UIImagePickerController - 保存和检索照片从应用程序文档目录

Question

这让我疯狂！

我已成功将照片保存到我的应用程序文档目录中，如果我从照相机卷中选择现有照片。执行此操作的代码如下所示。注意我知道这部分工作，因为在模拟器中，我可以浏览到apps Documents文件夹并查看正在保存的文件。

实施例 “保存” 代码：

//Note: code above snipped to keep this part of the question short 
    case 1: 
    { 
     // select from library 
     NSLog(@"select from camera roll"); 

     if([util_ isPhotoLibraryAvailable]) 
     { 
      UIImagePickerController *controller = [[UIImagePickerController alloc] init]; 
      controller.sourceType = UIImagePickerControllerSourceTypePhotoLibrary; 
      NSMutableArray *mediaTypes = [[NSMutableArray alloc] init]; 
      if([util_ canUserPickPhotosFromPhotoLibrary]) 
      { 
       [mediaTypes addObject:(__bridge NSString *)kUTTypeImage]; 
      } 
      controller.mediaTypes = mediaTypes; 
      controller.delegate = self; 
      controller.modalTransitionStyle = UIModalTransitionStyleFlipHorizontal; 
      [self presentModalViewController:controller animated:YES]; 
     } 
    } break; 
//code below snipped out 

，一旦图象被取或选自：

- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info 
{ 
    NSLog(@"picker returned successfully"); 

    NSString *mediaType = [info objectForKey:UIImagePickerControllerMediaType]; 
    if([mediaType isEqualToString:(__bridge NSString *)kUTTypeImage]) 
    { 
     UIImage *originalImage = [info objectForKey:UIImagePickerControllerOriginalImage]; 
     UIImage *resizedImage = [util_ createThumbnailForImage:originalImage thumbnailSize:[util_ determineIPhoneScreenSize]]; 
     NSData *imageData = UIImagePNGRepresentation(resizedImage); 
     NSString* imageName = @"MyImage.png"; 
     NSArray* paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES); 
     NSString* documentsDirectory = [paths objectAtIndex:0]; 
     NSString* fullPathToFile = [documentsDirectory stringByAppendingPathComponent:imageName];   
     [imageData writeToFile:fullPathToFile atomically:NO]; 

     NSLog(@"fullPathToFile %@", fullPathToFile); 
     // this outputs the following path in the debugger 
     // fullPathToFile /Users/me/Library/Application Support/iPhone Simulator/5.0/Applications/47B01A4C-C54F-45C4-91A3-C4D7FF9F95CA/Documents/MyImage.png 

     // rest snipped out - at this point I see the image in the simulators/app/Documents directory 

现在 - 不工作（读取和显示照片）的部分：

// code above snipped out (we're in tableView:cellForRowAtIndexPath) 

imageButton_ = [[UIButton alloc] initWithFrame:CGRectMake(5, 5, 200, 200)]; 
NSString* imageName = [contentArray_ objectAtIndex:indexPath.row]; 
NSArray* paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES); 
SString* documentsDirectory = [paths objectAtIndex:0]; 
NSString* fullPathToFile = [documentsDirectory stringByAppendingPathComponent:imageName]; 
UIImage *image = [UIImage imageNamed:fullPathToFile]; 
[imageButton_ setImage:image forState:UIControlStateNormal]; 

[cell addSubview:imageButton_]; 

NSLog(@"fullPathToFile: %@", fullPathToFile); 
// this outputs the following path in the debugger 
// fullPathToFile: /Users/me/Library/Application Support/iPhone Simulator/5.0/Applications/47B01A4C-C54F-45C4-91A3-C4D7FF9F95CA/Documents/MyImage.png 

return cell; 

}

因此，我得到一个没有图像显示在单元格中的空按钮。我也取代了按钮，一个UIImageView和仍然没有运气...

Answer 1

你的问题是在这里：

UIImage *image = [UIImage imageNamed:fullPathToFile]; 

UIImage imageNamed:仅在束图像。它不适用于文档目录中的图像。

改为尝试imageWithContentsOfFile:。