title: Android - PagerAdapter with Swipe
body: <p>I have a big problem with my first Android App</p>
  
  <p><strong>Goal:</strong></p>
  
  <p>I want change view into a ViewPager element when I swipe (left/right)</p>
  
  <p><strong>Problem</strong></p>
  
  <p>I wrote some lines of code, but don't works ._.</p>
  
  <p>I report my code:</p>
  
  <p>MainActivity.java</p>
  
  <pre><code>   package com.example.macbookpro.myapplication;
  
  import android.support.v4.view.ViewPager;
  import android.support.v7.app.AppCompatActivity;
  import android.os.Bundle;
  
  import java.util.ArrayList;
  
  public class MainActivity extends AppCompatActivity {
  
      @Override
      protected void onCreate(Bundle savedInstanceState) {
          super.onCreate(savedInstanceState);
          setContentView(R.layout.activity_main);
          Element element=new Element("nome1","surname1");
          Element element1=new Element("nome2","surname2");
          ArrayList&lt;Element&gt; elementArrayList=new ArrayList&lt;Element&gt;();
          elementArrayList.add(element);
          elementArrayList.add(element1);
          ViewPager viewPager=(ViewPager) findViewById(R.id.swipeView);
          ElementAdapter elementAdapter=new ElementAdapter(elementArrayList,this);
          viewPager.setAdapter(elementAdapter);
  
  
      }
  }
  </code></pre>
  
  <p>ElementAdapter.java</p>
  
  <pre><code>public class ElementAdapter extends PagerAdapter {
      private ArrayList&lt;Element&gt; element=new ArrayList&lt;Element&gt;();
      private Context ctx;
  
      public ElementAdapter(ArrayList&lt;Element&gt; element, Context ctx) {
          this.element = element;
          this.ctx = ctx;
      }
  
      @Override
      public Object instantiateItem(ViewGroup container, int position) {
          LayoutInflater inflater = (LayoutInflater) ctx.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
          View item_view = inflater.inflate(R.layout.element,container,false);
          TextView nome = (TextView) item_view.findViewById(R.id.nome);
          TextView surname= (TextView) item_view.findViewById(R.id.surname);
          nome.setText(element.get(position).getNome());
          surname.setText(element.get(position).getSurname());
          container.addView(item_view);
  
          return item_view;
      }
  
      @Override
      public int getCount() {
          return this.element.size();
      }
  
      @Override
      public boolean isViewFromObject(View view, Object object) {
          return false;
      }
  
      @Override
      public void destroyItem(ViewGroup container, int position, Object object) {
          super.destroyItem(container, position, object);
      }
  }
  </code></pre>
  
  <p>Element.java</p>
  
  <pre><code>public class Element {
      private String nome;
      private String surname;
  
      public Element(String nome, String surname) {
          this.nome = nome;
          this.surname = surname;
      }
  
      public String getNome() {
          return nome;
      }
  
      public void setNome(String nome) {
          this.nome = nome;
      }
  
      public String getSurname() {
          return surname;
      }
  
      public void setSurname(String surname) {
          this.surname = surname;
      }
  </code></pre>
  
  <p>ActivityMain.xml</p>
  
  <pre><code>&lt;?xml version="1.0" encoding="utf-8"?&gt;
  &lt;RelativeLayout 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"    tools:context="com.example.macbookpro.myapplication.MainActivity"&gt;
      &lt;View
          android:id="@+id/centerShim5"
          android:layout_height="0dp"
          android:layout_width="match_parent"
          android:layout_centerInParent="true"
          android:visibility="invisible" /&gt;
      &lt;android.support.v4.view.ViewPager
          android:id="@+id/swipeView"
          android:layout_height="match_parent"
          android:layout_width="match_parent"
          android:layout_centerInParent="true"
          android:layout_alignBottom="@id/centerShim5"
          android:visibility="visible" /&gt;
  
      &lt;Button
          android:text="Button"
          android:layout_width="wrap_content"
          android:layout_height="wrap_content"
          android:layout_alignParentBottom="true"
          android:layout_alignParentRight="true"
          android:layout_alignParentEnd="true"
          android:id="@+id/button" /&gt;
  &lt;/RelativeLayout&gt;
  </code></pre>
  
  <p>Element.xml</p>
  
  <pre><code>&lt;?xml version="1.0" encoding="utf-8"?&gt;
  &lt;RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
      android:orientation="vertical"
      android:layout_width="fill_parent"
      android:layout_height="?android:attr/listPreferredItemHeight"&gt;
  
      &lt;TextView
          android:id="@+id/nome"
          android:layout_width="wrap_content"
          android:layout_height="match_parent"
          android:gravity="center_vertical"
          android:text="Example application"
          android:textSize="20dp"
          android:layout_alignLeft="@+id/surname"
          android:layout_alignStart="@+id/surname"
          android:layout_above="@+id/surname" /&gt;
  
      &lt;TextView
          android:id="@+id/surname"
          android:layout_width="wrap_content"
          android:layout_height="wrap_content"
          android:ellipsize="marquee"
          android:singleLine="true"
          android:text="Description"
          android:textSize="12sp"
          android:textStyle="normal|bold|italic"
          android:layout_alignParentBottom="true"/&gt;
  
  &lt;/RelativeLayout&gt;
  </code></pre>
  
  <p>Please help me. i'm getting crazy</p>