Values Of Counter Changes After Scrolling Expendablelistview
I have an ExpandableListView of items and on list item I have TextView with two buttons to increment or decrements the value in TextView on clicks. The problem occurs every time I
Solution 1:
It is not a good idea to store quantity in ViewHolder. Hope below sample helps :)
MainActivity.java:
publicclassMainActivityextendsActivity {
Button clearChecks, putOrder;
ExpandableListView expandableListView;
ExpandableListViewAdapter expandableListAdapter;
int lastExpandedPosition = -1;
@OverrideprotectedvoidonCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
expandableListView = findViewById(R.id.expandedListView);
clearChecks = findViewById(R.id.btnClearChecks);
putOrder = findViewById(R.id.btnPutOrder);
List<String> listTitle = genGroupList();
expandableListAdapter = newExpandableListViewAdapter(this, listTitle, genChildList(listTitle));
expandableListView.setAdapter(expandableListAdapter);
expandableListView.setOnGroupExpandListener(newExpandableListView.OnGroupExpandListener() {
@OverridepublicvoidonGroupExpand(int groupPosition) {
if(lastExpandedPosition != -1 && (lastExpandedPosition != groupPosition)){
expandableListView.collapseGroup(lastExpandedPosition);
}
lastExpandedPosition = groupPosition;
}
});
clearChecks.setOnClickListener(newView.OnClickListener() {
@OverridepublicvoidonClick(View view) {
expandableListAdapter.clearChecks();
}
});
putOrder.setOnClickListener(newView.OnClickListener() {
@OverridepublicvoidonClick(View view) {
ArrayList<ChildItemSample> putOrder = expandableListAdapter.getOrderList();
String msg = "";
for(int i=0; i<putOrder.size(); i++){
msg += putOrder.get(i).getName() + ": " + putOrder.get(i).getQty() + "\n";
}
Toast.makeText(getBaseContext(), msg, Toast.LENGTH_LONG).show();
}
});
}
privateArrayList<String> genGroupList(){
ArrayList<String> listGroup = newArrayList<>();
for(int i=1; i<10; i++){
listGroup.add("Group: " + i);
}
return listGroup;
}
privateMap<String, List<ChildItemSample>> genChildList(List<String> header){
Map<String, List<ChildItemSample>> listChild = newHashMap<>();
for(int i=0; i<header.size(); i++){
List<ChildItemSample> testDataList = newArrayList<>();
int a = (int)(Math.random()*8);
for(int j=0; j<a; j++){
ChildItemSample testItem = newChildItemSample("Child " + (j + 1), 0);
testDataList.add(testItem);
}
listChild.put(header.get(i), testDataList);
}
return listChild;
}
}
ChildItemSample.java:
publicclassChildItemSample {
privateboolean checked = false;
privateString name;
private int qty;
public int getQty() {
return qty;
}
publicvoidsetQty(int qty) {
this.qty = qty;
}
publicbooleanisChecked() {
return checked;
}
publicvoidsetChecked(boolean checked) {
this.checked = checked;
}
publicStringgetName() {
return name;
}
publicChildItemSample(String name, int qty){
this.name = name;
this.qty = qty;
}
}
ExpandableListViewAdapter.java:
publicclassExpandableListViewAdapterextendsBaseExpandableListAdapter {
private Context context;
private List<String> listGroup;
private Map<String, List<ChildItemSample>> listChild;
privateint checkedBoxesCount;
privateboolean[] checkedGroup;
publicExpandableListViewAdapter(Context context, List<String> listGroup, Map<String,
List<ChildItemSample>> listChild) {
this.context = context;
this.listGroup = listGroup;
this.listChild = listChild;
checkedBoxesCount = 0;
checkedGroup = newboolean[listGroup.size()];
}
@OverridepublicintgetGroupCount() {
return listGroup.size();
}
@OverridepublicintgetChildrenCount(int groupPosition) {
return listChild.get(listGroup.get(groupPosition)).size();
}
@Overridepublic String getGroup(int groupPosition) {
return listGroup.get(groupPosition);
}
@Overridepublic ChildItemSample getChild(int groupPosition, int childPosition) {
return listChild.get(listGroup.get(groupPosition)).get(childPosition);
}
