1.เรียกใช้งานแอคทิวิตี้อื่น

เพิ่มแอคทิวิตี้ชื่อ SecondActivity

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/activity_main"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.phaisarn.jackapplication.MainActivity">

    <Button
        android:id="@+id/my_button1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Click1" />
</LinearLayout>

MainActivity.java

package com.phaisarn.jackapplication;

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

public class MainActivity extends AppCompatActivity {

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

        Button myButton1 = (Button) findViewById(R.id.my_button1);
        myButton1.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Intent intent = new Intent(getApplicationContext(), SecondActivity.class);
                startActivity(intent);
            }
        });
    }
}

activity_second.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/activity_second"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.phaisarn.jackapplication.SecondActivity">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="This is second activity." />
</LinearLayout>

2.เรียกใช้งานแอคทิวิตี้อื่นพร้อมส่งข้อมูลไปให้

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/activity_main"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.phaisarn.jackapplication.MainActivity">

    <EditText
        android:id="@+id/editText1"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_weight="1" />

    <Button
        android:id="@+id/my_button1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Click1" />
</LinearLayout>

MainActivity.java

package com.phaisarn.jackapplication;

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 {

    public static final String MESSAGE1 = "Message1";

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

        Button myButton1 = (Button) findViewById(R.id.my_button1);
        myButton1.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                EditText editText = (EditText) findViewById(R.id.editText1);
                String msg = editText.getText().toString();

                Intent intent = new Intent(getApplicationContext(), SecondActivity.class);
                intent.putExtra(MESSAGE1, msg);
                startActivity(intent);
            }
        });
    }
}

activity_second.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/activity_second"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.phaisarn.jackapplication.SecondActivity">

    <TextView
        android:id="@+id/textView2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="This is second activity."/>
</LinearLayout>

SecondActivity.java

package com.phaisarn.jackapplication;

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

public class SecondActivity extends AppCompatActivity {

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

        Intent intent = getIntent();
        String msg = intent.getStringExtra(MainActivity.MESSAGE1);

        TextView textView = (TextView) findViewById(R.id.textView2);
        textView.setText(msg);
    }
}

3.ส่งข้อมูลกลับมาให้แอคทิวิตี้ต้นทาง

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/activity_main"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.phaisarn.jackapplication.MainActivity">

    <Button
        android:id="@+id/my_button1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Click1" />
</LinearLayout>

MainActivity.java

package com.phaisarn.jackapplication;

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.Toast;

public class MainActivity extends AppCompatActivity {

    public static final String MESSAGE2 = "Message2";
    public static final int CODE = 1;

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

        Button myButton1 = (Button) findViewById(R.id.my_button1);
        myButton1.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Intent intent = new Intent(getApplicationContext(), SecondActivity.class);
                startActivityForResult(intent, CODE);
            }
        });
    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent intent) {
        if (requestCode == CODE) {
            if (resultCode == RESULT_OK) {
                String msg = intent.getStringExtra(MESSAGE2);
                Toast.makeText(this, msg, Toast.LENGTH_SHORT).show();
            }
        }
    }

}

activity_second.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/activity_second"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.phaisarn.jackapplication.SecondActivity">

    <EditText
        android:id="@+id/editText2"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_weight="1" />

    <Button
        android:id="@+id/my_button2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Return" />
</LinearLayout>

SecondActivity.java

package com.phaisarn.jackapplication;

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 SecondActivity extends AppCompatActivity {

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

        Button myButton2 = (Button) findViewById(R.id.my_button2);
        myButton2.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                EditText editText = (EditText) findViewById(R.id.editText2);
                String msg = editText.getText().toString();

                Intent intent = new Intent();
                intent.putExtra(MainActivity.MESSAGE2, msg);
                setResult(RESULT_OK, intent);
                finish();
            }
        });
    }
}