Android LiveData prevent receive the last value on observe

Question

Is it possible to prevent LiveData receive the last value when start observing? I am considering to use LiveData as events.

For example eve

Answer 1

Even i had the same requirement. I have achieved this by extending the MutableLiveData

package com.idroidz.android.ion.util;    
import android.arch.lifecycle.LifecycleOwner;
import android.arch.lifecycle.MutableLiveData;
import android.arch.lifecycle.Observer;
import android.support.annotation.MainThread;
import android.support.annotation.Nullable;

import java.util.concurrent.atomic.AtomicBoolean;

public class VolatileMutableLiveData extends MutableLiveData {


    private final AtomicBoolean mPending = new AtomicBoolean(false);

    @MainThread
    public void observe(LifecycleOwner owner, final Observer observer) {
        // Observe the internal MutableLiveData
        mPending.set(false);
        super.observe(owner, new Observer() {
            @Override
            public void onChanged(@Nullable T t) {
                if (mPending.get()) {
                    observer.onChanged(t);
                }
            }
        });
    }

    @MainThread
    public void setValue(@Nullable T t) {
        mPending.set(true);
        super.setValue(t);
    }

    /**
     * Used for cases where T is Void, to make calls cleaner.
     */
    @MainThread
    public void call() {
        setValue(null);
    }

    public void callFromThread() {
        super.postValue(null);
    }
}