Utilizzo dell'array SparceBoolen per conservare lo stato della casella di controllo in Android per un elenco orizzontale

Question

Cosa sto facendo ::

.
• Sto cercando di utilizzare un elenco orizzontale in un frammento
• Sto usando this post for my solution
• Sto usando un array booleano sparse per mantenere il mio stato di controllo onscrool

Cosa sono stato in grado di fare ::

.
• Usando la soluzione sono stato in grado di portare lo scorrimento orizzicante

Quale problema è previsto ::

.
• Ma quando ho provato ad aggiungere la logica del codice per Sparce Boolean Array, lo sono Ottenere questo errore come mostrato in LogCat
• Errore viene sollevato nella linea mCheckBox.setTag(position);
• Come posso risolvere questo?

---

.

Item_meal_type.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:background="#000000"
    android:orientation="vertical" >


    <ImageView
        android:id="@+id/image"
        android:layout_width="150dip"
        android:layout_height="150dip"
        android:scaleType="centerCrop"
        android:src="@drawable/ic_launcher" />

    <TextView
        android:id="@+id/title"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:gravity="center_horizontal"
        android:textColor="#000" />

    <CheckBox
        android:id="@+id/checkBox1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:layout_alignParentTop="true"
        android:text="CheckBox" />

</RelativeLayout>

.

frgmdfilter.java

public class FrgMdFilter extends Fragment {

    Button btnFilter;
    Spinner spnFilterByMealType;
    private TextView txtMinPrice,txtMaxPrice,txtMinDistance,txtMaxDistance,txtMinRating,txtMaxRating;
    private CheckBox chkPrice,chkDistance,chkRating;
    private static RelativeLayout progressLayout;

     private static String[] dataObjects = new String[]{ "Text #1",
            "Text #2",
            "Text #3" };

    //Constructor declaration on type newInstance
    public static FrgMdFilter newInstance() {
        FrgMdFilter fragment = new FrgMdFilter();
        return fragment;
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
            Bundle savedInstanceState) { 

        View view=inflater.inflate(R.layout.frg_md_filter, container, false);
        //setHasOptionsMenu(true);//For using actionbar menu from fragment
        setRetainInstance(true);

        progressLayout=(RelativeLayout) view.findViewById(R.id.progressLayout);
        progressLayout.setBackgroundColor(Color.parseColor("#2da2cd"));

        HorizontalListView hListView = (HorizontalListView) view.findViewById(R.id.listview);
        hListView.setAdapter(mAdapter);

        return view;

    }

    /*@Override
    public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
        inflater.inflate(R.menu.actionbar_sort_menu, menu);
    }*/

<------------Rest-----of-------------------------------------code-----in b/w-------------->

    /* private static String[] dataObjects = new String[]{ "Text #1",
            "Text #2",
            "Text #3" };*/ 

        private BaseAdapter mAdapter = new BaseAdapter() {
            /*CheckBox mCheckBox;*/
            SparseBooleanArray mSparseBooleanArray = new SparseBooleanArray();


            @Override
            public int getCount() {
                return dataObjects.length;
            }

            @Override
            public Object getItem(int position) {
                return null;
            }

            @Override
            public long getItemId(int position) {
                return 0;
            }

            @Override
            public View getView(int position, View convertView, ViewGroup parent) {
                View retval = LayoutInflater.from(parent.getContext()).inflate(R.layout.item_meal_type, null);
                TextView title = (TextView) retval.findViewById(R.id.title);
                title.setText(dataObjects[position]);

                CheckBox mCheckBox=(CheckBox) retval.findViewById(R.id.ch_bx);

                mCheckBox.setTag(position);
                mCheckBox.setChecked(mSparseBooleanArray.get(position));
                mCheckBox.setOnCheckedChangeListener(mCheckedChangeListener);

                return retval;
            }
            OnCheckedChangeListener mCheckedChangeListener = new OnCheckedChangeListener() {

                @Override
                public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
                    // TODO Auto-generated method stub
                    mSparseBooleanArray.put((Integer) buttonView.getTag(), isChecked);
                }
            };
        };  
}

.

