UIImagePickerController

紧接着上一篇文章,选取图像并研究了人脸识别,说到选取头像就离不开UIImagePickerController这个类,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。可能大家对这个已经很熟悉了,笔者当一种复习和巩固。
附原文链接:http://blog.sina.com.cn/s/blog_7b9d64af0101cfd9.html 这里写的非常全面了。

  • 1.检测设备是否支持
#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];
}
  • 2.ImagePickerControllerDelegate协议
#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];
}

  • 3.用摄像头进行拍照和录像功能(封装使用)
#pragma mark - 拍照点击按钮事件

- (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.");
    }
}
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,           //图片列表
    UIImagePickerControllerSourceTypeCamera,                   //摄像头
    UIImagePickerControllerSourceTypeSavedPhotosAlbum   //相机相册
};

分别表示:图片列表,摄像头,相机相册

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];

最后,需要注意的是这篇参考的原文写的时间比较久,可能部分已经被ios9所淘汰,但原理是互通的,而且原文作者是通过mrc写的,笔者只将部分精华摘取并学习。

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