iOS将图片保存到指定相册

最新推荐文章于 2019-06-23 15:19:30 发布

jeffasd

最新推荐文章于 2019-06-23 15:19:30 发布

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分类专栏： iOS

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iOS系统提供了保存图片的方法,但是该方法有一个弊端，该方法无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); 目前很多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，如下代码所示

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

@class UIImage;
typedef void (^STAlbumSaveHandler)(UIImage *image, NSError *error);

/**
 * @brief 将图片写入相册,使用ALAssetLibrary
 *
 * @param  image    需要写入的图片
 * @param  album    相册名称，如果相册不存在，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    需要写入的图片
 * @param  album    相册名称，如果相册不存在，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]

#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，这里每次都置空是因为期间如果操作相册了，下次保存之前希望能取到最新状态。
                     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 *)assetURL toAlbum:(NSString *)album completionHandler:(ALAssetsLibraryAccessFailureBlock)completionHandler {
    void (^assetForURLBlock)(NSURL *, ALAssetsGroup *) = ^(NSURL *URL, ALAssetsGroup *group) {
        [self assetForURL:assetURL
            resultBlock:^(ALAsset *asset) {
                [group addAsset:asset];
                completionHandler(nil);
            }
            failureBlock:^(NSError *error) { completionHandler(error); }];
    };
    __block ALAssetsGroup *group;
    [self enumerateGroupsWithTypes:ALAssetsGroupAlbum
                        usingBlock:^(ALAssetsGroup *_group, BOOL *stop) {
                            if ([album isEqualToString:[_group valueForProperty:ALAssetsGroupPropertyName]]) {
                                group = _group;
                            }
                            if (!_group) {
                                /// 循环结束
                                if (group) {
                                    assetForURLBlock(assetURL, group);
                                } else {
                                    [self addAssetsGroupAlbumWithName:album
                                                          resultBlock:^(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，使用方可以直接通过调用
extern void STImageWriteToPhotosAlbum(UIImage *image, NSString *album, STAlbumSaveHandler completionHandler);
就可以直接保存对应的image到对应的album，如果没有找到album，则会创建新的album，图片保存完毕之后，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