从 iphone 图片库中获取所有图片并在 UICollectionView 中显示

Posted 2023-04-15

【中文标题】从 iphone 图片库中获取所有图片并在 UICollectionView 中显示

【英文标题】：Get all Images from iphone image library and show in UICollectionView

【发布时间】：2014-12-10 11:40:08

【问题描述】：

我想将 iphone 图像库中的所有图像显示到 UICollectionView，但在完成 getAllPictures 方法后，allPhotosCollected: 方法未调用且图像未显示到 UICollectionView

- (void)viewDidLoad

    [super viewDidLoad];
    [self getAllPictures];
 

- (NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section
    return [imageArray count];



- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath
    static NSString *identifier = @"Cell";

    UICollectionViewCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:identifier forIndexPath:indexPath];

    UIImageView *recipeImageView = (UIImageView *)[cell viewWithTag:100];

    recipeImageView.image = [UIImage imageNamed:[imageArray objectAtIndex:indexPath.row]];
    cell.backgroundView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"photo-frame.png"]];

    return cell;



-(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]]];



                                 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

    NSLog(@"all pictures are %@",imgArray);
    [self.collectionView setDelegate:self];
    [self.collectionView setDataSource:self];

【问题讨论】：

***.com/questions/12633843/…

如果你有这么多图片，那么加载会占用大量内存。尝试使用更少的图片

我只有 2 张图片

@KiritModi 我已经检查了这个问题，但没有得到正确的答案

使用演示。 github.com/chiunam/CTAssetsPickerController

【参考方案1】：

请看下面的代码。我希望它对你有帮助。

从图库中获取所有图片

查看控制器头(.h)文件..

#import <UIKit/UIKit.h>
#import <AssetsLibrary/AssetsLibrary.h> 

@interface getPhotoLibViewController : UIViewController

    ALAssetsLibrary *library;
    NSArray *imageArray;
    NSMutableArray *mutableArray;


-(void)allPhotosCollected:(NSArray*)imgArray;

@end

实现文件(.m)

将全局计数变量声明为

static int count=0;

@implementation getPhotoLibViewController

-(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);
 

@结束 使用 getAllPicture 方法从照片库中获取照片。

或者你可以看看这个博客http://mutiselectimagepicker.blogspot.in/2014/08/imageselect-to-allow-multiple-selection.html

【参考方案2】：

你忘了重新加载collectionView数据，在获取所有图片后插入这行代码：

[self.collectionView reloadData];

但是，我建议您使用 Photos Framework 而不是 ALAssetsLibrary，因为 ALAssetsLibrary 已被弃用。这里(link) 是照片框架获取所有视频的示例，您必须对其进行修改以获取照片而不是视频。