将图像持久保存在 App 中 - 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);
    }
}
...
}

我想不通的是 writeToFile::: 返回 false 但在 error 中没有返回值所以我不知道出了什么问题。任何帮助将不胜感激，谢谢

Answer 1

您缺少一个“/”。行：

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

应该是：

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

那一行写着：

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

应该是：

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

---

更新：

而且，不应该：

NSData *webData = UIImagePNGRepresentation(editedImage);

是以下吗？

NSData *webData = UIImagePNGRepresentation(imageToUse);