@OverridepubliclonggetGroupId(int groupPosition) {
return groupPosition;
}
@OverridepubliclonggetChildId(int groupPosition, int childPosition) {
return childPosition;
}
@OverridepublicbooleanhasStableIds() {
returnfalse;
}
@Overridepublic View getGroupView(int groupPosition, boolean b, View view, ViewGroup viewGroup) {
StringitemGroup= getGroup(groupPosition);
GroupViewHolder groupViewHolder;
if(view == null){
LayoutInflaterinflater= (LayoutInflater)context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
view = inflater.inflate(R.layout.expanded_list_group, null);
groupViewHolder = newGroupViewHolder();
groupViewHolder.tvGroup = view.findViewById(R.id.tv_group);
groupViewHolder.cbGroup = view.findViewById(R.id.cb_group);
groupViewHolder.cbGroup.setOnClickListener(newView.OnClickListener() {
@OverridepublicvoidonClick(View view) {
intpos= (int)view.getTag();
checkedGroup[pos] = !checkedGroup[pos];
for(ChildItemSample item : listChild.get(listGroup.get(pos))){
item.setChecked(checkedGroup[pos]);
}
notifyDataSetChanged();
}
});
view.setTag(groupViewHolder);
}else {
groupViewHolder = (GroupViewHolder)view.getTag();
}
groupViewHolder.tvGroup.setText(String.format("%s (%d)", itemGroup, getChildrenCount(groupPosition)));
if(checkedGroup[groupPosition]) groupViewHolder.cbGroup.setChecked(true);
else groupViewHolder.cbGroup.setChecked(false);
groupViewHolder.cbGroup.setTag(groupPosition);
return view;
}
@Overridepublic View getChildView(int groupPosition, int childPosition, boolean b, View view, ViewGroup viewGroup) {
ChildItemSampleexpandedListText= getChild(groupPosition,childPosition);
ChildViewHolder childViewHolder;
if(view == null){
LayoutInflaterinflater= (LayoutInflater)context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
view = inflater.inflate(R.layout.expanded_list_item, null);
childViewHolder = newChildViewHolder();
childViewHolder.tvChild = view.findViewById(R.id.tv_child);
childViewHolder.cbChild = view.findViewById(R.id.cb_child);
childViewHolder.tvQty = view.findViewById(R.id.tv_qty);
childViewHolder.btInc = view.findViewById(R.id.bt_inc);
childViewHolder.btDec = view.findViewById(R.id.bt_dec);
childViewHolder.cbChild.setOnClickListener(newView.OnClickListener() {
@OverridepublicvoidonClick(View view) {
CheckBoxcb= (CheckBox) view;
Pospos= (Pos) cb.getTag();
ChildItemSampleselectedItem= getChild(pos.group, pos.child);
selectedItem.setChecked(cb.isChecked());
if(cb.isChecked()){
checkedBoxesCount++;
Toast.makeText(context,"Checked value is: " + getChild(pos.group, pos.child).getName(),
Toast.LENGTH_SHORT).show();
}else {
checkedBoxesCount--;
if(checkedBoxesCount == 0){
Toast.makeText(context,"nothing checked",Toast.LENGTH_SHORT).show();
}else {
Toast.makeText(context,"unchecked",Toast.LENGTH_SHORT).show();
}
}
notifyDataSetChanged();
}
});
childViewHolder.btInc.setOnClickListener(newView.OnClickListener() {
@OverridepublicvoidonClick(View view) {
Buttonbt= (Button) view;
Pospos= (Pos) bt.getTag();
ChildItemSampleselectedItem= getChild(pos.group, pos.child);
selectedItem.setQty(selectedItem.getQty() + 1);
notifyDataSetChanged();
}
});
childViewHolder.btDec.setOnClickListener(newView.OnClickListener() {
@OverridepublicvoidonClick(View view) {
Buttonbt= (Button) view;
Pospos= (Pos) bt.getTag();
ChildItemSampleselectedItem= getChild(pos.group, pos.child);
if(selectedItem.getQty() > 0) selectedItem.setQty(selectedItem.getQty() - 1);
notifyDataSetChanged();
}
});
}else {
childViewHolder = (ChildViewHolder)view.getTag();
}
childViewHolder.cbChild.setChecked(expandedListText.isChecked());
childViewHolder.tvChild.setText(expandedListText.getName() + " :");
childViewHolder.tvQty.setText("" + expandedListText.getQty());
childViewHolder.cbChild.setTag(newPos(groupPosition, childPosition));
childViewHolder.btInc.setTag(newPos(groupPosition, childPosition));
