Xcode 如何在启动时请求访问照片库?
我正在构建一个应用程序,让用户从他们的库中拍照来做事情。我使用的是X代码,我在“didFinishLaunchingWithOptions”下有此代码,但不断出现“未声明的标识符”错误。怎么办Xcode 如何在启动时请求访问照片库?,xcode,photo,startup,undeclared-identifier,Xcode,Photo,Startup,Undeclared Identifier,我正在构建一个应用程序,让用户从他们的库中拍照来做事情。我使用的是X代码,我在“didFinishLaunchingWithOptions”下有此代码,但不断出现“未声明的标识符”错误。怎么办 ALAssetsLibraryGroupsEnumerationResultsBlock assetGroupEnumerator = ^(ALAssetsGroup *assetGroup, BOOL *stop) { if (assetGroup != nil) { // do
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];
答案太晚了,但您需要定义库
ALAssetsLibrary *library = [[ALAssetsLibrary alloc] init];
或者,如果要重用库进行更多查询,最好使用类方法
+ (ALAssetsLibrary *)defaultAssetsLibrary
{
static dispatch_once_t pred = 0;
static ALAssetsLibrary *library = nil;
dispatch_once(&pred, ^{
library = [[ALAssetsLibrary alloc] init];
});
return library;
}
是否有任何特殊原因使您不将其置于ViewController的viewDidLoad方法下?