// activity_dialog_fragment_example.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
        xmlns:tools="http://schemas.android.com/tools"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        tools:context=".DialogFragmentExample"
        android:orientation="vertical"
        android:padding="16dp"
        android:gravity="center">
   
        <Button
           android:id="@+id/button_dialog"
           android:layout_width="match_parent"
           android:layout_height="wrap_content"
           android:background="@color/colorPrimaryDark"
           android:text="Open Dialog"
           android:textColor="@color/colorWhite"/>

</LinearLayout>
                                    
                                  

                                    
                                        // DialogFragmentExample.java
package com.example.widgets;
                                            
import androidx.fragment.app.FragmentManager;
import androidx.appcompat.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
                                            
public class DialogFragmentExample extends AppCompatActivity {
                                           
    Button button;
                                           
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_dialog_fragment_example);
                                           
        button=(Button)findViewById(R.id.button_dialog);
                                           
        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                showDiaolog();
            }
        });
                                           
                                           
    }
   
    public void showDiaolog(){
                                           
        FragmentManager fragmentManager=getSupportFragmentManager();
        MyDialogFragment myDialogFragment=new MyDialogFragment();
        myDialogFragment.show(fragmentManager, "MyDialogFragment");
                                           
    }
                                           
}
                                        

// MyDialogFragment.java
package com.example.widgets;
                                            
import android.app.AlertDialog;
import android.app.Dialog;
import android.content.DialogInterface;
import android.os.Bundle;
import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.fragment.app.DialogFragment;
import android.widget.Toast;
                                           
public class MyDialogFragment extends DialogFragment {
                                           
    @NonNull
    @Override
    public Dialog onCreateDialog(@Nullable Bundle savedInstanceState) {
                                           
        AlertDialog.Builder builder=new AlertDialog.Builder(getActivity());
        builder.setTitle("Dialog Fragment");
        builder.setMessage("This is a Dialog Fragment");
        builder.setPositiveButton("Ok!!", new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialogInterface, int i) {
                Toast.makeText(getActivity(),"Ok clicked",Toast.LENGTH_SHORT).show();
            }
        });
        builder.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialogInterface, int i) {
                Toast.makeText(getActivity(),"Cancel clicked",Toast.LENGTH_SHORT).show();
            }
        });
        AlertDialog alertDialog=builder.create();
                                           
        return alertDialog;
    }
} 
                                    
                                  

                                    
                                        // DialogFragmentExample.kt
package com.example.widgets

import android.os.Bundle
import androidx.fragment.app.FragmentManager
import androidx.appcompat.app.AppCompatActivity
import android.view.View
import android.widget.Button

class DialogFragmentExample : AppCompatActivity() {

    private lateinit var button: Button

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_dialog_fragment_example)

        button = findViewById(R.id.button_dialog)

        button.setOnClickListener {
            showDiaolog()
        }
    }

    private fun showDiaolog() {
        val fragmentManager: FragmentManager = supportFragmentManager
        val myDialogFragment = MyDialogFragment()
        myDialogFragment.show(fragmentManager, "MyDialogFragment")
    }
}

// MyDialogFragment.kt
package com.example.widgets

import android.app.AlertDialog
import android.app.Dialog
import android.content.DialogInterface
import android.os.Bundle
import androidx.fragment.app.DialogFragment
import android.widget.Toast

class MyDialogFragment : DialogFragment() {

    override fun onCreateDialog(savedInstanceState: Bundle?): Dialog {
        val builder = AlertDialog.Builder(requireActivity())
        builder.setTitle("Dialog Fragment")
        builder.setMessage("This is a Dialog Fragment")
        builder.setPositiveButton("Ok!!") { _, _ ->
            Toast.makeText(activity, "Ok clicked", Toast.LENGTH_SHORT).show()
        }
        builder.setNegativeButton("Cancel") { _, _ ->
            Toast.makeText(activity, "Cancel clicked", Toast.LENGTH_SHORT).show()
        }
        return builder.create()
    }
}