#pragma -mark UIImagePickerController delegate

-(void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info

{

    chosenImage = [info objectForKey:@"UIImagePickerControllerOriginalImage"];

    // 指定回调方法

    [picker dismissViewControllerAnimated:YES completion:NULL];

    NSURL *assetURL = [info objectForKey:UIImagePickerControllerReferenceURL];

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

        [library assetForURL:assetURL

                 resultBlock:^(ALAsset *asset) {

                     NSDictionary* imageMetadata = [[NSMutableDictionary alloc] initWithDictionary:asset.defaultRepresentation.metadata];

                     NSDictionary *GPSDict=[imageMetadata objectForKey:@"{GPS}"];

                     NSLog(@"时间:DateStamp:%@",[GPSDict  objectForKey:  @"DateStamp"]);

                 } 

                failureBlock:^(NSError *error) { 

                }];

}

NSURL *assetURL = [info objectForKey:UIImagePickerControllerReferenceURL];

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

        [library assetForURL:assetURL

                 resultBlock:^(ALAsset *asset) {

                     NSDate* date = [asset valueForProperty:ALAssetPropertyDate];

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

                 }

                failureBlock:^(NSError *error) {

                }];