ตัวอย่างโปรแกรม การใช้ SeekBar และเปลี่ยนสี Background ของ TextView

Code ในส่วนของ XML

<?xml version="1.0" encoding="utf-8"?>
<AbsoluteLayout 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="wrap_content"
    android:id="@+id/rTxt"
    android:textAppearance="?android:attr/textAppearanceLarge"
    android:layout_height="wrap_content"
    android:text="R : "
    android:layout_x="20dp"
    android:layout_y="10dp">
    </TextView>
    
    <TextView
    android:layout_width="wrap_content"
    android:id="@+id/bTxt"
    android:textAppearance="?android:attr/textAppearanceLarge"
    android:layout_height="wrap_content"
    android:text="B : "
    android:layout_x="20dp"
    android:layout_y="50dp"
    ></TextView>
    
    <TextView
    android:layout_width="wrap_content"
    android:id="@+id/gTxt"
    android:textAppearance="?android:attr/textAppearanceLarge"
    android:layout_height="wrap_content" android:text="G : "
    android:layout_x="20dp" android:layout_y="90dp">
    </TextView>
    
    <SeekBar
    android:id="@+id/rBar"
    android:layout_height="wrap_content"
    android:layout_x="55dp"
    android:layout_y="10dp"
    android:max="255"
    android:layout_width="240px">
    </SeekBar>
    
    <SeekBar
    android:id="@+id/gBar"
    android:layout_height="wrap_content"
    android:layout_x="55dp"
    android:layout_y="50dp"
    android:max="255"
    android:layout_width="240px">
    </SeekBar>
    
    <SeekBar
    android:id="@+id/bBar"
    android:layout_height="wrap_content"
    android:layout_x="55dp"
    android:layout_y="90dp"
    android:max="255"
    android:layout_width="240px">
    </SeekBar>
    
    <TextView
    android:layout_width="250px"
    android:id="@+id/showColor"
    android:layout_height="250px" 
    android:background="#FFFFFF" 
    android:layout_x="37dp" 
    android:layout_y="136dp">
    </TextView>
    
</AbsoluteLayout>

Code ในส่วนของ JAVA

package slayer.RGB;

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

public class RGBActivity extends Activity {
 
 private SeekBar rBar;
 private SeekBar gBar;
 private SeekBar bBar;
 private TextView showColor;
 
 private int rValue;
 private int gValue;
 private int bValue;
 
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        initView();
    }
    
    private void initView()
    {
     rBar = (SeekBar)findViewById(R.id.rBar);
     rBar.setOnSeekBarChangeListener(new OnSeekBarChangeListener() {
   
   @Override
   public void onStopTrackingTouch(SeekBar arg0) {
    // TODO Auto-generated method stub
    
   }
   
   @Override
   public void onStartTrackingTouch(SeekBar arg0) {
    // TODO Auto-generated method stub
    
   }
   
   @Override
   public void onProgressChanged(SeekBar arg0, int arg1, boolean arg2) {
    // TODO Auto-generated method stub
    rValue = arg1;
    showResult();
   }
  });
     
     gBar = (SeekBar)findViewById(R.id.gBar);
     gBar.setOnSeekBarChangeListener(new OnSeekBarChangeListener() {
   
   @Override
   public void onStopTrackingTouch(SeekBar arg0) {
    // TODO Auto-generated method stub
    
   }
   
   @Override
   public void onStartTrackingTouch(SeekBar arg0) {
    // TODO Auto-generated method stub
    
   }
   
   @Override
   public void onProgressChanged(SeekBar arg0, int arg1, boolean arg2) {
    // TODO Auto-generated method stub
    gValue = arg1;
    showResult();
   }
  });
     
     bBar = (SeekBar)findViewById(R.id.bBar);
     bBar.setOnSeekBarChangeListener(new OnSeekBarChangeListener() {
   
   @Override
   public void onStopTrackingTouch(SeekBar arg0) {
    // TODO Auto-generated method stub
    
   }
   
   @Override
   public void onStartTrackingTouch(SeekBar arg0) {
    // TODO Auto-generated method stub
    
   }
   
   @Override
   public void onProgressChanged(SeekBar arg0, int arg1, boolean arg2) {
    // TODO Auto-generated method stub
    bValue = arg1;
    showResult();
   }
  });
     
     showColor = (TextView)findViewById(R.id.showColor);
    }
    
    private void showResult(){
     showColor.setText("rVal : " + rValue + "\ngVal : " + gValue + "\nbVal : " + bValue);
     showColor.setBackgroundColor(
       0xff000000
       + rValue * 0x10000
       + gValue * 0x100
       + bValue
   );
    }
}