Main Activity con tre bottoni, il bottone copia per copiare il testo inserito nel primo EditText nel secondo, il secondo bottone per passare ad altra finestra (activity secondaria), il terzo bottone chiude l'applicazione

Definizione layout prima activity.

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:orientation="vertical" android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:weightSum="1">

    <TextView
        android:id="@+id/textView"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Stringa da copiare" />

    <EditText
        android:id="@+id/editText"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:ems="10"
        android:inputType="textPersonName" />

    <Button
        android:id="@+id/button2"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Copia" />

    <TextView
        android:id="@+id/textView2"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Copia della stringa" />

    <EditText
        android:id="@+id/editText2"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:ems="10"
        android:inputType="textPersonName" />

    <ImageView
        android:id="@+id/imageView2"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        app:srcCompat="@mipmap/ic_launcher"
        android:layout_weight="0.72" />

    <Button
        android:id="@+id/avanti"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Avanti" />

    <Button
        android:id="@+id/fine"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Fine" />
<LinearLayout>
        

Codice della prima activity.

package com.example.emanuele.prova001;

import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;

public class MainActivity extends AppCompatActivity {

    private View.OnClickListener b2click = new View.OnClickListener() {
        public void onClick(View v) {
            EditText e1 = (EditText) findViewById(R.id.editText);
            EditText e2 = (EditText) findViewById(R.id.editText2);
            String s = e1.getText().toString();
            e2.setText(s);
        }
    };

    private View.OnClickListener avanticlick = new View.OnClickListener() {
        public void onClick(View v) {
            Intent myIntent = new Intent(v.getContext(), second.class);
            startActivity(myIntent);
        }
    };

    private View.OnClickListener fineclick = new View.OnClickListener() {
        public void onClick(View v) {
            System.exit(0);
        }
    };

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

        Button bcopia = (Button) findViewById(R.id.copia);
        bcopia.setOnClickListener(b2click);
        Button bavanti = (Button) findViewById(R.id.avanti);
        bavanti.setOnClickListener(avanticlick);
        Button bfine = (Button) findViewById(R.id.fine);
        bfine.setOnClickListener(fineclick);
    }
}
        

Definizione layout seconda activity, con bottone per tornare alla precedente.

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent" android:layout_height="match_parent">

    <TextView
        android:id="@+id/lblsecond"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="24dp"
        android:text="Secondo layout e activity"
        android:textSize="24sp"
        android:layout_alignParentTop="true"
        android:layout_centerHorizontal="true" />

    <ImageView
        android:id="@+id/imageView3"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_below="@+id/lblsecond"
        android:layout_centerHorizontal="true"
        android:layout_marginTop="47dp"
        app:srcCompat="@mipmap/ic_launcher" />

    <Button
        android:id="@+id/Cambia"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@+id/lblsecond"
        android:layout_centerHorizontal="true"
        android:layout_marginTop="20dp"
        android:text="Cambia immagine" />

    <Button
        android:id="@+id/torna"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentBottom="true"
        android:layout_centerHorizontal="true"
        android:layout_marginBottom="38dp"
        android:text="Torna" />

<RelativeLayout>
        

Codice della seconda activity.

package com.example.emanuele.prova001;

import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;

public class second extends AppCompatActivity {

    private View.OnClickListener tornaclick = new View.OnClickListener() {
        public void onClick(View v) {
        finish();
        }
    };

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

        Button b = (Button) findViewById(R.id.torna);
        b.setOnClickListener(tornaclick);
    }

}        
        

Gestione di semplice Toast, con tempo di visualizzazione lungo.

    private View.OnClickListener cambiaclick = new View.OnClickListener() {
        public void onClick(View v) {
            Toast.makeText(v.getContext(), "Elenco immagini vuoto",
                           Toast.LENGTH_LONG).show();
        }
    };
        

Gestione di un Toast con specifico layout.

    private View.OnClickListener cambiaclick = new View.OnClickListener() {
        public void onClick(View v) {
            LayoutInflater mInflater=LayoutInflater.from(v.getContext());
            View view=mInflater.inflate(R.layout.toast1, null);
            Toast toast=new Toast(v.getContext());
            view.setBackgroundResource(R.color.colorPrimaryDark);
            toast.setView(view);
            toast.setDuration(Toast.LENGTH_LONG);
            toast.show();
        }
    };
        

Gestione cambio immagine su oggetto ImageView.

ImageView image;

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

    // immagine
    image = (ImageView) findViewById(R.id.imageView3);
}

private View.OnClickListener cambiaclick = new View.OnClickListener() {
    public void onClick(View v) {
        // cambio immagine
        //image.setBackgroundResource(R.drawable.ic_localobidos);
        image.setImageResource(R.drawable.ic_localobidos);
    }
};