:%d",isRearSupport);

    //UIImagePickerController静态方法判断设备是否支持前置摄像头闪光灯／后置摄像头闪光灯
    /*
     typedef NS_ENUM(NSInteger, UIImagePickerControllerCameraDevice) {
     UIImagePickerControllerCameraDeviceRear,
     UIImagePickerControllerCameraDeviceFront
     };
     */
    BOOL isFlushSupport = [UIImagePickerController isFlashAvailableForCameraDevice:UIImagePickerControllerCameraDeviceRear];
    NSLog(@"rear flash support:%d",isFlushSupport);

    //UIImagePickerController静态方法返回前置摄像头／后置摄像头支持的拍摄类型
    /*
     typedef NS_ENUM(NSInteger, UIImagePickerControllerCameraDevice) {
     UIImagePickerControllerCameraDeviceRear,
     UIImagePickerControllerCameraDeviceFront
     };
     */
    //返回类型有照片和视频
    /*
     enum {
     UIImagePickerControllerCameraCaptureModePhoto,
     UIImagePickerControllerCameraCaptureModeVideo
     };
     typedef NSUInteger UIImagePickerControllerCameraCaptureMode;
     */
    NSArray* captureModes = [UIImagePickerController availableCaptureModesForCameraDevice:UIImagePickerControllerCameraDeviceRear];
    for (NSNumber* mode in captureModes) {
        NSLog(@"capture modes:%d",[mode integerValue]);
    }

    //UIImagePickerController静态方法返回照相机／相册／照片库所支持的媒体类型
    /*
     typedef NS_ENUM(NSInteger, UIImagePickerControllerSourceType) {
     UIImagePickerControllerSourceTypePhotoLibrary,
     UIImagePickerControllerSourceTypeCamera,
     UIImagePickerControllerSourceTypeSavedPhotosAlbum
     };
     */
    //返回类型有kUTTypeMovie,kUTTypeImage，其他类型均在<MobileCoreServices/MobileCoreServices.h>下
    NSArray* mediaTypes = [UIImagePickerController availableMediaTypesForSourceType:UIImagePickerControllerSourceTypeCamera];
    for (NSString* type in mediaTypes) {
        NSLog(@"media types:%@",type);
    }

UIImagePickerController从拍照、图库、相册获取图片

iOS 获取图片有三种方法：
1. 直接调用摄像头拍照
2. 从相册中选择
3. 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：
1. 初始化UIImagePickerController 类；
2. 设置UIImagePickerController 实例的数据来源类型（下面解释）；
3. 设置设置代理；
4. 如果需要做图片修改的话设置allowsEditing =yes。
数据来源类型一共有三种：

    enum {
       UIImagePickerControllerSourceTypePhotoLibrary ,//来自图库
       UIImagePickerControllerSourceTypeCamera ,//来自相机
       UIImagePickerControllerSourceTypeSavedPhotosAlbum //来自相册
    };

在用这些来源的时候最好检测以下设备是否支持；

     if([UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera])
        {
            NSLog(@"支持相机");
        }
        if([UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypePhotoLibrary])
        {
            NSLog(@"支持图库");
        }
        if ([UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeSavedPhotosAlbum])
        {
            NSLog(@"支持相片库");
        }

调用摄像头来获取资源

    - (void)viewDidLoad {
        [super viewDidLoad];
        picker = [[UIImagePickerController alloc]init];
        picker.view.backgroundColor = [UIColor orangeColor];
        UIImagePickerControllerSourceType sourcheType = UIImagePickerControllerSourceTypeCamera;
        picker.sourceType = sourcheType;
        picker.delegate = self;
        picker.allowsEditing = YES;
    }

上面只是实例了UIImagePickerController及其属性在需要获取图片的时候需要弹出窗口调用
[self presentViewController:picker animated:YES completion:nil];
我们还需要代理来获取我们选中的图片
UIImagePickerControllerDelegate
代理中一共三个方法其中一个3.0 已经废弃了，只剩下两个我们需要用的

    - (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary
     *)info;

当用户选取完成后调用；
- (void)imagePickerControllerDidCancel:(UIImagePickerController *)picker;
当用户取消选取时调用；
- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info;
选取的信息都在info中，info 是一个字典。
字典中的键：

    NSString *const  UIImagePickerControllerMediaType ;指定用户选择的媒体类型（文章最后进行扩展）
    NSString *const  UIImagePickerControllerOriginalImage ;原始图片
    NSString *const  UIImagePickerControllerEditedImage ;修改后的图片
    NSString *const  UIImagePickerControllerCropRect ;裁剪尺寸
    NSString *const  UIImagePickerControllerMediaURL ;媒体的URL
    NSString *const  UIImagePickerControllerReferenceURL ;原件的URL
    NSString *const  UIImagePickerControllerMediaMetadata;当来数据来源是照相机的时候这个值才有效

UIImagePickerController 的更多参数参考这里。
代理中的功能参考这里。
UIImagePickerControllerMediaType 包含着KUTTypeImage 和KUTTypeMovie
KUTTypeImage 包含：

    1   const CFStringRef  kUTTypeImage ;抽象的图片类型
    2   const CFStringRef  kUTTypeJPEG ;
    3   const CFStringRef  kUTTypeJPEG2000 ;
    4   const CFStringRef  kUTTypeTIFF ;
    5   const CFStringRef  kUTTypePICT ;
    6   const CFStringRef  kUTTypeGIF ;
    7   const CFStringRef  kUTTypePNG ;
    8   const CFStringRef  kUTTypeQuickTimeImage ;
    9   const CFStringRef  kUTTypeAppleICNS 
    10  const CFStringRef kUTTypeBMP;
    11  const CFStringRef  kUTTypeICO;

KUTTypeMovie 包含

1   const CFStringRef  kUTTypeAudiovisualContent ;抽象的声音视频
2   const CFStringRef  kUTTypeMovie ;抽象的媒体格式（声音和视频）
3   const CFStringRef  kUTTypeVideo ;只有视频没有声音
4   const CFStringRef  kUTTypeAudio ;只有声音没有视频
5   const CFStringRef  kUTTypeQuickTimeMovie ;
6   const CFStringRef  kUTTypeMPEG ;
7   const CFStringRef  kUTTypeMPEG4 ;
8   const CFStringRef  kUTTypeMP3 ;
9   const CFStringRef  kUTTypeMPEG4Audio ;
10  const CFStringRef  kUTTypeAppleProtectedMPEG4Audio;