• ALAssetsLibrary学习总结


    添加AssetsLibrary.framework

    然后引入

    #import <AssetsLibrary/ALAssetsLibrary.h>

    一个获取所有图片的类

    #import <UIKit/UIKit.h>
    #include<AssetsLibrary/AssetsLibrary.h> 
    
    @interface ViewController : UIViewController{
      ALAssetsLibrary *library;
      
      NSArray *imageArray;
      
      NSMutableArray *mutableArray;
    }
    -(void)allPhotosCollected:(NSArray*)imgArray;
    @end
    #import "ViewController.h"
    
    @interface ViewController ()
    
    @end
    
    static int count=0;
    
    @implementation ViewController
    
    - (void)viewDidLoad
    {
      [super viewDidLoad];
      [self getAllPictures];
    }
    
    //获取所有图片
    -(void)getAllPictures
    
    {
      imageArray=[[NSArray alloc] init];
      mutableArray =[[NSMutableArray alloc]init];
      NSMutableArray* assetURLDictionaries = [[NSMutableArray alloc] init];
      library = [[ALAssetsLibrary alloc] init];
      void (^assetEnumerator)( ALAsset *, NSUInteger, BOOL *) = ^(ALAsset *result, NSUInteger index, BOOL *stop) {
        if(result != nil) {
          if([[result valueForProperty:ALAssetPropertyType] isEqualToString:ALAssetTypePhoto]) {
            [assetURLDictionaries addObject:[result valueForProperty:ALAssetPropertyURLs]];
            NSURL *url= (NSURL*) [[result defaultRepresentation]url];
            
            [library assetForURL:url
             
                 resultBlock:^(ALAsset *asset) {
                   
                   [mutableArray addObject:[UIImage imageWithCGImage:[[asset defaultRepresentation] fullScreenImage]]];
    
                   if ([mutableArray count]==count)
                     
                   {
                     
                     imageArray=[[NSArray alloc] initWithArray:mutableArray];
                     
                     [self allPhotosCollected:imageArray];
                     
                   }
                   
                 }
                failureBlock:^(NSError *error){ NSLog(@"operation was not successfull!"); } ];
          }
          
        }
        
      };
    
      NSMutableArray *assetGroups = [[NSMutableArray alloc] init];
      void (^ assetGroupEnumerator) ( ALAssetsGroup *, BOOL *)= ^(ALAssetsGroup *group, BOOL *stop) {
        
        if(group != nil) {
          
          [group enumerateAssetsUsingBlock:assetEnumerator];
          
          [assetGroups addObject:group];
          
          count=[group numberOfAssets];
          
        }
        
      };
      assetGroups = [[NSMutableArray alloc] init];
      [library enumerateGroupsWithTypes:ALAssetsGroupAll
       
                   usingBlock:assetGroupEnumerator
       
                 failureBlock:^(NSError *error) {NSLog(@"There is an error");}];
      
    }
    
    
    
    -(void)allPhotosCollected:(NSArray*)imgArray
    {
      //write your code here after getting all the photos from library...
      NSLog(@"all pictures are %@",imgArray);
    }
    
    
    @end

    以下是关于AssetsLibrary的一些方法说明,仅供参考

    //初始化,这个简单
    if (!self.assetsLibrary) {
    _assetsLibrary = [[ALAssetsLibrary alloc] init];
    }
    //添加一个group,成功后查看一些信息
    [_assetsLibrary addAssetsGroupAlbumWithName:@"tesddt" 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]);
    } failureBlock:^(NSError *error) {
    
    }];

    可以通过valueForProperty获取到图片的信息,包括类型, Location , 时长,方向,日期,格式 , URL地址。

    NSString * nsALAssetPropertyType = [ asset valueForProperty:ALAssetPropertyType ] ;

    NSString * nsALAssetPropertyLocation = [ asset valueForProperty:ALAssetPropertyLocation ] ;

