ClientCursorAdapter.getFilter()‘auf einer Null-Objekt Referenz

Question

Ich CursorAdapter und ListView mit meiner Liste von Songs und Filter in searchView angezeigt werden, aber das Problem ist, wenn ich das searchView Symbol tippen habe ich diesen Fehler habe und zeige die Fehler an diesem Code

adapter.getFilter().filter(newText); 

Hier ist mein Code

Unter onCreateOptionsMenu()

SearchView searchView = (SearchView) item.getActionView(); 
searchView.setQueryHint("Search Title/Artist"); 

searchView.setOnQueryTextListener(new SearchView.OnQueryTextListener() { 

    @Override 
    public boolean onQueryTextSubmit(String query) { 
     return false; 
    } 

    @Override 
    public boolean onQueryTextChange(String newText) { 

     adapter.getFilter().filter(newText); 
     return false; 
    } 
}); 

die Cursor

Cursor res = db.query("songs",null,null,null,null,null,"title"); 


     ClientCursorAdapter adapter = new ClientCursorAdapter(MainActivity.this,res, CursorAdapter.FLAG_REGISTER_CONTENT_OBSERVER); 
//// 
//// 
     lv.setAdapter(adapter); 

row_layout.xml

<?xml version="1.0" encoding="utf-8"?> 
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" 
    xmlns:app="http://schemas.android.com/apk/res-auto" 
    android:layout_width="match_parent" android:layout_height="80dp" 
    android:background="@color/black"> 


    <TextView 
     android:id="@+id/Title" 
     android:layout_width="wrap_content" 
     android:layout_height="37.5dp" 
     android:text="Title" 
     android:paddingLeft="10dp" 
     android:textSize="22dp" 
     android:gravity="center_vertical" 
     android:textColor="#FFFFFF" 
     android:layout_alignParentLeft="true" /> 

    <ToggleButton 
     android:id="@+id/minus_one" 
     android:layout_width="20dp" 
     android:layout_height="20dp" 
     android:layout_alignParentRight="true" 
     android:checked="true" 
     android:focusable="false" 
     android:focusableInTouchMode="false" 
     android:textOn="" 
     android:textColor="@color/colorAccent" 
     android:layout_marginRight="5dp" 
     android:background="@drawable/minus_one" 
     android:textOff="" 
     /> 
    <ToggleButton 
     android:id="@+id/favorite" 
     android:layout_width="20dp" 
     android:layout_height="20dp" 
     android:layout_alignParentRight="true" 
     android:layout_below="@+id/minus_one" 
     android:layout_marginTop="@dimen/activity_horizontal_margin" 
     android:checked="true" 
     android:textOn="" 
     android:focusable="false" 
     android:focusableInTouchMode="false" 
     android:layout_marginRight="5dp" 
     android:background="@drawable/favorite" 
     android:textOff="" 
     /> 


    <TextView 
     android:id="@+id/Artist" 
     android:layout_width="wrap_content" 
     android:layout_height="37.5dp" 
     android:text="Artist" 
     android:paddingLeft="10dp" 
     android:textColor="#707070" 
     android:layout_below="@+id/Title" 
     /> 
    <View 
     android:layout_width="match_parent" 
     android:layout_height="2dp" 
     android:background="#4f5051" 
     android:layout_below="@+id/Artist" 
     > 

    </View> 



</RelativeLayout> 

ClientCursorAdapter.java

class ClientCursorAdapter extends CursorAdapter { 
    Context context; 
    public ClientCursorAdapter(Context context, Cursor c, int flags) { 
     super(context, c, flags); 
     this.context = context; 
    } 

    @Override 
    public View newView(Context context, Cursor cursor, ViewGroup viewGroup) { 
     LayoutInflater inflater = (LayoutInflater)context.getSystemService(Context.LAYOUT_INFLATER_SERVICE); 
     View v = inflater.inflate(R.layout.row_layout,viewGroup,false); 
     return v; 
    } 

    @Override 
    public void bindView(View view, Context context, Cursor cursor) { 

     TextView title = view.findViewById(R.id.Title); 
     TextView artist = view.findViewById(R.id.Artist); 
     ToggleButton music = view.findViewById(R.id.minus_one); 
     ToggleButton favorite = view.findViewById(R.id.favorite); 

     title.setText(cursor.getString(cursor.getColumnIndex("TITLE"))); 
     artist.setText(cursor.getString(cursor.getColumnIndex("ARTIST"))); 

    } 
} 

dann haben Aufruf bekam ich Dieser Fehler

Prozess: com.example.mcgyver.sdalyrics, PID: 5851

java.lang.NullPointerException: Versuch virtuelle Methode ‚android.widget.Filter com.example.mcgyver aufzurufen .sdalyrics.ClientCursorAdapter.getFilter()‘auf eine null Objektreferenz bei com.example.mcgyver.sdalyrics.MainActivity $ 2.onQueryTextChange (MainActivity.java:125) bei android.support.v7.widget.SearchView. onTextChanged (SearchView.java:1232) bei android.support.v7.widget.SearchView $ 12.onTextChanged (SearchView.java:1762)

Answer 1

Die ClientCursorAdapter noch nicht als onCreateOptionsMenu erstellt. Verwenden Sie den folgenden Code,

if(adapter!=null){ 
    adapter.getFilter().filter(newText); 
}