childViewHolder.btDec.setTag(newPos(groupPosition, childPosition));
view.setTag(childViewHolder);
return view;
}
publicvoidclearChecks() {
for(int i=0; i<checkedGroup.length; i++) checkedGroup[i] = false;
for(List<ChildItemSample> value : listChild.values()) {
for (ChildItemSample sample : value) {
sample.setChecked(false);
}
}
checkedBoxesCount = 0;
notifyDataSetChanged();
}
@OverridepublicbooleanisChildSelectable(int groupPosition, int childPosition) {
returntrue;
}
privateclassGroupViewHolder {
CheckBox cbGroup;
TextView tvGroup;
}
privateclassChildViewHolder {
CheckBox cbChild;
TextView tvChild;
TextView tvQty;
Button btInc;
Button btDec;
}
privateclassPos {
int group;
int child;
Pos(int group, int child){
this.group = group;
this.child = child;
}
}
public ArrayList<ChildItemSample> getOrderList(){
ArrayList<ChildItemSample> overallOrder = newArrayList<>();
for(int i=0; i<getGroupCount(); i++){
for(int j=0; j<getChildrenCount(i); j++){
if(getChild(i,j).getQty() > 0){
ChildItemSamplenewOrder=newChildItemSample(getGroup(i) + ">" +
getChild(i, j).getName(), getChild(i, j).getQty());
overallOrder.add(newOrder);
}
}
}
return overallOrder;
}
}
activity_main.xml:
<?xml version="1.0" encoding="utf-8"?><LinearLayoutxmlns:android="http://schemas.android.com/apk/res/android"android:layout_width="match_parent"android:layout_height="match_parent"android:orientation="vertical"><LinearLayoutandroid:layout_width="match_parent"android:layout_height="wrap_content"android:orientation="horizontal"><Buttonandroid:id="@+id/btnClearChecks"android:layout_width="match_parent"android:layout_height="wrap_content"android:layout_weight="1"android:text="Clear Checks" /><Buttonandroid:id="@+id/btnPutOrder"android:layout_width="match_parent"android:layout_height="wrap_content"android:layout_weight="1"android:text="Put Order" /></LinearLayout><ExpandableListViewandroid:id="@+id/expandedListView"android:layout_width="match_parent"android:layout_height="match_parent"></ExpandableListView></LinearLayout>expanded_list_group.xml:
<?xml version="1.0" encoding="utf-8"?><LinearLayoutxmlns:android="http://schemas.android.com/apk/res/android"android:orientation="horizontal"android:layout_width="match_parent"android:layout_height="wrap_content"android:descendantFocusability="blocksDescendants" ><CheckBoxandroid:id="@+id/cb_group"android:layout_width="wrap_content"android:layout_height="wrap_content"android:layout_marginLeft="40dp"android:layout_gravity="center_vertical" /><TextViewandroid:id="@+id/tv_group"android:layout_width="wrap_content"android:layout_height="wrap_content"android:text="Text"android:textSize="30sp" /></LinearLayout>expanded_list_item.xml:
<?xml version="1.0" encoding="utf-8"?><RelativeLayoutxmlns:android="http://schemas.android.com/apk/res/android"android:layout_width="match_parent"android:layout_height="wrap_content" ><CheckBoxandroid:id="@+id/cb_child"android:layout_width="wrap_content"android:layout_height="wrap_content"android:layout_alignParentStart="true"android:layout_centerVertical="true"android:layout_marginLeft="60dp" /><TextViewandroid:id="@+id/tv_child"android:layout_width="wrap_content"android:layout_height="wrap_content"android:layout_centerVertical="true"android:layout_toRightOf="@+id/cb_child"android:text="Child: "android:textSize="20sp" /><TextViewandroid:id="@+id/tv_qty"android:layout_width="wrap_content"android:layout_height="wrap_content"android:layout_centerVertical="true"android:layout_toRightOf="@+id/tv_child"android:text="0"android:textSize="20sp" /><Buttonandroid:id="@+id/bt_inc"android:layout_width="wrap_content"android:layout_height="wrap_content"android:layout_toLeftOf="@+id/bt_dec"android:text="+" /><Buttonandroid:id="@+id/bt_dec"android:layout_marginRight="10dp"android:layout_width="wrap_content"android:layout_height="wrap_content"android:layout_alignParentEnd="true"android:text="-" /></RelativeLayout>Solution 2:
