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フラグメント内にアダプタを使用してnullpointer例外が発生しました。グリッドビューを使用しています。アプリを起動するとページャは、タブにフラグメントをロードしますが、アダプターは、ヌル送信し、アプリがここフラグメント内のグリッドビューに関する問題
を停止uは私のmainactivity見ることができます：
：uは私のページアダプターを見ることができます。ここpublic class MainLayout extends AppCompatActivity {
ViewPager pager;
TabLayout tabLayout;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main_layout);
pager = (ViewPager) findViewById(R.id.view_pager);
tabLayout = (TabLayout) findViewById(R.id.tab_layout);
// Fragment manager to add fragment in viewpager we will pass object of Fragment manager to adpater class.
FragmentManager manager = getSupportFragmentManager();
//object of com.example.babus.konektamos.PagerAdapter passing fragment manager object as a parameter of constructor of com.example.babus.konektamos.PagerAdapter class.
PagerAdapter adapter = new PagerAdapter(manager);
//set Adapter to view pager
pager.setAdapter(adapter);
//set tablayout with viewpager
tabLayout.setupWithViewPager(pager);
// adding functionality to tab and viewpager to manage each other when a page is changed or when a tab is selected
pager.addOnPageChangeListener(new TabLayout.TabLayoutOnPageChangeListener(tabLayout));
//Setting tabs from adpater
tabLayout.setTabsFromPagerAdapter(adapter);
}
//inicio menu
@Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case R.id.tuto:
Intent i = new Intent(MainLayout.this, Tutorial.class);
finish();
startActivity(i);
return true;
default:
return super.onOptionsItemSelected(item);
}
}
//final menu
//modificamos el boton atras para que no nos devuelva al wizzard
@Override
public void onBackPressed(){
finish();
Intent intent = new Intent(Intent.ACTION_MAIN);
intent.addCategory(Intent.CATEGORY_HOME);
intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
startActivity(intent);
}
}
を
public class PagerAdapter extends FragmentStatePagerAdapter {
public PagerAdapter(FragmentManager fm) {
super(fm);
}
@Override
public Fragment getItem(int position) {
Fragment frag = null;
switch (position){
case 0:
frag = new OfertasFragment();
break;
case 1:
frag = new NegociosFragment();
break;
case 2:
frag = new TarjetaFragment();
break;
}
return frag;
}
@Override
public int getCount() {
return 3;
}
@Override
public CharSequence getPageTitle(int position) {
String title = " ";
switch (position){
case 0:
title = "Ofertas";
break;
case 1:
title = "Negocios";
break;
case 2:
title = "Tarjeta";
break;
}
return title;
}
}
これはフラグメントのXMLである：
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.example.babus.konektamos.OfertasFragment">
<!-- TODO: Update blank fragment layout -->
<GridView
android:id="@+id/grid"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:columnWidth="120dp"
android:horizontalSpacing="@dimen/espacio_grilla"
android:numColumns="2"
android:padding="@dimen/espacio_grilla"
android:verticalSpacing="@dimen/espacio_grilla" />
そしてここでuが私の断片を見ることができます：
public class OfertasFragment extends Fragment implements AdapterView.OnItemClickListener{
private GridView gridView;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
//inicio gridview
gridView = (GridView) this.getActivity().findViewById(R.id.grid);
gridView.setAdapter(new AdaptadorDeCupones(this.getActivity()));
gridView.setOnItemClickListener(this);
//fin gridview
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
View view = inflater.inflate(R.layout.fragment_ofertas,container,false);
return view;
}
@Override
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
}
//Inicio detalle cupones
//@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
cupones item = (cupones) parent.getItemAtPosition(position);
Intent intent = new Intent(this.getActivity(), ActividadDetalle.class);
intent.putExtra(ActividadDetalle.EXTRA_PARAM_ID, item.getId());
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
ActivityOptionsCompat activityOptions =
ActivityOptionsCompat.makeSceneTransitionAnimation(
this.getActivity(),
new Pair<View, String>(view.findViewById(R.id.imagen_cupon),
ActividadDetalle.VIEW_NAME_HEADER_IMAGE)
);
ActivityCompat.startActivity(this.getActivity(), intent, activityOptions.toBundle());
} else
startActivity(intent);
}
//final detalle cupones
}
ありがとうございました。 – Mihawk
ようこそ。 – mdDroid