iOS攝像頭和相冊-UIImagePickerController常用操作


在一些應用中,我們需要用到iOS設備的攝像頭進行拍照,視頻。並且從相冊中選取我們需要的圖片或者視頻。
關於iOS攝像頭和相冊的應用,可以使用UIImagePickerController類來完成控制。
關於UIImagePickerController的相關知識,
如下:
 
iOS的一些設備上都安裝了攝像頭。現在絕大多數都有了。
在編程中,我們是用相應的東西來進行照相,錄像等功能。
 
一、UIImagePickerController類

UIImagePickerController 這個類可以為大家提供照相的功能,以及圖片,視頻瀏覽的功能。 

 
二、檢查硬件是否安裝有攝像頭或者允許操作相冊
 
這些公共的方法,我們也許會用到,我就貼了!So easy!!!
 

#pragma mark - 攝像頭和相冊相關的公共類

 

// 判斷設備是否有攝像頭

- (BOOL) isCameraAvailable{

    return [UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera];

}

 

// 前面的攝像頭是否可用

- (BOOL) isFrontCameraAvailable{

    return [UIImagePickerControllerisCameraDeviceAvailable:UIImagePickerControllerCameraDeviceFront];

}

 

// 后面的攝像頭是否可用

- (BOOL) isRearCameraAvailable{

    return [UIImagePickerControllerisCameraDeviceAvailable:UIImagePickerControllerCameraDeviceRear];

}

 

 

// 判斷是否支持某種多媒體類型:拍照,視頻

- (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;

}

 

// 檢查攝像頭是否支持錄像

- (BOOL) doesCameraSupportShootingVideos{

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

}

 

// 檢查攝像頭是否支持拍照

- (BOOL) doesCameraSupportTakingPhotos{

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

}

 

#pragma mark - 相冊文件選取相關

// 相冊是否可用

- (BOOL) isPhotoLibraryAvailable{

    return [UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypePhotoLibrary];

}

 

// 是否可以在相冊中選擇視頻

- (BOOL) canUserPickVideosFromPhotoLibrary{

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

}

 

// 是否可以在相冊中選擇視頻

- (BOOL) canUserPickPhotosFromPhotoLibrary{

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

}

 
三、用攝像頭進行拍照和錄像功能
 
1.我們將UIImagePickerController功能寫在一個按鈕的點擊事件中:
 

 

#pragma mark - 拍照按鈕事件

 

- (void)ClickControlAction:(id)sender{

    // 判斷有攝像頭,並且支持拍照功能

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

        // 初始化圖片選擇控制器

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

        [controller setSourceType:UIImagePickerControllerSourceTypeCamera];// 設置類型

 

        

        // 設置所支持的類型,設置只能拍照,或則只能錄像,或者兩者都可以

        NSString *requiredMediaType = ( NSString *)kUTTypeImage;

        NSString *requiredMediaType1 = ( NSString *)kUTTypeMovie;

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

        [controller setMediaTypes:arrMediaTypes];

        

        // 設置錄制視頻的質量

        [controller setVideoQuality:UIImagePickerControllerQualityTypeHigh];

        //設置最長攝像時間

        [controller setVideoMaximumDuration:10.f];

        

 

        [controller setAllowsEditing:YES];// 設置是否可以管理已經存在的圖片或者視頻

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

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

        [controller release];

    } else {

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

    }

}

 
 
解釋:
 
2. setSourceType方法
 
通過設置setSourceType方法可以確定調用出來的UIImagePickerController所顯示出來的界面
 

typedef NS_ENUM(NSInteger, UIImagePickerControllerSourceType) {

    UIImagePickerControllerSourceTypePhotoLibrary,

    UIImagePickerControllerSourceTypeCamera,

    UIImagePickerControllerSourceTypeSavedPhotosAlbum

};

 
分別表示:圖片列表,攝像頭,相機相冊
 
3.setMediaTypes方法
 

// 設置所支持的類型,設置只能拍照,或則只能錄像,或者兩者都可以

        NSString *requiredMediaType = ( NSString *)kUTTypeImage;

        NSString *requiredMediaType1 = ( NSString *)kUTTypeMovie;

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

        [controller setMediaTypes:arrMediaTypes];

 
 
4.關於UIImagePickerControllerDelegate協議
 
我們要對我們拍攝的照片和視頻進行存儲,那么就要實現UIImagePickerControllerDelegate協議的方法。
 

#pragma mark - UIImagePickerControllerDelegate 代理方法

 

 

