无法从绝对路径将图像加载到 UIImageView

Question

我使用 UIImagePickerController 来选择图像并加载到我的 UIImageView，但我想保存用户选择并稍后加载它，我认为将绝对路径保存到用户默认值但不起作用（

我如何保存路径 // 一切正常

-(void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:   (NSDictionary *)info
{

[self.backgroundImage setImage:info[UIImagePickerControllerOriginalImage]];
NSURL* localUrl = (NSURL *)[info valueForKey:UIImagePickerControllerReferenceURL];

//in localUrl I see: assets-library://asset/asset.JPG?id=B6C0A21C-07C3-493D-8B44-3BA4C9981C25&ext=JPG

NSUserDefaults *saves = [NSUserDefaults standardUserDefaults];
[saves setValue:[localUrl absoluteString] forKey:@"backimage"];
[saves synchronize];

[self dismissViewControllerAnimated:YES completion:nil];
}

我如何尝试加载：//不工作（

NSUserDefaults *saves = [NSUserDefaults standardUserDefaults];

if(![saves objectForKey:@"backimage"]){

 [self.backgroundImage setImage:[UIImage imageNamed:@"gameBackiPhone"]];

}else{

 NSURL *url = [NSURL URLWithString:[saves objectForKey:@"backimage"]];

//in url I see: assets-library://asset/asset.JPG?id=B6C0A21C-07C3-493D-8B44-3BA4C9981C25&ext=JPG

 UIImage *bimage = [[UIImage alloc] initWithData:[NSData dataWithContentsOfURL:url]];

 [self.backgroundImage setImage:bimage];

}

我怎么会找不到。

Answer 1

不能直接使用 Asset URL 加载图片，需要使用 ALAssetsLibrary 类来实现。使用以下 sn-p 通过 Asset URL 加载图像。

// *** It will return Asset from URL passed, create Image from Asset and set into your `UIImageView` ***
ALAssetsLibraryAssetForURLResultBlock resultblock = ^(ALAsset *myasset)
{
    ALAssetRepresentation *rep = [myasset defaultRepresentation];
    CGImageRef iref = [rep fullResolutionImage];
    if (iref) {
        UIImage *largeimage = [UIImage imageWithCGImage:iref];
        yourImageView.image = largeImage;
    }
};

// *** If any error occurs while getting image from Asset Library following block will be invoked ***
ALAssetsLibraryAccessFailureBlock failureblock  = ^(NSError *myerror)
{
    NSLog(@"Can't get image - %@",[myerror localizedDescription]);
};

// *** Set Asset URL to load Image (assets-library://asset/asset.JPG?id=B6C0A21C-07C3-493D-8B44-3BA4C9981C25&ext=JPG) ***
[NSURL *asseturl = [NSURL URLWithString:yourURL];
// *** Create ALAssetsLibrary Instance and load Image ***
ALAssetsLibrary* assetslibrary = [[[ALAssetsLibrary alloc] init] autorelease];
[assetslibrary assetForURL:asseturl
            resultBlock:resultblock
           failureBlock:failureblock];

不要忘记在您的项目中导入AssetsLibrary 框架。