android:Timer

final Handler h2 = new Handler();
h2.postDelayed(new Runnable() {
       public void run() {
           Toast.makeText(getApplicationContext(), "timer running", Toast.LENGTH_LONG).show();
       }
   },2000);

android: Set Validation error for edittext in android

 @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        Button btn =(Button)findViewById(R.id.button1);
        btn.setOnClickListener(new OnClickListener() {
            
            @Override
            public void onClick(View v) {
                 EditText edittext =(EditText)findViewById(R.id.editText1);
                if(edittext.getText().length()==0){
                    edittext.requestFocus();
                    edittext.setError("please enter the value");
                }
            }
        });
    }

android: Emulator design

http://codebutler.com/2012/10/10/configuring-a-usable-android-emulator/

android: Listview with radio button single click

http://www.coderzheaven.com/2011/10/13/how-to-create-a-custom-listview-in-android/