MBProgressHUD 不更新进度

Question

我正在从照片库中导入多张照片，我想使用 MBProgressHUD 显示进度。我正在使用 QBImagePickerController 导入照片。我的照片导入成功。但是 MBProgressHUD 中的进度条没有更新。以下是我的代码

-(void)qb_imagePickerController:(QBImagePickerController *)imagePickerController didSelectAssets:(NSArray *)assets {
   if (imagePickerController.filterType == QBImagePickerControllerFilterTypePhotos) {
    MBProgressHUD *hud = [MBProgressHUD showHUDAddedTo:self.navigationController.view animated:YES];]

    // Set the determinate mode to show task progress.
    hud.mode = MBProgressHUDModeDeterminateHorizontalBar;
    hud.delegate = self;

    hud.labelText = NSLocalizedString(@"Importing Photos", nil);
    hud.dimBackground = YES;
    hud.detailsLabelFont = [UIFont systemFontOfSize:12.0f];
    hud.detailsLabelText = NSLocalizedString(@"Please wait...", nil);
    hud.progress = 0.0f;

    [self importPhotosForArray:assets];
   }
    [self dismissImagePickerController];
}

 - (void) importPhotosForArray:(NSArray *)info {
       for (ALAsset *selectedImageAsset in info) {
       ALAssetsLibrary *assetsLibrary = [[ALAssetsLibrary alloc] init];
    [assetsLibrary assetForURL:[selectedImageAsset defaultRepresentation].url resultBlock: ^(ALAsset *asset){
        ALAssetRepresentation *representation = [asset defaultRepresentation];
        CGImageRef imageRef = [representation fullResolutionImage];
        if (imageRef) {
            UIImage *image = [UIImage imageWithCGImage:imageRef];
            NSData *imageData = UIImageJPEGRepresentation(image, 1.0);

            // Create a file name for the image
            NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
            [dateFormatter setTimeStyle:NSDateFormatterMediumStyle];
            [dateFormatter setDateStyle:NSDateFormatterMediumStyle];
            NSString *imageName = [NSString stringWithFormat:@"photo-%@.png", [dateFormatter stringFromDate:[NSDate date]]];
            // Now we get the full path to the file
            NSString *fullPathToFile = [self.folder.fullPath stringByAppendingPathComponent:imageName];
            // Write out the data.
            [imageData writeToFile:fullPathToFile atomically:NO];

            sleep(1.0);
            progress = ++index/[info count];

            [MBProgressHUD HUDForView:self.navigationController.view].progress = progress;

            if (progress >= 1.0) {
                [[MBProgressHUD HUDForView:self.navigationController.view] hide:YES];
                    [self reloadData];
            }
        }
    } failureBlock: ^(NSError *error){
        // Handle failure.
        NSLog(@"Failure");
    }];
   }
}

Answer 1

将 MBProgressHUD 声明为属性并在任何地方使用它。

@property (nonatomic, strong) MBProgressHUD *hud;

-(void)qb_imagePickerController:(QBImagePickerController *)imagePickerController didSelectAssets:(NSArray *)assets {

    if (imagePickerController.filterType == QBImagePickerControllerFilterTypePhotos) {

            self.hud = [MBProgressHUD showHUDAddedTo:self.navigationController.view animated:YES];]

           // Set the determinate mode to show task progress.
           self.hud.mode = MBProgressHUDModeDeterminateHorizontalBar;
           self.hud.delegate = self;

           self.hud.labelText = NSLocalizedString(@"Importing Photos", nil);
           self.hud.dimBackground = YES;
           self.hud.detailsLabelFont = [UIFont systemFontOfSize:12.0f];
           self.hud.detailsLabelText = NSLocalizedString(@"Please wait...", nil);
           self.hud.progress = 0.0f;

           [self importPhotosForArray:assets];
        }
            [self dismissImagePickerController];
}

- (void) importPhotosForArray:(NSArray *)info {

   for (ALAsset *selectedImageAsset in info) {

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

          [assetsLibrary assetForURL:[selectedImageAsset defaultRepresentation].url resultBlock: ^(ALAsset *asset){

