iOS將圖片保存到指定相冊

http://bluereader.org/article/102764087

 

iOS系統提供了保存圖片的方法,可是該方法有一個弊端，該方法沒法指定要保存圖片的相冊名稱。
UIKIT_EXTERN void UIImageWriteToSavedPhotosAlbum(UIImage *image, id completionTarget, SEL completionSelector, void *contextInfo); 目前不少圖片相關應用都會將圖片寫入指定相冊，下面提供簡單的寫入指定相冊的方法。
我大概設計了這麼幾個接口，以下代碼所示

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

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@class UIImage; typedef void (^STAlbumSaveHandler)(UIImage *image, NSError *error); /** * @brief 將圖片寫入相冊,使用ALAssetLibrary * * @param image 須要寫入的圖片 * @param album 相冊名稱，若是相冊不存在，則新建相冊 * @param completionHandler 回調 */ extern void STImageWriteToPhotosAlbum(UIImage *image, NSString *album, STAlbumSaveHandler completionHandler); @interface STAlbumManager : NSObject + (instancetype)sharedManager; /** * @brief 將圖片寫入相冊,使用ALAssetLibrary * * @param image 須要寫入的圖片 * @param album 相冊名稱，若是相冊不存在，則新建相冊 * @param completionHandler 回調 */ - (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

實現文件

[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，這裏每次都置空是由於期間若是操做相冊了，下次保存以前但願能取到最新狀態。 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){/// 循環結束if(group){assetForURLBlock(assetURL,group);}else{[selfaddAssetsGroupAlbumWithName:albumresultBlock:^(ALAssetsGroup*group){assetForURLBlock(assetURL,group);}failureBlock:completionHandler];}}}failureBlock:completionHandler];}@end

簡單介紹一下代碼的使用方法
該接口定義申明瞭一個 C方法，用來提供便捷的保存調用，使用方能夠直接經過調用
extern void STImageWriteToPhotosAlbum(UIImage *image, NSString *album, STAlbumSaveHandler completionHandler);
就能夠直接保存對應的image到對應的album，若是沒有找到album，則會建立新的album，圖片保存完畢以後，會調用block回調。
或者使用Manager單例所提供的方法 - (void)saveImage:(UIImage *)image toAlbum:(NSString *)album completionHandler:(STAlbumSaveHandler)completionHandler 
這樣就實現了將圖片保存到指定相冊,感謝 技術笨 提供Demo