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Руководство Android AlertDialog

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1- Android AlertDialog

Android AlertDialog это диалоговое окно отображающее сообщение и поддерживает 1, 2 или 3 button, он помогает вам легко создавать диалоговое окно с несколькими кодовыми строкамию
AlertDialog включает 3 зоны:
  1. Зона заголовка (Title area)
  2. Зона содержания (Content area)
  3. Зона содержащая кнопки (Buttons area)
Landscape screen
Portrait screen

Title area

Используйте метод setTitle(), setIcon() чтобы настроить заголовок и иконку для диалогового окна, они будут видны на Title area. Или используйте метод setCustomTitle(View) если вы хотите получить кастомизированную зону заголовка (Title area).

Content area

Зона содержания (Content area) может отображать сообщение, список выборов,...

Buttons area

Данная зона имеет максимум 3 button: Positive button, Negative button, Neutral button. В них 2 первые button поддерживают Text & Icon, а Neutral button поддерживает только Text, но вы можете отобразить для нее иконку с маленьким трюком (Смотрите в примере).

2- Пример AlertDialog (1)

Просмотр примера:
AlertButtonExample0.java
package org.o7planning.alertdialogexample;

import android.content.Context;
import android.content.DialogInterface;
import android.graphics.drawable.Drawable;
import android.widget.Toast;

import androidx.appcompat.app.AlertDialog;

public class AlertDialogExample0 {

    public static void showAlertDialog(final Context context)  {
        final Drawable positiveIcon = context.getResources().getDrawable(R.drawable.icon_positive);
        final Drawable negativeIcon = context.getResources().getDrawable(R.drawable.icon_negative);
        final Drawable neutralIcon = context.getResources().getDrawable(R.drawable.icon_neutral);

        AlertDialog.Builder builder = new AlertDialog.Builder(context);

        // Set Title and Message:
        builder.setTitle("Title").setMessage("This is a message");

        //
        builder.setCancelable(true);
        builder.setIcon(R.drawable.icon_title);

        // Create "Positive" button with OnClickListener.
        builder.setPositiveButton("Positive", new DialogInterface.OnClickListener() {
            public void onClick(DialogInterface dialog, int id) {
                Toast.makeText(context,"You choose positive button",
                        Toast.LENGTH_SHORT).show();
            }
        });
        builder.setPositiveButtonIcon(positiveIcon);

        // Create "Negative" button with OnClickListener.
        builder.setNegativeButton("Negative", new DialogInterface.OnClickListener() {
            public void onClick(DialogInterface dialog, int id) {
                Toast.makeText(context,"You choose positive button",
                        Toast.LENGTH_SHORT).show();
                //  Cancel
                dialog.cancel();
            }
        });
        builder.setNegativeButtonIcon(negativeIcon);

        // Create "Neutral" button with OnClickListener.
        builder.setNeutralButton("Neutral", new DialogInterface.OnClickListener() {
            public void onClick(DialogInterface dialog, int id) {
                //  Action for 'NO' Button
                Toast.makeText(context,"You choose neutral button",
                        Toast.LENGTH_SHORT).show();
            }
        });
        builder.setNeutralButtonIcon(neutralIcon); // Not working!!!

        // Create AlertDialog:
        AlertDialog alert = builder.create();
        alert.show();
    }
}

3- Пример AlertDialog (2)

AlertDialogExample2.java
package org.o7planning.alertdialogexample;

import android.app.Activity;
import android.content.Context;
import android.content.DialogInterface;
import android.graphics.drawable.Drawable;
import android.widget.Toast;

import androidx.appcompat.app.AlertDialog;

public class AlertDialogExample2 {

    public static void showAlertDialog(final Context context)  {
        final Drawable positiveIcon = context.getResources().getDrawable(R.drawable.icon_positive);
        final Drawable negativeIcon = context.getResources().getDrawable(R.drawable.icon_negative);

        AlertDialog.Builder builder = new AlertDialog.Builder(context);

        // Set Title and Message:
        builder.setTitle("Confirmation").setMessage("Do you want to close this app?");

        //
        builder.setCancelable(true);
        builder.setIcon(R.drawable.icon_title);

        // Create "Yes" button with OnClickListener.
        builder.setPositiveButton("Yes", new DialogInterface.OnClickListener() {
            public void onClick(DialogInterface dialog, int id) {
                Toast.makeText(context,"You choose Yes button",
                        Toast.LENGTH_SHORT).show();
                Activity activity = (Activity) context;
                activity.finish();
            }
        });
        builder.setPositiveButtonIcon(positiveIcon);

