Hide button in ExpandableListView

Question

I've just gotten an ExpandableListView setup and everything works fine so far. On the group/parent I have a TextView and and Button. The purpose of the list is to have people sample different sounds that are included in the app, and it they click the button then the sounds will be saved to the SD Card. Here's a link to what I have so far: https://i.sstatic.net/SZNXg.jpg

My question is whether or not it's possible that after someone clicks the button and chooses to purchase the pack if it's possible to hide just that one button and not all of the buttons in every group.

Here's is my main layout (expandablelistview_main.xml):

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

        <TextView
            android:id="@+id/soundpacktitle"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginTop="@dimen/expandablelistview_main_soundpacktitle_topmargin"
            android:layout_centerHorizontal="true"
            android:text="@string/soundpacktitle"
            android:textSize="@dimen/expandablelistview_main_soundpacktitle_textsize" />

        <ExpandableListView 
            android:id="@+id/soundpacklist" 
            android:layout_width="fill_parent"
            android:layout_height="0dp"
            android:layout_below="@+id/soundpacktitle"
            android:layout_above="@+id/soundpackbottombar"
            android:layout_marginTop="@dimen/expandablelistview_main_soundpacklist_topmargin"
            android:transcriptMode="disabled"
            android:cacheColorHint="#00000000"
            android:listSelector="@android:color/transparent" />   
    </RelativeLayout> 

Here is my group/parent layout (expandablelistview_group.xml):

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="?android:attr/listPreferredItemHeight"
    android:orientation="horizontal" >

    <TextView
        android:id="@+id/grouptextview"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerVertical="true"
        android:gravity="center_vertical"
        android:layout_marginLeft="@dimen/expandablelistview_group_grouptextview_leftmargin"        
        android:textSize="@dimen/expandablelistview_group_grouptextview_textsize" />

    <Button
        android:id="@+id/buypackbutton"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:gravity="center_vertical"
        android:layout_alignParentRight="true" 
        android:focusable="false" 
        android:focusableInTouchMode="false"
        android:text="@string/buypack"
        android:padding="@dimen/expandablelistview_group_buypackbutton_padding"
        android:textSize="@dimen/expandablelistview_group_buypackbutton_textsize"
        android:textStyle="bold" />

</RelativeLayout>

Here is my java class:

public class InAppSounds extends Activity {
    private ExpandableListView soundpacklist;

    private ArrayList<String> groups;
    private ArrayList<ArrayList<ArrayList<String>>> childs;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.expandablelistview_main);

        TextView soundpacktitle = (TextView) findViewById(R.id.soundpacktitle);
        soundpacktitle.setTypeface(printbold);

        // Declare the ExpandableListView and set's the indicator to the list arrows
        soundpacklist = (ExpandableListView) findViewById(R.id.soundpacklist);
        soundpacklist.setGroupIndicator(getResources().getDrawable(R.drawable.list_groupselector));

        LoadData();

        myExpandableAdapter adapter = new myExpandableAdapter(this, groups, childs);
        soundpacklist.setAdapter(adapter);
    }

    // Loads the ExpandableListView with parent and children groups
    private void LoadData() {
        groups = new ArrayList<String>();
        childs = new ArrayList<ArrayList<ArrayList<String>>>();

        // String array that stores the parent and child names
        String[] soundpackgroups = getResources().getStringArray(R.array.soundpackgroups);
        String[] soundpack1 = getResources().getStringArray(R.array.soundpack1);
        String[] soundpack2 = getResources().getStringArray(R.array.soundpack2);
        String[] soundpack3 = getResources().getStringArray(R.array.soundpack3);

        // First Sound Pack and their songs
        groups.add(soundpackgroups[0]);
        childs.add(new ArrayList<ArrayList<String>>());
        for (int a = 0; a < soundpack1.length; a++) {
            childs.get(0).add(new ArrayList<String>());
            childs.get(0).get(a).add(soundpack1[a]);
        }

        // Second Sound Pack and their songs
        groups.add(soundpackgroups[1]);
        childs.add(new ArrayList<ArrayList<String>>());
        for (int a = 0; a < soundpack2.length; a++) {
            childs.get(1).add(new ArrayList<String>());
            childs.get(1).get(a).add(soundpack2[a]);
        }

        // Third Sound Pack and their songs
        groups.add(soundpackgroups[2]);
        childs.add(new ArrayList<ArrayList<String>>());
        for (int a = 0; a < soundpack3.length; a++) {
            childs.get(2).add(new ArrayList<String>());
            childs.get(2).get(a).add(soundpack3[a]);
        }
    }

    public class myExpandableAdapter extends BaseExpandableListAdapter {

        private final ArrayList<String> groups;

        private final ArrayList<ArrayList<ArrayList<String>>> children;

        private final Context context;

        public myExpandableAdapter(Context context, ArrayList<String> groups,
                ArrayList<ArrayList<ArrayList<String>>> children) {
            this.context = context;
            this.groups = groups;
            this.children = childs;
        }

        @Override
        public boolean areAllItemsEnabled() {
            return true;
        }

        @Override
        public ArrayList<String> getChild(int groupPosition, int childPosition) {
            return children.get(groupPosition).get(childPosition);
        }

