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iOS摄像头和相册-UIImagePickerController

2023-03-15 23:19:13 时间

本文参考自：http://blog.sina.com.cn/s/blog_7b9d64af0101cfd9.html

在原文的基础上，增加了存储图片到app和从app存储中读取图片。

引

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。

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 *)kUTTypeMovie sourceType:UIImagePickerControllerSourceTypePhotoLibrary];  
}  
  
// 是否可以在相册中选择视频  
- (BOOL) canUserPickPhotosFromPhotoLibrary{  
    return [self cameraSupportsMedia:( NSString *)kUTTypeImage sourceType:UIImagePickerControllerSourceTypePhotoLibrary];  
}

三、用摄像头进行拍照和录像功能

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.");  
    }  
}

具体解释一下：

1、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

2、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];

3、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:(voidvoid *)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！

五、info信息

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。

1、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 = "";  
}

2、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";  
}

六、存储图片到app中和从app中读取图片

1、把选择的图片存储到app中

NSString *imagePath = [[NSHomeDirectory() stringByAppendingPathComponent:@"Documents"] stringByAppendingPathComponent:@"image.png"];  
[UIImagePNGRepresentation(pickedImage) writeToFile:imagePath atomically:YES];

2、从app中读取存储的图片

NSString *imagePath = [[NSHomeDirectory() stringByAppendingPathComponent:@"Documents"] stringByAppendingPathComponent:@"image.png"];  
UIImage *image = [[UIImage alloc] initWithContentsOfFile:imagePath];  
if (image) {  
    self.imageView.image = image;  
}

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