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Daniel Luberda edited this page Dec 20, 2015 · 24 revisions

ImageService.Initialize() method

TODO

Async/Await support and custom exception handling

If you don't want to use the Retry() functionality but have your custom error handling/retry logic (for example: because you use Polly). Then you can use IntoAsync() instead of Into()

try {
	// IntoAsync does not swallow exceptions so you should surround it with a try/catch
	await ImageService.LoadUrl(urlToImage).IntoAsync(_imageView);
} catch (Exception ex) {
	// do whatever you want...
}

Stop pending requests

If you want to stop pending loading requests. For example when your activity gets paused/resumed:

protected override void OnPause()
{
	base.OnPause();
	ImageService.SetExitTasksEarly(true);
}

protected override void OnResume()
{
	base.OnResume();
	ImageService.SetExitTasksEarly(false);
}

Scroll high performances

If you want to load many images in a scrollable list view or horizontal list view and you have performance issues while you fling. In our app with more than 1000 items in an horizontal list view it was the case. To solve it we used:

_myListView.ScrollStateChanged += (object sender, ScrollStateChangedEventArgs scrollArgs) => {
  switch (scrollArgs.ScrollState)
  {
    case ScrollState.Fling:
      ImageService.SetPauseWork(true); // all image loading requests will be silently canceled
      break;
    case ScrollState.Idle:
      ImageService.SetPauseWork(false); // loading requests are allowed again
      
      // Here you should have your custom method that forces redrawing visible list items
      _myListView.ForcePdfThumbnailsRedraw();
      break;
  }
};

Custom loading logic

Customizing the loading logic is very easy: inherit from ImageLoaderTask, put your own logic, and then pass the instance to ImageService: ImageService.LoadImage(customImageTask).