log

06-04 12:45:53.270: E/AndroidRuntime(7658): FATAL EXCEPTION: main
06-04 12:45:53.270: E/AndroidRuntime(7658): java.lang.NullPointerException
06-04 12:45:53.270: E/AndroidRuntime(7658):     at com.findmybuffet.fragments.FrgMdFilter$1.getView(FrgMdFilter.java:293)
06-04 12:45:53.270: E/AndroidRuntime(7658):     at com.findmybuffet.utilities.HorizontalListView.fillListRight(HorizontalListView.java:232)
06-04 12:45:53.270: E/AndroidRuntime(7658):     at com.findmybuffet.utilities.HorizontalListView.fillList(HorizontalListView.java:217)
06-04 12:45:53.270: E/AndroidRuntime(7658):     at com.findmybuffet.utilities.HorizontalListView.onLayout(HorizontalListView.java:195)
06-04 12:45:53.270: E/AndroidRuntime(7658):     at android.view.View.layout(View.java:11180)
06-04 12:45:53.270: E/AndroidRuntime(7658):     at android.view.ViewGroup.layout(ViewGroup.java:4203)
06-04 12:45:53.270: E/AndroidRuntime(7658):     at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1628)
06-04 12:45:53.270: E/AndroidRuntime(7658):     at android.widget.LinearLayout.layoutHorizontal(LinearLayout.java:1617)
06-04 12:45:53.270: E/AndroidRuntime(7658):     at android.widget.LinearLayout.onLayout(LinearLayout.java:1401)
06-04 12:45:53.270: E/AndroidRuntime(7658):     at android.view.View.layout(View.java:11180)
06-04 12:45:53.270: E/AndroidRuntime(7658):     at android.view.ViewGroup.layout(ViewGroup.java:4203)
06-04 12:45:53.270: E/AndroidRuntime(7658):     at android.widget.RelativeLayout.onLayout(RelativeLayout.java:925)
06-04 12:45:53.270: E/AndroidRuntime(7658):     at android.view.View.layout(View.java:11180)
06-04 12:45:53.270: E/AndroidRuntime(7658):     at android.view.ViewGroup.layout(ViewGroup.java:4203)
06-04 12:45:53.270: E/AndroidRuntime(7658):     at android.widget.RelativeLayout.onLayout(RelativeLayout.java:925)
06-04 12:45:53.270: E/AndroidRuntime(7658):     at android.view.View.layout(View.java:11180)
06-04 12:45:53.270: E/AndroidRuntime(7658):     at android.view.ViewGroup.layout(ViewGroup.java:4203)
06-04 12:45:53.270: E/AndroidRuntime(7658):     at android.widget.RelativeLayout.onLayout(RelativeLayout.java:925)
06-04 12:45:53.270: E/AndroidRuntime(7658):     at android.view.View.layout(View.java:11180)
06-04 12:45:53.270: E/AndroidRuntime(7658):     at android.view.ViewGroup.layout(ViewGroup.java:4203)
06-04 12:45:53.270: E/AndroidRuntime(7658):     at android.widget.FrameLayout.onLayout(FrameLayout.java:431)
06-04 12:45:53.270: E/AndroidRuntime(7658):     at android.view.View.layout(View.java:11180)
06-04 12:45:53.270: E/AndroidRuntime(7658):     at android.view.ViewGroup.layout(ViewGroup.java:4203)
06-04 12:45:53.270: E/AndroidRuntime(7658):     at android.widget.FrameLayout.onLayout(FrameLayout.java:431)
06-04 12:45:53.270: E/AndroidRuntime(7658):     at android.view.View.layout(View.java:11180)
06-04 12:45:53.270: E/AndroidRuntime(7658):     at android.view.ViewGroup.layout(ViewGroup.java:4203)
06-04 12:45:53.270: E/AndroidRuntime(7658):     at android.support.v4.widget.DrawerLayout.onLayout(DrawerLayout.java:678)
06-04 12:45:53.270: E/AndroidRuntime(7658):     at android.view.View.layout(View.java:11180)
06-04 12:45:53.270: E/AndroidRuntime(7658):     at android.view.ViewGroup.layout(ViewGroup.java:4203)
06-04 12:45:53.270: E/AndroidRuntime(7658):     at android.widget.FrameLayout.onLayout(FrameLayout.java:431)
06-04 12:45:53.270: E/AndroidRuntime(7658):     at android.view.View.layout(View.java:11180)
06-04 12:45:53.270: E/AndroidRuntime(7658):     at android.view.ViewGroup.layout(ViewGroup.java:4203)
06-04 12:45:53.270: E/AndroidRuntime(7658):     at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1628)
06-04 12:45:53.270: E/AndroidRuntime(7658):     at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1486)
06-04 12:45:53.270: E/AndroidRuntime(7658):     at android.widget.LinearLayout.onLayout(LinearLayout.java:1399)
06-04 12:45:53.270: E/AndroidRuntime(7658):     at android.view.View.layout(View.java:11180)
06-04 12:45:53.270: E/AndroidRuntime(7658):     at android.view.ViewGroup.layout(ViewGroup.java:4203)
06-04 12:45:53.270: E/AndroidRuntime(7658):     at android.widget.FrameLayout.onLayout(FrameLayout.java:431)
06-04 12:45:53.270: E/AndroidRuntime(7658):     at android.view.View.layout(View.java:11180)
06-04 12:45:53.270: E/AndroidRuntime(7658):     at android.view.ViewGroup.layout(ViewGroup.java:4203)
06-04 12:45:53.270: E/AndroidRuntime(7658):     at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1468)
06-04 12:45:53.270: E/AndroidRuntime(7658):     at android.view.ViewRootImpl.handleMessage(ViewRootImpl.java:2418)
06-04 12:45:53.270: E/AndroidRuntime(7658):     at android.os.Handler.dispatchMessage(Handler.java:99)
06-04 12:45:53.270: E/AndroidRuntime(7658):     at android.os.Looper.loop(Looper.java:137)
06-04 12:45:53.270: E/AndroidRuntime(7658):     at android.app.ActivityThread.main(ActivityThread.java:4340)
06-04 12:45:53.270: E/AndroidRuntime(7658):     at java.lang.reflect.Method.invokeNative(Native Method)
06-04 12:45:53.270: E/AndroidRuntime(7658):     at java.lang.reflect.Method.invoke(Method.java:511)
06-04 12:45:53.270: E/AndroidRuntime(7658):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)
06-04 12:45:53.270: E/AndroidRuntime(7658):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)
06-04 12:45:53.270: E/AndroidRuntime(7658):     at dalvik.system.NativeStart.main(Native Method)

.

Answer 1

Qui (CheckBox) retval.findViewById(R.id.ch_bx) sta restituendo l'istanza null poiché non è presente alcuna casella di controllo con ID R.id.ch_bx nel tuo layout ...

Quindi sostituisci

retval.findViewById(R.id.ch_bx)

.

con

retval.findViewById(R.id.checkBox1)

.

Vedi il tuo file di layout.ID di quella casella di controllo è checkBox1 ...