CODEWITHSUNDEEP
javaandroidmultithreadingkotlin
Lucas Sousa
Lucas Sousa

Reputation: 352

Application freezes when setting TextView text

I have to update a TextView from another class (not a activity) with the result from a method which can be slow to finish its search. While the method don't finish I thought set the TextView text to something like "loading..." and finally, after method result is ok, set the text to that result. Currently I'm doing something like this:

textView.setText("loading...");
Search s = searcher.search();
textView.setText(s.result);

Firstly, this still freezes the application until result is ok, once didn't not used new Threads. I know that to set content to Android widgets we have to do it inside the uiThread, but I don't know how to do it in my case, once I'm not inside a Activity.

In second place, that approach are not showing the "loading..." text. When I call that code the application just freezes and back with the final text.

Then, how to avoid that freeze/breaking until content is ok?

Upvotes: 0

Views: 2892

Answers (2)

Richard Stokes
Richard Stokes

Reputation: 543

I think the main thing to understand is that only UI specific tasks should run on the UI thread. If it is not UI related then it should run on another thread ideally as an AsyncTask.

Performing a search, generally speaking, is very performance heavy as you have pointed out. This will block the UI thread from updating the UI which will lead to unresponsive UIs and users may perceive this a crash or a slow app.

So firstly, to run the updating on the UI Thread.

runOnUiThread(() ->{textView.setText("loading...");});

then perform the search on a different thread

then once the search is finished update the UI using the same method as above

Upvotes: 0

Dmytro Ivanov
Dmytro Ivanov

Reputation: 1310

Do not do heavy operation inside MainThread (UI) in Android. For your case take a look to AsyncTask. It give you a method doInBackground where you should make some background stuff (http request, file i/o) then you will get call onPostExecute, that method will called on UI Thread with the results of doInBackground method. Another example.

Upvotes: 1

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