android - studio - Fragmento no muestra el contenido de TabHost en la segunda vez

tabs con fragments android

Question

Bueno ... estoy trabajando con fragmentos, android.support.v4.widget.DrawerLayout, TabHost y ViewPager ... Tengo el siguiente código:

main_base.xml

<android.support.v4.widget.DrawerLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/drawer_layout"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

<FrameLayout
        android:id="@+id/content_frame"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />

<ListView
        android:id="@+id/listado_pintado"
        android:layout_width="240dp"
        android:layout_height="match_parent"
        android:layout_gravity="start"
        android:choiceMode="singleChoice"
        android:divider="@android:color/transparent"
        android:dividerHeight="0dp"
        android:background="#fff"/>

mi actividad:

Actividad principal

package com.examples.planets;

import android.annotation.SuppressLint;
import android.app.Fragment;
import android.app.FragmentManager;
import android.content.Context;
import android.content.res.Configuration;
import android.os.Bundle;
import android.support.v4.app.ActionBarDrawerToggle;
import android.support.v4.app.FragmentActivity;
import android.support.v4.view.GravityCompat;
import android.support.v4.view.PagerAdapter;
import android.support.v4.view.ViewPager;
import android.support.v4.widget.DrawerLayout;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.widget.TabHost;

import com.examples.planets.TabsFragmentos;
import com.examples.planets.fragmentos.mercury.TabFragmentDescribeMercury;
import com.examples.planets.fragmentos.mercury.TabFragmentShowMercury;
import com.examples.planets.paginadores.AdaptadorDePaginas;
import com.examples.planets.utilidades.enums.Menu_;

import java.util.HashMap;
import java.util.List;
import java.util.Vector;

public class Main_Activity extends FragmentActivity{


    public DrawerLayout mDrawerLayout;
    private ListView mDrawerList;
    private ActionBarDrawerToggle mAccionadorDelDrawer;

    private CharSequence mDrawerTitulo;
    private CharSequence mTitulo;
    private String[] menuPrincipal;


    public void cargarMenu(){
        //Titulo
        mTitulo = mDrawerTitulo = getTitle();

        //Main_Activity Principal
        menuPrincipal = getResources().getStringArray(R.array.menu_principal_array);

        //Diseñador del Layout
        mDrawerLayout = (DrawerLayout) findViewById(R.id.drawer_layout);


        mDrawerList = (ListView) findViewById(R.id.listado_pintado);


        mDrawerLayout.setDrawerShadow(R.drawable.drawer_shadow, GravityCompat.START);


        mDrawerList.setAdapter(new ArrayAdapter<String>(this,
                R.layout.menu_listado, menuPrincipal));


        mDrawerList.setOnItemClickListener(new DrawerItemClickListener());


        getActionBar().setDisplayHomeAsUpEnabled(true);
        getActionBar().setHomeButtonEnabled(true);

        mAccionadorDelDrawer = new ActionBarDrawerToggle(
                this,                  /* host Activity */
                mDrawerLayout,         /* DrawerLayout object */
                R.drawable.ic_drawer,  /* Imagen del Accionador del menu */
                R.string.drawer_open,  /* "open drawer" description for accessibility */
                R.string.drawer_close  /* "close drawer" description for accessibility */
        ) {
            public void onDrawerClosed(View view) {
                getActionBar().setTitle(mTitulo);
                invalidateOptionsMenu();
            }

            public void onDrawerOpened(View drawerView) {
                getActionBar().setTitle(mDrawerTitulo);
                invalidateOptionsMenu();
            }
        };
        mDrawerLayout.setDrawerListener(mAccionadorDelDrawer);
    }

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

        cargarMenu();

    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        MenuInflater inflater = getMenuInflater();
        //inflater.inflate(R.menu.main, menu);
        return super.onCreateOptionsMenu(menu);
    }


    @Override
    public boolean onPrepareOptionsMenu(Menu menu) {
        // If the nav drawer is open, hide action items related to the content view
        boolean drawerOpen = mDrawerLayout.isDrawerOpen(mDrawerList);
        //menu.findItem(R.id.action_websearch).setVisible(!drawerOpen);
        return super.onPrepareOptionsMenu(menu);
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {

        if (mAccionadorDelDrawer.onOptionsItemSelected(item)) {
            return true;
        }

        return super.onOptionsItemSelected(item);
    }


    private class DrawerItemClickListener implements ListView.OnItemClickListener {
        @Override
        public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
            selectItem(position);
        }
    }


    private void selectItem(int position) {
        android.support.v4.app.FragmentManager manager = super.getSupportFragmentManager();
        TabsFragmentos firstFragment = new TabsFragmentos(position, this, super.getSupportFragmentManager());
        manager.beginTransaction()
                .replace(R.id.content_frame, firstFragment).commit();


        mDrawerList.setItemChecked(position, true);
        setTitle(menuPrincipal[position]);
        mDrawerLayout.closeDrawer(mDrawerList);
        //cargarMenu();
    }

