如何在啓動時要求訪問照片庫？

Question

我正在構建一個應用程序，讓用戶從他們的圖庫中拍照來做事情。我正在使用X代碼，並且我在'didFinishLaunchingWithOptions'下面有了這段代碼，但不斷收到'未聲明的標識符'錯誤。該怎麼辦？

ALAssetsLibraryGroupsEnumerationResultsBlock assetGroupEnumerator = 
^(ALAssetsGroup *assetGroup, BOOL *stop) { 
    if (assetGroup != nil) { 
     // do somthing 
    } 
}; 

ALAssetsLibraryAccessFailureBlock assetFailureBlock = ^(NSError *error) { 
    LogError(@"Error enumerating photos: %@",[error description]); 

}; 

NSUInteger groupTypes = ALAssetsGroupAll; 

[library enumerateGroupsWithTypes:groupTypes usingBlock:assetGroupEnumerator failureBlock:assetFailureBlock]; 

Answer 1

太晚了一個答案，但你需要定義庫

ALAssetsLibrary *library = [[ALAssetsLibrary alloc] init]; 

或更好地使用一個類的方法，如果你打算重用庫更多查詢

+ (ALAssetsLibrary *)defaultAssetsLibrary 
{ 
    static dispatch_once_t pred = 0; 
    static ALAssetsLibrary *library = nil; 
    dispatch_once(&pred, ^{ 
     library = [[ALAssetsLibrary alloc] init]; 
    }); 
    return library; 
}