ajouter et supprimer dynamiquement une vue dans la visionneuse

(J'ai trouvé une solution - veuillez consulter mon message dans la section Réponse ci-dessous.)

Dans mon application, l'utilisateur commencera par une vue unique de ses données. Je voudrais ajouter un ViewPager et permettre à l'utilisateur d'ajouter plus de vues comme souhaité. Comment puis-je faire cela? (Je ne veux pas utiliser le FragmentPagerAdapter.)

J'ai lu d'innombrables articles et aperçus, mais il me manque encore quelque chose. Voici ce que je pense comprendre:

MainActivity crée un ViewPager et un PagerAdapter:

ViewPager pager = null;
MainPagerAdapter adapter = null;
public void onCreate (Bundle savedInstanceState)
{
  super.onCreate (savedInstanceState);
  pager = new ViewPager (this);
  setContentView (pager);

  adapter = new MainPagerAdapter();
  pager.setAdapter (adapter); 

  View v0 = code_to_create_initial_view();
  adapter.add (v0, 0);      
}

Utilisez un PagerAdapter pour fournir les ensembles de vues. Pour cela, il semble que j'ai besoin de méthodes pour ajouter et supprimer des vues, quelque chose comme ça; évidemment plus est nécessaire pour dire que les éléments de ViewPager ont changé et comment montrer le changement:

class MainPagerAdapter extends PagerAdapter
{
  // This holds all the currently displayable views, in order from left to right.
  private ArrayList<View> views = new ArrayList<View>();

  public void addView (View v, int position)
  {
    views.add (position, v);
  }

  public void removeView (int position)
  {
    views.remove (position);
  }
}

De plus, je dois implémenter les méthodes vituelles suivantes. Je suis perdu ici - comment les appelle-t-on et que sont-ils censés faire (ok, getCount est évident)?

  public object instantiateItem (ViewGroup pager, int position);
  public void destroyItem (ViewGroup, int, Object);
  public int getCount ();
  public boolean isViewFromObject (View, Object);

• À quoi servent les paramètres ViewGroup - le groupe conteneur n'est-il pas le ViewPager lui-même?
• Que fait isViewFromObject - comment un objet est-il associé à une vue en premier lieu?
• Dois-je appeler startUpdate et finishUdate lorsque j'ajoute ou supprime des vues?

Merci.

Après avoir déterminé quelles méthodes ViewPager sont appelées par ViewPager et lesquelles sont utilisées à d'autres fins, j'ai trouvé une solution. Je le présente ici car je vois que beaucoup de gens ont eu du mal avec cela et je n'ai vu aucune autre réponse pertinente.

Tout d'abord, voici mon adaptateur; j'espère que les commentaires dans le code sont suffisants:

public class MainPagerAdapter extends PagerAdapter
{
  // This holds all the currently displayable views, in order from left to right.
  private ArrayList<View> views = new ArrayList<View>();

  //-----------------------------------------------------------------------------
  // Used by ViewPager.  "Object" represents the page; tell the ViewPager where the
  // page should be displayed, from left-to-right.  If the page no longer exists,
  // return POSITION_NONE.
  @Override
  public int getItemPosition (Object object)
  {
    int index = views.indexOf (object);
    if (index == -1)
      return POSITION_NONE;
    else
      return index;
  }

  //-----------------------------------------------------------------------------
  // Used by ViewPager.  Called when ViewPager needs a page to display; it is our job
  // to add the page to the container, which is normally the ViewPager itself.  Since
  // all our pages are persistent, we simply retrieve it from our "views" ArrayList.
  @Override
  public Object instantiateItem (ViewGroup container, int position)
  {
    View v = views.get (position);
    container.addView (v);
    return v;
  }

  //-----------------------------------------------------------------------------
  // Used by ViewPager.  Called when ViewPager no longer needs a page to display; it
  // is our job to remove the page from the container, which is normally the
  // ViewPager itself.  Since all our pages are persistent, we do nothing to the
  // contents of our "views" ArrayList.
  @Override
  public void destroyItem (ViewGroup container, int position, Object object)
  {
    container.removeView (views.get (position));
  }

  //-----------------------------------------------------------------------------
  // Used by ViewPager; can be used by app as well.
  // Returns the total number of pages that the ViewPage can display.  This must
  // never be 0.
  @Override
  public int getCount ()
  {
    return views.size();
  }

  //-----------------------------------------------------------------------------
  // Used by ViewPager.
  @Override
  public boolean isViewFromObject (View view, Object object)
  {
    return view == object;
  }

  //-----------------------------------------------------------------------------
  // Add "view" to right end of "views".
  // Returns the position of the new view.
  // The app should call this to add pages; not used by ViewPager.
  public int addView (View v)
  {
    return addView (v, views.size());
  }

