Open one form to another form

activity_main.xml

<RelativeLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent"
    android:layout_height="match_parent" android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    android:paddingBottom="@dimen/activity_vertical_margin"
    tools:context=".MainActivity">


    <LinearLayout
        android:orientation="vertical"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:layout_alignParentLeft="true"
        android:layout_alignParentStart="true"
        android:layout_marginTop="49dp">


        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Main window"
            android:id="@+id/tv" />

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

</RelativeLayout>

activity_second.xml

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"

    xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent"

    android:layout_height="match_parent" android:paddingLeft="@dimen/activity_horizontal_margin"

    android:paddingRight="@dimen/activity_horizontal_margin"

    android:paddingTop="@dimen/activity_vertical_margin"

    android:paddingBottom="@dimen/activity_vertical_margin"

    tools:context="com.example.user.newwindowopen.second">

    <TextView android:text="New window"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content" />

    <Button

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:text="New Button"

        android:id="@+id/btn1"

        android:layout_centerVertical="true"

        android:layout_alignParentLeft="true"

        android:layout_alignParentStart="true" />

</RelativeLayout>

activity_third.xml

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"

    xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent"

    android:layout_height="match_parent" android:paddingLeft="@dimen/activity_horizontal_margin"

    android:paddingRight="@dimen/activity_horizontal_margin"

    android:paddingTop="@dimen/activity_vertical_margin"

    android:paddingBottom="@dimen/activity_vertical_margin"

    tools:context="com.example.user.newwindowopen.third">

    <TextView

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:text="Third activity"

        android:id="@+id/tv1"

        android:layout_alignParentTop="true"

        android:layout_alignParentLeft="true"

        android:layout_alignParentStart="true"

        android:layout_marginTop="123dp" />

</RelativeLayout>

MainActivity.java

package com.example.user.newwindowopen;

import android.content.Intent;

import android.support.v7.app.ActionBarActivity;

import android.os.Bundle;

import android.view.Menu;

import android.view.MenuItem;

import android.view.View;

import android.widget.Button;

import android.widget.EditText;

import android.widget.TextView;

import static android.view.View.OnClickListener;

public class MainActivity extends ActionBarActivity implements OnClickListener{

    TextView tv;

    Button btn;

    @Override

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);

        init();

    }

    private void init() {

        tv = (TextView) findViewById(R.id.tv);

        btn = (Button) findViewById(R.id.btn);

       btn.setOnClickListener(this);

    }

    @Override

    public void onClick(View v) {

        Intent intent = new Intent(this,second.class);

        this.startActivity(intent);

    }

}

second.java

package com.example.user.newwindowopen;

import android.content.Intent;
import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;

import org.w3c.dom.Text;


public class second extends ActionBarActivity implements View.OnClickListener{

    TextView tv1;
    Button btn1;

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

    private void init() {

        tv1 = (TextView) findViewById(R.id.tv1);
        btn1 = (Button) findViewById(R.id.btn1);
        btn1.setOnClickListener(this);
    }

    public void onClick(View v) {

        Intent intent = new Intent(this, third.class);
        this.startActivity(intent);

    }
}

third.java

package com.example.user.newwindowopen;

import android.support.v7.app.ActionBarActivity;

import android.os.Bundle;

import android.view.Menu;

import android.view.MenuItem;

public class third extends ActionBarActivity {

    @Override

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_third);

    }

}

ListView for adding objects

activity_main.xml

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent"
    android:layout_height="match_parent"      android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    android:paddingBottom="@dimen/activity_vertical_margin" tools:context=".MainActivity">


    <EditText
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/etCountry"
        android:hint="Country"
        android:layout_below="@+id/textView"
        android:layout_alignParentLeft="true"
        android:layout_alignParentStart="true" />

    <EditText
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/etPopulation"
        android:inputType="number"
        android:hint="Population"
        android:layout_below="@+id/etCountry"
        android:layout_alignParentLeft="true"
        android:layout_alignParentStart="true" />

    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Add"
        android:id="@+id/btn"
        android:layout_below="@+id/etPopulation"
        android:layout_alignParentLeft="true"
        android:layout_alignParentStart="true" />


    <TextView android:text="@string/hello_world" android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/textView" />

