DialogFragment

android.app.DialogFragment, was introduced from API Level 11 (Android 3.0), displays a dialog window, floating on top of its activity's window.



- Create a new MyDialogFragment.java class extends android.app.DialogFragment.

package com.exercise.AndroidDialogFragment;

import android.app.AlertDialog;
import android.app.Dialog;
import android.app.DialogFragment;
import android.content.DialogInterface;
import android.os.Bundle;

public class MyDialogFragment extends DialogFragment {
 
 static MyDialogFragment newInstance() {
  
  String title = "My Fragment";
  
        MyDialogFragment f = new MyDialogFragment();
        Bundle args = new Bundle();
        args.putString("title", title);
        f.setArguments(args);
        return f;
    }

 @Override
 public Dialog onCreateDialog(Bundle savedInstanceState) {
  String title = getArguments().getString("title");
  Dialog myDialog = new AlertDialog.Builder(getActivity())
     .setIcon(R.drawable.ic_launcher)
     .setTitle(title)
     .setPositiveButton("OK", 
       new DialogInterface.OnClickListener() {
        
        @Override
        public void onClick(DialogInterface dialog, int which) {
         ((AndroidDialogFragmentActivity)getActivity()).okClicked();
        }
       })
     .setNegativeButton("Cancel", 
       new DialogInterface.OnClickListener() {
        
        @Override
        public void onClick(DialogInterface dialog, int which) {
         ((AndroidDialogFragmentActivity)getActivity()).cancelClicked();
        }
       })
     .create();

  return myDialog;
 }
 
}

- Modify main.xml layout to add a button to open the dialog.

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical" >

    <TextView
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="@string/hello" />
    <Button
        android:id="@+id/opendialog"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="Open Dialog" />

</LinearLayout>

- Main activity, AndroidDialogFragmentActivity.java

package com.exercise.AndroidDialogFragment;

import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.Toast;

public class AndroidDialogFragmentActivity extends Activity {
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        
        Button buttonOpenDialog = (Button)findViewById(R.id.opendialog);
        buttonOpenDialog.setOnClickListener(new Button.OnClickListener(){

   @Override
   public void onClick(View arg0) {
    OpenDialog();
   }});
        
    }
    
    void OpenDialog(){
     MyDialogFragment myDialogFragment = MyDialogFragment.newInstance();
     myDialogFragment.show(getFragmentManager(), "myDialogFragment");
    }

 public void okClicked() {
  Toast.makeText(AndroidDialogFragmentActivity.this, 
    "OK Clicked!", 
    Toast.LENGTH_LONG).show();
 }

 public void cancelClicked() {
  Toast.makeText(AndroidDialogFragmentActivity.this, 
    "Cancel Clicked!", 
    Toast.LENGTH_LONG).show();
 }
}

Download the files.