Caixa de Diálogo (Alert Dialog)

Na linguagem Java usa-se a classe JOptionPane para criar as caixas de diálogo. No Android usa-se a classe AlertDialog para o mesmo propósito. As caixas de diálogo são usadas geralmente para obter uma informação simples do usuário, "sim" ou "não" referente à uma pergunta.

Material para mais detalhes:

GOOGLE DEVELOPERS. Caixas de diálogo. Disponível em: https://developer.android.com/guide/topics/ui/dialogs?hl=pt-br#java. Acessado em: 14 jul. 2025.

Exemplos práticos (AlertDialog Basic)

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">
    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Hello World!"
        android:id="@+id/textViewHello"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>

MyDialogFragment.java

import android.app.Dialog;
import android.content.DialogInterface;
import android.os.Bundle;
import android.widget.Toast;
import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.appcompat.app.AlertDialog;
import androidx.fragment.app.DialogFragment;
public class MyDialogFragment extends DialogFragment {
// O uso do fragmento ajuda a evitar problemas com as caixas de diálogos, como a perda do estado do diálogo durante rotações de tela.
    @NonNull
    @Override
    public Dialog onCreateDialog(@Nullable Bundle savedInstanceState) {
        AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());
        builder.setMessage("Como está o clima hoje?")
                .setTitle("Responda a pergunta")
                .setIcon(R.mipmap.ic_launcher)
                .setPositiveButton("Quente", new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialogInterface, int i) {
                        Toast.makeText(getActivity().getApplicationContext(),
                                "Beba muita água", Toast.LENGTH_SHORT).show();
                    }
                })
                .setNegativeButton("Frio", new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialogInterface, int i) {
                        Toast.makeText(getActivity().getApplicationContext(),
                                "Coloque um casaco", Toast.LENGTH_SHORT).show();
                    }
                })
                .setNeutralButton("Ameno", new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialogInterface, int i) {
                        Toast.makeText(getActivity().getApplicationContext(),
                                "Aproveite o dia!!", Toast.LENGTH_SHORT).show();
                    }
                });
        AlertDialog dialog = builder.create();
//onDismiss não pertence ao ciclo de vida do DialogFragment, mas pode ser usado quando o diálogo for fechado pelo usuário.
        dialog.setOnDismissListener(new DialogInterface.OnDismissListener() {
            @Override
            public void onDismiss(DialogInterface dialog) {
                Toast.makeText(getActivity().getApplicationContext(), "Encerrando o diálogo", Toast.LENGTH_SHORT).show();
            }
        });
        return dialog;
    }//onCreateDialog
}//class

MainActivity.java

import androidx.appcompat.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.TextView;
public class MainActivity extends AppCompatActivity {
    private TextView textViewHello;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        textViewHello = findViewById(R.id.textViewHello);
        textViewHello.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                openAlertDialog();
            }
        });
    }
    private void openAlertDialog() {
        MyDialogFragment mdf = new MyDialogFragment();
        mdf.show(getSupportFragmentManager(),"clima");
    }//private
}//class

Exemplos práticos (AlertDialog Personalizado)

colors.xml

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <color name="black">#FF000000</color>
    <color name="white">#FFFFFFFF</color>
    <color name="red">#D02C2C</color>
    <color name="green">#4CAF50</color>
</resources>

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">
    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Clicar"
        android:id="@+id/btnClicar"
        android:textAppearance="@style/TextAppearance.AppCompat.Large"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>