  //-----------------------------------------------------------------------------
  // Add "view" at "position" to "views".
  // Returns position of new view.
  // The app should call this to add pages; not used by ViewPager.
  public int addView (View v, int position)
  {
    views.add (position, v);
    return position;
  }

  //-----------------------------------------------------------------------------
  // Removes "view" from "views".
  // Retuns position of removed view.
  // The app should call this to remove pages; not used by ViewPager.
  public int removeView (ViewPager pager, View v)
  {
    return removeView (pager, views.indexOf (v));
  }

  //-----------------------------------------------------------------------------
  // Removes the "view" at "position" from "views".
  // Retuns position of removed view.
  // The app should call this to remove pages; not used by ViewPager.
  public int removeView (ViewPager pager, int position)
  {
    // ViewPager doesn't have a delete method; the closest is to set the adapter
    // again.  When doing so, it deletes all its views.  Then we can delete the view
    // from from the adapter and finally set the adapter to the pager again.  Note
    // that we set the adapter to null before removing the view from "views" - that's
    // because while ViewPager deletes all its views, it will call destroyItem which
    // will in turn cause a null pointer ref.
    pager.setAdapter (null);
    views.remove (position);
    pager.setAdapter (this);

    return position;
  }

  //-----------------------------------------------------------------------------
  // Returns the "view" at "position".
  // The app should call this to retrieve a view; not used by ViewPager.
  public View getView (int position)
  {
    return views.get (position);
  }

  // Other relevant methods:

  // finishUpdate - called by the ViewPager - we don't care about what pages the
  // pager is displaying so we don't use this method.
}

Et voici quelques extraits de code montrant comment utiliser l'adaptateur.

class MainActivity extends Activity
{
  private ViewPager pager = null;
  private MainPagerAdapter pagerAdapter = null;

  //-----------------------------------------------------------------------------
  @Override
  public void onCreate (Bundle savedInstanceState)
  {
    super.onCreate(savedInstanceState);
    setContentView (R.layout.main_activity);

    ... do other initialization, such as create an ActionBar ...

    pagerAdapter = new MainPagerAdapter();
    pager = (ViewPager) findViewById (R.id.view_pager);
    pager.setAdapter (pagerAdapter);

    // Create an initial view to display; must be a subclass of FrameLayout.
    LayoutInflater inflater = context.getLayoutInflater();
    FrameLayout v0 = (FrameLayout) inflater.inflate (R.layout.one_of_my_page_layouts, null);
    pagerAdapter.addView (v0, 0);
    pagerAdapter.notifyDataSetChanged();
  }

  //-----------------------------------------------------------------------------
  // Here's what the app should do to add a view to the ViewPager.
  public void addView (View newPage)
  {
    int pageIndex = pagerAdapter.addView (newPage);
    // You might want to make "newPage" the currently displayed page:
    pager.setCurrentItem (pageIndex, true);
  }

  //-----------------------------------------------------------------------------
  // Here's what the app should do to remove a view from the ViewPager.
  public void removeView (View defunctPage)
  {
    int pageIndex = pagerAdapter.removeView (pager, defunctPage);
    // You might want to choose what page to display, if the current page was "defunctPage".
    if (pageIndex == pagerAdapter.getCount())
      pageIndex--;
    pager.setCurrentItem (pageIndex);
  }

  //-----------------------------------------------------------------------------
  // Here's what the app should do to get the currently displayed page.
  public View getCurrentPage ()
  {
    return pagerAdapter.getView (pager.getCurrentItem());
  }

  //-----------------------------------------------------------------------------
  // Here's what the app should do to set the currently displayed page.  "pageToShow" must
  // currently be in the adapter, or this will crash.
  public void setCurrentPage (View pageToShow)
  {
    pager.setCurrentItem (pagerAdapter.getItemPosition (pageToShow), true);
  }
}

Enfin, vous pouvez utiliser les éléments suivants pour votre activity_main.xmlmise en page:

<?xml version="1.0" encoding="utf-8"?>
<android.support.v4.view.ViewPager
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/view_pager"
    android:layout_width="match_parent"
    android:layout_height="match_parent" >

</android.support.v4.view.ViewPager>

Je cherchais une solution simple pour supprimer dynamiquement les vues du viewpager (sans fragments). Donc, si vous avez des informations auxquelles appartiennent vos pages, vous pouvez les définir sur Afficher comme balise. Juste comme ça (code de l'adaptateur):

@Override
public Object instantiateItem(ViewGroup collection, int position)
{
    ImageView iv = new ImageView(mContext);
    MediaMessage msg = mMessages.get(position);
    ...

    iv.setTag(media);
    return iv;
}

@Override
public int getItemPosition (Object object)
{
    View o = (View) object;
    int index = mMessages.indexOf(o.getTag());
    if (index == -1)
        return POSITION_NONE;
    else
        return index;
}

Il vous suffit de supprimer vos informations de mMessages, puis d'appeler notifyDataSetChanged()votre adaptateur. Mauvaise nouvelle il n'y a pas d'animation dans ce cas.

