Android-如何显示版本号并制作3秒跳转页

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_height="match_parent"
android:layout_width="match_parent"
android:background="@drawable/launch_bg">
<TextView
android:id="@+id/tv_version"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerInParent="true"
android:textColor="@android:color/white"
android:textSize="14sp"/>
<RelativeLayout>

public class SplashActivity extends AppCompatActivity{
private TextView textView;
@Override
protected void onCreate(Bundle savedInstanceState){
 super.onCreate(savedInstanceState);
 setContentView(R.layout.activity_splash);
 
 setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_PORTRAIT);
  textView = findViewById(R.id.tv_version);
 
 try{
   PackageInfo info = getPackageManager().getPackageInfo(getPackageName(),0);
   textView.setText("version:"+info.versionName);
 }catch(PackageManger.NameNotFoundException e){
   e.printStackTrace();
 }

 Timer timer = new Timer();
 TimerTask timerTask = new TimeTask(){
  @Override
  public void run(){
   Intent intent = new Intent(SplashActivity.this,MainActivity.class);
   startActivity(intent);
   SplashActivity.this.finish();
   }
 };
 timer.schedule(timerTask,3000);
}
}