java - Update the UI outside the main thread

Question

I am totaly new to android and just want to know if it is any working and possible way to update the UI outside the main thread. Just from my code I have listed below I know that from this code; It is not possible at all. But, the thing is I just want to update the UI using another thread. Please help me thanks in advance!

 package com.example.app;

 import java.util.Random;
  import android.os.Bundle;
  import android.app.Activity;
  import android.view.Menu;
 import android.view.View;
  import android.widget.Button;
 import android.widget.ImageView;
import android.widget.TextView;

public class MainActivity extends Activity {
private Button b;
public ImageView I1;
 public ImageView I2;
 public ImageView I3;
public ImageView I4;
public TextView T;
public TextView s;
@Override

protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);

 I1=new ImageView(this);
 I1=(ImageView) findViewById(R.id.imag1);
 I1.setVisibility(View.INVISIBLE);

 I2=new ImageView(this);
 I2=(ImageView) findViewById(R.id.imag2);
 I2.setVisibility(View.INVISIBLE);

 I3=new ImageView(this);
 I3=(ImageView) findViewById(R.id.imag3);
 I3.setVisibility(View.INVISIBLE);

 I4=new ImageView(this);
 I4=(ImageView) findViewById(R.id.imag4);
 I4.setVisibility(View.INVISIBLE);

 T=(TextView)findViewById(R.id.time);
 s=(TextView)findViewById(R.id.score);

Thread t=new Thread(new MyThread());
t.start();
  }

@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}

private class MyThread implements Runnable{
Random randomGenerator = new Random();
int n;
public void run(){

    while(true){
        n=randomGenerator.nextInt(8);

        if(n==1){
            I1.setVisibility(View.VISIBLE);

        }
        if(n==2){
            I2.setVisibility(View.VISIBLE);
        }

        if(n==3){
            I3.setVisibility(View.VISIBLE);
        }

        if(n==4){
            I4.setVisibility(View.VISIBLE);
        }
        try {
            Thread.currentThread().sleep(500);
        } catch (InterruptedException e) {
            // TODO Auto-generated catch block
             e.getStackTrace();
        }
    }

   }




   }
   }

Answer 1

Use activity.runOnUiThread

Acivity.runOnUiThread(new Runnable() {
    public void run() {
        //something here
    }
});