iOS摄像头和相册-UIImagePickerController-浅析(转)

iOS摄像头和相册-UIImagePickerController-浅析(转)

转自：http://blog.sina.com.cn/s/blog_7b9d64af0101cfd9.html

在一些应用中，我们需要用到iOS设备的摄像头进行拍照，视频。并且从相册中选取我们需要的图片或者视频。

关于iOS摄像头和相册的应用，可以使用UIImagePickerController类来完成控制。

关于UIImagePickerController的相关知识，

如下：

 

iOS的一些设备上都安装了摄像头。现在绝大多数都有了。

在编程中，我们是用相应的东西来进行照相，录像等功能。

 

一、UIImagePickerController类

UIImagePickerController 这个类可以为大家提供照相的功能,以及图片,视频浏览的功能。 

 

二、检查硬件是否安装有摄像头或者允许操作相册

 

这些公共的方法，我们也许会用到，我就贴了！So easy！！！

 #pragma mark - 摄像头和相册相关的公共类

// 判断设备是否有摄像头

- (BOOL) isCameraAvailable{

    return [UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera];

}

// 前面的摄像头是否可用

- (BOOL) isFrontCameraAvailable{

    return [UIImagePickerControllerisCameraDeviceAvailable:UIImagePickerControllerCameraDeviceFront];

}

 

// 后面的摄像头是否可用

- (BOOL) isRearCameraAvailable{

    return [UIImagePickerControllerisCameraDeviceAvailable:UIImagePickerControllerCameraDeviceRear];

} 

// 判断是否支持某种多媒体类型：拍照，视频

- (BOOL) cameraSupportsMedia:(NSString *)paramMediaType sourceType:(UIImagePickerControllerSourceType)paramSourceType{

    __block BOOL result = NO;

    if ([paramMediaType length] == 0){

        NSLog(@"Media type is empty.");

        return NO;

    }

    NSArray *availableMediaTypes =[UIImagePickerControlleravailableMediaTypesForSourceType:paramSourceType];

    [availableMediaTypes enumerateObjectsUsingBlock:^(id obj, NSUInteger idx, BOOL*stop) {

                                                        NSString *mediaType = (NSString *)obj;

                                                        if ([mediaTypeisEqualToString:paramMediaType]){

                                                            result = YES;

                                                            *stop= YES;

                                                        }    }];

    return result;

}

// 检查摄像头是否支持录像

- (BOOL) doesCameraSupportShootingVideos{

    return [self cameraSupportsMedia:( NSString *)kUTTypeMoviesourceType:UIImagePickerControllerSourceTypeCamera];

}

 // 检查摄像头是否支持拍照

- (BOOL) doesCameraSupportTakingPhotos{

    return [self cameraSupportsMedia:( NSString *)kUTTypeImagesourceType:UIImagePickerControllerSourceTypeCamera];

}

 #pragma mark - 相册文件选取相关

// 相册是否可用

- (BOOL) isPhotoLibraryAvailable{

    return [UIImagePickerController isSourceTypeAvailable: UIImagePickerControllerSourceTypePhotoLibrary];

}

 

// 是否可以在相册中选择视频

- (BOOL) canUserPickVideosFromPhotoLibrary{

    return [self cameraSupportsMedia:( NSString *)kUTTypeMoviesourceType:UIImagePickerControllerSourceTypePhotoLibrary];

}

 // 是否可以在相册中选择视频

- (BOOL) canUserPickPhotosFromPhotoLibrary{

    return [self cameraSupportsMedia:( NSString *)kUTTypeImagesourceType:UIImagePickerControllerSourceTypePhotoLibrary];

}

三、用摄像头进行拍照和录像功能

 

1.我们将UIImagePickerController功能写在一个按钮的点击事件中：

 #pragma mark - 拍照按钮事件

 - (void)ClickControlAction:(id)sender{

    // 判断有摄像头，并且支持拍照功能

    if ([self isCameraAvailable] && [self doesCameraSupportTakingPhotos]){

        // 初始化图片选择控制器

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

        [controller setSourceType:UIImagePickerControllerSourceTypeCamera];// 设置类型

 

        

        // 设置所支持的类型，设置只能拍照，或则只能录像，或者两者都可以

        NSString *requiredMediaType = ( NSString *)kUTTypeImage;

        NSString *requiredMediaType1 = ( NSString *)kUTTypeMovie;

        NSArray *arrMediaTypes=[NSArray arrayWithObjects:requiredMediaType, requiredMediaType1,nil];

        [controller setMediaTypes:arrMediaTypes]; 

