将捕获的图像保存在 NSDocument 目录路径中并加载到集合视图中

Question

我正在开发相机应用程序。我需要将捕获的图像存储到 NSDocumentDirectory 并将该图像加载到 Collection 视图中。我只使用了数组。我对 NSDocument 目录了解不多。请任何人帮助我做到这一点。 这是我的代码，我将捕获图像保存到 nsdocument 目录路径中

-(IBAction)takephoto:(id)sender
{
tapCount += 1;
AVCaptureConnection *videoConnection  = nil;
for(AVCaptureConnection *connection in StillImageOutput.connections)
{
    for(AVCaptureInputPort *port in  [connection inputPorts])
    {
        if ([[port mediaType] isEqual:AVMediaTypeVideo]){
            videoConnection =connection;
            break;

        }
    }
}


[StillImageOutput captureStillImageAsynchronouslyFromConnection:videoConnection completionHandler:^(CMSampleBufferRef imageDataSampleBuffer, NSError *error){


    if (imageDataSampleBuffer!=NULL) {

        NSData *imageData =[AVCaptureStillImageOutput jpegStillImageNSDataRepresentation:imageDataSampleBuffer];


        self.image = [ UIImage imageWithData:imageData];




        //Saving Image in Document directory Path
        NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
        NSString *documentDirectory = paths.firstObject;
        NSData *imageData1 = UIImagePNGRepresentation(self.image);

        NSString *imageFolder = @"Photos";

        NSDateFormatter *dateFormat = [[NSDateFormatter alloc]init];

        [dateFormat setDateFormat:@"yyyMMddHHmmss"];
        NSDate *now = [NSDate date];
        NSString *theDate = [dateFormat stringFromDate:now];
        NSString *myUniqueName = [NSString stringWithFormat:@"Photo-%@.png",theDate];

        NSString *imagePath = [NSString stringWithFormat:@"%@/%@",documentDirectory,imageFolder];

        BOOL isDir;
        NSFileManager *fileManager= [NSFileManager defaultManager];
        if(![fileManager fileExistsAtPath:imagePath isDirectory:&isDir])
            if(![fileManager createDirectoryAtPath:imagePath withIntermediateDirectories:YES attributes:nil error:NULL])
                NSLog(@"Error: folder creation failed %@", documentDirectory);

        [[NSFileManager defaultManager] createFileAtPath:[NSString stringWithFormat:@"%@/%@", imagePath, myUniqueName] contents:nil attributes:nil];
        [imageData writeToFile:[NSString stringWithFormat:@"%@/%@", imagePath, myUniqueName] atomically:YES];
  [self.collection_View reloadData];
      }
}];

inViewDidLoad

     NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);

NSString *documentDirectory = paths.firstObject;
NSString *fullPath = [NSString stringWithFormat:@"%@/%@", documentDirectory, @"Photos"]; // image path is same as above
NSArray *dirContents = [[NSFileManager defaultManager] contentsOfDirectoryAtPath:fullPath error:nil];
      self.fileList=[[NSMutableArray alloc]init];
      self.fileName=[[NSMutableArray alloc]init];

if ([[NSFileManager defaultManager] fileExistsAtPath:fullPath]) {

    for (NSString *filename in dirContents) {
        NSString *fileExt = [filename pathExtension];
        if ([fileExt isEqualToString:@"png"]) {
            NSString *fullPth = [fullPath stringByAppendingPathComponent:filename];
            [self.fileList addObject:fullPth];
            [self.fileName addObject:filename];
            NSLog(@"File name : %@ ",filename);
            NSLog(@"fullPth : %@ ",fullPth);

        }
    }


} else {

    NSLog(@"No Files");
}

这是我的代码，我正在将 nsdocumnet 目录路径中的图像加载到集合视图中。

          -(UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath
  {
        CollectionViewCell *Cell = [collectionView dequeueReusableCellWithReuseIdentifier:@"Cell" forIndexPath:indexPath];
//Loading images from path

//Cell.image_View.image = nil;
NSString *filePath = [self.fileList objectAtIndex:indexPath.row];

UIImage *image =[UIImage imageWithContentsOfFile:filePath];
dispatch_queue_t queue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_HIGH, 0ul);
dispatch_async(queue, ^{



    dispatch_async(dispatch_get_main_queue(), ^{
        if (image) {

            Cell.image_View.image = image;

           // [activityIndicator stopAnimating];
            //activityIndicator.hidden = YES;
            self.collection_View.hidden = NO;


        } else {
            Cell.image_View.image = [UIImage imageNamed:@"tours-walk.png"];
        }
    });
});

Cell.layer.shouldRasterize = true;
Cell.layer.rasterizationScale = [UIScreen mainScreen].scale;
 return Cell;}

我已经尝试过，它正在获取图像并保存在 nsdocumentdirectory 路径中，但它只显示以前的图像。如果我再次运行它，它会显示最新的图像。请帮助我。检查此代码并提出任何想法

