iOS开发之保存照片到本身建立的相簿

iOS开发之保存照片到系统相册（Photo Album） ，

保存照片还能够用ALAssetsLibrary，ALAssetsLibrary提供了咱们对iOS设备中的相片、视频的访问，是链接应用程序和相册之间访问的一个桥梁。

接下来，咱们来详细讲解一下关于系统相册权限获取、保存照片、建立本身的相簿等等功能。

建立本身的相簿

这也是一种比较建立的做法，建立本身的相簿，而后把照片或者视频保存到本身的相簿中。相关代码以下：

ALAssetsLibrary *library = [[ALAssetsLibrary alloc] init];
[library addAssetsGroupAlbumWithName:@"test" resultBlock:^(ALAssetsGroup *group) { //建立相簿成功 } failureBlock:^(NSError *error) { //失败 }];

保存照片

这个方法也是将照片保存到系统相簿里面，不是保存到本身建立的相簿里面。代码以下：

ALAssetsLibrary *library = [[ALAssetsLibrary alloc]init];
[library writeImageToSavedPhotosAlbum:image.CGImage orientation:(ALAssetOrientation)image.imageOrientation completionBlock:^(NSURL *asSetUrl,NSError *error){ if (error) { //失败 }else{ UIAlertView *alert = [[UIAlertView alloc]initWithTitle:@"存储成功" message:nil delegate:nil cancelButtonTitle:@"肯定" otherButtonTitles:nil, nil]; [alert show]; } }];

获取权限

在保存照片以前，若是用户关闭相册权限，这个时候是保存失败的。若是你不作任何处理，用户是不会知道本身保存失败了。因此，咱们能够在保存照片以前，作出相应的提示。如何获取这个权限呢？通常有两种方法：

1. 建立相簿失败

2. 保存照片失败

在上面两个方法建立本身的相簿和保存照片的失败结果里，咱们能够弹出获取照片权限失败的提示。咱们拿第一个建立相簿失败来举例：

ALAssetsLibrary *library = [[ALAssetsLibrary alloc] init];
[library addAssetsGroupAlbumWithName:@"test" resultBlock:^(ALAssetsGroup *group) { //建立相簿成功 } failureBlock:^(NSError *error) { UIAlertView *alert = [[UIAlertView alloc]initWithTitle:@"存储失败" message:@"请打开 设置-隐私-照片 来进行设置" delegate:nil cancelButtonTitle:@"肯定" otherButtonTitles:nil, nil]; [alert show]; }];

在保存照片失败的结果里，咱们也能够弹出相应的提示，让用户打开应用程序的相册权限。

保存照片到本身的相簿

下面这段代码是在大谷歌里面找到的，亲自测试过是能够用的，整理以下：

#pragma mark - 建立相册 - (void)createAlbum { ALAssetsLibrary *assetsLibrary = [[ALAssetsLibrary alloc] init]; NSMutableArray *groups=[[NSMutableArray alloc]init]; ALAssetsLibraryGroupsEnumerationResultsBlock listGroupBlock = ^(ALAssetsGroup *group, BOOL *stop) { if (group) { [groups addObject:group]; } else { BOOL haveHDRGroup = NO; for (ALAssetsGroup *gp in groups) { NSString *name =[gp valueForProperty:ALAssetsGroupPropertyName]; if ([name isEqualToString:@"iOSDevTip"]) { haveHDRGroup = YES; } } if (!haveHDRGroup) { //do add a group named "XXXX" [assetsLibrary addAssetsGroupAlbumWithName:@"iOSDevTip" resultBlock:^(ALAssetsGroup *group) { [groups addObject:group]; } failureBlock:nil]; haveHDRGroup = YES; } } }; //建立相簿 [assetsLibrary enumerateGroupsWithTypes:ALAssetsGroupAlbum usingBlock:listGroupBlock failureBlock:nil]; [self saveToAlbumWithMetadata:nil imageData:UIImagePNGRepresentation(self.image) customAlbumName:@"iOSDevTip" completionBlock:^ { //这里能够建立添加成功的方法 } failureBlock:^(NSError *error) { //处理添加失败的方法显示alert让它回到主线程执行，否则那个框框死活不愿弹出来 dispatch_async(dispatch_get_main_queue(), ^{ //添加失败通常是由用户不容许应用访问相册形成的，这边能够取出这种状况加以判断一下 if([error.localizedDescription rangeOfString:@"User denied access"].location != NSNotFound ||[error.localizedDescription rangeOfString:@"用户拒绝访问"].location!=NSNotFound){ UIAlertView *alert=[[UIAlertView alloc]initWithTitle:error.localizedDescription message:error.localizedFailureReason delegate:nil cancelButtonTitle:NSLocalizedString(@"ok", nil) otherButtonTitles: nil]; [alert show]; } }); }]; } - (void)saveToAlbumWithMetadata:(NSDictionary *)metadata imageData:(NSData *)imageData customAlbumName:(NSString *)customAlbumName completionBlock:(void (^)(void))completionBlock failureBlock:(void (^)(NSError *error))failureBlock { ALAssetsLibrary *assetsLibrary = [[ALAssetsLibrary alloc] init]; __weak ALAssetsLibrary *weakSelf = assetsLibrary; void (^AddAsset)(ALAssetsLibrary *, NSURL *) = ^(ALAssetsLibrary *assetsLibrary, NSURL *assetURL) { [assetsLibrary assetForURL:assetURL resultBlock:^(ALAsset *asset) { [assetsLibrary enumerateGroupsWithTypes:ALAssetsGroupAll usingBlock:^(ALAssetsGroup *group, BOOL *stop) { if ([[group valueForProperty:ALAssetsGroupPropertyName] isEqualToString:customAlbumName]) { [group addAsset:asset]; if (completionBlock) { completionBlock(); } } } failureBlock:^(NSError *error) { if (failureBlock) { failureBlock(error); } }]; } failureBlock:^(NSError *error) { if (failureBlock) { failureBlock(error); } }]; }; [assetsLibrary writeImageDataToSavedPhotosAlbum:imageData metadata:metadata completionBlock:^(NSURL *assetURL, NSError *error) { if (customAlbumName) { [assetsLibrary addAssetsGroupAlbumWithName:customAlbumName resultBlock:^(ALAssetsGroup *group) { if (group) { [weakSelf assetForURL:assetURL resultBlock:^(ALAsset *asset) { [group addAsset:asset]; if (completionBlock) { completionBlock(); } } failureBlock:^(NSError *error) { if (failureBlock) { failureBlock(error); } }]; } else { AddAsset(weakSelf, assetURL); } } failureBlock:^(NSError *error) { AddAsset(weakSelf, assetURL); }]; } else { if (completionBlock) { completionBlock(); } } }]; }

ALAssetsLibrary+CustomPhotoAlbum保存照片

github上有一个项目ALAssetsLibrary+CustomPhotoAlbum，讲保存照片作了很好的封装。使用以前记得先导入头文件：

#import "ALAssetsLibrary+CustomPhotoAlbum.h"

保存照片到本身的相簿，直接调用：

ALAssetsLibrary *library = [[ALAssetsLibrary alloc] init];
[library saveImage:self.image toAlbum:@"gang" completion:^(NSURL *assetURL, NSError *error) { if (!error) { } } failure:^(NSError *error) { }];

ALAssetsLibrary+CustomPhotoAlbum对保存视频的封装也是很是好的。