        // 设置录制视频的质量

        [controller setVideoQuality:UIImagePickerControllerQualityTypeHigh];

        //设置最长摄像时间

        [controller setVideoMaximumDuration:10.f];

        [controller setAllowsEditing:YES];// 设置是否可以管理已经存在的图片或者视频

        [controller setDelegate:self];// 设置代理

        [self.navigationController presentModalViewController:controller animated:YES];

        [controller release];

    } else {

        NSLog(@"Camera is not available.");

    }

}

解释：

 

2. setSourceType方法

 

通过设置setSourceType方法可以确定调用出来的UIImagePickerController所显示出来的界面

 

typedef NS_ENUM(NSInteger, UIImagePickerControllerSourceType) {

    UIImagePickerControllerSourceTypePhotoLibrary,

    UIImagePickerControllerSourceTypeCamera,

    UIImagePickerControllerSourceTypeSavedPhotosAlbum

};

分别表示：图片列表，摄像头，相机相册

3.setMediaTypes方法

 // 设置所支持的类型，设置只能拍照，或则只能录像，或者两者都可以

        NSString *requiredMediaType = ( NSString *)kUTTypeImage;

        NSString *requiredMediaType1 = ( NSString *)kUTTypeMovie;

        NSArray *arrMediaTypes=[NSArray arrayWithObjects:requiredMediaType, requiredMediaType1,nil];

        [controller setMediaTypes:arrMediaTypes];

4.关于UIImagePickerControllerDelegate协议

 

我们要对我们拍摄的照片和视频进行存储，那么就要实现UIImagePickerControllerDelegate协议的方法。

#pragma mark - UIImagePickerControllerDelegate 代理方法

// 保存图片后到相册后，调用的相关方法，查看是否保存成功

- (void) imageWasSavedSuccessfully:(UIImage *)paramImage didFinishSavingWithError:(NSError *)paramError contextInfo:(void *)paramContextInfo{

    if (paramError == nil){

        NSLog(@"Image was saved successfully.");

    } else {

        NSLog(@"An error happened while saving the image.");

        NSLog(@"Error = %@", paramError);

    }

}

 

// 当得到照片或者视频后，调用该方法

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

    NSLog(@"Picker returned successfully.");

    NSLog(@"%@", info);

    NSString *mediaType = [info objectForKey:UIImagePickerControllerMediaType];

    // 判断获取类型：图片

    if ([mediaType isEqualToString:( NSString *)kUTTypeImage]){

        UIImage *theImage = nil;

        // 判断，图片是否允许修改

        if ([picker allowsEditing]){

            //获取用户编辑之后的图像

            theImage = [info objectForKey:UIImagePickerControllerEditedImage];

        } else {

            // 照片的元数据参数

            theImage = [info objectForKey:UIImagePickerControllerOriginalImage];

              }

        // 保存图片到相册中

        SEL selectorToCall = @selector(imageWasSavedSuccessfully:didFinishSavingWithError:contextInfo:);

        UIImageWriteToSavedPhotosAlbum(theImage, self,selectorToCall, NULL);    

    }else if ([mediaType isEqualToString:(NSString *)kUTTypeMovie]){

        // 判断获取类型：视频

        //获取视频文件的url

        NSURL* mediaURL = [info objectForKey:UIImagePickerControllerMediaURL];

        //创建ALAssetsLibrary对象并将视频保存到媒体库

        // Assets Library 框架包是提供了在应用程序中操作图片和视频的相关功能。相当于一个桥梁，链接了应用程序和多媒体文件。

        ALAssetsLibrary *assetsLibrary = [[ALAssetsLibrary alloc] init];

        // 将视频保存到相册中

        [assetsLibrary writeVideoAtPathToSavedPhotosAlbum:mediaURL

                                          completionBlock:^(NSURL *assetURL, NSError *error) {

                                              if (!error) {

                                                  NSLog(@"captured video saved with no error.");

                                              }else{

                                                  NSLog(@"error occured while saving the video:%@", error);

                                              }

                                          }];

        [assetsLibrary release];

 }

        [picker dismissModalViewControllerAnimated:YES];

}

// 当用户取消时，调用该方法

- (void)imagePickerControllerDidCancel:(UIImagePickerController *)picker{

    

    [picker dismissModalViewControllerAnimated:YES];

}

四、从相册获取图片和视频数据

 