    NSString * nsALAssetPropertyDuration = [ asset valueForProperty:ALAssetPropertyDuration ] ;

    NSString * nsALAssetPropertyOrientation = [ asset valueForProperty:ALAssetPropertyOrientation ] ;

    NSString * nsALAssetPropertyDate = [ asset valueForProperty:ALAssetPropertyDate ] ;

    NSString * nsALAssetPropertyRepresentations = [ asset valueForProperty:ALAssetPropertyRepresentations ] ;

    NSString * nsALAssetPropertyURLs = [ asset valueForProperty:ALAssetPropertyURLs ] ;

    NSString * nsALAssetPropertyAssetURL = [ asset valueForProperty:ALAssetPropertyAssetURL ] ;

    //通过url地址在相册资源中获取该地址的资源文件ALAsset,有可能是相片或视频
    [_library assetForURL:[NSURL URLWithString:@""] resultBlock:^(ALAsset *asset) {
    
    
    //     NSString *const ALAssetPropertyType;
    //     NSString *const ALAssetPropertyLocation;
    //     NSString *const ALAssetPropertyDuration;
    //     NSString *const ALAssetPropertyOrientation;
    //     NSString *const ALAssetPropertyDate;
    //     NSString *const ALAssetPropertyRepresentations;
    //     NSString *const ALAssetPropertyURLs;
    //     NSString *const ALAssetPropertyAssetURL;
    
    
    
    //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]);
    } failureBlock:^(NSError *error) {
    
    }];
    //通过url地址获取相册资源中的一个相册
    [_library groupForURL:groupURL resultBlock:^(ALAssetsGroup *group) {
    NSLog(@"ALAssetsGroupPropertyName:%@",[group valueForProperty:ALAssetsGroupPropertyName]);
    } failureBlock:^(NSError *error) {
    
    }];
    //根据选择的类型遍历相册资源中的相对应类型的所有相册,其中stop行参是指针,表示是否停止迭代,当赋值为false则停止
    
    //        enum {
    //        ALAssetsGroupLibrary        = (1 << 0),
    //        ALAssetsGroupAlbum          = (1 << 1),
    //        ALAssetsGroupEvent          = (1 << 2),
    //        ALAssetsGroupFaces          = (1 << 3),
    //        ALAssetsGroupSavedPhotos    = (1 << 4),
    //        ALAssetsGroupPhotoStream    = (1 << 5),
    //        ALAssetsGroupAll            = 0xFFFFFFFF,
    //        };
    
    [_library enumerateGroupsWithTypes:ALAssetsGroupAll usingBlock:^(ALAssetsGroup *group, BOOL *stop) {
    NSLog(@"group name:%@",[group valueForProperty:ALAssetsGroupPropertyName]);
    } failureBlock:^(NSError *error) {
    
    }];
    //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) {
    
    }];
    //保存图片到系统默认的相册中,使用cgimageref的形式,并且选择图片以什么旋转方向的形式保存,并返回照片的url地址
    
    //        typedef enum {
    //        ALAssetOrientationUp,            // default orientation
    //        ALAssetOrientationDown,          // 180 deg rotation
    //        ALAssetOrientationLeft,          // 90 deg CCW
    //        ALAssetOrientationRight,         // 90 deg CW
    //        ALAssetOrientationUpMirrored,    // as above but image mirrored along other axis. horizontal flip
    //        ALAssetOrientationDownMirrored,  // horizontal flip
    //        ALAssetOrientationLeftMirrored,  // vertical flip
    //        ALAssetOrientationRightMirrored, // vertical flip
    //        } ALAssetOrientation;
    
    UIImage* image = [UIImage imageNamed:@"test.png"];
    [_library writeImageToSavedPhotosAlbum:[image CGImage] orientation:ALAssetOrientationLeft completionBlock:^(NSURL *assetURL, NSError *error) {
    NSLog(@"save image:%@",assetURL);
    }];
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  • 原文地址:https://www.cnblogs.com/yjg2014/p/4280894.html
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