Pass back data from dialog to activity

In the article "Create custom dialog with EditText", a dialog with user editable field (EditText) was implemented. To pass back the user enter data from dialog to activity, we can create a global variable. Because both the main activity and the dialog are in the same class, such that both can access the global variable directly.

Main code in MainActivity.java.

package com.AndroidCustomDialog;

import android.os.Bundle;
import android.app.Activity;
import android.app.Dialog;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;

public class MainActivity extends Activity {
 
 static final int CUSTOM_DIALOG_ID = 0;
  
 TextView customDialog_TextView;
 EditText customDialog_EditText;
 Button customDialog_Update, customDialog_Dismiss;
 
 String result = "";
 TextView textReturned;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        
        textReturned = (TextView)findViewById(R.id.textreturned);
        
        Button buttonStartDialog = (Button)findViewById(R.id.startdialog);
        buttonStartDialog.setOnClickListener(new Button.OnClickListener(){
         
         @Override
         public void onClick(View arg0) {
          // TODO Auto-generated method stub
          showDialog(CUSTOM_DIALOG_ID); 
         }});
    }
    
    private Button.OnClickListener customDialog_UpdateOnClickListener
     = new Button.OnClickListener(){
     
     @Override
     public void onClick(View arg0) {
      // TODO Auto-generated method stub
      customDialog_TextView.setText(customDialog_EditText.getText().toString());
      
      result = customDialog_EditText.getText().toString();
      textReturned.setText(result);
     } 
    };
    
    private Button.OnClickListener customDialog_DismissOnClickListener
     = new Button.OnClickListener(){
     
     @Override
     public void onClick(View arg0) {
      // TODO Auto-generated method stub
      dismissDialog(CUSTOM_DIALOG_ID); 
     } 
    };
     
    @Override
    protected Dialog onCreateDialog(int id) {
     // TODO Auto-generated method stub
     Dialog dialog = null;;
     
     switch(id) {
     case CUSTOM_DIALOG_ID:
      dialog = new Dialog(MainActivity.this);
      
      dialog.setContentView(R.layout.customlayout);
      dialog.setTitle("Custom Dialog");
      
      customDialog_EditText = (EditText)dialog.findViewById(R.id.dialogedittext);
      customDialog_TextView = (TextView)dialog.findViewById(R.id.dialogtextview);
      customDialog_Update = (Button)dialog.findViewById(R.id.dialogupdate);
      customDialog_Dismiss = (Button)dialog.findViewById(R.id.dialogdismiss);
      customDialog_Update.setOnClickListener(customDialog_UpdateOnClickListener);
      customDialog_Dismiss.setOnClickListener(customDialog_DismissOnClickListener);
      break; 
     }
     return dialog; 
    }
    
}

/res/layout/customlayout.xml, the layout of the dialog.

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/customdialog"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:padding="10dp">
<ImageView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:src="@drawable/ic_launcher"/>
<TextView
    android:id="@+id/dialogtextview"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"/>
<EditText
    android:id="@+id/dialogedittext"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"/>
<Button
    android:id="@+id/dialogupdate"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:text="Update"/>
<Button
    android:id="@+id/dialogdismiss"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:text="Dismiss"/>
</LinearLayout>

Main layout, /res/layout/activity_main.xml.

<?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_world"/>
<Button
    android:id="@+id/startdialog"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:text=" Start Dialog "/>
<TextView
    android:id="@+id/textreturned"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"/>
</LinearLayout>

Next:
- DialogFragment with interface to pass data back to activity