Benutzeradapter kann nicht auf ListView gesetzt werden

Ich versuche einen Kundenadapter auf ListView zu setzen, erhalte aber immer NullException. Das ist mein Adapter:Benutzeradapter kann nicht auf ListView gesetzt werden

public class MainActivity extends AppCompatActivity { 
    private static final String TAG = MainActivity.class.getSimpleName(); 
    MovieAdapter mAdapter; 
    List<Movie> mMovies = new ArrayList<Movie>(); 

    private NowPlaying mNowPlaying; 

    @BindView(android.R.id.list) 
    ListView mListView; 
    @BindView(android.R.id.empty) 
    TextView mEmptyView; 
    private MovieApi mMovieApi; 

    @Override 
    protected void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.activity_main); 
     ButterKnife.bind(this); 

//  final MovieAdapter adapter = new MovieAdapter(this, mMovies); 
// 
     mMovieApi = RetrofitUtils.get(getString(R.string.api_key)).create(MovieApi.class); 
     mMovieApi.getNowPlaying().enqueue(new Callback<NowPlaying>() { 

      @Override 
      public void onResponse(Call<NowPlaying> call, Response<NowPlaying> response) { 

       Log.d("Response", String.valueOf(response.isSuccessful())); 
       mMovies = response.body().getMovies(); 
       mAdapter = new MovieAdapter(this, mMovies); 
       mListView.setAdapter(mAdapter); 
       mListView.setEmptyView(mEmptyView); 



      } 

      @Override 
      public void onFailure(Call<NowPlaying> call, Throwable t) { 
       Log.e("Error", t.getMessage()); 
       Toast.makeText(MainActivity.this, "OK", Toast.LENGTH_SHORT).show(); 



      } 
     }); 



    } 
}

Mein Stack Trace:

10-15 23:04:19.480 12537-12537/com.example.rubit1359.bigcornbox E/AndroidRuntime: FATAL EXCEPTION: main 
                        Process: com.example.rubit1359.bigcornbox, PID: 12363 
                        java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.ListView.setAdapter(android.widget.ListAdapter)' on a null object reference 
                         at com.example.rubit1359.bigcornbox.ui.MainActivity$1.onResponse(MainActivity.java:57) 
                         at retrofit2.ExecutorCallAdapterFactory$ExecutorCallbackCall$1$1.run(ExecutorCallAdapterFactory.java:68) 
                         at android.os.Handler.handleCallback(Handler.java:815) 
                         at android.os.Handler.dispatchMessage(Handler.java:104) 
                         at android.os.Looper.loop(Looper.java:194) 
                         at android.app.ActivityThread.main(ActivityThread.java:5637) 
                         at java.lang.reflect.Method.invoke(Native Method) 
                         at java.lang.reflect.Method.invoke(Method.java:372) 
                         at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:960) 
                         at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:755)

ich gedebuggt haben die App, um sicherzustellen, dass die mMovies Listview gefüllt sind

public class MovieAdapter extends BaseAdapter{ 
    private Context mContext; 
    // Add mVar of resource, an array for example 
    private List<Movie> mMovies; 



    // Automatically create constructor for all mVar 


    public MovieAdapter(Context context, List<Movie> movies) { 
     mContext = context; 
     mMovies = movies; 
    } 

    public MovieAdapter(Callback<NowPlaying> callback, List<Movie> movies) { 
    } 


    // Automatically create required methods and override them with mVar 
    @Override 
    public int getCount() { 
     return mMovies.size(); 
    } 

    @Override 
    public Object getItem(int position) { 
     return mMovies.get(position); 
    } 

    @Override 
    public long getItemId(int position) { 
     return 0; // Use to easier get position reference 
    } 

    @Override 
    public View getView(int position, View convertView, ViewGroup parent) { 
     ViewHolder holder; 

     if (convertView == null) { 
      // If the ListView is brand new 

      convertView = LayoutInflater.from(mContext).inflate(R.layout.list_movie_item, 
        parent, false); 
      // Get layout from the context and inflate it the daily_list_item. 

