我如何避免从AlassetLibrary的位置服务？ [英] How can i avoid location service from AlassetLibrary?

问题描述

可能重复：

b $ b我是iphone开发和obj-c的新手。我在我的应用程序中使用ALAssetLibrary从照片库中检索图像。
我确定 ALAssetPropertyLocation 属性键仅在调用者启用位置服务时可用。它是检索资产的位置信息的关键。但是我没有使用ALAssetPropertyLocationProperty.i只使用 ALAssetPropertyURLs 。

Hi all, I am a newbie in iphone development and obj-c. i am using "ALAssetLibrary" in my Application to retrieve images from Photo Library. I identified that "ALAssetPropertyLocation"Property Key only available if location services are enabled for the caller. it is the key to retrieve the location information of the asset.But i am not using "ALAssetPropertyLocation"Property.i am using only ALAssetPropertyURLs.

我试图在一个新的设备部署我的应用程序有一个消息框，消息定位服务需要..
我可以隐藏ALAssetPropertyLocation属性？

whenever i am trying to deploy my Application in a new device there is a message box with the message "Location Service needed.." can i able to hide the "ALAssetPropertyLocation"Property?

我真的很感激，如果有人可以帮助我以正确的方式来处理我的问题，如果可能的话，任何示例代码让我开始。

I would really appreciate if someone could assist me in the correct way to approach my problem, and if possible any sample code to get my started.

谢谢提前：）

这是我的代码：

//Getting image url from dictionary according to the user input
NSURL *imageurl = [dict objectForKey: [youSaid text]];   

//Getting asset from url
typedef void (^ALAssetsLibraryAssetForURLResultBlock)(ALAsset *asset);
typedef void (^ALAssetsLibraryAccessFailureBlock)(NSError *error);    
ALAssetsLibraryAssetForURLResultBlock resultblock = ^(ALAsset *myasset)
{
    ALAssetRepresentation *rep = [myasset defaultRepresentation];
    CGImageRef iref = [rep fullResolutionImage];
    //Setting asset image to image view according to the image url
    [imageview setImage:[UIImage imageWithCGImage:iref]];        
};
ALAssetsLibraryAccessFailureBlock failureblock  = ^(NSError *myerror)
{
    NSLog(@"Error, cant get image - %@",[myerror localizedDescription]);
}; 

if(imageurl != nil)
{
ALAssetsLibrary *assetLibrary=[[ALAssetsLibrary alloc] init];
[assetLibrary assetForURL:imageurl resultBlock:resultblock    failureBlock:failureblock];      
}

推荐答案

启用位置服务使用AssetsLibrary的要求。
原因是照片库中的任何照片/视频可能包含地理数据。这些数据不仅可以通过ALAssetPropertyURLs获得，还可以从资产中读取原始数据（通过使用getAllSetsRepresentation的getBytes：fromOffset：length：error：Method）。因为没有办法从原始图像数据剥离地理元数据（如果位置服务被禁用），我想设计决定是使位置服务强制使用AssetsLibrary。

enabling "location services "is a requirement for using the AssetsLibrary. The reason is that any photos/videos in the Photo-Library might contain geodata. This data is not just available through ALAssetPropertyURLs, but also if you read out the raw data from the asset (by using the getBytes:fromOffset:length:error: Method of ALAssetsRepresentation). Cause there is no way to strip the geo metadata from the raw image data (in case location services are disabled), I guess the design decision was made to make "location services" mandatory for using the AssetsLibrary.

此要求可能会让用户感到困惑。因此，您需要执行以下两项操作：

This requirement might be confusing to the user. So you need to do 2 things:

1）如果用户拒绝访问位置服务，则会在您的应用需要此访问权限时显示一条清除消息，实际上不确定当前位置或任何GPS /数据。

1) If the user denies access to location services, then present a clear message while your app needs this access and that the app does not actually determine the current position or any GPS/data.

2）显示清楚的说明如何启用位置服务，一旦用户按下否​​ 。

2) Display clear instructions how to enable location services, once the user has pressed "NO" on the initial dialog.

干杯，

Hendrik

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