使用AWS for ios下载图像

我不熟悉ios编程，请原谅我的错误。 我正在开发一个应用程序，需要上传和下载文件，基本上是图像文件。我使用AWS ios sdk。我能够下载图像文件并将其保存到文档文件夹（在模拟器上测试时）

问题是，一旦下载图像，我就必须将其移动到iphone的照片库中。代码是：-

-(IBAction)downloadButtonAction:(id)sender;
{


    NSMutableArray *rowsToBeDownloaded = [[NSMutableArray alloc] init];
    NSMutableArray *indexPaths = [[NSMutableArray alloc] init];
    int index = 0;


    for (NSNumber *rowSelected in selectedArray)
    {
        if ([rowSelected boolValue])
        {

            [rowsToBeDownloaded addObject:[objects objectAtIndex:index]];
            NSUInteger pathSource[2] = {0, index};
            NSIndexPath *path = [NSIndexPath indexPathWithIndexes:pathSource length:2];

            [indexPaths addObject:path];
        }       
        index++;

    }

    if([rowsToBeDownloaded count]==0)
    {
        UIAlertView *alert=[[UIAlertView alloc]initWithTitle:@"Alert" message:@"Please select a file to download" delegate:self cancelButtonTitle:@"Ok" otherButtonTitles:nil];
        [alert show];
        [alert release];
    }
    else 
    {

        for (id value in rowsToBeDownloaded)
        {
            NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
            NSString *documentsDirectory = [paths objectAtIndex:0];
            NSString *path = [documentsDirectory stringByAppendingPathComponent:value];

        AmazonS3Client *s3Client = [[AmazonS3Client alloc] initWithAccessKey:accessKey withSecretKey:secretKey];

        NSOutputStream *stream = [[NSOutputStream alloc] initToFileAtPath:path append:NO];
        [stream scheduleInRunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode];
        [stream open];

        S3GetObjectRequest *request = [[S3GetObjectRequest alloc] initWithKey:value withBucket:self.bucket];
        request.outputStream = stream;
        [s3Client getObject:request];

        //UIImageWriteToSavedPhotosAlbum(self.selectedImage, nil,nil,nil);

        [stream close];
        [stream release];
        [request release];
        }
    }   
    [indexPaths release];
    [rowsToBeDeleted release];
    [self populateSelectedArray];
    [self transferImagesToPhotolibrary];


}



-(void)transferImagesToPhotolibrary
{
    //int index=0;
//  
//  NSMutableArray*imgArr=[[NSMutableArray alloc] init];
//  NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
//  NSString *documentsDirectory = [paths objectAtIndex:0];
//  NSDirectoryEnumerator *directoryEnumerator = [[NSFileManager defaultManager] enumeratorAtPath:documentsDirectory];
//  
//  
//  for (NSString *path in directoryEnumerator) 
//  {
//      if([[path pathExtension]isEqualToString:@"png"])
//      { 
//          [imgArr addObject:path];         
//              //UIImage*img=[UIImage imageNamed:path];
//              //UIImageWriteToSavedPhotosAlbum(img, nil,nil,nil);
//
//      }
//  }


    NSMutableArray*imgArr=[[NSMutableArray alloc] init];
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *documentsDirectory = [paths objectAtIndex:0];
    NSDirectoryEnumerator *directoryEnumerator = [[NSFileManager defaultManager] enumeratorAtPath:documentsDirectory];

    for (NSString *path in directoryEnumerator) 
    {

        if([[path pathExtension]isEqualToString:@"png"])
        { 
            printf("\n path is %s",[path UTF8String]);

            [imgArr addObject:path];         
        }

    }
    for(int i=0;i<[imgArr count];i++)
    {

    UIImage*img=[UIImage imageNamed:[imgArr objectAtindex:i]];

        UIImageWriteToSavedPhotosAlbum(img, nil,nil,nil);


