Change Text color using setTextColor()

package com.exercise.AndroidTextColor;

import android.app.Activity;
import android.os.Bundle;
import android.widget.SeekBar;
import android.widget.TextView;

public class AndroidTextColor extends Activity {
 
 SeekBar seekRed, seekGreen, seekBlue, seekAlpha;
    TextView targetText;
 
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        
        targetText = (TextView)findViewById(R.id.targetview);
        
        seekRed = (SeekBar)findViewById(R.id.seekred);
        seekGreen = (SeekBar)findViewById(R.id.seekgreen);
        seekBlue = (SeekBar)findViewById(R.id.seekblue);
        seekAlpha = (SeekBar)findViewById(R.id.seekalpha);
        
        seekRed.setOnSeekBarChangeListener(seekChangeListener);
        seekGreen.setOnSeekBarChangeListener(seekChangeListener);
        seekBlue.setOnSeekBarChangeListener(seekChangeListener);
        seekAlpha.setOnSeekBarChangeListener(seekChangeListener);
    }
    
    private SeekBar.OnSeekBarChangeListener seekChangeListener
    = new SeekBar.OnSeekBarChangeListener(){

  @Override
  public void onProgressChanged(SeekBar arg0, int arg1, boolean arg2) {
   // TODO Auto-generated method stub
   updateTextColor();
  }

  @Override
  public void onStartTrackingTouch(SeekBar arg0) {
   // TODO Auto-generated method stub
   
  }

  @Override
  public void onStopTrackingTouch(SeekBar arg0) {
   // TODO Auto-generated method stub
   
  }};
    
    private void updateTextColor(){
     
     int red = seekRed.getProgress();
     int green = seekGreen.getProgress();
     int blue = seekBlue.getProgress();
     int alpha = seekAlpha.getProgress();

     targetText.setTextColor(
       ((alpha << 24) & 0xFF000000)
       + ((red << 16) & 0x00FF0000)
       + ((green << 8) & 0x0000FF00)
       + (blue & 0x000000FF));

    }
}

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    >
<TextView  
    android:layout_width="fill_parent" 
    android:layout_height="wrap_content" 
    android:text="@string/hello"
    />
<TextView  
    android:layout_width="fill_parent" 
    android:layout_height="wrap_content" 
    android:text="RED"
    />
<SeekBar
    android:id="@+id/seekred"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:max="255"
    />
<TextView  
    android:layout_width="fill_parent" 
    android:layout_height="wrap_content" 
    android:text="GREEN"
    />
<SeekBar
    android:id="@+id/seekgreen"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:max="255"
    />
<TextView  
    android:layout_width="fill_parent" 
    android:layout_height="wrap_content" 
    android:text="BLUE"
    />
<SeekBar
    android:id="@+id/seekblue"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:max="255"
    />
<TextView  
    android:layout_width="fill_parent" 
    android:layout_height="wrap_content" 
    android:text="ALPHA"
    />
<SeekBar
    android:id="@+id/seekalpha"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:max="255"
    />
<TextView 
    android:id="@+id/targetview"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:text="How to change Text Color?"
    />
</LinearLayout>