      // Use ViewHolder to create smooth scrolling list 

      holder = new ViewHolder(convertView); 

      // Set the tag for reuse the View 
      convertView.setTag(holder); 

     } else { 
      holder = (ViewHolder) convertView.getTag(); 
     } 

     //Set content to holderVar from get 
     //Create the ModelClass object as an element in the array 
     // Remember even the Image need to be set (different from MainAct) 
     Movie movie = mMovies.get(position); 
     holder.mTvLeftTitle.setText(movie.getTitle()); 
     holder.mTvLeftOverview.setText(movie.getOverview()); 
//  holder.mTvLeftCast.setText(movie.getCast()); 
     Glide.with(mContext) 
       .load(movie.getPosterPath()) 
       .into(holder.mImgLeftPoster); 

     holder.mTvRightTitle.setText(movie.getTitle()); 
     holder.mTvRightOverview.setText(movie.getOverview()); 
//  holder.mTvLeftCast.setText(movie.getCast()); 
     Glide.with(mContext) 
       .load(movie.getPosterPath()) 
       .into(holder.mImgRightPoster); 


     return convertView; 
    } 

    // Create class ViewHolder with Widget as variable based on Model class 
    static class ViewHolder { 
     // Using ButterKnife to create and hook Widget (remember the Image, too) 
     @BindView(R.id.rlLeftLayout) 
     RelativeLayout mRlLeftLayout; 
     @BindView(R.id.tvLeftTitle) 
     TextView mTvLeftTitle; 
     @BindView(R.id.tvLeftOverview) 
       TextView mTvLeftOverview; 
     @BindView(R.id.tvLeftCast) 
     TextView mTvLeftCast; 
     @BindView(R.id.imgLeftPoster) 
     ImageView mImgLeftPoster; 

     @BindView(R.id.rlRightLayout) 
     RelativeLayout mRlRightLayout; 
     @BindView(R.id.tvRightTitle) 
     TextView mTvRightTitle; 
     @BindView(R.id.tvRightOverview) 
     TextView mTvRightOverview; 
     @BindView(R.id.tvRightCast) 
     TextView mTvRightCast; 
     @BindView(R.id.imgRightPoster) 
     ImageView mImgRightPoster; 


     ViewHolder(View view) { 
      ButterKnife.bind(this, view); 
     } 
    } 
}

Diese meine Aktivität ist . Allerdings kann ich den Adapter nicht einstellen. Jeder kann mir helfen, den Fehler zu erkennen. Danke.

UPDATE XML

XML Aktivität

<?xml version="1.0" encoding="utf-8"?> 
<RelativeLayout 
    xmlns:android="http://schemas.android.com/apk/res/android" 
    xmlns:tools="http://schemas.android.com/tools" 
    android:id="@+id/activity_main" 
    android:layout_width="match_parent" 
    android:layout_height="match_parent" 
    android:background="@color/darkness" 
    tools:context="com.example.rubit1359.bigcornbox.ui.MainActivity"> 

    <ListView 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     android:layout_alignParentTop="true" 
     android:id="@+id/ListView" 
     android:layout_alignParentStart="true" 
     android:layout_alignParentLeft="true"/> 

    <TextView 
     android:text="There is no data to display" 
     android:textStyle="bold" 
     android:textSize="20sp" 
     android:layout_centerHorizontal="true" 
     android:layout_centerVertical="true" 
     android:textColor="@color/colorWhite" 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     android:id="@+id/EmptyView" 
     /> 

</RelativeLayout>

Adapter 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" 
       xmlns:tools="http://schemas.android.com/tools" 
       android:layout_width="match_parent" 
       android:layout_height="match_parent" 
       android:background="@color/darkness"> 


