Spinner setOnItemSelectedListener in Fragment

Question

Я хочу использовать Spinner в фрагменте, но это дает мне ошибку на слушателя. Я знаю, что здесь есть несколько схожие вопросы, но я никак не мог понять, в чем моя проблема. В чем проблема? Вот мой onCreateView:

@Override 
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { 
    View v = inflater.inflate(R.layout.maps, container, false); 

    // Gets the MapView from the XML layout and creates it 
    mapView = (MapView) v.findViewById(R.id.mapview); 
    mapView.onCreate(savedInstanceState); 
    mapView.onResume(); 

    // Gets to GoogleMap from the MapView and does initialization stuff 
    mapView.getMapAsync(this) 

    // get Spinner reference 
    Spinner spinner = (Spinner) v.findViewById(R.id.spinner); 

    // Spinner click listener 
    spinner.setOnItemSelectedListener(this);     **<======ERROR======** 

    // Spinner Drop down elements 
    List<String> buses = new ArrayList<>(); 
    buses.add("Összes megálló - válassz egy járatot"); 
    buses.add("26"); 
    buses.add("35"); 
    buses.add("37"); 
    buses.add("42"); 

    // Creating array adapter for spinner 
    ArrayAdapter<String> dataAdapter = new ArrayAdapter<>(getActivity(), android.R.layout.simple_spinner_item, buses); 

    // Drop down style will be listview with radio button 
    dataAdapter.setDropDownViewResource(android.R.layout.select_dialog_singlechoice); 

    // attaching data adapter to spinner 
    spinner.setAdapter(dataAdapter); 

    return v; 
} 
@Override 
public void onItemSelected(AdapterView<?> parent, View view, int pos, long id) { 
    caseno = parent.getSelectedItemPosition(); 
    switch(caseno) { 
     case 0: { 

      //some code 

      break; 
     } 
     case 1: { 
       //some code 

      break; 
     } 

    } 
} 

public void onNothingSelected(AdapterView<?> arg0) { 
    Toast.makeText(getActivity(), "Nincs kiválasztott járat", Toast.LENGTH_LONG).show(); 
} 

Моя раскладка:

<?xml version="1.0" encoding="utf-8"?> 
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" 
android:orientation="vertical" android:layout_width="match_parent" 
android:layout_height="match_parent"> 

<com.google.android.gms.maps.MapView android:id="@+id/mapview" 
    android:layout_width="fill_parent" 
    android:layout_height="fill_parent" 
    android:layout_below="@id/line"/> 

<RelativeLayout 
    android:layout_width="match_parent" 
    android:layout_height="50dp" 
    android:layout_margin="10dp" 
    android:background="@drawable/shadow"> 

    <Spinner 
     android:id="@+id/spinner" 
     android:layout_width="match_parent" 
     android:layout_height="match_parent" 
     android:paddingStart="8dp"/> 

</RelativeLayout> 

Ошибка:

E/AndroidRuntime: FATAL EXCEPTION: main 
       Process: com.koostamas.justtry, PID: 32434 
       java.lang.NullPointerException 
        at com.koostamas.justtry.Map.onCreateView(Map.java:151) 
        at android.support.v4.app.Fragment.performCreateView(Fragment.java:2189) 
        at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1299) 
        at android.support.v4.app.FragmentManagerImpl.moveFragmentToExpectedState(FragmentManager.java:1528) 
        at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1595) 
        at android.support.v4.app.BackStackRecord.executeOps(BackStackRecord.java:757) 
        at android.support.v4.app.FragmentManagerImpl.executeOps(FragmentManager.java:2355) 
        at android.support.v4.app.FragmentManagerImpl.executeOpsTogether(FragmentManager.java:2146) 
        at android.support.v4.app.FragmentManagerImpl.optimizeAndExecuteOps(FragmentManager.java:2098) 
        at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:2008) 
        at android.support.v4.app.FragmentManagerImpl$1.run(FragmentManager.java:710) 
        at android.os.Handler.handleCallback(Handler.java:733) 
        at android.os.Handler.dispatchMessage(Handler.java:95) 
        at android.os.Looper.loop(Looper.java:136) 
        at android.app.ActivityThread.main(ActivityThread.java:5146) 
        at java.lang.reflect.Method.invokeNative(Native Method) 
        at java.lang.reflect.Method.invoke(Method.java:515) 
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:732) 
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:566) 
        at dalvik.system.NativeStart.main(Native Method) 

Answer 1

Вы должны реализовать спиннера OnItemSelectedListener:

spinner.setOnItemSelectedListener(new OnItemSelectedListener() { 
    @Override 
    public void onItemSelected(AdapterView<?> parent, View view, int pos,long id) 
    { 
     //Called when item is selected, use position of item to find it from list of items 
    } 

    @Override 
    public void onNothingSelected(AdapterView<?> arg0) 
    { 
     //Called when no item is selected 
    } 
}); 

Answer 2

в Fragment вашу потребность реализовать этот интерфейс AdapterView.OnItemClickListener или вы можете попробовать это один

spinner.setOnItemSelectedListener(new OnItemSelectedListener() { 

      @Override 
      public void onItemSelected(AdapterView<?> adapterView, View view, 
        int position, long id) { 
       Object item = adapterView.getItemAtPosition(position); 
       if (item != null) { 
        Toast.makeText(getContext(), item.toString(), 
          Toast.LENGTH_SHORT).show(); 
       } 
       Toast.makeText(getContext(), "Selected", 
         Toast.LENGTH_SHORT).show(); 

      } 

      @Override 
      public void onNothingSelected(AdapterView<?> adapterView) { 
       // TODO Auto-generated method stub 

      } 
     }); 

Answer 3

С помощью кок внутри фрагмента,

---

Bonus: настроить свой стиль вращателя

private Spinner SortBySpinner; 
private SpinnerAdapter SortBy_adapterz; 
public static final String[] SortAdapterz = {"", 

     " newest "," top brains "," most seen ","" 
}; 

XML

   <Spinner 
       android:layout_width="match_parent" 
       android:layout_height="match_parent" 
       android:id="@+id/TimeSpinner"/> 

---

настроив адаптер

 oSpinner = (Spinner) v.findViewById(R.id.TimeSpinner); 
     oAdapter = new ArrayAdapter<String>(getActivity(),R.layout.cutomized_spinner, SortAdapterz); 

---

cutomized_spinner.xml

<TextView 
xmlns:android="http://schemas.android.com/apk/res/android" 
android:layout_width="match_parent" 
android:layout_height="wrap_content" 
android:textSize="15sp" 
android:layout_weight="1" 
android:gravity="center" 
android:text=" egypt " 
android:fontFamily="sans-serif-smallcaps" 
android:textColor="#464646" 
android:textColorHint="#ffcc00" 
android:padding="5dip" 
android:layout_centerInParent="true" 
/> 

---

наконец

  oSpinner.setAdapter(oAdapter); 

---

как определить значения?

oSpinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() { 
     @Override 
     public void onItemSelected(AdapterView<?> parent, View view, int position, long id) { 
      cck = parent.getItemAtPosition(position).toString(); 

      System.out.println("Value was --->" + cck); 

     } 
     @Override 
     public void onNothingSelected(AdapterView<?> parent) { 
     } 
    }); 

результат