Codigo

package com.example.ronin.primeiroapp;

import android.content.Intent;
import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.TextView;

import com.google.zxing.integration.android.IntentIntegrator;
import com.google.zxing.integration.android.IntentResult;


public class MainActivity extends ActionBarActivity {
    public static final int REQUEST_CODE = 0;
    private TextView txResult;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        txResult = (TextView) findViewById(R.id.textView);
    }

    public void callZXing(View view){
        Intent it = new Intent(MainActivity.this, com.google.zxing.client.android.CaptureActivity.class);
        startActivityForResult(it, REQUEST_CODE);
    }
    @Override
    public void onActivityResult(int requestCode, int resultCode, Intent data) {
        if (REQUEST_CODE == requestCode && RESULT_OK == resultCode) {
            txResult.setText("RESULTADO: " + data.getStringExtra("SCAN_RESULT") + " (" + data.getStringExtra("SCAN_FORMAT") + ")");
        }
    }
    @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);
    }
}