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Android Extend BaseExpandableListAdapter

I am trying to extend the BaseExpandableListAdapter, however, when I scroll through the list and I select one of the elements to expand, the list order is reversed. For example, if I have a list of 4 elements and select the 1st element, the order (top to bottom) will now be 4, 3, 2, 1 with the 4th element (now top). If I do not increase the 4th element, the order will return to 1, 2, 3, 4 without extended elements.

Here is my implementation:

public class SensorExpandableAdapter extends BaseExpandableListAdapter {

    private static final int FILTER_POSITION = 0;
    private static final int FUNCTION_POSITION = 1;
    private static final int NUMBER_OF_CHILDREN = 2;
    ArrayList<SensorType> mParentGroups;
    private Context mContext;
    private LayoutInflater mInflater;

    public SensorExpandableAdapter(ArrayList<SensorType> parentGroup, Context context) {
        mParentGroups = parentGroup;
        mContext = context;
        mInflater = LayoutInflater.from(mContext);
    }
    @Override
    public Object getChild(int groupPosition, int childPosition) {
        // TODO Auto-generated method stub
        if(childPosition == FILTER_POSITION) return "filter";
        else return "function";
    }

    @Override
    public long getChildId(int groupPosition, int childPosition) {
        return childPosition;
    }

    @Override
    public View getChildView(int groupPosition, int childPosition,
            boolean isLastChild, View convertView, ViewGroup parent) {
        if(convertView == null)
        {
            convertView = (RelativeLayout)mInflater.inflate(R.layout.sensor_row_list_item, parent, false);
            if(childPosition == FILTER_POSITION) {
                ((CheckBox)convertView.findViewById(R.id.chkTextAddFilter)).setText("Add Filter");
            } else {
                ((CheckBox)convertView.findViewById(R.id.chkTextAddFilter)).setText("Add Function"); 
                ((CheckBox)convertView.findViewById(R.id.chkTextAddFilter)).setEnabled(false);
            }
        }
        return convertView;
    }

    @Override
    public int getChildrenCount(int groupPosition) {
        // TODO Auto-generated method stub
        return NUMBER_OF_CHILDREN;
    }

    @Override
    public Object getGroup(int groupPosition) {
        return mParentGroups.get(groupPosition);
    }

    @Override
    public int getGroupCount() {
        // TODO Auto-generated method stub
        return mParentGroups.size();
    }

    @Override
    public long getGroupId(int groupPosition) {
        // TODO Auto-generated method stub
        return groupPosition;
    }

    @Override
    public View getGroupView(int groupPosition, boolean isExpanded,
            View convertView, ViewGroup parent) {
        if(convertView == null)
        {
            convertView = mInflater.inflate(android.R.layout.simple_expandable_list_item_1, parent, false);
            TextView tv = ((TextView)convertView.findViewById(android.R.id.text1));
            tv.setText(mParentGroups.get(groupPosition).toString());
        }
        return convertView;
    }

    @Override
    public boolean hasStableIds() {
        // TODO Auto-generated method stub
        return true;
    }

    @Override
    public boolean isChildSelectable(int groupPosition, int childPosition) {
        // TODO Auto-generated method stub
        return true;
    }
}

`

I just need to take a simple ArrayList of my own SensorType class. Children are the same for all classes, only two.

, LongClickable? ExpandableListActivity getExpandableListView().setOnLongClickableListener() ..., TextView OnLongClickableListener, .

!

+3
4
public View getGroupView(int groupPosition, boolean isExpanded,
            View convertView, ViewGroup parent) {
        if(convertView == null)
        {

"". .

+3

: ; , , .

, chome2phone.

:

public View getChildView(int groupPosition, int childPosition,
            boolean isLastChild, View convertView, ViewGroup parent) {
        if(convertView == null)
        {
            convertView = (RelativeLayout)mInflater.inflate(R.layout.sensor_row_list_item, parent, false);
            if(childPosition == FILTER_POSITION) {
                ((CheckBox)convertView.findViewById(R.id.chkTextAddFilter)).setText("Add Filter");
            } else {
                ((CheckBox)convertView.findViewById(R.id.chkTextAddFilter)).setText("Add Function"); 
                ((CheckBox)convertView.findViewById(R.id.chkTextAddFilter)).setEnabled(false);
            }
        }
        return convertView;
    }

AS @Dan , convertView - , :

convertView: , . , . , , . , convertView getChildView (int, int, boolean, View, ViewGroup).

, getChildView(), , , , ; , (LIFO).

;

if (convertView == null)

, / , ( ) - :

public View getChildView(int groupPosition, int childPosition,boolean isLastChild, View convertView, ViewGroup parent) {
    RelativeLayout mItemView;
    if (null == convertView || !(convertView instanceof RelativeLayout)) {
        mItemView = (RelativeLayout)mInflater.inflate(R.layout.sensor_row_list_item, parent, false);
    }else{
        mItemView = (RelativeLayout) convertView;
    }
    if(childPosition == FILTER_POSITION) {
        ((CheckBox)convertView.findViewById(R.id.chkTextAddFilter)).setText("Add Filter");
    } else {
        ((CheckBox)convertView.findViewById(R.id.chkTextAddFilter)).setText("Add Function"); 
        ((CheckBox)convertView.findViewById(R.id.chkTextAddFilter)).setEnabled(false);
    }
}
return convertView;

, convertView .