Il y a pas mal de discussions autour de ce sujet

• ViewPager PagerAdapter ne met pas à jour la vue
• Mettre à jour ViewPager dynamiquement?
• Suppression de fragments de FragmentStatePagerAdapter

Bien que nous le voyions souvent, l'utilisation POSITION_NONEne semble pas être la voie à suivre car elle est très inefficace en termes de mémoire.

Ici, dans cette question, nous devrions envisager d'utiliser l'approche d'Alvaro :

... consiste à setTag()utiliser la méthode instantiateItem()lors de l'instanciation d'une nouvelle vue. Ensuite, au lieu d'utiliser notifyDataSetChanged(), vous pouvez utiliser findViewWithTag()pour trouver la vue que vous souhaitez mettre à jour.

Voici une réponse SO avec un code basé sur cette idée

J'ai fait un programme similaire. J'espère que cela vous aidera. Dans sa première activité, quatre données de grille peuvent être sélectionnées. Sur l'activité suivante, il y a un pager de vue qui contient deux pages obligatoires et 4 autres pages seront là, qui seront visibles en fonction des données de grille sélectionnées.

Voici la principale activité MainActivity

    package com.example.jeffy.viewpagerapp;
    import android.content.Context;
    import android.content.Intent;
    import android.content.SharedPreferences;
    import android.database.Cursor;
    import android.database.SQLException;
    import android.database.sqlite.SQLiteDatabase;
    import android.database.sqlite.SQLiteOpenHelper;
    import android.os.Bundle;
    import android.os.Parcel;
    import android.support.design.widget.FloatingActionButton;
    import android.support.design.widget.Snackbar;
    import android.support.v7.app.AppCompatActivity;
    import android.support.v7.widget.Toolbar;
    import android.util.Log;
    import android.view.View;
    import android.view.Menu;
    import android.view.MenuItem;
    import android.widget.AdapterView;
    import android.widget.Button;
    import android.widget.GridView;
    import java.lang.reflect.Array;
    import java.util.ArrayList;
    public class MainActivity extends AppCompatActivity {
    SharedPreferences pref;
    SharedPreferences.Editor editor;
    GridView gridView;
    Button button;
    private static final String DATABASE_NAME = "dbForTest.db";
    private static final int DATABASE_VERSION = 1;
    private static final String TABLE_NAME = "diary";
    private static final String TITLE = "id";
    private static final String BODY = "content";
    DBHelper  dbHelper = new DBHelper(this);
    ArrayList<String> frags = new ArrayList<String>();
    ArrayList<FragmentArray> fragmentArray = new ArrayList<FragmentArray>();
    String[] selectedData;
    Boolean port1=false,port2=false,port3=false,port4=false;
    int Iport1=1,Iport2=1,Iport3=1,Iport4=1,location;



    // This Data show in grid ( Used by adapter )
        CustomGridAdapter customGridAdapter = new           CustomGridAdapter(MainActivity.this,GRID_DATA);
    static final String[ ] GRID_DATA = new String[] {
            "1" ,
            "2",
            "3" ,
            "4"
    };
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);
        frags.add("TabFragment3");
        frags.add("TabFragment4");
        frags.add("TabFragment5");
        frags.add("TabFragment6");
        dbHelper = new DBHelper(this);
        dbHelper.insertContact(1,0);
        dbHelper.insertContact(2,0);
        dbHelper.insertContact(3,0);
        dbHelper.insertContact(4,0);
        final Bundle selected = new Bundle();
        button = (Button) findViewById(R.id.button);
        pref = getApplicationContext().getSharedPreferences("MyPref", MODE_PRIVATE);
        editor = pref.edit();
        gridView = (GridView) findViewById(R.id.gridView1);

        gridView.setAdapter(customGridAdapter);

