Question

我正在开发一款iOS应用。用户可以用相机拍照，这张照片应该显示并保存在我的应用程序中。即使应用程序重新启动。我有以下代码来拍照：

- (void)takePictureFromCamera {

     if ([UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera]) {
         UIImagePickerController *imagePicker = [[UIImagePickerController alloc] init];
         imagePicker.delegate = self;
         imagePicker.sourceType = UIImagePickerControllerSourceTypeCamera;
         imagePicker.mediaTypes = @[(NSString *) kUTTypeImage];
         imagePicker.allowsEditing = NO;
         [self presentViewController:imagePicker animated:YES completion:nil];
         _newMedia = YES;   
    }      
}

这种将图片保存到相机胶卷的方法：

- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info {
     NSString *mediaType = info[UIImagePickerControllerMediaType];
     [self dismissViewControllerAnimated:YES completion:nil];

     if ([mediaType isEqualToString:(NSString *)kUTTypeImage]) {
         UIImage *image = info[UIImagePickerControllerOriginalImage];

         if (_newMedia) {
             UIImageWriteToSavedPhotosAlbum(image,
                                       self,
                                       @selector(image:finishedSavingWithError:contextInfo:),
                                       nil);
          }
     }         
}

如何在我的应用程序中保存图片，如果应用程序重新启动，则直接显示网格中的早期拍摄图片或类似内容。

Answer 1

帮助方法

-(NSURL *)getDocumentsPathURL
{
    //document directory of app
    return [[NSFileManager defaultManager] URLForDirectory:NSDocumentDirectory
                                                  inDomain:NSUserDomainMask
                                         appropriateForURL:nil
                                                    create:YES
                                                     error:nil];
}

您的UIImagePickerController委托方法：

#define k_IMAGE_NAME @"DefaultImage.png"

-(void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info
{
    NSString *mediaType = info[UIImagePickerControllerMediaType];
    [self dismissViewControllerAnimated:YES completion:nil];

    if ([mediaType isEqualToString:(NSString *)kUTTypeImage]) {
        UIImage *image = info[UIImagePickerControllerOriginalImage];

        //append filename to document directory url
        NSURL *urlSave = [[self getDocumentsPathURL] URLByAppendingPathComponent:k_IMAGE_NAME];

        //do something to previously taken image (in this case: delete it)
        if ([[NSFileManager defaultManager] fileExistsAtPath:urlSave.path]) {
            [[NSFileManager defaultManager] removeItemAtPath:urlSave.path error:nil];
        }

        //save image to document directory
        [UIImagePNGRepresentation(image) writeToFile:urlSave.path atomically:YES];

        //optional: save image to photo library
        UIImageWriteToSavedPhotosAlbum(image, nil, nil, nil);
    }
}

加载图片的方式（应用启动时或任何时候）

-(void)loadDefaultImage
{
    NSURL *urlImage = [[self getDocumentsPathURL] URLByAppendingPathComponent:k_IMAGE_NAME];

    if ([[NSFileManager defaultManager] fileExistsAtPath:urlImage.path]) {
        NSData *dataFile = [[NSFileManager defaultManager] contentsAtPath:urlImage.path];
        UIImage *image = [UIImage imageWithData:dataFile];

        [imageView setImage:image];
    }
    else {
        NSLog(@"Image not found");
    }
}

Answer 2

回答你的第一个问题：

    [UIImagePNGRepresentation(your_image) writeToFile:filePath atomically:YES];

您的代码变为：

 -(void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info
{
     NSString *mediaType = info[UIImagePickerControllerMediaType];
     [self dismissViewControllerAnimated:YES completion:nil];

     if ([mediaType isEqualToString:(NSString *)kUTTypeImage]) {
         UIImage *image = info[UIImagePickerControllerOriginalImage];

          [UIImagePNGRepresentation(image) writeToFile:filePath atomically:YES];
     }         
}

Answer 3

您可以将图像保存在apps文档目录中

    -(void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info
    {
        NSString *mediaType = info[UIImagePickerControllerMediaType];
        [self dismissViewControllerAnimated:YES completion:nil];
        if ([mediaType isEqualToString:(NSString *)kUTTypeImage])
        {

            UIImage *image = info[UIImagePickerControllerOriginalImage];
            if(image)
            {
                NSArray *path = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,NSUserDomainMask, YES);
                NSString *documentsPath = [path objectAtIndex:0];
                NSString *filePath = [documentsPath stringByAppendingPathComponent:@"anyName.png"];
                [image writeFileToPath : filePath];
            }


        }

    }


    For retrieving the file you can use

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

iOS拍照并保存在应用程序中

3 个答案: