iOS开发之获取系统相册中的图片与视频(内带url转换)

话不多说,直接上代码

[objc] view
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#import <AssetsLibrary/AssetsLibrary.h>  // 必须导入  

  

// 照片原图路径  

#define KOriginalPhotoImagePath   \  

[[NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES) objectAtIndex:0] stringByAppendingPathComponent:@"OriginalPhotoImages"]  

  

// 视频URL路径  

#define KVideoUrlPath   \  

[[NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES) objectAtIndex:0] stringByAppendingPathComponent:@"VideoURL"]  

  

// caches路径  

#define KCachesPath   \  

[NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES) objectAtIndex:0]  

  

// MainViewController  

@interface MTHMainViewController ()  

  

@property (nonatomic,strong) MTHNextViewController *nextVC;  

@property (nonatomic,strong) NSMutableArray        *groupArrays;  

@property (nonatomic,strong) UIImageView           *litimgView;  

  

@end  

  

@implementation MTHMainViewController  

  

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil  

{  

    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];  

    if (self) {  

        // Custom initialization  

    }  

    return self;  

}  

  

- (void)viewDidLoad  

{  

    [super viewDidLoad];  

    // Do any additional setup after loading the view.  

    self.navigationItem.title = @"Demo";  

    self.view.backgroundColor = [UIColor clearColor];  

      

    // 初始化  

    self.groupArrays = [NSMutableArray array];  

      

    // 测试BarItem  

    self.navigationItem.rightBarButtonItem = [[UIBarButtonItem alloc] initWithTitle:@"测试" style:UIBarButtonItemStylePlain target:self action:@selector(testRun)];  

      

    // 测试手势  

    UIPanGestureRecognizer *panRecognizer = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(didClickPanGestureRecognizer:)];  

    [self.navigationController.view addGestureRecognizer:panRecognizer];  

      

    // 图片或者视频的缩略图显示  

    self.litimgView = [[UIImageView alloc] initWithFrame:CGRectMake(100, 200, 120, 120)];  

    [self.view addSubview:_litimgView];  

}  

  

  

- (void)testRun  

{  

    __weak MTHMainViewController *weakSelf = self;  

    dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{  

        ALAssetsLibraryGroupsEnumerationResultsBlock listGroupBlock = ^(ALAssetsGroup *group, BOOLBOOL *stop) {  

            if (group != nil) {  

                [weakSelf.groupArrays addObject:group];  

            } else {  

                [weakSelf.groupArrays enumerateObjectsUsingBlock:^(id obj, NSUInteger idx, BOOLBOOL *stop) {  

                    [obj enumerateAssetsUsingBlock:^(ALAsset *result, NSUInteger index, BOOLBOOL *stop) {  

                        if ([result thumbnail] != nil) {  

                            // 照片  

                            if ([[result valueForProperty:ALAssetPropertyType] isEqualToString:ALAssetTypePhoto]){  

                                  

                                NSDate *date= [result valueForProperty:ALAssetPropertyDate];  

                                UIImage *image = [UIImage imageWithCGImage:[result thumbnail]];  

                                NSString *fileName = [[result defaultRepresentation] filename];  

                                NSURL *url = [[result defaultRepresentation] url];  

                                int64_t fileSize = [[result defaultRepresentation] size];  

                                  

                                NSLog(@"date = %@",date);  

                                NSLog(@"fileName = %@",fileName);  

                                NSLog(@"url = %@",url);  

                                NSLog(@"fileSize = %lld",fileSize);  

                                  

                                // UI的更新记得放在主线程,要不然等子线程排队过来都不知道什么年代了,会很慢的  

                                dispatch_async(dispatch_get_main_queue(), ^{  

                                    self.litimgView.image = image;  

                                });  

                            }  

                            // 视频  

                            else if ([[result valueForProperty:ALAssetPropertyType] isEqualToString:ALAssetTypeVideo] ){  

                              

                                // 和图片方法类似  

                            }  

                        }  

                    }];  

                }];  

  

            }  

        };  

          

        ALAssetsLibraryAccessFailureBlock failureBlock = ^(NSError *error)  

        {  

              

            NSString *errorMessage = nil;  

              

            switch ([error code]) {  

                case ALAssetsLibraryAccessUserDeniedError:  

                case ALAssetsLibraryAccessGloballyDeniedError:  

                    errorMessage = @"用户拒绝访问相册,请在<隐私>中开启";  

                    break;  

                      

                default:  

                    errorMessage = @"Reason unknown.";  

                    break;  

            }  

              

            dispatch_async(dispatch_get_main_queue(), ^{  

                UIAlertView *alertView = [[UIAlertView alloc]initWithTitle:@"错误,无法访问!"  