    <ListView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/lv"
        android:layout_below="@+id/textView"
        android:layout_alignParentLeft="true"
        android:layout_alignParentStart="true"
        android:layout_marginTop="119dp" />

    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Clear"
        android:id="@+id/btn1"
        android:layout_below="@+id/etPopulation"
        android:layout_alignRight="@+id/lv"
        android:layout_alignEnd="@+id/lv"
        android:layout_marginRight="56dp"
        android:layout_marginEnd="56dp" />



</RelativeLayout>

customitem.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="horizontal" android:layout_width="match_parent"
    android:layout_height="wrap_content">


    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="asddff"
        android:textSize="24sp"
        android:padding="16dp"
        android:id="@+id/tv" />

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="population"
        android:textColor="#ff9857ff"
        android:textSize="24sp"
        android:padding="16dp"
        android:id="@+id/tv1" />

</LinearLayout>


MainActivity.java

package com.example.user.listview;


        import android.content.Intent;
        import android.support.v7.app.ActionBarActivity;
        import android.os.Bundle;
        import android.view.Menu;
        import android.view.MenuItem;
        import android.widget.AdapterView;
        import android.widget.Button;
        import android.view.View;
        import android.widget.EditText;
        import android.widget.ListView;
        import android.widget.Toast;

        import java.util.ArrayList;
        import java.util.List;


public class MainActivity extends ActionBarActivity implements View.OnClickListener{

    EditText etCountry;
    EditText etPopulation;
    CountryAdapter adapter;
    Button btn;
    Button btn1;

    ListView lv;
    List<Country> countryInfo;
    Country country;



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

        init();
    }

    private void init() {

        countryInfo = new ArrayList<Country>();
        etCountry = (EditText) findViewById(R.id.etCountry);
        etPopulation = (EditText) findViewById(R.id.etPopulation);
        btn = (Button) findViewById(R.id.btn);
        btn1 = (Button) findViewById(R.id.btn1);
        btn.setOnClickListener(this);
        btn1.setOnClickListener(this);
        lv = (ListView) findViewById(R.id.lv);
        //lv.setOnItemClickListener(this);

    }


    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.menu_main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();

        //noinspection SimplifiableIfStatement
        if (id == R.id.action_settings) {
            return true;
        }

        return super.onOptionsItemSelected(item);
    }

    @Override
    public void onClick(View v) {

        if(v.getId()==R.id.btn) {

            country = new Country();
            country.setCountry(etCountry.getText().toString());
            country.setPolulation(etPopulation.getText().toString());
            countryInfo.add(country);

            adapter = new CountryAdapter(this, countryInfo);
            lv.setAdapter(adapter);

            adapter.notifyDataSetChanged();

            etCountry.setText("");
            etPopulation.setText("");
        }

        if(v.getId()==R.id.btn1)
        {

            adapter.clear();

        }

    }

}

CountryAdapter.java

package com.example.user.listview;

import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.TextView;

import java.util.List;

/**
 * Created by PC21 on 24/1/2015.
 */
public class CountryAdapter extends ArrayAdapter<Country> {

    LayoutInflater inflater;
    ViewHolder holder;
    public CountryAdapter(Context context, List<Country> objects) {
        super(context, 0, objects);
        inflater = (LayoutInflater) context.getSystemService(context.LAYOUT_INFLATER_SERVICE);
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {

        if(convertView == null)  // getting from catch
        {
            convertView = inflater.inflate(R.layout.customitem,null);

            holder = new ViewHolder();
            holder.tv = (TextView) convertView.findViewById(R.id.tv);
            holder.tv1 = (TextView) convertView.findViewById(R.id.tv1);
            convertView.setTag(holder);

        } else {
            holder = (ViewHolder) convertView.getTag();
        }

        Country c1 = getItem(position);
        holder.tv.setText(c1.getCountry());
        holder.tv1.setText(c1.getPolulation());
        return convertView;
    }
    static class ViewHolder{
        public  TextView tv;
        public TextView tv1;
    }

}

Country.java

package com.example.user.listview;

/**

 * Created by PC21 on 24/1/2015.

 */

public class Country {

    private String country;

    private String polulation;

    public String getCountry() {

        return country;

    }

    public void setCountry(String country) {

        this.country = country;

    }

    public String getPolulation() {

        return polulation;

    }

    public void setPolulation(String polulation) {

        this.polulation = polulation;

    }

}

Output: