How the detect the "edittext" box whether it is nothing in Android?

Question

I want to program a function that the toast exist when there is nothing in the "edittext" box (id / password), but it dosen't work.

import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.content.Intent;
import android.widget.EditText; 
import android.widget.Toast; 
import android.view.View.OnClickListener; 
import android.text.Editable; 

public class Test extends Activity
{

  /** Called when the activity is first created. */
  @Override
  public void onCreate(Bundle savedInstanceState)
  {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);
    Button button1 = (Button) findViewById(R.id.button1);
    EditText id = (EditText) findViewById(R.id.id);
    EditText pwd = (EditText) findViewById(R.id.pwd);
    Editable Str_id;
    Editable Str_pwd;
    Str_id = id.getText();
    Str_pwd = pwd.getText();



    button1.setOnClickListener(new Button.OnClickListener()
    {

      public void onClick(View v){
        if(Str_id==null || Str_pwd == null){
        Toast.makeText(Test.this, "Please Enter User ID / Password", Toast.LENGTH_LONG).show();

     }
    });
    }



  }

Answer 1

move the following lines inside onClick and try:

Str_id = id.getText(); 
Str_pwd = pwd.getText(); 

EDIT: Move

Editable Str_id; 
Editable Str_pwd; 
Str_id = id.getText(); 
Str_pwd = pwd.getText();

inside onClick().