    @Override
    public void setTitle(CharSequence title) {
        mTitulo = title;
        getActionBar().setTitle(mTitulo);
    }

    /**
     * Cuando usamos el ActionBarDrawerToggle, se debería llamar este durante el
     * onPostCreate() y el onConfigurationChanged()...
     */

    @Override
    protected void onPostCreate(Bundle savedInstanceState) {
        super.onPostCreate(savedInstanceState);
        onRestoreInstanceState.
        mAccionadorDelDrawer.syncState();
    }

    @Override
    public void onConfigurationChanged(Configuration newConfig) {
        super.onConfigurationChanged(newConfig);
        mAccionadorDelDrawer.onConfigurationChanged(newConfig);
    }



}

Y el TabFragments es Fragmento:

package com.examples.planets.fragmentos;


import java.util.HashMap;
import java.util.List;
import java.util.Vector;

import android.annotation.SuppressLint;
import android.content.Context;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentTransaction;
import android.support.v4.view.ViewPager;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TabHost;
import android.widget.TabHost.TabContentFactory;

....

/**
 * @author roldan
 *
 */
@SuppressLint("ValidFragment")
public class TabsFragmentos extends Fragment implements TabHost.OnTabChangeListener, ViewPager.OnPageChangeListener {

    private TabHost mTabHost;
    private HashMap<String, TabInfo> mapTabInfo = new HashMap<String, TabInfo>();
    private TabInfo mLastTab = null;
    private AdaptadorDePaginas mAdaptadorPaginas;
    private ViewPager mViewPager;


    private int posicion;
    private FragmentManager supportFragmentManager;
    private static Menu_Principal menu_principal;

    public static TabsFragmentos newInstance() {
        return new TabsFragmentos();
    }


    public TabsFragmentos(){

    }

    public TabsFragmentos(int position, Menu_Principal menu_principal, FragmentManager supportFragmentManager) {
        this.posicion = position;
        this.menu_principal = menu_principal;
        this.supportFragmentManager = supportFragmentManager;
    }

    /**
     *
     * @author mwho
     *
     */
    private class TabInfo {
         private String tag;
         private Class<?> clss;
         private Bundle args;
         private android.support.v4.app.Fragment fragment;
         TabInfo(String tag, Class<?> clazz, Bundle args) {
             this.tag = tag;
             this.clss = clazz;
             this.args = args;
         }

    }
    /**
     *
     * @author mwho
     *
     */
    class TabFactory implements TabContentFactory {

        private final Context mContext;

        /**
         * @param context
         */
        public TabFactory(Context context) {
            mContext = context;
        }

        /** (non-Javadoc)
         * @see android.widget.TabHost.TabContentFactory#createTabContent(String)
         */
        public View createTabContent(String tag) {
            View v = new View(mContext);
            v.setMinimumWidth(0);
            v.setMinimumHeight(0);
            return v;
        }

    }

    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        //int posicion = getArguments().getInt(ARGUMENTO_);

        super.onCreate(savedInstanceState);

        if (savedInstanceState != null) {
            mTabHost.setCurrentTabByTag(savedInstanceState.getString("tab")); //set the tab as per the saved state
        }

        View rootView = null;
        if (Menu_.MERCURY.getPosicion()== posicion){
            //rootView = inflater.inflate(R.layout.fragmento_palabra_bk, container, false);
            rootView = inflater.inflate(R.layout.fragmentos_base, container, false);



            initialiseTabHost(rootView, savedInstanceState);

            intialiseViewPager(rootView);

        }
        return rootView;
    }

    /** (non-Javadoc)
     * @see android.support.v4.app.FragmentActivity#onSaveInstanceState(android.os.Bundle)
     */
    public void onSaveInstanceState(Bundle outState) {
        outState.putString("tab", mTabHost.getCurrentTabTag()); //save the tab selected
        super.onSaveInstanceState(outState);
    }

