Hướng dẫn và ví dụ Android CharacterPickerDialog

package org.o7planning.characterpickerdialogexample;

import android.os.Bundle;
import android.text.Editable;
import android.text.method.CharacterPickerDialog;
import android.util.Log;
import android.view.KeyEvent;
import android.view.View;
import android.widget.AdapterView;
import android.widget.EditText;

import androidx.appcompat.app.AppCompatActivity;

public class MainActivity extends AppCompatActivity {

    private static final String LOG_TAG  = "AndroidExample";

    private EditText editText;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        this.editText = this.findViewById(R.id.editText);
        this.editText.setOnKeyListener(new View.OnKeyListener() {
            @Override
            public boolean onKey(View v, int keyCode, KeyEvent event) {
                return handleOnKey(  keyCode,   event);
            }
        });
    }

    private boolean handleOnKey(int keyCode, KeyEvent event)  {
        if(event.getAction() == KeyEvent.ACTION_DOWN) {
            return false;
        }

        char base = (char) event.getUnicodeChar();
        Log.i(LOG_TAG, "keyCode: " + keyCode + ", Base character: " + base);

        final String accentedString = AccentedStringUtils.getAccentedString(base);
        if(accentedString == null)  {
            return false;
        }
        final Editable editable = this.editText.getText();

        CharacterPickerDialog dialog= new CharacterPickerDialog(this, new View(this), editable, accentedString,false) {
            // User click on Cancel button.
            @Override
            public void onClick (View v) {
                // Do something here
                // ...
                super.onClick(v);
            }

            // User click on Character button.
            @Override
            public void onItemClick(AdapterView parent, View view, int position, long id){
                // Do something here
                // ...
                super.onItemClick(parent, view, position, id);
            }
        };
        dialog.show();

        return false;
    }

}

package org.o7planning.characterpickerdialogexample;

public class AccentedStringUtils {

    //
    // Vietnamese special characters.
    //
    private static final String[] ACCENTED_STRINGS = {
            "aáàãảạăắằẵẳặâấầẫẩậ",
            "AÁÀÃẢẠĂẮẰẴẲẶÂẤẦẪẨẬ",
            "dđ",
            "DĐ",
            "eéèẽẻẹêếềễểệ",
            "EÉÈẼẺẸÊẾỀỄỂỆ",
            "iíìĩỉị",
            "IÍÌĨỈỊ",
            "oóòõỏọôốồỗổộơớờỡởợ",
            "OÓÒÕỎỌÔỐỒỖỔỘƠỚỜỠỞỢ",
            "uúùũủụưứừữửự",
            "UÚÙŨỦỤƯỨỪỮỬỰ",
            "yýỳỹỷỵ",
            "YÝỲỸỶỴ"
    };

    public static String getAccentedString(char base)  {
         for(int i = 0; i< ACCENTED_STRINGS.length; i++) {
             String accentedString = ACCENTED_STRINGS[i];
             if(accentedString.charAt(0) == base)  {
                 return accentedString;
             }
         }
         return null;
    }
}