Refresh scrollview sample of local ui refresh in Activity

1. Create a layout file containing ScrollView:

2. Refresh ScrollView

package com.example.uirefresh;
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.ScrollView;
import android.widget.TextView;
public class MainActivity extends Activity implements android.view.View.OnClickListener{
private Button btnExit;
private TextView text;
private ScrollView scroll;
private boolean bool = true;
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    btnExit = (Button) findViewById(R.id.exit);
    text    = (TextView) findViewById(R.id.text);
    scroll  = (ScrollView) findViewById(R.id.scroll);
    btnExit.setOnClickListener(this);
    // In the main thread main In the open 1 The child thread refreshes the local ScrollView
    new Thread(new RefreshThread()).start();    
}
@Override
public void onClick(View v) {
    switch(v.getId()) {
    case R.id.exit :
        finish();
        break;
    }
}   
public class RefreshThread implements Runnable{
    @Override
    public void run() {
        while(bool) {
            try {
                Thread.sleep(5000);// every 5 seconds 1 time 
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            synchronized (this) {
                                // with post Methods the refresh 
                text.post(new Runnable() {                  
                    @Override
                    public void run() {
                        text.append("Hello World...n");
                    }
                });
            }
        }
    }       
}   
@Override
protected void onDestroy(){
    super.onDestroy();
    bool = false;
}
}