I have gone through all the places in my code in where I am using fragmentpagestateAdapter.
I am using fragmentStatePagerAdapter at four different position. When trying to reproduce this issue the stack trace produced is of different from the one I am encountering with my user and last note: this error is not encountered on all running devices or my test devices.
java.lang.NullPointerException!
1. at android.support.v4.app.FragmentStatePagerAdapter.a(FragmentStatePagerAdapter.jav a:116)
2 at android.support.v4.view.ViewPager.addNewItem(ViewPager.java:870)
3 at android.support.v4.view.ViewPager.populate(ViewPager.java:1020)
4 at android.support.v4.view.ViewPager.populate(ViewPager.java:952)
5 at android.support.v4.view.ViewPager.onMeasure(ViewPager.java:1474)
6 at android.view.View.measure(View.java:16840)
7 at android.widget.RelativeLayout.measureChildHorizontal(RelativeLayout.java:728)
8 at android.widget.RelativeLayout.onMeasure(RelativeLayout.java:477)
9 at android.view.View.measure(View.java:16840)
10 at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5245)
11 at android.widget.FrameLayout.onMeasure(FrameLayout.java:310)
12 at android.support.v7.widget.ContentFrameLayout.onMeasure(ContentFrameLayout.java:135)
13 at android.view.View.measure(View.java:16840)
14 at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5245)
15 at android.widget.FrameLayout.onMeasure(FrameLayout.java:310)
16 at android.view.View.measure(View.java:16840)
17 at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5245)
18 at android.widget.FrameLayout.onMeasure(FrameLayout.java:310)
19 at android.view.View.measure(View.java:16840)
20 at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5245)
21 at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.enter code herejava:1410)
22 at android.widget.LinearLayout.measureVertical(LinearLayout.java:695)
23 at android.widget.LinearLayout.onMeasure(LinearLayout.java:588)
24 at android.view.View.measure(View.java:16840)
25 at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5245)
26 at android.widget.FrameLayout.onMeasure(FrameLayout.java:310)
27 at com.android.internal.policy.impl.PhoneWindow$DecorView.onMeasure(PhoneWindow.java:2586)
28 at android.view.View.measure(View.java:16840)
29 at android.view.ViewRootImpl.performMeasure(ViewRootImpl.java:2074)
30 at android.view.ViewRootImpl.measureHierarchy(ViewRootImpl.java:1234)
31 at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1417)
32 at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1131)
33 at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:6286)
34 at android.view.Choreographer$CallbackRecord.run(Choreographer.java:791)
35 at android.view.Choreographer.doCallbacks(Choreographer.java:591)
36 at android.view.Choreographer.doFrame(Choreographer.java:561)
37 at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:777)
38 at android.os.Handler.handleCallback(Handler.java:730)
39 at android.os.Handler.dispatchMessage(Handler.java:92)
40 at android.os.Looper.loop(Looper.java:177)
41 at android.app.ActivityThread.main(ActivityThread.java:5493)
42 at java.lang.reflect.Method.invokeNative(Native Method)
43 at java.lang.reflect.Method.invoke(Method.java:525)
44 at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1225)
45 at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1041)
46 at dalvik.system.NativeStart.main(Native Method)
First pager implementation.
public class MyPagerAdapter extends FragmentStatePagerAdapter {
private int mCutOffPage;
private Fragment mPrimaryItem;
public MyPagerAdapter(FragmentManager fm) {
super(fm);
}
@Override
public Fragment getItem(int i) {
if (i >= mCurrentPageSequence.size()) {
return null;
}
return mCurrentPageSequence.get(i).createFragment();
}
@Override
public int getItemPosition(Object object) {
// TODO: be smarter about this
if (object == mPrimaryItem) {
// Re-use the current fragment (its position never changes)
return POSITION_UNCHANGED;
}
return POSITION_NONE;
}
@Override
public void setPrimaryItem(ViewGroup container, int position,
Object object) {
super.setPrimaryItem(container, position, object);
mPrimaryItem = (Fragment) object;
}
@Override
public int getCount() {
return Math.min(mCutOffPage + 1, mCurrentPageSequence == null ? 1
: mCurrentPageSequence.size());
}
public void setCutOffPage(int cutOffPage) {
if (cutOffPage < 0) {
cutOffPage = Integer.MAX_VALUE;
}
mCutOffPage = cutOffPage;
}
public int getCutOffPage() {
return mCutOffPage;
}
public Fragment getPrimaryItem() {
return mPrimaryItem;
}
}
Second Pager Adapter "Iam not using this one in my code ."