    <RelativeLayout 
     android:id="@+id/rlLeftLayout" 
     android:layout_width="match_parent" 
     android:layout_height="wrap_content" 
     android:layout_alignParentLeft="true" 
     android:layout_alignParentStart="true" 
     android:layout_alignParentTop="true" 
     android:background="@color/skypeGray"> 


     <LinearLayout 
      android:layout_width="match_parent" 
      android:layout_height="wrap_content" 
      android:layout_alignBottom="@+id/imgLeftScoreBackground" 
      android:layout_alignTop="@+id/imgLeftPoster" 
      android:layout_toEndOf="@+id/imgLeftScoreBackground" 
      android:layout_toRightOf="@+id/imgLeftScoreBackground" 
      android:gravity="center_vertical" 
      android:orientation="vertical" 
      android:padding="16dp"> 

      <TextView 
       android:id="@+id/tvLeftTitle" 
       android:layout_width="match_parent" 
       android:layout_height="wrap_content" 
       android:lineSpacingExtra="5dp" 
       android:text="Captain America: Civil War" 
       android:textAlignment="viewEnd" 
       android:textColor="@color/redmilk" 
       android:textSize="15sp" 
       android:textStyle="bold"/> 

      <TextView 
       android:id="@+id/tvLeftOverview" 
       android:layout_width="match_parent" 
       android:layout_height="wrap_content" 
       android:layout_marginTop="15dp" 
       android:ellipsize="end" 
       android:lineSpacingExtra="5dp" 
       android:maxLines="5" 
       android:text="Following the events of Age of Ultron, the collective goverments of the world pass an act designed to regulate all superhuman activity. This polarizes opinion amongst the Avengers, causing two factions to side..." 
       android:textAlignment="viewEnd" 
       android:textColor="@color/colorWhite" 
       android:textSize="12sp"/> 

      <TextView 
       android:id="@+id/tvLeftCast" 
       android:layout_width="match_parent" 
       android:layout_height="wrap_content" 
       android:layout_marginTop="20dp" 
       android:text="Chris Evans, Robert Downey Jr." 
       android:textAlignment="viewEnd" 
       android:textColor="@color/colorWhite" 
       android:textSize="12sp" 
       android:textStyle="bold|italic"/> 
     </LinearLayout> 

     <ImageView 
      android:id="@+id/imgLeftPoster" 
      android:layout_width="120dp" 
      android:layout_height="180dp" 
      android:layout_alignParentLeft="true" 
      android:layout_alignParentStart="true" 
      android:layout_alignParentTop="true" 
      app:srcCompat="@drawable/poster"/> 

     <ImageView 
      android:id="@+id/imgLeftScoreBackground" 
      android:layout_width="wrap_content" 
      android:layout_height="wrap_content" 
      android:layout_below="@+id/imgLeftPoster" 
      android:layout_marginTop="3dp" 
      app:srcCompat="@drawable/background"/> 

    </RelativeLayout> 

    <RelativeLayout 
     android:id="@+id/rlRightLayout" 
     android:layout_width="match_parent" 
     android:layout_height="wrap_content" 
     android:layout_alignParentEnd="true" 
     android:layout_alignParentRight="true" 
     android:layout_alignParentTop="true" 
     android:background="@color/skypeGray"> 

     <ImageView 
      android:id="@+id/imgRightPoster" 
      android:layout_width="120dp" 
      android:layout_height="180dp" 
      android:layout_alignParentEnd="true" 
      android:layout_alignParentRight="true" 
      android:layout_alignParentTop="true" 
      app:srcCompat="@drawable/poster"/> 

     <ImageView 
      android:id="@+id/imgRightScoreBackground" 
      android:layout_width="wrap_content" 
      android:layout_height="wrap_content" 
      android:layout_alignParentEnd="true" 
      android:layout_alignParentRight="true" 
      android:layout_below="@+id/imgRightPoster" 
      android:layout_marginTop="3dp" 
      app:srcCompat="@drawable/background_right"/> 


