package unknownmoon.cryforlight;

import android.os.Bundle;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.util.Log;
import android.view.View;
import android.view.Menu;
import android.view.MenuItem;

public class MainActivity extends AppCompatActivity {
    private Boolean mIsServiceOn = false;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);

        toolbar.setLogo(R.mipmap.ic_launcher);

        FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
        fab.setActivated(mIsServiceOn);
    }

    public void onServiceButtonToggled(View view) {
        mIsServiceOn = !mIsServiceOn;

        FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
        fab.setActivated(mIsServiceOn);

//                Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
//                        .setAction("Action", null).show();
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.menu_main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();

        //noinspection SimplifiableIfStatement
        if (id == R.id.action_settings) {
            return true;
        }

        return super.onOptionsItemSelected(item);
    }
}

package unknownmoon.cryforlight;

import android.os.Bundle;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.util.Log;
import android.view.View;
import android.view.Menu;
import android.view.MenuItem;

public class MainActivity extends AppCompatActivity {
    private Boolean mIsServiceOn = false;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);
        getSupportActionBar().setDisplayShowTitleEnabled(false);

        toolbar.setLogo(R.mipmap.ic_launcher);

        FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
        fab.setActivated(mIsServiceOn);
    }

    public void onServiceButtonToggled(View view) {
        mIsServiceOn = !mIsServiceOn;

        FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
        fab.setActivated(mIsServiceOn);

//                Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
//                        .setAction("Action", null).show();
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.menu_main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();

        //noinspection SimplifiableIfStatement
        if (id == R.id.action_settings) {
            return true;
        }

        return super.onOptionsItemSelected(item);
    }
}

Hide app name in action bar