        // Create "No" button with OnClickListener.
        builder.setNegativeButton("No", new DialogInterface.OnClickListener() {
            public void onClick(DialogInterface dialog, int id) {
                Toast.makeText(context,"You choose No button",
                        Toast.LENGTH_SHORT).show();
                //  Cancel
                dialog.cancel();
            }
        });
        builder.setNegativeButtonIcon(negativeIcon);

        // Create AlertDialog:
        AlertDialog alert = builder.create();
        alert.show();
    }
}

4- Пример AlertDialog (List)

Например AlertDialog со списком выборов для пользователя.
AlertDialogListExample.java
package org.o7planning.alertdialogexample;

import android.app.Activity;
import android.content.Context;
import android.content.DialogInterface;
import android.graphics.drawable.Drawable;
import android.widget.Toast;

import androidx.appcompat.app.AlertDialog;

public class AlertDialogListExample {

    public static void showAlertDialog(final Activity activity)  {
        final Drawable negativeIcon = activity.getResources().getDrawable(R.drawable.icon_negative);

        AlertDialog.Builder builder = new AlertDialog.Builder(activity);

        // Set Title.
        builder.setTitle("Select an Animal");

        // Add a list
        final String[] animals = {"Horse", "Cow", "Camel", "Sheep", "Goat"};
        builder.setItems(animals, new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialog, int which) {
                String animal = animals[which];

                dialog.dismiss(); // Close Dialog
                // Do some thing....
                // For example: Call method of MainActivity.
                Toast.makeText(activity,"You select: " + animal,
                        Toast.LENGTH_SHORT).show();
                // activity.someMethod(animal);
            }
        });

        //
        builder.setCancelable(true);
        builder.setIcon(R.drawable.icon_title);

        // Create "Cancel" button with OnClickListener.
        builder.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
            public void onClick(DialogInterface dialog, int id) {
                Toast.makeText(activity,"You choose No button",
                        Toast.LENGTH_SHORT).show();
                //  Cancel
                dialog.cancel();
            }
        });
        builder.setNegativeButtonIcon(negativeIcon);

        // Create AlertDialog:
        AlertDialog alert = builder.create();
        alert.show();
    }

}

5- Пример AlertDialog (Single Choice)

AlertDialogSingleChoiceExample.java
package org.o7planning.alertdialogexample;

import android.app.Activity;
import android.content.DialogInterface;
import android.widget.Toast;

import androidx.appcompat.app.AlertDialog;

import java.util.HashSet;
import java.util.Set;

public class AlertDialogSingleChoiceExample {


    public static void showAlertDialog(final Activity activity)  {
        AlertDialog.Builder builder = new AlertDialog.Builder(activity);

        // Set Title.
        builder.setTitle("Select an Animal");

        // Add a list
        final String[] animals = {"Horse", "Cow", "Camel", "Sheep", "Goat"};

        int checkedItem = 3; // Sheep
        final Set<String> selectedItems = new HashSet<String>();
        selectedItems.add(animals[checkedItem]);

        builder.setSingleChoiceItems(animals, checkedItem, new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialog, int which) {
                // Do Something...
                selectedItems.clear();
                selectedItems.add(animals[which]);
            }
        });

        //
        builder.setCancelable(true);
        builder.setIcon(R.drawable.icon_title);

        // Create "Yes" button with OnClickListener.
        builder.setPositiveButton("OK", new DialogInterface.OnClickListener() {
            public void onClick(DialogInterface dialog, int id) {
                if(selectedItems.isEmpty()) {
                    return;
                }
                String animal = selectedItems.iterator().next();

                // Close Dialog
                dialog.dismiss();
                // Do something, for example: Call a method of Activity...
                Toast.makeText(activity,"You select " + animal,
                        Toast.LENGTH_SHORT).show();

            }
        });

        // Create "Cancel" button with OnClickListener.
        builder.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
            public void onClick(DialogInterface dialog, int id) {
                Toast.makeText(activity,"You choose Cancel button",
                        Toast.LENGTH_SHORT).show();
                //  Cancel
                dialog.cancel();
            }
        });

        // Create AlertDialog:
        AlertDialog alert = builder.create();
        alert.show();
    }

}

6- Пример AlertDialog (Multi Choice)

AlertDialogMultiChoiceExample.java
package org.o7planning.alertdialogexample;

import android.app.Activity;
import android.content.DialogInterface;
import android.widget.Toast;

import androidx.appcompat.app.AlertDialog;

import java.util.HashSet;
import java.util.Set;

public class AlertDialogMultiChoiceExample {


    public static void showAlertDialog(final Activity activity)  {
        AlertDialog.Builder builder = new AlertDialog.Builder(activity);