adapter = new FragmentStatePagerAdapter(getSupportFragmentManager()) {
@Override
public Fragment getItem(int position) {
switch (position) {
// case 0 : return new FragmentOn1();
// case 1 : return new FragmentOn2();
// case 2 : return new FragmentOn3();
default: return null;
}
}
@Override
public int getCount() {
return 3; // Hard coded 3, because we are displaying 3 fragments
}
};
3rd Fragment pager Adapter
private class ViewPagerAdapter extends FragmentStatePagerAdapter {
String user_id;
private SparseArrayCompat<BInterfaceScrollTabHolder> mScrollTabHolders;
private InterfaceScrollTabHolder mListener;
public ViewPagerAdapter(FragmentManager fm, String user_id) {
super(fm);
this.user_id = user_id;
mScrollTabHolders = new SparseArrayCompat<InterfaceScrollTabHolder>();
}
public void setTabHolderScrollingContent(BInterfaceScrollTabHolder listener) {
mListener = listener;
}
public SparseArrayCompat<BInterfaceScrollTabHolder> getScrollTabHolders() {
return mScrollTabHolders;
}
public Fragment getItem(int num) {
FragmentScrollTabHolder fragment;
if (num == 0) {
fragment = FragmentActivities_.newInstance(this.user_id, num);
} else if (num == 1) {
fragment = FragmentFollowers_.newInstance(this.user_id, num);
} else if (num == 2) {
fragment = FragmentFollowing_.newInstance(this.user_id, num);
} else {
fragment = FragmentActivities_.newInstance(this.user_id, num);
}
mScrollTabHolders.put(num, fragment);
if (mListener != null) {
fragment.setScrollTabHolder(mListener);
}
return fragment;
}
@Override
public int getCount() {
return 3;
}
@Override
public CharSequence getPageTitle(int position) {
if (position == 0) {
return "\nActivities";
} else if (position == 1) {
if (follower_count > 0) {
return follower_count + "\nFollowers";
} else {
return "\nFollowers";
}
} else if (position == 2) {
if (following_count > 0) {
return following_count + "\nFollowing";
} else {
return "\nFollowing";
}
}
return "\nActivities";
}
@Override
public void destroyItem(ViewGroup container, int position, Object object) {
}
}
fourth pager apdapter .
public class BAdapterFragmentViewPager extends FragmentStatePagerAdapter{
SparseArray<Fragment> mPageReference = new SparseArray<Fragment>();
boolean tab_available ;
public BAdapterFragmentViewPager(FragmentManager fm ) {
super(fm);
}
public void setIs_contest_tab_available(boolean tab_available ) {
this.tab_available = tab_available ;
notifyDataSetChanged();
}
@Override
public Fragment getItem(int num) {
Fragment fragment = null;
if (num == 0) {
fragment = FragmentGeneral_.newInstance();
} else if(num == 1) {
fragment = BFragmentSolvedCases_.newInstance();
} else if(num == 2) {
fragment = FragmentTrending_.newInstance();
}else if(num == 3 && tab_available ){
fragment = FragmentContest_.newInstance();
}
mPageReference.put(num, fragment);
return fragment;
}
@Override
public int getCount() {
int size ;
if(tab_available ) {
size = 4;
}else{
size = 3;
}
return size ;
}
@Override
public CharSequence getPageTitle(int position) {
if (position == 0) {
return "All";
} else if (position == 1) {
return "Solved";
} else if (position == 2) {
return "Trending";
}else if( position == 3 && is_contest_tab_available){
return "Contest";
}
return "All";
}
@Override
public void destroyItem(ViewGroup container, int position, Object object) {
}
public Fragment getFragment(int key) {
return mPageReference.get(key);
}
}