MyDialogFragment.java

import android.app.Dialog;
import android.content.DialogInterface;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.widget.EditText;
import android.widget.Toast;
import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.appcompat.app.AlertDialog;
import androidx.fragment.app.DialogFragment;
public class MyDialogFragment extends DialogFragment {
    @NonNull
    @Override
    public Dialog onCreateDialog(@Nullable Bundle savedInstanceState) {
        //return super.onCreateDialog(savedInstanceState);
        AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());
        LayoutInflater inflater = getLayoutInflater();
        View view = inflater.inflate(R.layout.dialog,null);
        EditText editTextNome = view.findViewById(R.id.editTextNome);
        builder.setView(view)
                .setTitle("Personalizado")
                .setPositiveButton("Sim", new DialogInterface.OnClickListener(){
                    @Override
                    public void onClick(DialogInterface dialogInterface, int i) {
                        String nome = editTextNome.getText().toString();
                        Toast.makeText(getActivity().getApplicationContext(),
                                "Você clicou em sim "+nome, Toast.LENGTH_SHORT).show();
                    }
                })
                .setNeutralButton("Não", new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialogInterface, int i) {
                        String nome = editTextNome.getText().toString();
                        Toast.makeText(getActivity().getApplicationContext(),
                                "Você clicou em não "+nome, Toast.LENGTH_SHORT).show();
                    }
                });
        return builder.create();
    }
}//class

MainActivity.java

import androidx.appcompat.app.AlertDialog;
import androidx.appcompat.app.AppCompatActivity;
import android.content.DialogInterface;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;
public class MainActivity extends AppCompatActivity {
    private Button buttonClicar;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        buttonClicar = findViewById(R.id.btnClicar);
        buttonClicar.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                openAlertDialog();
            }
        });
    }
    private void openAlertDialog() {
        MyDialogFragment mdf = new MyDialogFragment();
        mdf.show(getSupportFragmentManager(),"personalizado");
    }
}

dialog.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical" android:layout_width="match_parent"
    android:layout_margin="10dp"
    android:padding="20dp"
    android:background="@color/red"
    android:layout_height="wrap_content">
    <ImageView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:src="@mipmap/ic_launcher"/>
    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textAppearance="@style/TextAppearance.AppCompat.Large"
        android:text="AlertaDialog Personalizado"/>
    <EditText
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/editTextNome"
        android:hint="Digite seu nome"/>
    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content">
        <Button
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="teste"
            android:textAppearance="@style/TextAppearance.AppCompat.Medium"
            android:background="@color/green"/>
    </LinearLayout>
</LinearLayout>

Exemplos práticos (AlertDialog List)

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">
    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Hello World!"
        android:id="@+id/textViewHello"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>

string.xml

<resources>
    <string name="app_name">AlertDialogList</string>
    <array name="array_semana">
        <item>Segunda-feira</item>
        <item>Terça-feira</item>
        <item>Quarta-feira</item>
        <item>Quinta-feira</item>
        <item>sexta-feira</item>
    </array>
</resources>

MyDialogFragment.java

import android.app.Dialog;
import android.content.DialogInterface;
import android.content.res.Resources;
import android.os.Bundle;
import android.widget.Toast;
import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.appcompat.app.AlertDialog;
import androidx.fragment.app.DialogFragment;
public class MyDialogFragment extends DialogFragment {
    @NonNull
    @Override
    public Dialog onCreateDialog(@Nullable Bundle savedInstanceState) {
        //return super.onCreateDialog(savedInstanceState);
        AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());
        builder.setTitle("Escolha o dia da semana")
                .setIcon(R.mipmap.ic_launcher)
                .setItems(R.array.array_semana, new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialogInterface, int i) {
                        Toast.makeText(getActivity().getApplicationContext(),
                                "Você clicou em: "+i, Toast.LENGTH_SHORT).show();
                        Toast.makeText(getActivity().getApplicationContext(),
                                recuperarItem(i), Toast.LENGTH_SHORT).show();
                    }
                });
        return builder.create();
    }//method
    private String recuperarItem(int i){
        Resources resources = getResources();
        String[] dias_semana = resources.getStringArray(R.array.array_semana);
        return dias_semana[i];
    }
}//class

MainActivity.java

import androidx.appcompat.app.AppCompatActivity;
import android.content.res.Resources;
import android.os.Bundle;
import android.view.View;
import android.widget.TextView;
public class MainActivity extends AppCompatActivity {
    private TextView textViewHello;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        textViewHello = findViewById(R.id.textViewHello);
        textViewHello.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                openAlertDialogList();
            }
        });
    }//onCreate
    private void openAlertDialogList() {
        MyDialogFragment mdf = new MyDialogFragment();
        mdf.show(getSupportFragmentManager(),"lista_semana");
    }
}//class