        gridView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
              //view.findViewById(R.id.grid_item_image).setVisibility(View.VISIBLE);
                location = position + 1;
                if (position == 0) {
                    Iport1++;
                    Iport1 = Iport1 % 2;
                    if (Iport1 % 2 == 1) {
                        //dbHelper.updateContact(1,1);
                        view.findViewById(R.id.grid_item_image).setVisibility(View.VISIBLE);
                        dbHelper.updateContact(1,1);
                    } else {
                        //dbHelper.updateContact(1,0);
                        view.findViewById(R.id.grid_item_image).setVisibility(View.INVISIBLE);
                        dbHelper.updateContact(1, 0);
                    }
                }
                if (position == 1) {
                    Iport2++;
                    Iport1 = Iport1 % 2;
                    if (Iport2 % 2 == 1) {
                        //dbHelper.updateContact(2,1);
                        view.findViewById(R.id.grid_item_image).setVisibility(View.VISIBLE);
                        dbHelper.updateContact(2, 1);
                    } else {
                        //dbHelper.updateContact(2,0);
                        view.findViewById(R.id.grid_item_image).setVisibility(View.INVISIBLE);
                        dbHelper.updateContact(2,0);
                    }
                }
                if (position == 2) {
                    Iport3++;
                    Iport3 = Iport3 % 2;
                    if (Iport3 % 2 == 1) {
                        //dbHelper.updateContact(3,1);
                        view.findViewById(R.id.grid_item_image).setVisibility(View.VISIBLE);
                        dbHelper.updateContact(3, 1);
                    } else {
                        //dbHelper.updateContact(3,0);
                        view.findViewById(R.id.grid_item_image).setVisibility(View.INVISIBLE);
                        dbHelper.updateContact(3, 0);
                    }
                }
                if (position == 3) {
                    Iport4++;
                    Iport4 = Iport4 % 2;
                    if (Iport4 % 2 == 1) {
                        //dbHelper.updateContact(4,1);
                       view.findViewById(R.id.grid_item_image).setVisibility(View.VISIBLE);
                        dbHelper.updateContact(4, 1);
                    } else {
                        //dbHelper.updateContact(4,0);
                       view.findViewById(R.id.grid_item_image).setVisibility(View.INVISIBLE);
                        dbHelper.updateContact(4,0);
                    }
                }
            }
        });
        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                editor.putInt("port1", Iport1);
                editor.putInt("port2", Iport2);
                editor.putInt("port3", Iport3);
                editor.putInt("port4", Iport4);
                Intent i = new Intent(MainActivity.this,Main2Activity.class);
                if(Iport1==1)
                    i.putExtra("3","TabFragment3");
                else
                    i.putExtra("3", "");
                if(Iport2==1)
                    i.putExtra("4","TabFragment4");
                else
                    i.putExtra("4","");
                if(Iport3==1)
                    i.putExtra("5", "TabFragment5");
                else
                    i.putExtra("5","");
                if(Iport4==1)
                    i.putExtra("6", "TabFragment6");
                else
                    i.putExtra("6","");
                dbHelper.updateContact(0, Iport1);
                dbHelper.updateContact(1, Iport2);
                dbHelper.updateContact(2, Iport3);
                dbHelper.updateContact(3, Iport4);
                startActivity(i);
            }
        });
    }
}

Ici TabFragment1, TabFragment2 etc. sont des fragments à afficher sur le viewpager.Et je ne montre pas les mises en page car elles sont hors de portée de ce projet.

MainActivity aura l'intention de Main2Activity Main2Activity

    package com.example.jeffy.viewpagerapp;

import android.content.Intent;
import android.database.Cursor;
import android.os.Bundle;
import android.support.design.widget.CollapsingToolbarLayout;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.support.design.widget.TabLayout;
import android.support.v4.view.ViewPager;
import android.support.v4.widget.NestedScrollView;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.text.TextUtils;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.FrameLayout;

import java.util.ArrayList;

public class Main2Activity extends AppCompatActivity {

    private ViewPager pager = null;
    private PagerAdapter pagerAdapter = null;
    DBHelper dbHelper;
    Cursor rs;
    int port1,port2,port3,port4;
    //-----------------------------------------------------------------------------
    @Override
    public void onCreate (Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main2);
        Toolbar toolbar = (Toolbar) findViewById(R.id.MyToolbar);
        setSupportActionBar(toolbar);

        getSupportActionBar().setDisplayHomeAsUpEnabled(true);

        CollapsingToolbarLayout collapsingToolbar =
                (CollapsingToolbarLayout) findViewById(R.id.collapse_toolbar);


        NestedScrollView scrollView = (NestedScrollView) findViewById (R.id.nested);
        scrollView.setFillViewport (true);

        ArrayList<String > selectedPort = new ArrayList<String>();

        Intent intent = getIntent();
        String Tab3 = intent.getStringExtra("3");
        String Tab4 = intent.getStringExtra("4");
        String Tab5 = intent.getStringExtra("5");
        String Tab6 = intent.getStringExtra("6");

