package com.example.anthony.helloandroid;

import android.app.Activity;
import android.app.AlertDialog;
import android.content.DialogInterface;
import android.content.Intent;
import android.content.res.Configuration;
import android.content.res.Resources;
//import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.EditText;
import android.widget.RadioButton;

import java.util.HashMap;
import java.util.Locale;
import java.util.Map;

public class MainActivity extends Activity {
    public static final String EXTRA_GREETING = "com.example.anthony.Greet";

    public static final Map<RadioButton, Locale> localeMap = new HashMap<>();

    private Resources resources;
    private Configuration configuration;

    private RadioButton rbEnglish;
    private RadioButton rbFrench;
    private RadioButton rbSpanish;

    private AlertDialog.Builder noNameDialogBuilder;
    private EditText txtName;

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

        resources = getResources();
        configuration = resources.getConfiguration();

        rbEnglish = findViewById(R.id.rbEnglish);
        rbFrench = findViewById(R.id.rbFrench);
        rbSpanish = findViewById(R.id.rbSpanish);

        txtName = findViewById(R.id.txtName);

        noNameDialogBuilder = new AlertDialog.Builder(this)
            .setMessage("Please enter your name.")
            .setNeutralButton("OK",
            (DialogInterface dialog, int which) -> dialog.dismiss());


        fillLocaleMap();
    }

    public void helloButtonClick(View view){
        String name = txtName.getText().toString();
        if(name.equals("")){
            noNameDialogBuilder.show();
        }
        else{
            greet();
        }
    }

    public void greet(){

        String name = txtName.getText().toString();
        String greeting = generateGreeting(name);

        Intent intent = new Intent(this, GreetActivity.class);
        intent.putExtra(EXTRA_GREETING, greeting);

        startActivity(intent);
    }

    private String generateGreeting(String name){
        String greeting = getString(R.string.greeting);
        greeting += " " + name + "!";
        return greeting;
    }

    private void fillLocaleMap(){
        localeMap.put(rbEnglish, Locale.ENGLISH);
        localeMap.put(rbFrench, Locale.FRENCH);
        localeMap.put(rbSpanish, new Locale("es"));
    }

    public void setLocale(View view){
        RadioButton rbView = (RadioButton) view;
        Locale locale = localeMap.get(rbView);
        configuration.setLocale(locale);
        resources.updateConfiguration(configuration, resources.getDisplayMetrics());
        recreate();
    }
}

package com.example.anthony.helloandroid;

import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.TextView;

public class GreetActivity extends AppCompatActivity {

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

        // Get the Intent that started this activity and extract the string
        Intent intent = getIntent();
        String message = intent.getStringExtra(MainActivity.EXTRA_GREETING);

        // Capture the layout's TextView and set the string as its text
        TextView textView = findViewById(R.id.txtGreeting);
        textView.setText(message);
    }
}