Dynamic ListView with Custom Adapter in Android

Introduction

There are some situations when Android Application Developers need to customize a listview. To customize a ListView, you need to customize Adapter of the ListView. Without an Adapter, you cannot implement a dynamic ListView. The Adapter will inherit BaseAdapter class of Android, you can manage everything inside the Adapter class. Those who have basic knowledge of Android can easily understand this tip.

Background

I faced a lot of situations where I had to implement dynamic ListView which changes according to user's input.

Using the Code

Here, I am going to show how a ListView of some Members can be generated. The YourAdapter class extends BaseAdapter and Override some methods of it. The getView method returns a View, so be very careful about that. The YourAdapter constructor receives the context of the Activity, the data as a ArrayList. You may use List rather than ArrayList but I have used this for a purpose. And the third parameter is the size of the listview. After that, inside getView() method, here are some checkings which change the ListView dynamically. You can change the background of the items of list. You can change the textView or ImageView or EditText or anything of the ListItem. For this, I put the ListItem as a Linear Layout.

I have set proper comments beside the code snippets, so you can have an idea about what is going on here.

class YourAdapter extends BaseAdapter {

    Context context;
    ArrayList aL;
    int count = 0;
    int limit;
    private LayoutInflater inflater = null;

    public YourAdapter(Context context, ArrayList aL, int size) {
        this.context = context;
        this.aL = aL;
        this.limit = size;
        inflater = (LayoutInflater) context
                .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
    }

    @Override
    public int getCount() {
        return limit;
    }

    @Override
    public Object getItem(int position) {
        return this.aL.get(position);
    }

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

    @Override
    public int getViewTypeCount() {
        return getCount();
    }

    @Override
    public int getItemViewType(int position) {
        return position;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        View vi = convertView;

        LinearLayout lL = null;
        if (vi == null) {
            vi = inflater.inflate(R.layout.list_item,
                null); //Layout of an item of a ListView
        }

        lL= (LinearLayout) vi.findViewById(R.id.linearLayoutList);

        TextView data = (TextView) lL.findViewById
            (R.id.textListItem); //A textView in item of ListView
        ImageView memberIcon =
        (ImageView) lL.findViewById(R.id.maleOrFemale); // An ImageView in
                                                        // item of the ListView

        ArrayList savedPositions = db.getTempData(); // Get some Flgs from Database

        List<Integer> loanDepositAmount =
            db.getLoanInfoOfMembers(); // Get loan amounts of members
        List<String> genderList =
            db.getAllGenderOfMembers();// Get genders of the members


        for (int i = 0; i < genderList.size(); i++) {
            if (position == i) {
                String maleOrFemale = "";
                try {
                    maleOrFemale = genderList.get(position).toString();
                } catch (Exception e) {
                    e.toString();
                }
                if (maleOrFemale.equals("Female")) {
                    memberIcon.setBackgroundResource(R.drawable.female); //Set Female image
                } else {
                    memberIcon.setBackgroundResource(R.drawable.male); // Set Male Image
                }
                if (newMembers.get(position).toString().contains("New")) {
                    data.setTextColor(Color.parseColor
                        ("#086A87"));//Change the text color of new members
                }
                if (position == loanDepositAmount.get(i)) {
                   data.setTextColor(Color.parseColor
                    ("#FE2E2E")); //Mark red to the members
                                            //those have loan dues
                }
            }
        }

        for (int i = 0; i < savedPositions.size(); i++) {
            if (position == Integer.parseInt(savedPositions.get(i)
                    .toString())) {
                rL.setBackgroundDrawable(new ColorDrawable(Color
                    .parseColor("#31B404")));//Change Background to
                                        //Green for the previously saved members
            }
        }

        data.setText(newMembers.get(position).toString());

        return vi;
    }
}

After creating the customized adapter class, you need to set this in a ListView. Suppose there's a ListView named listMembers, then:

ArrayList memberData;
ListView listMembers;
DatabaseHelper db;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.your_activity_layout);

        memberData= new ArrayList<String>();
        listMembers = (ListView) 
        findViewById(R.id.listViewMembers); //listViewMembers in layout file
        db = new DatabaseHelper(getApplicationContext());

        memberData = db.getAllMembers(); // Populating the List with Database data
        
        listMembers.setAdapter(new YourAdapter
        (YourClass.this, memberData, memberData.size()));
    }

You can change the size according to user's input also, suppose you select Male from a ComboBox, then only Male Member's data will be shown. The output is like this image for this scenario:

Points of Interest

There are a lot of things, I had so much fun while implementing these. I removed other data validations and threading from the code for clear understanding. There, you can set a lot of checkings and change items of the ListView as per your desire.