          ALAssetRepresentation *representation = [asset defaultRepresentation];
          CGImageRef imageRef = [representation fullResolutionImage];

        if (imageRef) {

              UIImage *image = [UIImage imageWithCGImage:imageRef];
              NSData *imageData = UIImageJPEGRepresentation(image, 1.0);

        // Create a file name for the image
        NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
        [dateFormatter setTimeStyle:NSDateFormatterMediumStyle];
        [dateFormatter setDateStyle:NSDateFormatterMediumStyle];
        NSString *imageName = [NSString stringWithFormat:@"photo-%@.png", [dateFormatter stringFromDate:[NSDate date]]];
        // Now we get the full path to the file
        NSString *fullPathToFile = [self.folder.fullPath stringByAppendingPathComponent:imageName];
        // Write out the data.
        [imageData writeToFile:fullPathToFile atomically:NO];

        sleep(1.0);
        progress = ++index/[info count];

        self.hud.progress = progress;

        if (progress >= 1.0) {

         [MBProgressHUD hideAllHUDsForView:self.navigationController.view animated:YES];

                [self reloadData];
        }
    }
} failureBlock: ^(NSError *error){
    // Handle failure.
    NSLog(@"Failure");
  }];
}
}

试试这个因为根据您的代码，每次 MBProgressHUD 的新对象获取和更新时您都会更新进度

Answer 2

UI 更新（即更改进度条）must be made on the main thread 否则您可能会遭受不可预测的副作用。

The user interface element may not be redrawn after your property changes

我相信 ALAssetsLibrary.assetForURL 是在后台线程中自动发生的。要解决这个问题，您需要使用 solution 来让您运行主线程上的 UI 更新。在这种情况下，您的 UI 更新将是这一行

[MBProgressHUD HUDForView:self.navigationController.view].progress = progress;

所以尝试这样的事情：

dispatch_async(dispatch_get_main_queue(), ^{
    [MBProgressHUD HUDForView:self.navigationController.view].progress = progress;
});

此外，您应该通过在每次 index 更新时打印出值来验证 ++index/[info count] 是否确实如您预期的那样增加。

Answer 3

试试这个代码。将您的 importPhotosForArray 方法替换为以下内容。

- (void) importPhotosForArray:(NSArray *)info {
dispatch_async(dispatch_get_global_queue(QOS_CLASS_USER_INITIATED, 0), ^{
    __block float progress = 0.0f;
    __block float index = 0.0f;

    for (ALAsset *selectedImageAsset in info) {
        ALAssetRepresentation *representation = [selectedImageAsset defaultRepresentation];
        CGImageRef imageRef = [representation fullResolutionImage];
        if (imageRef) {
            UIImage *image = [UIImage imageWithCGImage:imageRef];
            NSData *imageData = UIImagePNGRepresentation(image);

            // Create a file name for the image
            NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
            [dateFormatter setTimeStyle:NSDateFormatterMediumStyle];
            [dateFormatter setDateStyle:NSDateFormatterMediumStyle];
            NSString *imageName = [NSString stringWithFormat:@"photo-%@.png", [dateFormatter stringFromDate:[NSDate date]]];
            // Now we get the full path to the file
            NSString *fullPathToFile = [self.folder.fullPath stringByAppendingPathComponent:imageName];
            // Write out the data.
            [imageData writeToFile:fullPathToFile atomically:YES];

            sleep(1);

            progress = ++index/[info count];

            dispatch_async(dispatch_get_main_queue(), ^{
                // Instead we could have also passed a reference to the HUD
                // to the HUD to myProgressTask as a method parameter.
                [MBProgressHUD HUDForView:self.navigationController.view].progress = progress;
            });

            if (progress >= 1.0) {
                dispatch_async(dispatch_get_main_queue(), ^{
                    // Instead we could have also passed a reference to the HUD
                    // to the HUD to myProgressTask as a method parameter.
                    [[MBProgressHUD HUDForView:self.navigationController.view] hide:YES];
                    [self reloadData];
                });
            }
        }
    }
});

}

MBProgressHUD 不更新进度

MBProgressHUD not updating progress

objective-c

ios

mbprogresshud