code: package me.dm7.barcodescanner.zxing.sample;
  
  import android.support.v7.app.ActionBar;
  import android.support.v7.app.AppCompatActivity;
  import android.support.v7.widget.Toolbar;
  import android.view.MenuItem;
  
  public class BaseScannerActivity extends AppCompatActivity {
      public void setupToolbar() {
          Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
          setSupportActionBar(toolbar);
          final ActionBar ab = getSupportActionBar();
          if(ab != null) {
              ab.setDisplayHomeAsUpEnabled(true);
          }
      }
  
      @Override
      public boolean onOptionsItemSelected(MenuItem item) {
          switch (item.getItemId()) {
              // Respond to the action bar's Up/Home button
              case android.R.id.home:
                  finish();
                  return true;
          }
          return super.onOptionsItemSelected(item);
      }
  }
  