アダプタエラー：NullPointerException：仮想メソッド 'intを呼び出しようとしました。android.view.getImportantForAccessibility（）

Question

このnullポインタの原因を見つけることができません。imは子と親のrowviewを返します。私は通常、nullを返すいくつかのビューが原因でそれを読んだが、私はこの場合エラーを見つけることができません。私はそれが原因だと思う

if(estadoMateria.equals("Puede cursar") || estadoMateria.equals("Puede inscribirse")) { 
    parentHolder.tvEstado.setText(estadoMateria); 
    return null; 
} 

：あなたはこれらの行を持ってgetGroupView方法では事前のおかげで答えを

マイアダプターコード

public class CorrAdapter extends BaseExpandableListAdapter { 

private List<Correlativa> materias; 
private LayoutInflater inflater = null; 

public CorrAdapter(Context context, List<Correlativa> materias) { 
    this.materias = materias; 
    inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE); 
} 

@Override 
public int getGroupCount() { 
    return materias.size(); 
} 

@Override 
public int getChildrenCount(int i) { 
    return materias.get(i).getCorrelativas().size(); 
} 

@Override 
public Object getGroup(int i) { 
    return null; 
} 

@Override 
public Object getChild(int i, int i1) { 
    return null; 
} 

@Override 
public long getGroupId(int i) { 
    return 0; 
} 

@Override 
public long getChildId(int i, int i1) { 
    return 0; 
} 

@Override 
public boolean hasStableIds() { 
    return false; 
} 

@Override 
public View getGroupView(int i, boolean b, View view, ViewGroup viewGroup) { 


    ParentHolder parentHolder; 
    View rowView = view; 

    if (rowView == null) { 

     rowView = inflater.inflate(R.layout.expandable_parent, viewGroup, false); 
     parentHolder = new ParentHolder(); 

     parentHolder.tvMateria = (TextView) rowView.findViewById(R.id.tvCorrMateria); 
     parentHolder.tvEstado = (TextView) rowView.findViewById(R.id.tvCorrEstado); 

     rowView.setTag(parentHolder); 
    } else { 

     parentHolder = (ParentHolder) view.getTag(); 

    } 



    parentHolder.tvMateria.setText(materias.get(i).getNombreMateria()); 

    String estadoMateria = materias.get(i).getCorrelativas().get(0); 

    if(estadoMateria.equals("Puede cursar") || estadoMateria.equals("Puede inscribirse")) { 
     parentHolder.tvEstado.setText(estadoMateria); 
     return null; 
    } 

    else 
     parentHolder.tvEstado.setText("No cumple correlativas"); 


    return rowView; 
} 

@Override 
public View getChildView(int i, int i1, boolean b, View view, ViewGroup viewGroup) { 

    View rowView = view; 
    ChildHolder childHolder; 

    if (rowView == null) { 

     rowView = inflater.inflate(R.layout.expandable_child, viewGroup, false); 
     childHolder = new ChildHolder(); 

     childHolder.tvCorr = (TextView) rowView.findViewById(R.id.tvCorr2); 
     rowView.setTag(childHolder); 

    } else { 

     childHolder = (ChildHolder) rowView.getTag(); 

    } 

    childHolder.tvCorr.setText(materias.get(i).getCorrelativas().get(i1)); 

    return rowView; 
} 

@Override 
public boolean isChildSelectable(int i, int i1) { 
    return false; 
} 

private static class ParentHolder { 
    TextView tvMateria, tvEstado; 
} 

private static class ChildHolder { 
    TextView tvCorr; 
} 

Logcatエラー

E/AndroidRuntime: FATAL EXCEPTION: main 
                      Process: com.technocell.myapplication, PID: 27851 
                      java.lang.NullPointerException: Attempt to invoke virtual method 'int android.view.View.getImportantForAccessibility()' on a null object reference 
                       at android.widget.AbsListView.obtainView(AbsListView.java:2388) 
                       at android.widget.ListView.measureHeightOfChildren(ListView.java:1326) 
                       at android.widget.ListView.onMeasure(ListView.java:1233) 
                       at android.view.View.measure(View.java:19857) 
                       at android.widget.RelativeLayout.measureChildHorizontal(RelativeLayout.java:715) 
                       at android.widget.RelativeLayout.onMeasure(RelativeLayout.java:461) 
                       at android.view.View.measure(View.java:19857) 
                       at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6083) 
                       at android.widget.FrameLayout.onMeasure(FrameLayout.java:185) 
                       at android.view.View.measure(View.java:19857) 
                       at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6083) 
                       at android.support.design.widget.CoordinatorLayout.onMeasureChild(CoordinatorLayout.java:714) 
                       at android.support.design.widget.CoordinatorLayout.onMeasure(CoordinatorLayout.java:786) 
                       at android.view.View.measure(View.java:19857) 
                       at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6083) 
                       at android.widget.FrameLayout.onMeasure(FrameLayout.java:185) 
                       at android.support.v7.widget.ContentFrameLayout.onMeasure(ContentFrameLayout.java:139) 
                       at android.view.View.measure(View.java:19857) 
                       at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6083) 
                       at android.support.v7.widget.ActionBarOverlayLayout.onMeasure(ActionBarOverlayLayout.java:393) 
                       at android.view.View.measure(View.java:19857) 
                       at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6083) 
                       at android.widget.FrameLayout.onMeasure(FrameLayout.java:185) 
                       at android.view.View.measure(View.java:19857) 
                       at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6083) 
                       at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1464) 
                       at android.widget.LinearLayout.measureVertical(LinearLayout.java:758) 
                       at android.widget.LinearLayout.onMeasure(LinearLayout.java:640) 
                       at android.view.View.measure(View.java:19857) 
                       at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6083) 
                       at android.widget.FrameLayout.onMeasure(FrameLayout.java:185) 
                       at com.android.internal.policy.DecorView.onMeasure(DecorView.java:689) 
                       at android.view.View.measure(View.java:19857) 
                       at android.view.ViewRootImpl.performMeasure(ViewRootImpl.java:2275) 
                       at android.view.ViewRootImpl.measureHierarchy(ViewRootImpl.java:1366) 
                       at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1619) 
                       at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1254) 
                       at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:6338) 
                       at android.view.Choreographer$CallbackRecord.run(Choreographer.java:874) 
                       at android.view.Choreographer.doCallbacks(Choreographer.java:686) 
                       at android.view.Choreographer.doFrame(Choreographer.java:621) 
                       at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:860) 
                       at android.os.Handler.handleCallback(Handler.java:751) 
                       at android.os.Handler.dispatchMessage(Handler.java:95) 
                       at android.os.Looper.loop(Looper.java:154) 
                       at android.app.ActivityThread.main(ActivityThread.java:6119) 
                       at java.lang.reflect.Method.invoke(Native Method) 
                       at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:886) 
                       at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:776) 

Answer 1

場合によってはnullが返されます。このように修正してください：

if(estadoMateria.equals("Puede cursar") || estadoMateria.equals("Puede inscribirse")) { 
    parentHolder.tvEstado.setText(estadoMateria); 
}