                                                                   message:errorMessage  

                                                                  delegate:self  

                                                         cancelButtonTitle:@"确定"  

                                                         otherButtonTitles:nil, nil nil];  

                [alertView show];  

            });  

        };  

          

          

        ALAssetsLibrary *assetsLibrary = [[ALAssetsLibrary alloc]  init];  

        [assetsLibrary enumerateGroupsWithTypes:ALAssetsGroupAll  

                                     usingBlock:listGroupBlock failureBlock:failureBlock];  

    });  

}  



      @但是:

      按照上面方法直接取出来的路径是无法传输的,必须自己转化成NSData对象重新写入沙盒路径

[objc] view
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// 将原始图片的URL转化为NSData数据,写入沙盒  

- (void)imageWithUrl:(NSURL *)url withFileName:(NSString *)fileName  

{  

    // 进这个方法的时候也应该加判断,如果已经转化了的就不要调用这个方法了  

    // 如何判断已经转化了,通过是否存在文件路径  

    ALAssetsLibrary *assetLibrary = [[ALAssetsLibrary alloc] init];  

    // 创建存放原始图的文件夹--->OriginalPhotoImages  

    NSFileManager * fileManager = [NSFileManager defaultManager];  

    if (![fileManager fileExistsAtPath:KOriginalPhotoImagePath]) {  

        [fileManager createDirectoryAtPath:KOriginalPhotoImagePath withIntermediateDirectories:YES attributes:nil error:nil];  

    }  

    dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{  

        if (url) {  

            // 主要方法  

            [assetLibrary assetForURL:url resultBlock:^(ALAsset *asset) {  

                ALAssetRepresentation *rep = [asset defaultRepresentation];  

                Byte *buffer = (Byte*)malloc((unsigned long)rep.size);  

                NSUInteger buffered = [rep getBytes:buffer fromOffset:0.0 length:((unsigned long)rep.size) error:nil];  

                NSData *data = [NSData dataWithBytesNoCopy:buffer length:buffered freeWhenDone:YES];  

                NSString * imagePath = [KOriginalPhotoImagePath stringByAppendingPathComponent:fileName];  

                [data writeToFile:imagePath atomically:YES];  

            } failureBlock:nil];  

        }  

    });  

}  

  

// 将原始视频的URL转化为NSData数据,写入沙盒  

- (void)videoWithUrl:(NSURL *)url withFileName:(NSString *)fileName  

{  

    // 解析一下,为什么视频不像图片一样一次性开辟本身大小的内存写入?  

    // 想想,如果1个视频有1G多,难道直接开辟1G多的空间大小来写?  

    ALAssetsLibrary *assetLibrary = [[ALAssetsLibrary alloc] init];  

    dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{  

        if (url) {  

            [assetLibrary assetForURL:url resultBlock:^(ALAsset *asset) {  

                ALAssetRepresentation *rep = [asset defaultRepresentation];  

                NSString * videoPath = [KCachesPath stringByAppendingPathComponent:fileName];  

                char constconst *cvideoPath = [videoPath UTF8String];  

                FILEFILE *file = fopen(cvideoPath, "a+");  

                if (file) {  

                    const int bufferSize = 11024 * 1024;  

                    // 初始化一个1M的buffer  

                    Byte *buffer = (Byte*)malloc(bufferSize);  

                    NSUInteger read = 0, offset = 0, written = 0;  

                    NSError* err = nil;  

                    if (rep.size != 0)  

                    {  

                        do {  

                            read = [rep getBytes:buffer fromOffset:offset length:bufferSize error:&err];  

                            written = fwrite(buffer, sizeof(char), read, file);  

                            offset += read;  

                        } while (read != 0 && !err);//没到结尾，没出错，ok继续  

                    }  

                    // 释放缓冲区，关闭文件  

                    free(buffer);  

                    buffer = NULL;  

                    fclose(file);  

                    file = NULL;  

                }  

            } failureBlock:nil];  

        }  

    });  

}