public class ListViewAdapter extends ArrayAdapter<DataModel> {
// Declare Variables
Context context;
LayoutInflater inflater;
List<DataModel> datamodel;
private SparseBooleanArray mSelectedItemsIds;
String producttype;
MyDatabaseHelper dbManager;
int counter;
int Quantity = 0;
HashMap<Integer, Integer> hashMap;
static final String TAG = "LISTT";
public ListViewAdapter(Context context, int resourceId,
List<DataModel> worldpopulationlist, String Type) {
super(context, resourceId, worldpopulationlist);
mSelectedItemsIds = new SparseBooleanArray();
this.context = context;
this.datamodel = worldpopulationlist;
this.producttype = Type;
inflater = LayoutInflater.from(context);
hashMap = new HashMap<Integer, Integer>();
}
private class ViewHolder {
TextView tv;
TextView Quantity;
TextView cost;
ImageView img;
ImageView plusitem;
ImageView minusitem;
TextView itemnumber;
}
@Override
public int getCount() {
return super.getCount();
}
public View getView(final int position, View view, ViewGroup parent) {
final ViewHolder holder;
if (view == null) {
holder = new ViewHolder();
view = inflater.inflate(R.layout.listitem, null);
//
dbManager = new MyDatabaseHelper(context);
holder.tv = (TextView) view.findViewById(R.id.textView1);
holder.img = (ImageView) view.findViewById(R.id.imageView1);
holder.Quantity = (TextView) view.findViewById(R.id.textView3);
holder.cost = (TextView) view.findViewById(R.id.textView2);
view.setTag(holder);
} else {
holder = (ViewHolder) view.getTag();
}
// Capture position and set to the TextViews
String rupee = context.getResources().getString(R.string.Rs);
// final MyDatabaseHelper dbManager = new MyDatabaseHelper(context);
dbManager.open();
holder.tv.setText(datamodel.get(position).getProductname());
holder.Quantity.setText(datamodel.get(position)
.getProdcutQuantity());
holder.cost.setText(rupee + datamodel.get(position).getProdcutCost());
//holder.img.setImageResource(datamodel.get(position).getProductimage());
// dbManager.open();
String imgae = dbManager.GetimageUrl(datamodel.get(position).getProdcutid());
String imageUrl = "http://bhaskarmart.com/Images/" + imgae;
Picasso.with(context).load(imageUrl).into(holder.img);
holder.plusitem = (ImageView) view.findViewById(R.id.imageButton2);
holder.plusitem.setTag(position);
holder.minusitem = (ImageView) view.findViewById(R.id.imageButton);
holder.minusitem.setTag(position);
holder.itemnumber = (TextView) view.findViewById(R.id.textView4);
holder.img.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View view) {
imagealert(position);
}
});
// dbManager.open();
holder.itemnumber.setText(dbManager.GetEachShopedItemCount(datamodel
.get(position).getProdcutid()));
// holder.itemnumber.setText("5");
holder.plusitem.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View arg0) {
int index = Integer.parseInt(arg0.getTag().toString());
Log.e(TAG, Integer.toString(index));
int quantity;
if (hashMap.containsKey(index)) {
quantity = hashMap.get(index);
} else
quantity = 0;
quantity++;
hashMap.put(index, quantity);
// dbManager.open();
if (dbManager.GetEachShopedItemCount(
datamodel.get(position).getProdcutid()).equals("")) {
holder.itemnumber.setText(quantity + "");
// dbManager.open();
dbManager.AddShopingItem(datamodel.get(position)
.getProdcutid(), producttype,
datamodel.get(position).getProductname(), datamodel
.get(position).getProdcutQuantity(),
datamodel.get(position).getProdcutCost(), String
.valueOf(datamodel.get(position)
.getProductimage()), String
.valueOf(quantity), "true");
} else {
// dbManager.open();
int dbvalue = Integer.parseInt(dbManager
.GetEachShopedItemCount(datamodel.get(position)
.getProdcutid()));
int totalvaue = dbvalue;
totalvaue++;
holder.itemnumber.setText(totalvaue + "");
// dbManager.open();
dbManager.AddShopingItem(datamodel.get(position)
.getProdcutid(), producttype,
datamodel.get(position).getProductname(), datamodel
.get(position).getProdcutQuantity(),
datamodel.get(position).getProdcutCost(), String
.valueOf(datamodel.get(position)
.getProductimage()), String
.valueOf(totalvaue), "true");
}
// holder.itemnumber.setText(quantity + "");
// holder.itemnumber.invalidate();
// holder.itemnumber
// .setText(datamodel.get(position).getEachProdcutcount());
sendBroadcaset(true);
}
});
holder.minusitem.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
int index = Integer.parseInt(v.getTag().toString());
Log.e(TAG, Integer.toString(index));
int quantity;
if (hashMap.containsKey(index)) {
quantity = hashMap.get(index);
} else
quantity = 0;
quantity--;
if (quantity < 0)
quantity = 0;
hashMap.put(index, quantity);
// holder.itemnumber.setText(quantity + "");
// holder.itemnumber.invalidate();
// holder.itemnumber
// .setText(datamodel.get(position).getEachProdcutcount());
// dbManager.open();
if (dbManager.GetEachShopedItemCount(
datamodel.get(position).getProdcutid()).equals("")) {
holder.itemnumber.setText(quantity + "");
dbManager.AddShopingItem(datamodel.get(position)
.getProdcutid(), producttype,
datamodel.get(position).getProductname(), datamodel
.get(position).getProdcutQuantity(),
datamodel.get(position).getProdcutCost(), String
.valueOf(datamodel.get(position)
.getProductimage()), String
.valueOf(quantity), "true");
} else {
// dbManager.open();
int dbvalue = Integer.parseInt(dbManager
.GetEachShopedItemCount(datamodel.get(position)
.getProdcutid()));
int totalvaue = dbvalue + quantity;
int nexttotvalue;
if (totalvaue > 0) {
nexttotvalue = --totalvaue;
// Toast.makeText(context, String.valueOf(nexttotvalue),
// 10000).show();
} else {
nexttotvalue = 0;
}
// if (totalvaue < 0)
// totalvaue = 0;
holder.itemnumber.setText(totalvaue + "");
// dbManager.open();
dbManager.AddShopingItem(datamodel.get(position)
.getProdcutid(), producttype,
datamodel.get(position).getProductname(), datamodel
.get(position).getProdcutQuantity(),
datamodel.get(position).getProdcutCost(), String
.valueOf(datamodel.get(position)
.getProductimage()), String
.valueOf(totalvaue), "true");
}
sendBroadcaset(false);
}
});
return view;
}
这是我的代码我在Fragment ListView中使用这个适配器我有5个选项卡每个选项卡都与片段集成，每个片段我使用listView适配器当我从选项卡1转到选项卡2然后当我来时没有异常来从选项卡5返回到选项卡2然后在适配器中出现此异常
java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.Object android.content.Context.getSystemService(java.lang.String)' on a null object reference
和例外
at info.androidhive.materialdesign.adapter.ListViewAdapter.<init>(ListViewAdapter.java:43)
这是这一行：
super(context, resourceId, worldpopulationlist);
请告诉我如何解决此异常建议我
答案 0 :(得分：1)
试试这个
listviewadapter = new ListViewAdapter(getActivity(), R.layout.listitem, lstDataModel, "2");
而不是
listviewadapter = new wholeandflavoradapter(getActivity(), R.layout.listitem, lstDataModel, "2");