1.我们将功能封装在一个按钮的点击事件中

#pragma mark - 相册操作

 - (void)ClickShowPhotoAction:(id)sender{

    if ([self isPhotoLibraryAvailable]){

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

         [controller setSourceType:UIImagePickerControllerSourceTypePhotoLibrary];// 设置类型

        NSMutableArray *mediaTypes = [[NSMutableArray alloc] init];

        if ([self canUserPickPhotosFromPhotoLibrary]){

            [mediaTypes addObject:( NSString *)kUTTypeImage];

        }

        if ([self canUserPickVideosFromPhotoLibrary]){

            [mediaTypes addObject:( NSString *)kUTTypeMovie];

        }

        [controller setMediaTypes:mediaTypes];

        [controller setDelegate:self];// 设置代理

        [self.navigationController presentModalViewController:controller animated:YES];

        [controller release];

        [mediaTypes release];   

} } 

2.关于UIImagePickerControllerDelegate协议，我们可以重用。

 

在这里，就不用赘述了！

 

最后，需要说的是，UIImagePickerControllerDelegate协议中

-(void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info方法，中的info值，会根据我们操作的类型不同，而产生了不同的数据信息：

 当操作的为图片时：：{

    UIImagePickerControllerCropRect = "NSRect: {{0, 405}, {2448, 2449}}";

    UIImagePickerControllerEditedImage = "";

    UIImagePickerControllerMediaMetadata =     {

        DPIHeight = 72;

        DPIWidth = 72;

        Orientation = 6;

        "{Exif}" =         {

            ApertureValue = "2.526068811667588";

            BrightnessValue = "-0.0709875088566263";

            ColorSpace = 1;

            DateTimeDigitized = "2013:04:05 16:43:00";

            DateTimeOriginal = "2013:04:05 16:43:00";

            ExposureMode = 0;

            ExposureProgram = 2;

            ExposureTime = "0.05882352941176471";

            FNumber = "2.4";

            Flash = 24;

            FocalLenIn35mmFilm = 35;

            FocalLength = "4.28";

            ISOSpeedRatings =             (

                400

            );

            MeteringMode = 5;

            PixelXDimension = 3264;

            PixelYDimension = 2448;

            SceneType = 1;

            SensingMethod = 2;

            Sharpness = 0;

            ShutterSpeedValue = "4.099543917546131";

            SubjectArea =             (

                1631,

                1223,

                881,

                881

            );

            WhiteBalance = 0;

        };

        "{TIFF}" =         {

            DateTime = "2013:04:05 16:43:00";

            Make = Apple;

            Model = "iPhone 4S";

            Software = "5.1.1";

            XResolution = 72;

            YResolution = 72;

        };

    };

    UIImagePickerControllerMediaType = "public.image";

    UIImagePickerControllerOriginalImage = "";

}

 

当我们操作的为视频时：

 

{

    UIImagePickerControllerMediaType = "public.movie";

    UIImagePickerControllerMediaURL = "file://localhost/private/var/mobile/Applications/22A14825-DD7E-48E1-A1D5-2D85B82095B5/tmp/capture-T0x1363a0.tmp.etXfD4/capturedvideo.MOV";

}

 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

1.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);
    }

2.UIImagePickerController属性详解：

    //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：

3.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..");
}

4.自定义相机拍照画面：

   //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  = NO;

    UIToolbar* tool = [[UIToolbar alloc]initWithFrame:CGRectMake(0, self.view.frame.size.height-55, self.view.frame.size.width, 75)];
    tool.barStyle = UIBarStyleBlackTranslucent;
    UIBarButtonItem* cancel = [[UIBarButtonItem alloc]initWithBarButtonSystemItem:UIBarButtonSystemItemCancel target:self action:@selector(cancelCamera)];
    UIBarButtonItem* add = [[UIBarButtonItem alloc]initWithBarButtonSystemItem:UIBarButtonSystemItemSave target:self action:@selector(savePhoto)];
    [tool setItems:[NSArray arrayWithObjects:cancel,add, nil]];
   //把自定义的view设置到imagepickercontroller的overlay属性中

   imagepicker.cameraOverlayView = tool;

-(void)cancelCamera{
    [imagepicker dismissModalViewControllerAnimated:YES];
}
-(void)savePhoto{
    //拍照，会自动回调- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info，对于自定义照相机界面，拍照后回调可以不退出实现连续拍照效果
    [imagepicker takePicture];
}

 

5.UIImagePickerController是继承UINavigationController,所以可以push和pop一些viewcontroller进行导航效果。例如，自定义照相机画面的时候可以在拍摄完后push一个viewcontroller用于对照片进行编辑。

 

 

花开花谢春不管,水暖水寒鱼自知.