Navigation tiroir et vue pager dans la même activité

Je suis en train de mettre en œuvre à la fois de navigation tiroir et vue pager dans une même activité. Navigation tiroir fonctionne très bien mais la vue pager ne fonctionne pas, aussi je suis pointeur null en balayage à droite lors de la navigation tiroir est ouvert (pointeur Null à android. de soutien. v4. widget de. DrawerLayout. isContentView(DrawerLayout.java:840). Je joins le principal xml de mise en page et le code ci-dessous.

<android.support.v4.view.ViewPager
    android:id="@+id/viewpager"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent" >
</android.support.v4.view.ViewPager>

<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" >     
    <ListView
        android:id="@+id/left_drawer"
        android:layout_width="240dp"
        android:layout_height="match_parent"
        android:layout_gravity="start"
        android:background="#111"
        android:choiceMode="singleChoice"
        android:divider="@android:color/transparent"
        android:dividerHeight="0dp" />
</android.support.v4.widget.DrawerLayout>

Classe d'activité est donnée ci-dessous

public class MainActivity extends Activity {
private DrawerLayout mDrawerLayout;
private ListView mDrawerList;
private ActionBarDrawerToggle mDrawerToggle;
private CharSequence mDrawerTitle;
private CharSequence mTitle;
private String[] mPlanetTitles;
private MainActivity mContext;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mContext = this;
ViewPager vp = (ViewPager) findViewById(R.id.viewpager);
CustomPagerAdapter adapter = new CustomPagerAdapter(mContext);
vp.setAdapter(adapter);
vp.setPageTransformer(false, new ViewPager.PageTransformer() {
@Override
public void transformPage(View page, float position) {
final float normalizedposition = Math.abs(Math.abs(position) - 1);
page.setScaleX(normalizedposition / 2 + 0.5f);
page.setScaleY(normalizedposition / 2 + 0.5f);
}
});
mTitle = mDrawerTitle = getTitle();
mPlanetTitles = getResources().getStringArray(R.array.planets_array);
mDrawerLayout = (DrawerLayout) findViewById(R.id.drawer_layout);
mDrawerList = (ListView) findViewById(R.id.left_drawer);
//set a custom shadow that overlays the main content when the drawer
//opens
mDrawerLayout.setDrawerShadow(R.drawable.drawer_shadow, GravityCompat.START);
//set up the drawer's list view with items and click listener
mDrawerList.setAdapter(new ArrayAdapter<String>(this,
R.layout.drawer_list_item, mPlanetTitles));
mDrawerList.setOnItemClickListener(new DrawerItemClickListener());
//enable ActionBar app icon to behave as action to toggle nav drawer
getActionBar().setDisplayHomeAsUpEnabled(true);
getActionBar().setHomeButtonEnabled(true);
//ActionBarDrawerToggle ties together the the proper interactions
//between the sliding drawer and the action bar app icon
mDrawerToggle = new ActionBarDrawerToggle(
this, /* host Activity */
mDrawerLayout, /* DrawerLayout object */
R.drawable.ic_drawer, /* nav drawer image to replace 'Up' caret */
R.string.drawer_open, /*
* "open drawer" description for
* accessibility
*/
R.string.drawer_close /*
* "close drawer" description for
* accessibility
*/
) {
@Override
public void onDrawerClosed(View view) {
getActionBar().setTitle(mTitle);
invalidateOptionsMenu(); //creates call to
//onPrepareOptionsMenu()
}
@Override
public void onDrawerOpened(View drawerView) {
getActionBar().setTitle(mDrawerTitle);
invalidateOptionsMenu(); //creates call to
//onPrepareOptionsMenu()
}
};
mDrawerLayout.setDrawerListener(mDrawerToggle);
if (savedInstanceState == null) {
selectItem(0);
}
}
@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);
return super.onPrepareOptionsMenu(menu);
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
//The action bar home/up action should open or close the drawer.
//ActionBarDrawerToggle will take care of this.
if (mDrawerToggle.onOptionsItemSelected(item)) {
return true;
}
//Handle action buttons
return true;
}
/* The click listner for ListView in the navigation drawer */
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) {
//update selected item and title, then close the drawer
mDrawerList.setItemChecked(position, true);
setTitle(mPlanetTitles[position]);
mDrawerLayout.closeDrawer(mDrawerList);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
//Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
@Override
protected void onPostCreate(Bundle savedInstanceState) {
super.onPostCreate(savedInstanceState);
//Sync the toggle state after onRestoreInstanceState has occurred.
mDrawerToggle.syncState();
}
public class CustomPagerAdapter extends PagerAdapter {
private Context context;
int index = 2;
//public CustomPagerAdapter(Context context, Vector<View> pages) {
//this.context = context;
//this.pages = pages;
//}
public CustomPagerAdapter(Context context) {
this.context = context;
this.index = 2;
}
@Override
public Object instantiateItem(ViewGroup container, int position) {
LayoutInflater inflater = (LayoutInflater.from(container.getContext()));
//View page = pages.get(position);
View view = null;
if (position == 0) {
view = inflater.inflate(R.layout.page_one_views, null);
((ViewPager) container).addView(view);
}
else {
//page.setBackgroundColor(colors.get(position));
//container.addView(page);
view = inflater.inflate(R.layout.page_two, null);
((ViewPager) container).addView(view);
}
return view;
}
@Override
public int getCount() {
return index;
}
@Override
public boolean isViewFromObject(View view, Object object) {
return view.equals(object);
}
@Override
public void destroyItem(ViewGroup container, int position, Object object) {
container.removeView((View) object);
}
}

}

S'il vous plaît aider moi. Merci d'avance