Tools - Get Version Code/Name

//Create variable versionName and versionCode
String versionName = "null";
int versionCode = -1;
try {
android.content.pm.PackageInfo packageInfo = MainActivity.this.getPackageManager().getPackageInfo(getPackageName(), 0);
versionName = packageInfo.versionName;
versionCode = packageInfo.versionCode;
} catch (android.content.pm.PackageManager.NameNotFoundException e) {
e.printStackTrace();
}
//textview set text
TextView textViewVersionInfo = (TextView) findViewById(R.id.textview1);
textViewVersionInfo.setText(String.format("Version Name: %s Version Code:%d", versionName, versionCode));