AboutActivity.java

package com.aspsine.swipetoloadlayout.demo;

import android.content.pm.PackageInfo;
import android.content.pm.PackageManager;
import android.os.Bundle;
import android.support.v7.app.ActionBar;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.MenuItem;
import android.widget.TextView;


public class AboutActivity extends AppCompatActivity {


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_about);

        final Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);

        setSupportActionBar(toolbar);
        ActionBar actionBar = getSupportActionBar();
        if (actionBar != null) {
            actionBar.setDisplayHomeAsUpEnabled(true);
        }

        TextView tvVersion = (TextView) findViewById(R.id.tvVersion);
        tvVersion.setText("V " + getVersion());
    }

    private String getVersion() {
        String version = null;
        try {
            PackageManager packageManager = getPackageManager();
            PackageInfo packInfo = packageManager.getPackageInfo(getPackageName(), 0);
            version = packInfo.versionName;
        } catch (Exception e) {
            e.printStackTrace();
        }
        return version;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        int id = item.getItemId();
        switch (id) {
            case android.R.id.home:
                onBackPressed();
                return true;
        }
        return super.onOptionsItemSelected(item);
    }
}