Try this adapter:
publicclassExpandableListAdapterextendsBaseExpandableListAdapter {
classViewHolder {
TextView childText;
TextView counterText;
Button addItemButton;
Button deleteItemButton;
}
classChildItem{
String name;
int quantity;
ChildItem(String name, int quantity){
this.name = name;
this.quantity = quantity;
}
}
classPos{
int group;
int child;
Pos(int group, int child){
this.group = group;
this.child = child;
}
}
private Context context;
private List<String> listDataHeader;
//private HashMap<String, List<String>> listHashMap;private HashMap<String, List<ChildItem>> listChildMap;
publicExpandableListAdapter(Context context, List<String> listDataHeader, HashMap<String, List<String>> listHashMap) {
this.context = context;
this.listDataHeader = listDataHeader;
listChildMap = newHashMap<>();
for(int i=0; i<getGroupCount(); i++){
List<ChildItem> listTemp = newArrayList<>();
for(int j=0; j<listHashMap.get(listDataHeader.get(i)).size(); j++){
listTemp.add(newChildItem(listHashMap.get(listDataHeader.get(i)).get(j), 0));
}
listChildMap.put(listDataHeader.get(i), listTemp);
}
}
@OverridepublicintgetGroupCount() {
return listDataHeader.size();
}
@OverridepublicintgetChildrenCount(int groupPosition) {
return listChildMap.get(listDataHeader.get(groupPosition)).size();
}
@Overridepublic String getGroup(int groupPosition) {
return listDataHeader.get(groupPosition);
}
@Overridepublic ChildItem getChild(int groupPosition, int childPosition) {
return listChildMap.get(listDataHeader.get(groupPosition)).get(childPosition);
}
@OverridepubliclonggetGroupId(int groupPosition) {
return groupPosition;
}
@OverridepubliclonggetChildId(int groupPosition, int childPosition) {
return childPosition;
}
@OverridepublicbooleanhasStableIds() {
returnfalse;
}
@Overridepublic View getGroupView(int groupPosition, boolean isExpanded, View convertView, ViewGroup parent) {
StringheaderTitle= getGroup(groupPosition);
if(convertView == null) {
LayoutInflaterinflater= (LayoutInflater) this.context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
convertView = inflater.inflate(R.layout.list_group, null);
}
TextViewlistHeader= (TextView) convertView.findViewById(R.id.list_header);
listHeader.setTypeface(null, Typeface.BOLD);
listHeader.setText(headerTitle);
return convertView;
}
@Overridepublic View getChildView(int groupPosition, int childPosition, boolean isLastChild, View convertView, ViewGroup parent) {
ViewHolder viewHolder;
if(convertView == null) {
LayoutInflaterinflater= (LayoutInflater) this.context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
convertView = inflater.inflate(R.layout.list_item, null);
TextViewtextListChild= (TextView) convertView.findViewById(R.id.list_item_header);
TextViewitemsCounter= (TextView) convertView.findViewById(R.id.items_counter);
ButtonaddItemButton= (Button) convertView.findViewById(R.id.plus_btn);
viewHolder = newViewHolder();
viewHolder.childText = textListChild;
viewHolder.counterText = itemsCounter;
viewHolder.addItemButton = addItemButton;
} else {
viewHolder = (ViewHolder) convertView.getTag();
}
ChildItemchild= getChild(groupPosition, childPosition);
viewHolder.childText.setText(child.name);
viewHolder.counterText.setText("" + child.quantity);
viewHolder.addItemButton.setOnClickListener(newView.OnClickListener(){
@OverridepublicvoidonClick(View v) {
Pospos= (Pos)v.getTag();
ChildItemselectedItem= getChild(pos.group, pos.child);
selectedItem.quantity = selectedItem.quantity + 1;
notifyDataSetChanged();
PutOrderDrinks.addOrder(selectedItem.name);
}
});
viewHolder.addItemButton.setTag(newPos(groupPosition, childPosition));
convertView.setTag(viewHolder);
return convertView;
}
@OverridepublicbooleanisChildSelectable(int groupPosition, int childPosition) {
returntrue;
}
}
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