Android App gestoppt, wenn benutzerdefinierte Listenansicht ruft

Question

Ich habe versucht, eine einfache benutzerdefinierte Listenansicht mit einem Basisadapter zu erstellen. Wenn ich die App starte, stoppte sie. Wenn ich den Fehler mit der getView-Methode überprüfe. Ich habe viele Male versucht, es zu reparieren, aber es hat nicht funktioniert. Bitte helfen Sie mir, eine Lösung für dieses Problem zu finden.

Meine benutzerdefinierte Adapterklasse.

public class activity_one extends Activity { 



    ListView list; 

@Override 
protected void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.activity1); 

    list=(ListView)findViewById(R.id.listView2); 
    list.setAdapter(new VivzAdapter(this)); 


} 


class SingleRow{ 
    ListView list; 
    String polices; 
    String policenum; 
    SingleRow(String polices, String policenum) { 
     this.polices = polices; 
     this.policenum=policenum; 
    } 



} 
class VivzAdapter extends BaseAdapter { 

    ArrayList<SingleRow> list; 
    Context context; 
    VivzAdapter(Context c){ 
     list=new ArrayList<SingleRow>(); 

     Resources res=c.getResources(); 
     String[] polices=res.getStringArray(R.array.polices); 
     String[] policenum=res.getStringArray(R.array.policenum); 
     for(int i=0;i<10;i++) 
     { 
      list.add(new SingleRow(polices[i], policenum[i])); 
     } 
    } 

    @Override 
    public int getCount() { 
     return list.size(); 
    } 

    @Override 
    public Object getItem(int i) { 
     return list.get(i); 
    } 

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

    @Override 
    public View getView(int i, View view, ViewGroup viewGroup) { 


     LayoutInflater inflater = (LayoutInflater)context.getSystemService(Context.LAYOUT_INFLATER_SERVICE); 
     View row= inflater.inflate(R.layout.listview_singlerow,viewGroup,false); 
     TextView polices=(TextView) row.findViewById(R.id.org_name); 
     TextView policenum=(TextView)row.findViewById(R.id.cn_num); 

     SingleRow temp=list.get(i); 

     polices.setText(temp.polices); 
     policenum.setText(temp.policenum); 

     return row; 
    } 
}} 

Benutzerdefinierte Liste Ansicht xml

<?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" 
    android:background="#ffffffff"> 
<ImageView 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:id="@+id/imageView2" 
    android:src="@drawable/hello_avator" 
    android:layout_alignParentTop="true" 
    android:layout_margin="10dp" 
    android:layout_alignParentLeft="true" 
    android:layout_alignParentStart="true" /> 

<TextView 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:textAppearance="?android:attr/textAppearanceLarge" 
    android:text="Company Name" 
    android:id="@+id/org_name" 
    android:layout_alignTop="@+id/imageView2" 
    android:layout_toRightOf="@+id/imageView2" 
    android:layout_alignParentRight="true" 
    android:layout_alignParentEnd="true" /> 

<TextView 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:textAppearance="?android:attr/textAppearanceSmall" 
    android:text="000-0000000" 
    android:id="@+id/cn_num" 
    android:layout_alignLeft="@+id/org_name" 
    android:layout_alignStart="@+id/org_name" 
    android:layout_alignParentRight="true" 
    android:layout_alignParentEnd="true" 
    android:layout_below="@+id/org_name" 
    android:layout_alignBottom="@+id/imageView2" /> 

Logcat

java.lang.NullPointerException 
     at com.example.abc.helloapp.activity_one$VivzAdapter.getView(activity_one.java:116) 
     at android.widget.AbsListView.obtainView(AbsListView.java:2267) 
     at android.widget.ListView.measureHeightOfChildren(ListView.java:1244) 
     at android.widget.ListView.onMeasure(ListView.java:1156) 
     at android.view.View.measure(View.java:15172) 
     at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:4814) 
     at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1390) 
     at android.widget.LinearLayout.measureVertical(LinearLayout.java:681) 
     at android.widget.LinearLayout.onMeasure(LinearLayout.java:574) 
     at android.view.View.measure(View.java:15172) 
     at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:4814) 
     at android.widget.FrameLayout.onMeasure(FrameLayout.java:310) 
     at android.view.View.measure(View.java:15172) 
     at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:4814) 
     at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1390) 
     at android.widget.LinearLayout.measureVertical(LinearLayout.java:681) 
     at android.widget.LinearLayout.onMeasure(LinearLayout.java:574) 
     at android.view.View.measure(View.java:15172) 
     at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:4814) 
     at android.widget.FrameLayout.onMeasure(FrameLayout.java:310) 
     at com.android.internal.policy.impl.PhoneWindow$DecorView.onMeasure(PhoneWindow.java:2148) 
     at android.view.View.measure(View.java:15172) 
     at android.view.ViewRootImpl.performMeasure(ViewRootImpl.java:1848) 
     at android.view.ViewRootImpl.measureHierarchy(ViewRootImpl.java:1100) 
     at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1273) 
     at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:998) 
     at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:4212) 
     at android.view.Choreographer$CallbackRecord.run(Choreographer.java:725) 
     at android.view.Choreographer.doCallbacks(Choreographer.java:555) 
     at android.view.Choreographer.doFrame(Choreographer.java:525) 
     at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:711) 
     at android.os.Handler.handleCallback(Handler.java:615) 
     at android.os.Handler.dispatchMessage(Handler.java:92) 
     at android.os.Looper.loop(Looper.java:137) 
     at android.app.ActivityThread.main(ActivityThread.java:4745) 
     at java.lang.reflect.Method.invokeNative(Native Method) 
     at java.lang.reflect.Method.invoke(Method.java:511) 
     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786) 
     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553) 
     at dalvik.system.NativeStart.main(Native Method) 

Answer 1

Sie haben context Variable in den Adapter verpassten Initialisierung somit diese Linie mit NPE nicht

LayoutInflater inflater = (LayoutInflater)context.getSystemService(Context.LAYOUT_INFLATER_SERVICE); 

wegen context natürlich, dieses Update Ihren Adapter Konstruktor lösen die Variable context mit dieser Linie context = c; so dass der Code sollte so sein zu initialisieren:

VivzAdapter(Context c){ 
    list=new ArrayList<SingleRow>(); 
    context = c; // add this 
    Resources res=c.getResources(); 
    String[] polices=res.getStringArray(R.array.polices); 
    String[] policenum=res.getStringArray(R.array.policenum); 
    for(int i=0;i<10;i++) 
    { 
     list.add(new SingleRow(polices[i], policenum[i])); 
    } 
}