1、ALAssetsLibrary 系统中的资源库，可以使用他来访问资源库中的资源，照片、视屏等。
[ALAssetsLibrary authorizationStatus];获取当前应用能否访问相册资源
[_library addAssetsGroupAlbumWIthName:@”” resultBlock:^(ALAssetsGroup *group) {
//查看相册的名字
NSLog(@"ALAssetsGroupPropertyName:%@",[group valueForProperty:ALAssetsGroupPropertyName]);
//查看相册的类型
NSLog(@"ALAssetsGroupPropertyType:%@",[group valueForProperty:ALAssetsGroupPropertyType]);
//查看相册的存储id
NSLog(@"ALAssetsGroupPropertyPersistentID:%@",[group valueForProperty:ALAssetsGroupPropertyPersistentID]);
//查看相册存储的位置地址
NSLog(@"ALAssetsGroupPropertyURL:%@",[group valueForProperty:ALAssetsGroupPropertyURL]);
groupURL = [group valueForProperty:ALAssetsGroupPropertyURL];
} failureBlock:^(NSError *error) {
}]; 添加相册
[_library assetForRUL:[NSURL URLWithString:@“”] resultBlock:^(ALAsset *asset) {
//查看资源的地理位置信息
NSLog(@"ALAssetPropertyLocation:%@",[asset valueForProperty:ALAssetPropertyLocation]);
//如果资源是视频，查看视频的时长
NSLog(@"ALAssetPropertyDuration:%@",[asset valueForProperty:ALAssetPropertyDuration]);
//查看资源的方向，图片的旋转方向
NSLog(@"ALAssetPropertyOrientation:%@",[asset valueForProperty:ALAssetPropertyOrientation]);
//查看资源的创建时间
NSLog(@"ALAssetPropertyDate:%@",[asset valueForProperty:ALAssetPropertyDate]);
//查看资源的描述信息
NSLog(@"ALAssetPropertyRepresentations:%@",[asset valueForProperty:ALAssetPropertyRepresentations]);
NSLog(@"ALAssetPropertyURLs:%@",[asset valueForProperty:ALAssetPropertyURLs]);
//查看资源的url路径
NSLog(@"ALAssetPropertyAssetURL:%@",[asset valueForProperty:ALAssetPropertyAssetURL]);
//asset 拿到的图片都是CGImageRef的
} failureBlock:^(NSError *error) {
}]; 使用url读取图片
[_library groupForURL:groupURL resultBlock:^(ALAssetsGroup *group) {
} failureBlock:^(NSError *error) {
}]; //通过url地址获取相册资源中的一个相册
[_library enumerateGroupsWithTypes:ALAssetsGroupAll usingBlock:^(ALAssetsGroup *group ,BOOL *stop) {
} failureBlock:^(NSError *error) {
}];//迭代资源库中的资源group
enum {
ALAssetsGroupLibrary = (1 << 0),
ALAssetsGroupAlbum = (1 << 1),
ALAssetsGroupEvent = (1 << 2),
ALAssetsGroupFaces = (1 << 3),
ALAssetsGroupSavedPhotos = (1 << 4),
ALAssetsGroupPhotoStream = (1 << 5),
ALAssetsGroupAll = 0xFFFFFFFF,
};
//保存图片到系统默认的相册中，使用nsdata的形式，并返回照片的url地址
[_library writeImageDataToSavedPhotosAlbum:nil metadata:nil completionBlock:^(NSURL *assetURL, NSError *error) {
}];
//保存图片到系统默认的相册中，使用cgimageref的形式，并返回照片的url地址
[_library writeImageToSavedPhotosAlbum:nil metadata:nil completionBlock:^(NSURL *assetURL, NSError *error) {
}];