    /**
     * Initializando el TabHost
     */
    private void initialiseTabHost(View rootView, Bundle args) {
        mTabHost = (TabHost)rootView.findViewById(android.R.id.tabhost);
        //mTabHost = (TabHost)findViewById(android.R.id.tabhost);

        mTabHost.setup();
        TabInfo tabInfo = null;
        TabsFragmentos.addTab(this, this.mTabHost, this.mTabHost.newTabSpec("Tab2").setIndicator("Buscar"), ( tabInfo = new TabInfo("Tab1", TabFragmentOne.class, args)));
        this.mapTabInfo.put(tabInfo.tag, tabInfo);
        TabsFragmentos.addTab(this, this.mTabHost, this.mTabHost.newTabSpec("Tab1").setIndicator("Crear"), ( tabInfo = new TabInfo("Tab2", TabFragmentTwo.class, args)));
        this.mapTabInfo.put(tabInfo.tag, tabInfo);

        // Default to first tab
        this.onTabChanged("Tab1");
        mTabHost.setOnTabChangedListener(this);
    }

    private void intialiseViewPager(View rootView) {


        List<android.support.v4.app.Fragment> fragments = new Vector<android.support.v4.app.Fragment>();
        fragments.add(android.support.v4.app.Fragment.instantiate(menu_principal, TabFragmentOne.class.getName()));
        fragments.add(android.support.v4.app.Fragment.instantiate(menu_principal, TabFragmentTwo.class.getName()));

        this.mAdaptadorPaginas  = new AdaptadorDePaginas(supportFragmentManager, fragments);
        //
        this.mViewPager = (ViewPager)rootView.findViewById(R.id.tabviewpager);
        this.mViewPager.setAdapter(this.mAdaptadorPaginas);
        this.mViewPager.setOnPageChangeListener(this);
    }

    /**
     * @param activity
     * @param tabHost
     * @param tabSpec
     */
    private static void addTab(TabsFragmentos activity, TabHost tabHost, TabHost.TabSpec tabSpec, TabInfo tabInfo) {
        // Attach a Tab view factory to the spec
        tabSpec.setContent(activity.new TabFactory(menu_principal));
        String tag = tabSpec.getTag();

        // Check to see if we already have a fragment for this tab, probably
        // from a previously saved state.  If so, deactivate it, because our
        // initial state is that a tab isn''t shown.
        if (tabInfo.fragment != null && !tabInfo.fragment.isDetached()) {
            FragmentTransaction ft = menu_principal.getSupportFragmentManager().beginTransaction();
            ft.detach(tabInfo.fragment);
            ft.commit();
            menu_principal.getSupportFragmentManager().executePendingTransactions();
        }

        tabHost.addTab(tabSpec);
    }

    public void onTabChanged(String tag) {
        try{
        //TabInfo newTab = this.mapTabInfo.get(tag);
        int pos = this.mTabHost.getCurrentTab();
        this.mViewPager.setCurrentItem(pos);
        }catch(Exception e){}
    }

    @Override
    public void onPageScrolled(int i, float v, int i2) {

    }

    @Override
    public void onPageSelected(int position) {
        // TODO Auto-generated method stub
        this.mTabHost.setCurrentTab(position);
    }

    @Override
    public void onPageScrollStateChanged(int i) {

    }


}

¿Cuál es el problema?

el código funciona bien la primera vez ... solo presionó cualquier opción y muestra las pestañas con su diseño asociado a los fragmentos TabFragmentOne o TabFragmentTwo. la segunda vez, este código solo muestra las pestañas pero no muestra el diseño asociado a los fragmentos TabFragmentOne o TabFragmentTwo.

¿que debería hacer?

Thx 4 de avance.

Answer 1

Para mí, el problema estaba en mi TabsAdapter . El único constructor se veía así:

public TabsAdapter(FragmentActivity activity, TabHost tabHost, ViewPager pager) {
    super(activity.getSupportFragmentManager());
    mContext = activity;
    mTabHost = tabHost;
    mViewPager = pager;
    mTabHost.setOnTabChangedListener(this);
    mViewPager.setAdapter(this);
    mViewPager.setOnPageChangeListener(this);
}

getSupportFragmentManager a getSupportFragmentManager que devuelve el FragmentManager asociado a nuestra FragmentActivity . Malo. Necesitamos la FM que gestiona nuestro Fragment actual. Crear un constructor alternativo (sobrecargado) que usara getChildFragmentManager hizo el truco.

public TabsAdapter(Fragment fragment, TabHost tabHost, ViewPager pager) {
    super(fragment.getChildFragmentManager());
    mContext = fragment.getActivity();
    mTabHost = tabHost;
    mViewPager = pager;
    mTabHost.setOnTabChangedListener(this);
    mViewPager.setAdapter(this);
    mViewPager.setOnPageChangeListener(this);
}

Su problema proviene del mismo problema, solo en un formato diferente. Reemplace sus llamadas a getSupportFragmentManager con getChildFragmentManager en su Fragment .