将图像持久保存在应用程序内 - iOS

Question

尝试使用照片选择器选择图像并将该图像内部保存在应用程序文件夹中。

- (void) imagePickerController: (UIImagePickerController *) pickerdidFinishPickingMediaWithInfo: (NSDictionary *) info { 

NSString *mediaType = [info objectForKey: UIImagePickerControllerMediaType]; 
UIImage *originalImage, *editedImage, *imageToUse; 

// Handle a still image picked from a photo album 
if (CFStringCompare ((CFStringRef) mediaType, kUTTypeImage, 0) 
    == kCFCompareEqualTo) { 

    editedImage = (UIImage *) [info objectForKey: 
           UIImagePickerControllerEditedImage]; 
    originalImage = (UIImage *) [info objectForKey: 
           UIImagePickerControllerOriginalImage]; 

    if (editedImage) { 
     imageToUse = editedImage; 
    } else { 
     imageToUse = originalImage; 
    } 
    // Do something with imageToUse 

    //save it 
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES); 
    NSString *documentsDirectory = [paths objectAtIndex:0]; 
    NSString *imageName = [documentsDirectory stringByAppendingString:[NSString stringWithFormat:@"%d", myUniqueID]]; 
    NSString *imagePath = [imageName stringByAppendingPathComponent:@".png"]; 

    NSData *webData = UIImagePNGRepresentation(editedImage); 
    NSError* error = nil; 
    bool success = [webData writeToFile:imagePath options:NULL error:&error]; 
    if (success) { 
     // successfull save 
     imageCount++; 
     [[NSUserDefaults standardUserDefaults] setInteger:imageCount forKey:@"imageCount"]; 
     NSLog(@"@Success save to: %@", imagePath); 
    } 
    else if (error) { 
     NSLog(@"Error:%@", error.localizedDescription); 
    } 
} 
... 
} 

我无法弄清楚什么是writeToFile:::回报false但没有值在error返回，所以我不能弄清楚怎么回事错了。任何帮助将不胜感激

Answer 1

你错过了一个“/”。行：

NSString *imageName = [documentsDirectory stringByAppendingString:[NSString stringWithFormat:@"%d", myUniqueID]]; 

应该是：

NSString *imageName = [documentsDirectory stringByAppendingPathComponent:[NSString stringWithFormat:@"%d", myUniqueID]]; 

而且这行：

NSString *imagePath = [imageName stringByAppendingPathComponent:@".png"]; 

应该是：

NSString *imagePath = [imageName stringByAppendingPathExtension:@"png"]; 

---

更新：

而且，不应该：

NSData *webData = UIImagePNGRepresentation(editedImage); 

是以下？

NSData *webData = UIImagePNGRepresentation(imageToUse);