that's great. thank H3R3T1C very much.

I am a novice too but I studied some thing. I don't know you want to study about J2ME, WinCE, or Android ?

in SecondClass

public static int colorstring=0xffffff00;//Yellow
chbRed = (CheckBox)findViewById(R.id.CheckBoxRed);//    #FF0000
	        chbRed.setonclickListener(new onclickListener()
	        {
	             
	            public void onclick(View v)
	            {
	                if(chbRed.isChecked())
	                {
                                 colorstring = 0xff0000ff;
				 chbRed.setChecked(false);
				 chbGreen.setChecked(false);
                         }

in FirstClass

tvAnh.setTextColor(SecondClass.colorstring);

but why when i click Checkbox the color in tvAnh ( TextView ) wasn't change ??/

i don't know how to use interfaces in java.

hi H3R3T1C,
I have 3 activity

TabActivity

public class TheSwitcherActivity extends TabActivity 
{
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
    
    
	    TabHost tabHost = getTabHost();
	    TabHost.TabSpec spec;
	    Intent intent;
	    
	    intent = new Intent().setClass(this,FirstClass.class);
	    spec = tabHost.newTabSpec("The Switcher").setIndicator("The Switcher").setContent(intent);
	    tabHost.addTab(spec);
	    
	    intent = new Intent().setClass(this,SecondClass.class);
	    spec = tabHost.newTabSpec("Option").setIndicator("Option").setContent(intent);
	    tabHost.addTab(spec);
    }
}

FirstClass

public class FirstClass extends   Activity
{
             String Color;
	     TextView tvAnh;
	    @Override protected void onCreate(Bundle savedInstanceState)
	{
	    super.onCreate(savedInstanceState);
	    setContentView(R.layout.tab_text);
	    tvAnh = (TextView)findViewById(R.id.textViewAnh);
	 
	     ///////////////////////////////////////////////////////////////////////
            //I read some book and i make class NhanMauTuSecondClass extends broadcastReceiver, but it can't work
	    IntentFilter filter = new IntentFilter();
	    NhanMauTuSecondClass receiver = new NhanMauTuSecondClass();
	    registerReceiver(receiver, filter);
	    Color = receiver.color;    
	    ///////////////////////////////////////////////////////////////////////

public class SecondClass extends Activity
{
         Intent i = new Intent("Color");
         protected void onCreate(Bundle savedInstanceState) 
	{
		// TODO Auto-generated method stub
		super.onCreate(savedInstanceState);
		setContentView(R.layout.tab_text2);
		
		chbRed = (CheckBox)findViewById(R.id.CheckBoxRed);//	#FF0000
		chbRed.setonclickListener(new onclickListener() 
		{
			
			public void onclick(View v) 
			{
				if(chbRed.isChecked())
				{
					chbBlue.setChecked(false);
					chbGreen.setChecked(false);
					i.putExtra("Color", "#FF0000");
					sendBroadcast(i);
				}
				
			}
		});
}

i want when i change state of checkbox in secondclass, the TextView in Firstclass will change color ???