// 保存圖片后到相冊后,調用的相關方法,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);

    }

}

 

// 當得到照片或者視頻后,調用該方法

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

    NSLog(@"Picker returned successfully.");

    NSLog(@"%@", info);

    NSString *mediaType = [infoobjectForKey:UIImagePickerControllerMediaType];

    // 判斷獲取類型:圖片

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

        UIImage *theImage = nil;

        // 判斷,圖片是否允許修改

        if ([picker allowsEditing]){

            //獲取用戶編輯之后的圖像

            theImage = [infoobjectForKey:UIImagePickerControllerEditedImage];

        } else {

            // 照片的元數據參數

            theImage = [infoobjectForKey:UIImagePickerControllerOriginalImage];

            

        }

        

        // 保存圖片到相冊中

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

        UIImageWriteToSavedPhotosAlbum(theImage,self,selectorToCall, NULL);

        

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

        // 判斷獲取類型:視頻

        //獲取視頻文件的url

        NSURL* mediaURL = [infoobjectForKey:UIImagePickerControllerMediaURL];

        //創建ALAssetsLibrary對象並將視頻保存到媒體庫

        // Assets Library 框架包是提供了在應用程序中操作圖片和視頻的相關功能。相當於一個橋梁,鏈接了應用程序和多媒體文件。

        ALAssetsLibrary *assetsLibrary = [[ALAssetsLibraryalloc] init];

        // 將視頻保存到相冊中

        [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];

}

 

 

 

// 當用戶取消時,調用該方法

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

    

    [picker dismissModalViewControllerAnimated:YES];

}

 
四、從相冊獲取圖片和視頻數據
 
1.我們將功能封裝在一個按鈕的點擊事件中
 

#pragma mark - 相冊操作

 

- (void)ClickShowPhotoAction:(id)sender{

    

    if ([self isPhotoLibraryAvailable]){

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

         [controller setSourceType:UIImagePickerControllerSourceTypePhotoLibrary];// 設置類型

        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];// 設置代理

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

        [controller release];

        [mediaTypes release];

        

    }

 

 

}

 
2.關於UIImagePickerControllerDelegate協議,我們可以重用。
 
在這里,就不用贅述了!
 
最后,需要說的是, UIImagePickerControllerDelegate協議中

-(void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info方法,中的info值,會根據我們操作的類型不同,而產生了不同的數據信息:

 

當操作的為圖片時::

 

 

{

    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 = "";

}

 
當我們操作的為視頻時:
 

{

    UIImagePickerControllerMediaType = "public.movie";

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

}

 
 
選擇資源以后獲取資源路徑:

- (void) pickImage: (id) sender

{

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

        if ([UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypePhotoLibrary]){

     ipc.sourceType =  UIImagePickerControllerSourceTypePhotoLibrary;

      ipc.mediaTypes =[UIImagePickerController availableMediaTypesForSourceType:ipc.sourceType];   

        }  

ipc.delegate = self;

ipc.allowsImageEditing = NO;

[self presentModalViewController:ipc animated:YES];

}

 

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

NSString *mediaType = [info objectForKey:UIImagePickerControllerMediaType];

if ([mediaType isEqualToString:@"public.image"]){

//UIImage *selectedImage = [info objectForKey:UIImagePickerControllerOriginalImage];

UIImage *image = [info objectForKey:@"UIImagePickerControllerOriginalImage"];

    NSLog(@"found an image");

[UIImageJPEGRepresentation(image, 1.0f) writeToFile:[self findUniqueSavePath] atomically:YES];

    SETIMAGE(image);

CFShow([[NSFileManager defaultManager] directoryContentsAtPath:[NSHomeDirectory() stringByAppendingString:@"/Documents"]]);

}

else if ([mediaType isEqualToString:@"public.movie"]){

 

NSURL *videoURL = [info objectForKey:UIImagePickerControllerMediaURL];

NSLog(@"found a video");

        NSData *webData = [NSData dataWithContentsOfURL:videoURL];

//NSData *video = [[NSString alloc] initWithContentsOfURL:videoURL];

[webData writeToFile:[self findUniqueMoviePath] atomically:YES];

CFShow([[NSFileManager defaultManager] directoryContentsAtPath:[NSHomeDirectory() stringByAppendingString:@"/Documents"]]);

//NSLog(videoURL);

}

[picker dismissModalViewControllerAnimated:YES];

}

 

摘自:http://blog.sina.com.cn/s/blog_7b9d64af0101cfd9.html  感謝博主分享


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