Exemplos práticos (AlertDialog with multiple choice)

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
   xmlns:app="http://schemas.android.com/apk/res-auto"
   xmlns:tools="http://schemas.android.com/tools"
   android:layout_width="match_parent"
   android:layout_height="match_parent"
   tools:context=".MainActivity">
   <TextView
       android:layout_width="wrap_content"
       android:layout_height="wrap_content"
       android:text="Hello World!"
       android:id="@+id/textViewHello"
       app:layout_constraintBottom_toBottomOf="parent"
       app:layout_constraintLeft_toLeftOf="parent"
       app:layout_constraintRight_toRightOf="parent"
       app:layout_constraintTop_toTopOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>

string.xml

<resources>
   <string name="app_name">AlertDialogFragmentTest</string>
   <array name="array_semana">
       <item>Segunda-feira</item>
       <item>Terça-feira</item>
       <item>Quarta-feira</item>
       <item>Quinta-feira</item>
       <item>Sexta-feira</item>
   </array>
</resources>

MyDialogFragment.java

import android.app.Dialog;
import android.content.DialogInterface;
import android.content.res.Resources;
import android.os.Bundle;
import android.widget.Toast;
import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.appcompat.app.AlertDialog;
import androidx.fragment.app.DialogFragment;
public class MyDialogFragment extends DialogFragment {
   @NonNull
   @Override
   public Dialog onCreateDialog(@Nullable Bundle savedInstanceState) {
      // return super.onCreateDialog(savedInstanceState);
      AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());
      builder.setTitle("Escolha o dia da semana: ")
              .setIcon(R.mipmap.ic_launcher)
              .setMultiChoiceItems(R.array.array_semana, null,       //adiciona uma lista de múltipla escolha
                      new DialogInterface.OnMultiChoiceClickListener() {
                  @Override
                  public void onClick(DialogInterface dialogInterface, int i, boolean b) {
                      if (b) {     //verificar qual item da lista foi selecionado
                        Toast.makeText(getActivity().getApplicationContext(),
                                recuperarItem(i), Toast.LENGTH_SHORT).show();   //mostra qual elemento foi selecionado
                      }
                  }//onClick
              });
      return builder.create();
   }//onCreateDialog
   private String recuperarItem(int i){
       Resources res = getResources();
       String[] dias_semana = res.getStringArray(R.array.array_semana);
       return dias_semana[i];
   }//
}//class

MainActivity.java

import androidx.appcompat.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.TextView;
public class MainActivity extends AppCompatActivity {
   private TextView textViewHello;
   @Override
   protected void onCreate(Bundle savedInstanceState) {
       super.onCreate(savedInstanceState);
       setContentView(R.layout.activity_main);
       textViewHello = findViewById(R.id.textViewHello);
       textViewHello.setOnClickListener(new View.OnClickListener() {
           @Override
           public void onClick(View view) {
               openAlertDialog();
           }
       });
   }//onCreate
   private void openAlertDialog(){
       MyDialogFragment mdf = new MyDialogFragment();   //criação do objeto da classe MyDialogFragment
       mdf.show(getSupportFragmentManager(),"semana");    //chame o método show passando um gerenciador de fragmento e a tag necessária para salvar/restaurar os dados referente do fragmento
   }//open
}//class

Para ter uma lista com única escolha basta trocar o método setMultiChoiceItems pelo método setSingleChoiceItems.

Veja o exemplo:

 .setSingleChoiceItems(R.array.array_semana, 0, new DialogInterface.OnClickListener() {
                   @Override
                   public void onClick(DialogInterface dialogInterface, int i) {
                       Toast.makeText(getActivity().getApplicationContext(),
                               recuperarItem(i), Toast.LENGTH_SHORT).show();
                   }
               });