Android ViewPager inside Layoutinflator

Question

I build a project. but I'm having problems. My project has page A , Page B

from Picture http://s20.postimg.org/5pupjbuyl/untitled.png

Page A is FrameLayout (id=layout) , in FrameLayout has LinearLayout and FrameLayout (id=content) Page B is FrameLayout (id=pager) , in FrameLayout has Viewpager

I would take Framelayout (id=content) in page A containing FrameLayout(id = pager) in page B

(Notice : I try to minimize my code because It many line)

PageIndicatorActivity .java

public class PageIndicatorActivity extends Activity {
...
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    ..
    ..
    ViewGroup Content = (ViewGroup)findViewById(R.id.layout);
    ViewBookAdapter pager = new ViewBookAdapter(this);
            Content.addView(pager.getView());
}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    getMenuInflater().inflate(R.menu.activity_main,menu);
    return true;
}}

pager.java

public class Pager extends PagerAdapter {

Activity activity;
private static String content[] = {"file:///android_asset/html/page1.html","file:///android_asset/html/page2.html"};

public Pager(Activity act) {
    activity = act;
}


public int getCount() {
    return content.length;
}

public Object instantiateItem(View collection, int position) {
    WebView view = new WebView(activity);
    view.loadUrl(content[position]);
    view.setLayoutParams(new LayoutParams(LayoutParams.MATCH_PARENT,LayoutParams.MATCH_PARENT));
    ((ViewPager) collection).addView(view, 0);



    return view;
}

 @Override
 public void destroyItem(View arg0, int arg1, Object arg2) {
  ((ViewPager) arg0).removeView((View) arg2);
 }

 @Override
 public boolean isViewFromObject(View arg0, Object arg1) {
  return arg0 == ((View) arg1);
 }

 @Override
 public Parcelable saveState() {
  return null;
 }}

and ViewBookAdapter.java

 class ViewBookAdapter {
Activity activity;
private LayoutInflater minflate;
private ViewPager myPager;

public ViewBookAdapter(Activity act){
    activity = act;
    myPager = (ViewPager)act.findViewById(R.id.viewPager);
    Pager p = new Pager(act);
    myPager.setAdapter(p);  // <--- THIS PROBLEM ---


}

public View getView(){
    LayoutInflater minflate = (LayoutInflater)activity.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
    View v = minflate.inflate(R.layout.pager, null);
    return v;   
}}

I have a probleam at myPager.setAdapter(p);

Android Report Bug is NullPointerException

How to solve?

THANK YOU FOR ANSWER ^^

PS. sorry english .

Answer 1

This is happening because your Activity does not have the ViewPager in its layout. Its in the other layout. You will need to do setAdapter in getView()

Answer 2

Your current PageIndicatorActivity layout does not have a ViewPager. If you need to continue this way you have to move to Activity(Page B) and follow your implementation.