        TabLayout tabLayout = (TabLayout) findViewById(R.id.tab_layout);
        tabLayout.addTab(tabLayout.newTab().setText("View"));
        tabLayout.addTab(tabLayout.newTab().setText("All"));

        selectedPort.add("TabFragment1");
        selectedPort.add("TabFragment2");
        if(Tab3!=null && !TextUtils.isEmpty(Tab3))
        selectedPort.add(Tab3);
        if(Tab4!=null && !TextUtils.isEmpty(Tab4))
        selectedPort.add(Tab4);
        if(Tab5!=null && !TextUtils.isEmpty(Tab5))
        selectedPort.add(Tab5);
        if(Tab6!=null && !TextUtils.isEmpty(Tab6))
        selectedPort.add(Tab6);



        dbHelper = new DBHelper(this);
//        rs=dbHelper.getData(1);
//        port1 = rs.getInt(rs.getColumnIndex("id"));
//
//        rs=dbHelper.getData(2);
//        port2 = rs.getInt(rs.getColumnIndex("id"));
//
//        rs=dbHelper.getData(3);
//        port3 = rs.getInt(rs.getColumnIndex("id"));
//
//        rs=dbHelper.getData(4);
//        port4 = rs.getInt(rs.getColumnIndex("id"));


        Log.i(">>>>>>>>>>>>>>", "port 1" + port1 + "port 2" + port2 + "port 3" + port3 + "port 4" + port4);

        if(Tab3!=null && !TextUtils.isEmpty(Tab3))
        tabLayout.addTab(tabLayout.newTab().setText("Tab 0"));
        if(Tab3!=null && !TextUtils.isEmpty(Tab4))
        tabLayout.addTab(tabLayout.newTab().setText("Tab 1"));
        if(Tab3!=null && !TextUtils.isEmpty(Tab5))
        tabLayout.addTab(tabLayout.newTab().setText("Tab 2"));
        if(Tab3!=null && !TextUtils.isEmpty(Tab6))
        tabLayout.addTab(tabLayout.newTab().setText("Tab 3"));
        tabLayout.setTabGravity(TabLayout.GRAVITY_FILL);

        final ViewPager viewPager = (ViewPager) findViewById(R.id.view_pager);
        final PagerAdapter adapter = new PagerAdapter
                (getSupportFragmentManager(), tabLayout.getTabCount(), selectedPort);
        viewPager.setAdapter(adapter);
        viewPager.addOnPageChangeListener(new TabLayout.TabLayoutOnPageChangeListener(tabLayout));
        tabLayout.setOnTabSelectedListener(new TabLayout.OnTabSelectedListener() {
            @Override
            public void onTabSelected(TabLayout.Tab tab) {
                viewPager.setCurrentItem(tab.getPosition());
            }

            @Override
            public void onTabUnselected(TabLayout.Tab tab) {

            }

            @Override
            public void onTabReselected(TabLayout.Tab tab) {

            }
        });
//        setContentView(R.layout.activity_main2);
//        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
//        setSupportActionBar(toolbar);

//        TabLayout tabLayout = (TabLayout) findViewById(R.id.tab_layout);
//        tabLayout.addTab(tabLayout.newTab().setText("View"));
//        tabLayout.addTab(tabLayout.newTab().setText("All"));
//        tabLayout.addTab(tabLayout.newTab().setText("Tab 0"));
//        tabLayout.addTab(tabLayout.newTab().setText("Tab 1"));
//        tabLayout.addTab(tabLayout.newTab().setText("Tab 2"));
//        tabLayout.addTab(tabLayout.newTab().setText("Tab 3"));
//        tabLayout.setTabGravity(TabLayout.GRAVITY_FILL);


}
    }

ViewPagerAdapter Viewpageradapter.class

package com.example.jeffy.viewpagerapp;

import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentStatePagerAdapter;
import android.support.v4.view.ViewPager;
import android.view.View;
import android.view.ViewGroup;

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

/**
 * Created by Jeffy on 25-01-2016.
 */
public class PagerAdapter extends FragmentStatePagerAdapter {
    int mNumOfTabs;

    List<String> values;

    public PagerAdapter(FragmentManager fm, int NumOfTabs, List<String> Port) {
        super(fm);
        this.mNumOfTabs = NumOfTabs;
        this.values= Port;
    }


    @Override
    public Fragment getItem(int position) {


        String fragmentName = values.get(position);
        Class<?> clazz = null;
        Object fragment = null;
        try {
            clazz = Class.forName("com.example.jeffy.viewpagerapp."+fragmentName);
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        }
        try {
            fragment = clazz.newInstance();
        } catch (InstantiationException e) {
            e.printStackTrace();
        } catch (IllegalAccessException e) {
            e.printStackTrace();
        }

        return (Fragment) fragment;
    }

    @Override
    public int getCount() {
        return values.size();
    }
}

Mise en page pour main2activity acticity_main2.xml

    <android.support.design.widget.CoordinatorLayout xmlns:android="http://schemas.android.com/apk/res/android"
        xmlns:app="http://schemas.android.com/apk/res-auto"
        android:id="@+id/main_content"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:fitsSystemWindows="true">

