无法从资产网址加载图片 [英] Unable to load image from asset URL

问题描述

我有一个课程，用于存储有关手机资产的信息（图片，视频）。

I have a class that stores information about the assets on the phone (images, videos).

我的班级有 ResourceURLString 定义为

@property NSURL *ResourceURL;

我在通过资产在手机上这样

Item.ResourceURLString = [[asset valueForProperty:ALAssetPropertyURLs] objectForKey:[[asset valueForProperty:ALAssetPropertyRepresentations] objectAtIndex:0]];

当用户点击图片时，我想加载图片。

When the user clicks on an image I want to load the image.

我的代码是这个

NSData *imageUrl = [NSData dataWithContentsOfURL:[NSURL URLWithString:[CurrentItem.ResourceURL absoluteString]]];    

Img = [UIImage imageWithData:imageUrl];

但是Image总是nil
我已经验证了ResourceURL属性包含URL
资产： library：//asset/asset.JPG？id = 82690321-91C1-4650-8348-F3FD93D14613& ext = JPG

But the Image is always nil I have verified that the ResourceURL property contains the URL assets: library://asset/asset.JPG?id=82690321-91C1-4650-8348-F3FD93D14613&ext=JPG

推荐答案

您无法以这种方式加载图片。

You can't load images in this way.

您需要使用 ALAssetsLibrary 这个类。

将assetslibrary框架添加到项目中并添加头文件。

Add assetslibrary framework to your project and add header files.

使用以下代码加载图片：

Use the below code for loading image:

ALAssetsLibraryAssetForURLResultBlock resultblock = ^(ALAsset *myasset)
{
    ALAssetRepresentation *rep = [myasset defaultRepresentation];
    CGImageRef iref = [rep fullResolutionImage];
    if (iref) {
        UIImage *largeimage = [UIImage imageWithCGImage:iref];
        yourImageView.image = largeImage;
    }
};

ALAssetsLibraryAccessFailureBlock failureblock  = ^(NSError *myerror)
{
    NSLog(@"Can't get image - %@",[myerror localizedDescription]);
};

NSURL *asseturl = [NSURL URLWithString:yourURL];
ALAssetsLibrary* assetslibrary = [[[ALAssetsLibrary alloc] init] autorelease];
[assetslibrary assetForURL:asseturl 
                   resultBlock:resultblock
                  failureBlock:failureblock];

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