, .

+1

, , .

public class Sample extends ExpandableListActivity {

    ExpandableListAdapter mAdapter;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onCreate(savedInstanceState);
          mAdapter = new MyExpandableListAdapter();
          setListAdapter(mAdapter);
          registerForContextMenu(getExpandableListView());
    }

   @Override
public void onCreateContextMenu(ContextMenu menu, View v,
        ContextMenuInfo menuInfo) {
    // TODO Auto-generated method stub
    super.onCreateContextMenu(menu, v, menuInfo);

      menu.setHeaderTitle("Sample menu");
      menu.add(0, 0, 0, R.string.expandable_list_sample_action);

}

    @Override
    public boolean onContextItemSelected(MenuItem item) {
        // TODO Auto-generated method stub

         ExpandableListContextMenuInfo info = (ExpandableListContextMenuInfo) item.getMenuInfo();

         String title = ((TextView) info.targetView).getText().toString();



         int type = ExpandableListView.getPackedPositionType(info.packedPosition);

         if (type == ExpandableListView.PACKED_POSITION_TYPE_CHILD) {
             int groupPos = ExpandableListView.getPackedPositionGroup(info.packedPosition); 
             int childPos = ExpandableListView.getPackedPositionChild(info.packedPosition); 
             Toast.makeText(Sample.this, title + ": Child " + childPos + " clicked in group " + groupPos,
                     Toast.LENGTH_SHORT).show();
             return true;
         } else if (type == ExpandableListView.PACKED_POSITION_TYPE_GROUP) {
             int groupPos = ExpandableListView.getPackedPositionGroup(info.packedPosition); 
             Toast.makeText(this, title + ": Group " + groupPos + " clicked", Toast.LENGTH_SHORT).show();
             return true;
         }

         return false;

    }
    /**
     * A simple adapter which maintains an ArrayList of photo resource Ids. 
     * Each photo is displayed as an image. This adapter supports clearing the
     * list of photos and adding a new photo.
     *
     */
    public class MyExpandableListAdapter extends BaseExpandableListAdapter {
        // Sample data set.  children[i] contains the children (String[]) for groups[i].
        private String[] groups = { "People Names", "Dog Names", "Cat Names", "Fish Names" };
        private String[][] children = {
                { "Arnold", "Barry", "Chuck", "David" },
                { "Ace", "Bandit", "Cha-Cha", "Deuce" },
                { "Fluffy", "Snuggles" },
                { "Goldy", "Bubbles" }
        };

        public Object getChild(int groupPosition, int childPosition) {
            return children[groupPosition][childPosition];
        }

        public long getChildId(int groupPosition, int childPosition) {
            return childPosition;
        }

        public int getChildrenCount(int groupPosition) {
            return children[groupPosition].length;
        }

        public TextView getGenericView() {
            // Layout parameters for the ExpandableListView
            AbsListView.LayoutParams lp = new AbsListView.LayoutParams(
                    ViewGroup.LayoutParams.FILL_PARENT, 64);

            TextView textView = new TextView(Sample.this);
            textView.setLayoutParams(lp);
            // Center the text vertically
            textView.setGravity(Gravity.CENTER_VERTICAL | Gravity.LEFT);
            // Set the text starting position
            textView.setPadding(36, 0, 0, 0);
            return textView;
        }

        public View getChildView(int groupPosition, int childPosition, boolean isLastChild,
                View convertView, ViewGroup parent) {
            TextView textView = getGenericView();
            textView.setText(getChild(groupPosition, childPosition).toString());
            return textView;
        }

        public Object getGroup(int groupPosition) {
            return groups[groupPosition];
        }

        public int getGroupCount() {
            return groups.length;
        }

        public long getGroupId(int groupPosition) {
            return groupPosition;
        }

        public View getGroupView(int groupPosition, boolean isExpanded, View convertView,
                ViewGroup parent) {
            TextView textView = getGenericView();
            textView.setText(getGroup(groupPosition).toString());
            return textView;
        }

        public boolean isChildSelectable(int groupPosition, int childPosition) {
            return true;
        }

        public boolean hasStableIds() {
            return true;
        }

    }}
+1

stackoverflow.com.

, , .

"", , , . ListView (http://www.youtube.com/watch?v=wDBM6wVEO70), convertView .

My solution is very simple and it works great in my case. I got the idea from the above video:

   public View getGroupView(int groupPosition, boolean isExpanded,
            View convertView, ViewGroup parent)     {

        // 1. Step: check if convertView can be re-used or if it should be created.

        if (convertView == null) {

                // create the view or inflate the view from xml here
                // Note: inlating is expensive process, so do it only if needed 
                //       (it needed when convertView can not be re-used)
                //
                // TODO: your code here

        }

        // 2. Step: populate the convertView with correct data.
        // Correct data can be accessed through groupPosition.
        //
        // TODO: your code here

        return convertView;
    }

I believe this second step was missing in the code provided in the question?

I hope this helps someone with the same problem.

  • Tuomas
+1
source

Source: https://habr.com/ru/post/1738739/

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