        <android.support.design.widget.AppBarLayout
            android:id="@+id/MyAppbar"
            android:layout_width="match_parent"
            android:layout_height="256dp"
            android:fitsSystemWindows="true">

            <android.support.design.widget.CollapsingToolbarLayout
                android:id="@+id/collapse_toolbar"
                android:layout_width="match_parent"
                android:layout_height="match_parent"
                app:layout_scrollFlags="scroll|exitUntilCollapsed"
                android:background="@color/material_deep_teal_500"
                android:fitsSystemWindows="true">

                <ImageView
                    android:id="@+id/bgheader"
                    android:layout_width="match_parent"
                    android:layout_height="match_parent"
                    android:scaleType="centerCrop"
                    android:fitsSystemWindows="true"
                    android:background="@drawable/screen"
                    app:layout_collapseMode="pin" />

                <android.support.v7.widget.Toolbar
                    android:id="@+id/MyToolbar"
                    android:layout_width="match_parent"
                    android:layout_height="?attr/actionBarSize"
                    app:layout_collapseMode="parallax" />





            </android.support.design.widget.CollapsingToolbarLayout>

        </android.support.design.widget.AppBarLayout>

        <android.support.v4.widget.NestedScrollView
            android:layout_width="match_parent"
            android:id="@+id/nested"
            android:layout_height="match_parent"
            android:layout_gravity="fill_vertical"
            app:layout_behavior="@string/appbar_scrolling_view_behavior">

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="vertical">
        <android.support.design.widget.TabLayout
            android:id="@+id/tab_layout"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_below="@+id/MyToolbar"
            android:background="?attr/colorPrimary"
            android:elevation="6dp"
            android:minHeight="?attr/actionBarSize"
            android:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar"/>


        <android.support.v4.view.ViewPager
            xmlns:android="http://schemas.android.com/apk/res/android"
            android:id="@+id/view_pager"
            android:layout_width="match_parent"
            android:layout_height="match_parent" >

        </android.support.v4.view.ViewPager>
    </LinearLayout>


        </android.support.v4.widget.NestedScrollView>

    </android.support.design.widget.CoordinatorLayout>

Mainactivity layout
activity_main.xml

        <?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"
    xmlns:tools="http://schemas.android.com/tools"
    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"
    app:layout_behavior="@string/appbar_scrolling_view_behavior"
    tools:context="com.example.jeffy.viewpagerapp.MainActivity"
    tools:showIn="@layout/activity_main">


<LinearLayout
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:orientation="vertical">

    <GridView xmlns:android="http://schemas.android.com/apk/res/android"
        android:id="@+id/gridView1"
        android:numColumns="2"
        android:gravity="center"
        android:columnWidth="100dp"
        android:stretchMode="columnWidth"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent" >

    </GridView>

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

</LinearLayout>




</RelativeLayout>

J'espère que cela aiderait quelqu'un ... Cliquez sur le bouton haut s'il vous plaît si cela vous a aidé

Voici une solution alternative à cette question. Mon adaptateur:

    private class PagerAdapter extends FragmentPagerAdapter implements 
                    ViewPager.OnPageChangeListener, TabListener {

    private List<Fragment> mFragments = new ArrayList<Fragment>();
    private ViewPager mPager;
    private ActionBar mActionBar;

    private Fragment mPrimaryItem;

    public PagerAdapter(FragmentManager fm, ViewPager vp, ActionBar ab) {
        super(fm);
        mPager = vp;
        mPager.setAdapter(this);
        mPager.setOnPageChangeListener(this);
        mActionBar = ab;
    }

    public void addTab(PartListFragment frag) {
        mFragments.add(frag);
        mActionBar.addTab(mActionBar.newTab().setTabListener(this).
                            setText(frag.getPartCategory()));
    }

    @Override
    public Fragment getItem(int position) {
        return mFragments.get(position);
    }

    @Override
    public int getCount() {
        return mFragments.size();
    }

    /** (non-Javadoc)
     * @see android.support.v4.app.FragmentStatePagerAdapter#setPrimaryItem(android.view.ViewGroup, int, java.lang.Object)
     */
    @Override
    public void setPrimaryItem(ViewGroup container, int position,
            Object object) {
        super.setPrimaryItem(container, position, object);
        mPrimaryItem = (Fragment) object;
    }

    /** (non-Javadoc)
     * @see android.support.v4.view.PagerAdapter#getItemPosition(java.lang.Object)
     */
    @Override
    public int getItemPosition(Object object) {
        if (object == mPrimaryItem) {
            return POSITION_UNCHANGED;
        }
        return POSITION_NONE;
    }