提前致谢！！！

Answer 1

当您要将图像保存到文档目录时

for (UIImage *img in arrImg)
{
   int i=0;
   NSString *pathName =nil;
   NSString *fileName = [[self getCurrentDate]stringByAppendingString:[self getCurrentTime]];
   fileName =[file_name stringByAppendingPathExtension:@"jpeg"];
   NSArray *paths1 =NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
   NSString *basePath =([paths1 count] >i) ? [paths1 objectAtIndex:i] : nil;
   NSString *path = [basePath stringByAppendingPathComponent:@"Photo"];
   //Get Directory in FileManager
   NSFileManager *fileManager =[NSFileManager defaultManager];
   if ([fileManager fileExistsAtPath:path])
      return;
   [fileManager createDirectoryAtPath:path  withIntermediateDirectories:NO attributes:nil error:nil];
   pathName =[path stringByAppendingPathComponent:file_name];
   NSData *imgData =UIImageJPEGRepresentation(image, 0.4);
   [imgData writeToFile:pathName atomically:YES];
   NSMutableArray *arrImgpath = [[NSMutableArray alloc]init];
   [arrImgPath addObject:pathName];
}

在上面的代码中，arrImg 将图像保存在数组中。

那你需要编写或调用下面的代码

-(NSString*)getCurrentTime
{
   //Get Current Time for saving Images
   NSString *path =nil;
   NSDateFormatter *timeFormatter =[[NSDateFormatter alloc]init];
   [timeFormatter setDateFormat:@"HH:mm:ss.SSS"];
   NSDate *now = [[NSDate alloc]init];

   NSString *str_time = [timeFormatter stringFromDate:now];
   NSString *curr_time;
   curr_time =[str_time stringByReplacingOccurrencesOfString:@"." withString:@""];

   path = [NSString stringWithFormat:@"%@",curr_time];

   return  path;
 }
 -(NSString*)getCurrentDate
 {
    NSString *today =nil;

    NSDateFormatter *dateFormatter1;
    dateFormatter1 =[[NSDateFormatter alloc]init];
    [dateFormatter1 setDateFormat:@"d MMM yyyy"];
    NSDate *now =[[NSDate alloc]init];
    NSLocale *usLocale =[[NSLocale alloc]initWithLocaleIdentifier:@"en_US"];
    [dateFormatter1 setLocale:usLocale];
    NSString *str_date =[dateFormatter1 stringFromDate:now];
    today=[NSString stringWithFormat:@"%@",str_date];
    return today;
 }

当你从目录路径获取图片时

-(NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section
{
  return arrImgpath.count;
}

-(UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath
{
  static NSString *cellIdentifier = @"cell";
  cell = (CustomCell *)[collectionView dequeueReusableCellWithReuseIdentifier:cellIdentifier forIndexPath:indexPath];
  if(cell==nil){
    NSArray *nib = [[NSBundle mainBundle] loadNibNamed:@"CustomCell" owner:self options:nil];
    cell = nib[0];
   }
   NSString *localPath=[NSString stringWithFormat:@"%@",[arrImgPath objectAtIndex:indexPath.row]];
   //Use either one
   NSURL *strPathURL=[NSURL fileURLWithPath:localPath];
   NSData *data = [NSData dataWithContentsOfURL:strPathURL];
   UIImage *imag = [[UIImage alloc] initWithData:data];
        //OR
   UIImage *imag = [UIImage imageWithContentsOfFile:localPath];
   cell.img.image = imag;


  return cell;
}

还需要在 viewDidLoad 方法中注册单元格

- (void)viewDidLoad
{
   UINib *cellNib = [UINib nibWithNibName:@"CustomCell" bundle:nil];
   [collectionView registerNib:cellNib forCellWithReuseIdentifier:@"cell"];  
}

Answer 2

试试这个代码。

 NSData *pngData = UIImagePNGRepresentation(image);

这会提取您捕获的图像的 PNG 数据。从这里，您可以将其写入文件：

NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);  
NSString *documentsPath = [paths objectAtIndex:0]; //Get the docs directory 
NSString *filePath = [documentsPath stringByAppendingPathComponent:@"image.png"]; //Add the file name
[pngData writeToFile:filePath atomically:YES]; //Write the file

稍后阅读它的工作方式相同。像我们上面那样构建路径，然后：

NSData *pngData = [NSData dataWithContentsOfFile:filePath];
UIImage *image = [UIImage imageWithData:pngData];

制作一个为你创建路径字符串的方法

- (NSString *)documentsPathForFileName:(NSString *)name
{
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,NSUserDomainMask, YES);  
    NSString *documentsPath = [paths objectAtIndex:0];
    return [documentsPath stringByAppendingPathComponent:name]; 
}

Answer 3

据我了解您的问题，您需要从 Gallery/PhotoLibrary 中选择多个图像并将所选图像加载到 Collectionview 中。 如果我是对的，那么使用这个库https://github.com/B-Sides/ELCImagePickerController。