     <LinearLayout 
      android:layout_width="match_parent" 
      android:layout_height="wrap_content" 
      android:layout_alignBottom="@+id/imgRightScoreBackground" 
      android:layout_alignTop="@+id/imgRightPoster" 
      android:layout_toLeftOf="@+id/imgRightScoreBackground" 
      android:layout_toStartOf="@+id/imgRightScoreBackground" 
      android:gravity="center_vertical" 
      android:orientation="vertical" 
      android:padding="16dp"> 

      <TextView 
       android:id="@+id/tvRightTitle" 
       android:layout_width="match_parent" 
       android:layout_height="wrap_content" 
       android:lineSpacingExtra="5dp" 
       android:text="Captain America: Civil War" 
       android:textAlignment="viewStart" 
       android:textColor="@color/redmilk" 
       android:textSize="15sp" 
       android:textStyle="bold"/> 

      <TextView 
       android:id="@+id/tvRightOverview" 
       android:layout_width="match_parent" 
       android:layout_height="wrap_content" 
       android:layout_marginTop="15dp" 
       android:ellipsize="end" 
       android:lineSpacingExtra="5dp" 
       android:maxLines="5" 
       android:text="Following the events of Age of Ultron, the collective goverments of the world pass an act designed to regulate all superhuman activity. This polarizes opinion amongst the Avengers, causing two factions to side..." 
       android:textAlignment="viewStart" 
       android:textColor="@color/colorWhite" 
       android:textSize="12sp"/> 

      <TextView 
       android:id="@+id/tvRightCast" 
       android:layout_width="match_parent" 
       android:layout_height="wrap_content" 
       android:layout_marginTop="20dp" 
       android:text="Chris Evans, Robert Downey Jr." 
       android:textAlignment="viewStart" 
       android:textColor="@color/colorWhite" 
       android:textSize="12sp" 
       android:textStyle="bold|italic"/> 
     </LinearLayout> 


    </RelativeLayout> 
</RelativeLayout>

Quelle

2016-10-15 Han Tran

Ihre mListView null ist –

Ja, ich weiß, aber Ich weiß nicht, warum es Null ist –

Haben Sie die ID li st in activity_main? –

Sie Listview-ID verwenden, die inbuild ist android.R.id.list, die Sie erfordert Ihre Aktivität mit ListActivity zu verlängern.

Also erweitern Sie Ihre Aktivität mit ListActivity. wie diese

public class MainActivity extends ListActivity

Oder Wenn Sie benutzerdefinierte Listenansicht mit Ihrer ID verwenden, dann gleiche Aktivität benutzen, geben Sie einfach die richtige ID, die Sie in Ihrem XML-Datei definiert und initialisiert werden.

So etwas wie dieses

ListView list = (ListView) view.findViewById(R.id.yourlistviewid);

Quelle

2016-10-15 16:22:15

Hier versuche ich, die ListView innerhalb einer normalen Aktivität zu verwenden, um die ActionBar zu behalten. Also habe ich den ListView an die Aktivität gebunden. Daher kann ich die ListActivity nicht erweitern. –

Verwenden Sie dann nicht 'android.R.id.list'. Verwenden Sie Ihre ListView mit Ihrer eigenen ID und initialisieren Sie diese, bevor Sie sie verwenden. Es gibt deswegen null. –

Ich versuche es einfach mit der @ + ID, aber das Problem ist immer noch da. –

Sie eine falsche ID bekommen: diese Zeilen ändern:

@BindView(android.R.id.list) 
ListView mListView;

zu:

@BindView(R.id.ListView) 
ListView mListView;

Quelle

2016-10-15 16:41:47

Die aktuellen XML-Dateien habe ich geändert, die android.id zu R.id.ListView. Ich habe die BindView auch in der Aktivität geändert.Das ist also nicht das Problem –

Schreiben Sie die gesamte Stack-Trace? –

Benutzeradapter kann nicht auf ListView gesetzt werden

Antwort

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