Using retrofit enqueue request in viewModel

Android Programming (4th Edition) 24. HTTP and Background Tasks
1

I try to set the return value of FlickrFetchr().fetchContents() to a liveData in viewModel, but the flickrRequest.enqueue method always return null before its onResponse return the actually value, how should I fix it?

2

Get the URL from FlickrFetchr and paste it into a browser to see if the URL is correct. If URL is correct then set a breakpoint at Callback’s onFailure function.