    @Override
    public void onTabSelected(Tab tab, FragmentTransaction ft) {
        mPager.setCurrentItem(tab.getPosition());
    }

    @Override
    public void onTabUnselected(Tab tab, FragmentTransaction ft) { }

    @Override
    public void onTabReselected(Tab tab, FragmentTransaction ft) { }

    @Override
    public void onPageScrollStateChanged(int arg0) { }

    @Override
    public void onPageScrolled(int arg0, float arg1, int arg2) { }

    @Override
    public void onPageSelected(int position) {
        mActionBar.setSelectedNavigationItem(position);
    }

    /**
     * This method removes the pages from ViewPager
     */
    public void removePages() {
        mActionBar.removeAllTabs();

                    //call to ViewPage to remove the pages
        vp.removeAllViews();
        mFragments.clear();

        //make this to update the pager
        vp.setAdapter(null);
        vp.setAdapter(pagerAdapter);
    }
}

Code à supprimer et à ajouter dynamiquement

//remove the pages. basically call to method removeAllViews from `ViewPager`
pagerAdapter.removePages();

pagerAdapter.addPage(pass your fragment);

Après les conseils de Peri Hartman, cela a commencé à fonctionner après avoir défini null do l'adaptateur ViewPager et remis l'adaptateur après la suppression des vues. Avant cela, la page 0 n'affichait pas le contenu de sa liste.

Merci.

J'ai créé une bibliothèque PagerAdapters personnalisée pour modifier les éléments de PagerAdapters de manière dynamique.

Vous pouvez modifier les éléments de manière dynamique comme suit en utilisant cette bibliothèque.

@Override
protected void onCreate(Bundle savedInstanceState) {
        /** ... **/
    adapter = new MyStatePagerAdapter(getSupportFragmentManager()
                            , new String[]{"1", "2", "3"});
    ((ViewPager)findViewById(R.id.view_pager)).setAdapter(adapter);
     adapter.add("4");
     adapter.remove(0);
}

class MyPagerAdapter extends ArrayViewPagerAdapter<String> {

    public MyPagerAdapter(String[] data) {
        super(data);
    }

    @Override
    public View getView(LayoutInflater inflater, ViewGroup container, String item, int position) {
        View v = inflater.inflate(R.layout.item_page, container, false);
        ((TextView) v.findViewById(R.id.item_txt)).setText(item);
        return v;
    }
}

La bibliothèque Thils prend également en charge les pages créées par Fragments.

Pour supprimer, vous pouvez utiliser ceci directement:

getSupportFragmentManager().beginTransaction().remove(fragment).
                            commitAllowingStateLoss();

fragment est le fragment que vous souhaitez supprimer.

Je trouve une bonne solution à ce problème, cette solution peut le faire fonctionner et pas besoin de recréer des fragments.
Mon point clé est:

1. configurez ViewPager chaque fois que vous supprimez ou ajoutez un onglet (Fragment).
2. Remplacez la méthode getItemId, retournez un identifiant spécifique plutôt qu'une position.

Code source

package com.zq.testviewpager;

import android.support.annotation.Nullable;
import android.support.design.widget.TabLayout;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;

import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter;
import android.support.v4.view.ViewPager;
import android.os.Bundle;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;

import android.widget.TextView;

import java.util.ArrayList;
import java.util.Arrays;
/**
 * Created by z8888q@gmail.com on 2017/5/31.
 * Implement dynamic delete or add tab(TAB_C in this test code).
 */
public class MainActivity extends AppCompatActivity {

    private static final int TAB_A = 1001;
    private static final int TAB_B = 1002;
    private static final int TAB_C = 1003;
    private static final int TAB_D = 1004;
    private static final int TAB_E = 1005;
    private Tab[] tabsArray = new Tab[]{new Tab(TAB_A, "A"),new Tab(TAB_B, "B"),new Tab(TAB_C, "C"),new Tab(TAB_D, "D"),new Tab(TAB_E, "E")};

    private ArrayList<Tab> mTabs = new ArrayList<>(Arrays.asList(tabsArray));

    private Tab[] tabsArray2 = new Tab[]{new Tab(TAB_A, "A"),new Tab(TAB_B, "B"),new Tab(TAB_D, "D"),new Tab(TAB_E, "E")};

    private ArrayList<Tab> mTabs2 = new ArrayList<>(Arrays.asList(tabsArray2));

    /**
     * The {@link android.support.v4.view.PagerAdapter} that will provide
     * fragments for each of the sections. We use a
     * {@link FragmentPagerAdapter} derivative, which will keep every
     * loaded fragment in memory. If this becomes too memory intensive, it
     * may be best to switch to a
     * {@link android.support.v4.app.FragmentStatePagerAdapter}.
     */
    private SectionsPagerAdapter mSectionsPagerAdapter;