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

        @Override
        public View getChildView(int groupPosition, final int childPosition,
                boolean isLastChild, View convertView, ViewGroup parent) {

            String child = getChild(groupPosition, childPosition).get(0);

            if (convertView == null) {
                LayoutInflater infalInflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
                convertView = infalInflater.inflate(R.layout.expandablelistview_child, null);
            }

            // TypeFace variable for the PrintBold
            printbold = Typeface.createFromAsset(getAssets(), "fonts/PrintBold.otf");

            TextView childtxt = (TextView) convertView.findViewById(R.id.childtextview);
            childtxt.setTypeface(printbold);
            childtxt.setText(child);

            return convertView;
        }

        @Override
        public int getChildrenCount(int groupPosition) {
            return children.get(groupPosition).size();
        }

        @Override
        public String getGroup(int groupPosition) {
            return groups.get(groupPosition);
        }

        @Override
        public int getGroupCount() {
            return groups.size();
        }

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

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

            final String group = getGroup(groupPosition);

            if (convertView == null) {
                LayoutInflater infalInflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
                convertView = infalInflater.inflate(R.layout.expandablelistview_group, null);
            }

            // TypeFace variable for the PrintBold
            printbold = Typeface.createFromAsset(getAssets(), "fonts/PrintBold.otf");

            TextView grouptxt = (TextView) convertView.findViewById(R.id.grouptextview);
            grouptxt.setTypeface(printbold);
            grouptxt.setText(group);

            final Button buypackbutton = (Button) convertView.findViewById(R.id.buypackbutton);
            buypackbutton.setClickable(true);

            buypackbutton.setOnClickListener(new OnClickListener() {
                @Override
                public void onClick(View view) {
                    AlertDialog.Builder alert = new AlertDialog.Builder(InAppSounds.this);
                    if (group.equals("Pack #1")) {
                        alert.setCancelable(false);
                        alert.setTitle(getString(R.string.buypacktitle));
                        alert.setIcon(getResources().getDrawable(R.drawable.ic_audioicon));
                        alert.setMessage(getString(R.string.buypackmsg));
                        alert.setPositiveButton("Yes", new DialogInterface.OnClickListener() {
                            @Override
                            public void onClick(DialogInterface dialog, int which) {
                                // check to make sure the SD card is mounted
                                // if not display an AlertDialog
                                if (!isSDPresent()) {
                                    sdcardalert();
                                }
                                else {
                                    // this will erase the button in all the groups, not just this group
                                    buypackbutton.setVisibility(View.INVISIBLE);
                                }
                            }
                        });
                        alert.setNegativeButton("No", new DialogInterface.OnClickListener() {
                            @Override
                            public void onClick(DialogInterface dialog, int which) {
                                dialog.cancel();
                            }
                        });
                        alert.show();
                    }
                }
            });

            return convertView;
        }

        @Override
        public boolean hasStableIds() {
            return true;
        }

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

I would appreciate any guidance in this matter. Thanks

Answer 1

Yes. It's easy. All that you have to do is get a reference to your button and set the visibility to gone. Like this:

Button sampleButton = (Button) findViewById(R.id.sample_button);
sampleButton.setVisiblity(View.GONE);

Note: when you set it to View.GONE the layout space that was initially given to it is also removed. If you just want to remove the button and keep the layout space use View.INVISIBLE instead.

EDIT: Here's how I would keep the button from reappearing: First, I would use a boolean to track the status of the button while the activity is active. Then in your override of getChildView I would check this boolean and set the visibility accordingly. Maybe insert something like this into the getChildView callback to keep the button from reappearing when the list item is clicked:

if (!showButton) {
Button button = (Button) findViewById(R.id.sample_button);
button.setVisibility(View.GONE);
}

As for coming back to the screen. To keep track of the whether not to show the button I would use a boolean and store it in SharedPreferences. Then, also in the getChildView callback, check the status of the boolean and set it accordingly. Something like this:

SharedPreferences settings = getSharedPreferences(PREFS_NAME, 0);
boolean showButtonStatusPref = settings.getBoolean("showButton", true);

if(!showButtonStatusPref) {
Button button = (Button) findViewById(R.id.sample_button);
button.setVisibility(View.GONE);
}

The only other thing you need to do is manage the status of each button.

EDIT 2: I completely overlooked the fact that the same layout is used for the child views (duh! brain cramp :)).

You could still use shared preferences to keep track of which samples have been downloaded (you could use Set for this). You would also need to create a way to assign "identifiers" to each sample. From there all that you would have to do is perform a check every time getChildView() is called and, if the Set contains the selected sample identifier, set the button visibility to gone. That should take care of showing the button when the sample hasn't been downloaded and not showing the button when the sample has been downloaded. Maybe something like this in the getChildView():

Set<String> defaultSet = new SortedSet<String>();
defaultSet.add("Nothing downloaded");
SharedPreferences settings = getSharedPreferences(PREFS_NAME, 0);
SortedSet<String> listOfDowloaded = settings.getStringSet("isDownloadedList", );

if (listOfDownLoaded.contains(sampleDownloadIdentifier)) {
Button button = (Button) findViewById(R.id.some_id);
button.setVisiblity(View.GONE);
}