iOS将图片保存到指定相册

http://bluereader.org/article/102764087

 

iOS系统提供了保存图片的方法,可是该方法有一个弊端，该方法没法指定要保存图片的相册名称。
UIKIT_EXTERN void UIImageWriteToSavedPhotosAlbum(UIImage *image, id completionTarget, SEL completionSelector, void *contextInfo); 目前不少图片相关应用都会将图片写入指定相册，下面提供简单的写入指定相册的方法。
我大概设计了这么几个接口，以下代码所示

[STAlumbManager.h] [url] [link text]

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@class UIImage; typedef void (^STAlbumSaveHandler)(UIImage *image, NSError *error); /** * @brief 将图片写入相册,使用ALAssetLibrary * * @param image 须要写入的图片 * @param album 相册名称，若是相册不存在，则新建相册 * @param completionHandler 回调 */ extern void STImageWriteToPhotosAlbum(UIImage *image, NSString *album, STAlbumSaveHandler completionHandler); @interface STAlbumManager : NSObject + (instancetype)sharedManager; /** * @brief 将图片写入相册,使用ALAssetLibrary * * @param image 须要写入的图片 * @param album 相册名称，若是相册不存在，则新建相册 * @param completionHandler 回调 */ - (void)saveImage:(UIImage *)image toAlbum:(NSString *)album completionHandler:(STAlbumSaveHandler)completionHandler; @end @interface ALAssetsLibrary (STAssetsLibrary) - (void)writeImage:(UIImage *)image toAlbum:(NSString *)album completionHandler:(STAlbumSaveHandler)completionHandler; @end

实现文件

[STAlumbManager.m] [url] [link text]

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#import "STAlbumManager.h" #import <UIKit/UIKit.h> void STImageWriteToPhotosAlbum(UIImage *image, NSString *album, STAlbumSaveHandler completionHandler) { [[STAlbumManager sharedManager] saveImage:image toAlbum:album completionHandler:completionHandler]; } @interface STAlbumManager () @property(nonatomic, strong) ALAssetsLibrary *assetsLibrary; @end @implementation STAlbumManager static STAlbumManager *_sharedManager; + (instancetype)sharedManager { static dispatch_once_t onceToken; dispatch_once(&onceToken, ^{ _sharedManager = [[self alloc] init]; }); return _sharedManager; } - (instancetype)init { self = [super init]; if (self) { } return self; } - (ALAssetsLibrary *)assetsLibrary { if (!_assetsLibrary) { _assetsLibrary = [[ALAssetsLibrary alloc] init]; } return _assetsLibrary; } - (void)saveImage:(UIImage *)image toAlbum:(NSString *)album completionHandler:(STAlbumSaveHandler)completionHandler { [self.assetsLibrary writeImage:image toAlbum:album completionHandler:^(UIImage *image, NSError *error) { if (completionHandler) { completionHandler(image, error); } /// 注意，这里每次都置空是由于期间若是操做相册了，下次保存以前但愿能取到最新状态。 self.assetsLibrary = nil; }]; } @end @implementation ALAssetsLibrary (STAssetsLibrary) - (void)writeImage:(UIImage *)image toAlbum:(NSString *)album completionHandler:(STAlbumSaveHandler)completionHandler { [self writeImageToSavedPhotosAlbum:image.CGImage orientation:(ALAssetOrientation)image.imageOrientation completionBlock:^(NSURL *assetURL, NSError *error) { if (error) { if (completionHandler) { completionHandler(image, error); } } else { [self addAssetURL:assetURL toAlbum:album completionHandler:^(NSError *error) { if (completionHandler) { completionHandler(image, error); } }]; } }]; } - (void)addAssetURL:(NSURL*)assetURLtoAlbum:(NSString*)albumcompletionHandler:(ALAssetsLibraryAccessFailureBlock)completionHandler{void(^assetForURLBlock)(NSURL*,ALAssetsGroup*)=^(NSURL*URL,ALAssetsGroup*group){[selfassetForURL:assetURLresultBlock:^(ALAsset*asset){[groupaddAsset:asset];completionHandler(nil);}failureBlock:^(NSError*error){completionHandler(error);}];};__blockALAssetsGroup*group;[selfenumerateGroupsWithTypes:ALAssetsGroupAlbumusingBlock:^(ALAssetsGroup*_group,BOOL*stop){if([albumisEqualToString:[_groupvalueForProperty:ALAssetsGroupPropertyName]]){group=_group;}if(!_group){/// 循环结束if(group){assetForURLBlock(assetURL,group);}else{[selfaddAssetsGroupAlbumWithName:albumresultBlock:^(ALAssetsGroup*group){assetForURLBlock(assetURL,group);}failureBlock:completionHandler];}}}failureBlock:completionHandler];}@end

简单介绍一下代码的使用方法
该接口定义申明了一个 C方法，用来提供便捷的保存调用，使用方能够直接经过调用
extern void STImageWriteToPhotosAlbum(UIImage *image, NSString *album, STAlbumSaveHandler completionHandler);
就能够直接保存对应的image到对应的album，若是没有找到album，则会建立新的album，图片保存完毕以后，会调用block回调。
或者使用Manager单例所提供的方法 - (void)saveImage:(UIImage *)image toAlbum:(NSString *)album completionHandler:(STAlbumSaveHandler)completionHandler 
这样就实现了将图片保存到指定相册,感谢 技术笨 提供Demo