Android ViewModel setValue function get stuck

To process the live data for signals, I defined following class SignalsViewModel and when I call the updateSignals function, it get stuck and doesn't run the next command.

I create the signalsViewModel using following code.

signalsViewModel = new ViewModelProvider(this).get(SignalsViewModel.class);

When I update the set the live data, app get stuck in the following function and doesn't run the next command.

// Get Stuck here.
signalsViewModel.updateSignals(booleen);

// Doesn't run the following command
sendNextRequest();

Here is the class definition of SignalsViewModel.

import androidx.lifecycle.LiveData;
import androidx.lifecycle.MutableLiveData;
import androidx.lifecycle.ViewModel;
import java.util.Arrays;

public class SignalsViewModel extends ViewModel {
    private final MutableLiveData<boolean[]> signals = new MutableLiveData<>(new boolean[4]);

    /**
     * Returns a LiveData that observers can watch.
     */
    public LiveData<boolean[]> getSignals() {
        return signals;
    }

    /**
     * Updates the signals. Observer only notified if values actually changed.
     */
    public void updateSignals(boolean[] newSignals) {
        if (newSignals == null || newSignals.length != 4) {
            throw new IllegalArgumentException("Signals array must have exactly 4 elements.");
        }

        boolean[] oldSignals = signals.getValue();
        if (!Arrays.equals(oldSignals, newSignals)) {
            // Make a copy to prevent external modification
            signals.setValue(Arrays.copyOf(newSignals, newSignals.length));
        }
    }
}

It was the thread issue. I called the function in the background thread and it didn't work. Should call in the UI thread.

'''

runOnUiThread (new Thread(new Runnable() {  
    public void run() {
        signalsViewModel.updateSignals(booleen);
    }
}));

'''