    /**
     * The {@link ViewPager} that will host the section contents.
     */
    private ViewPager mViewPager;
    private TabLayout tabLayout;

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

        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);
        // Create the adapter that will return a fragment for each of the three
        // primary sections of the activity.
        mSectionsPagerAdapter = new SectionsPagerAdapter(mTabs, getSupportFragmentManager());

        // Set up the ViewPager with the sections adapter.
        mViewPager = (ViewPager) findViewById(R.id.container);
        mViewPager.setAdapter(mSectionsPagerAdapter);

        tabLayout = (TabLayout) findViewById(R.id.tabs);
        tabLayout.setupWithViewPager(mViewPager);

        FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
        fab.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
                        .setAction("Action", null).show();
            }
        });

    }


    @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;
        }else if (id == R.id.action_delete) {
            int currentItemPosition = mViewPager.getCurrentItem();
            Tab currentTab = mTabs.get(currentItemPosition);

            if(currentTab.id == TAB_C){
                currentTab = mTabs.get(currentItemPosition == 0 ? currentItemPosition +1 : currentItemPosition - 1);
            }

            mSectionsPagerAdapter = new SectionsPagerAdapter(mTabs2, getSupportFragmentManager());
            mViewPager.setAdapter(mSectionsPagerAdapter);
            tabLayout.setupWithViewPager(mViewPager);


            mViewPager.setCurrentItem(mTabs2.indexOf(currentTab), false);
            return true;
        }else if (id == R.id.action_add) {

            int currentItemPosition = mViewPager.getCurrentItem();
            Tab currentTab = mTabs2.get(currentItemPosition);

            mSectionsPagerAdapter = new SectionsPagerAdapter(mTabs, getSupportFragmentManager());
            mViewPager.setAdapter(mSectionsPagerAdapter);
            tabLayout.setupWithViewPager(mViewPager);

            mViewPager.setCurrentItem(mTabs.indexOf(currentTab), false);
            return true;
        }else

        return super.onOptionsItemSelected(item);
    }

    /**
     * A placeholder fragment containing a simple view.
     */
    public static class PlaceholderFragment extends Fragment {
        /**
         * The fragment argument representing the section number for this
         * fragment.
         */
        private static final String ARG_SECTION_NUMBER = "section_number";

        public PlaceholderFragment() {
        }

        /**
         * Returns a new instance of this fragment for the given section
         * number.
         */
        public static PlaceholderFragment newInstance(int sectionNumber) {
            PlaceholderFragment fragment = new PlaceholderFragment();
            Bundle args = new Bundle();
            args.putInt(ARG_SECTION_NUMBER, sectionNumber);
            fragment.setArguments(args);
            return fragment;
        }

        @Override
        public void onCreate(@Nullable Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            Log.e("TestViewPager", "onCreate"+getArguments().getInt(ARG_SECTION_NUMBER));
        }

        @Override
        public void onDestroy() {
            super.onDestroy();
            Log.e("TestViewPager", "onDestroy"+getArguments().getInt(ARG_SECTION_NUMBER));
        }

        @Override
        public View onCreateView(LayoutInflater inflater, ViewGroup container,
                                 Bundle savedInstanceState) {
            View rootView = inflater.inflate(R.layout.fragment_main, container, false);
            TextView textView = (TextView) rootView.findViewById(R.id.section_label);
            textView.setText(getString(R.string.section_format, getArguments().getInt(ARG_SECTION_NUMBER)));
            return rootView;
        }
    }

    /**
     * A {@link FragmentPagerAdapter} that returns a fragment corresponding to
     * one of the sections/tabs/pages.
     */
    public class SectionsPagerAdapter extends FragmentPagerAdapter {
        ArrayList<Tab> tabs;

        public SectionsPagerAdapter(ArrayList<Tab> tabs, FragmentManager fm) {
            super(fm);
            this.tabs = tabs;
        }

        @Override
        public Fragment getItem(int position) {
            // getItem is called to instantiate the fragment for the given page.
            // Return a PlaceholderFragment (defined as a static inner class below).
            return PlaceholderFragment.newInstance(tabs.get(position).id);
        }

        @Override
        public int getCount() {
            return tabs.size();
        }

        @Override
        public long getItemId(int position) {
            return tabs.get(position).id;
        }

        @Override
        public CharSequence getPageTitle(int position) {
            return tabs.get(position).title;
        }
    }

    private static class Tab {
        String title;
        public int id;

        Tab(int id, String title){
            this.id = id;
            this.title = title;
        }

        @Override
        public boolean equals(Object obj) {
            if(obj instanceof Tab){
                return ((Tab)obj).id == id;
            }else{
                return false;
            }
        }
    }
}

Le code est à mon Github Gist .