    }

}

-（iAction）下载按钮操作：（id）发送方；
{
NSMutableArray*rowsToBeDownloaded=[[NSMutableArray alloc]init]；
NSMutableArray*indexPaths=[[NSMutableArray alloc]init]；
int指数=0；
对于（NSNumber*RowSelectedArray中选定的行）
{
如果（[rowSelected boolValue]）
{
[rowsToBeDownloaded addObject:[objects objectAtIndex:index]]；
NSU整数路径源[2]={0，索引}；
nsindepath*path=[nsindepath indexPathWithIndexes:pathSource长度：2]；
[indexPaths addObject:path]；
}       
索引++；
}
如果（[rowsToBeDownloaded count]==0）
{
UIAlertView*alert=[[UIAlertView alloc]initWithTitle:@“alert”消息：@“请选择要下载的文件”委托：自取消按钮：@“确定”其他按钮：无]；
[警报显示]；
[警报发布]；
}
其他的
{
for（行中的id值stobedownload）
{
NSArray*Path=NSSearchPathForDirectoriesInDomains（NSDocumentDirectory，NSUserDomainMask，是）；
NSString*documentsDirectory=[paths objectAtIndex:0]；
NSString*path=[DocumentsDirectoryStringByAppendingPathComponent:value]；
AmazonS3Client*s3Client=[[AmazonS3Client alloc]initWithAccessKey:accessKey with secretKey:secretKey]；
NSOutputStream*stream=[[NSOutputStream alloc]initToFileAtPath:path append:NO]；
[stream ScheduleRunLoop:[NSRunLoop currentRunLoop]forMode:NSDefaultRunLoopMode]；
[溪流开放]；
S3GetObjectRequest*request=[[S3GetObjectRequest alloc]initWithKey:value withBucket:self.bucket]；
request.outputStream=流；
[s3Client-getObject:request]；
//UIImageWriteToSavedPhotosAlbum（自选图像，无，无，无）；
[溪流关闭]；
[溪流释放]；
[请求释放]；
}
}   
[INDExpath释放]；
[rowsToBeDeleted释放]；
[自选阵营]；
[自转移影像停止摄影库]；
}
-（无效）转让影像停止酒店图书馆
{
//int指数=0；
//  
//NSMutableArray*imgArr=[[NSMutableArray alloc]init]；
//NSArray*Path=NSSearchPathForDirectoriesInDomains（NSDocumentDirectory，NSUserDomainMask，是）；
//NSString*documentsDirectory=[paths objectAtIndex:0]；
//NSDirectoryEnumerator*directoryEnumerator=[[NSFileManager defaultManager]枚举器路径：documentsDirectory]；
//  
//  
//for（directoryEnumerator中的NSString*路径）
//  {
//如果（[[path pathExtension]isEqualToString:@“png”]）
//      { 
//[imgArr addObject:path]；
////UIImage*img=[UIImage imagename:path]；
////UIImageWriteToSavedPhotosAlbum（img，nil，nil，nil）；
//
//      }
//  }
NSMutableArray*imgArr=[[NSMutableArray alloc]init]；
NSArray*Path=NSSearchPathForDirectoriesInDomains（NSDocumentDirectory，NSUserDomainMask，是）；
NSString*documentsDirectory=[paths objectAtIndex:0]；
NSDirectoryEnumerator*directoryEnumerator=[[NSFileManager defaultManager]枚举器路径：documentsDirectory]；
for（directoryEnumerator中的NSString*路径）
{
如果（[[path pathExtension]isEqualToString:@“png”]）
{ 
printf（“\n路径为%s，[path UTF8String]）；
[imgArr addObject:path]；
}
}
对于（inti=0；i，我终于能够解决这个问题。下面是为有需要的人编写的代码

    AmazonS3Client *s3Client = [[AmazonS3Client alloc] initWithAccessKey:accessKey withSecretKey:secretKey];
    NSOutputStream *stream = [[NSOutputStream alloc] initToFileAtPath:path append:NO];
    [stream scheduleInRunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode];
    [stream open];

    S3GetObjectRequest *request = [[S3GetObjectRequest alloc] initWithKey:value withBucket:self.bucket];
    request.outputStream = stream;
    [s3Client getObject:request];


//          NSMutableArray*imgArr=[[NSMutableArray alloc] init];
//          NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
//          NSString *documentsDirectory = [paths objectAtIndex:0];

        NSString *appFile = [documentsDirectory stringByAppendingPathComponent:value];
        NSData *myData = [[[NSData alloc] initWithContentsOfFile:appFile] autorelease];
        UIImage *img=[UIImage imageWithData:myData];
        UIImageWriteToSavedPhotosAlbum(img, nil,nil,nil);


    [stream close];
    [stream release];
    [request release];
    }

最后，我解决了这个问题，下面是代码。。