        // Set Title.
        builder.setTitle("Select an Animal");

        // Add a list
        final String[] animals = {"Horse", "Cow", "Camel", "Sheep", "Goat"};

        final boolean[] checkedInfos = new boolean[]{false, false, false, true, false}; // Sheep


        builder.setMultiChoiceItems(animals, checkedInfos, new DialogInterface.OnMultiChoiceClickListener()  {
            @Override
            public void onClick(DialogInterface dialog, int which, boolean isChecked) {
                checkedInfos[which] = isChecked;
            }
        });

        //
        builder.setCancelable(true);
        builder.setIcon(R.drawable.icon_title);

        // Create "Yes" button with OnClickListener.
        builder.setPositiveButton("OK", new DialogInterface.OnClickListener() {
            public void onClick(DialogInterface dialog, int id) {
                // Close Dialog
                dialog.dismiss();

                String s= null;
                for(int i=0; i< animals.length;i++)  {
                    if(checkedInfos[i]) {
                        if(s == null)  {
                            s = animals[i];
                        } else {
                            s+= ", " + animals[i];
                        }
                    }
                }
                s = s == null? "":s;

                // Do something, for example: Call a method of Activity...
                Toast.makeText(activity,"You select " + s,
                        Toast.LENGTH_SHORT).show();
            }
        });

        // Create "Cancel" button with OnClickListener.
        builder.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
            public void onClick(DialogInterface dialog, int id) {
                Toast.makeText(activity,"You choose Cancel button",
                        Toast.LENGTH_SHORT).show();
                //  Cancel
                dialog.cancel();
            }
        });

        // Create AlertDialog:
        AlertDialog alert = builder.create();
        alert.show();
    }

}

7- Пример кастомизированного Title Area

Применяя метод setCustomTitle(View) вы можете кастомизировать зону заголовка (Title area) у AlertDialog:
И можете использовать Android Resource File чтобы создать интерфейс для зоны заголовка (Title area).
AlertDialog.Builder builder = new AlertDialog.Builder(context);

// Custom Title Area.
LayoutInflater inflater = context.getLayoutInflater();
View view = inflater.inflate(R.layout.layout_custom_title, null);
builder.setCustomTitle(view);
...
        
// Create AlertDialog:
AlertDialog alert = builder.create();
alert.show();
OK, создайте Layout Resource File:
  • File > New > Android Resource File
    • File Name: layout_custom_title.xml
    • Resource type: Layout
    • Directory name: layout
Смоделируйте интерфейс для зоны заголовка (Title area):
layout_custom_title.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">

    <ImageView
        android:id="@+id/imageView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="16dp"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:srcCompat="@drawable/icon_title" />

    <TextView
        android:id="@+id/textView"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginStart="16dp"
        android:layout_marginLeft="16dp"
        android:layout_marginTop="8dp"
        android:layout_marginEnd="16dp"
        android:layout_marginRight="16dp"
        android:background="#E3DCC4"
        android:gravity="center"
        android:text="This is the Title"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/imageView" />

</androidx.constraintlayout.widget.ConstraintLayout>
AlertDialogCustomTitleExample.java
package org.o7planning.alertdialogexample;

import android.app.Activity;
import android.content.Context;
import android.content.DialogInterface;
import android.graphics.drawable.Drawable;
import android.view.LayoutInflater;
import android.view.View;
import android.widget.Toast;

import androidx.appcompat.app.AlertDialog;

public class AlertDialogCustomTitleExample {

    public static void showAlertDialog(final Activity context)  {
        final Drawable positiveIcon = context.getResources().getDrawable(R.drawable.icon_positive);

        AlertDialog.Builder builder = new AlertDialog.Builder(context);

        // Custom Title Area.
        LayoutInflater inflater = context.getLayoutInflater();
        View view = inflater.inflate(R.layout.layout_custom_title, null);
        builder.setCustomTitle(view);

        // Message.
        builder.setMessage("This is AlertDialog with Custom Title Area");
        //
        builder.setCancelable(true);
        builder.setIcon(R.drawable.icon_title);

        // Create "OK" button with OnClickListener.
        builder.setPositiveButton("OK", new DialogInterface.OnClickListener() {
            public void onClick(DialogInterface dialog, int id) {
            }
        });
        builder.setPositiveButtonIcon(positiveIcon);

        // Create AlertDialog:
        AlertDialog alert = builder.create();
        alert.show();
    }
}

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