Value not added in arraylist on checkbox click in listview.

Question

I have a DisplayStudentName.java file which is my main activity file. There is a model class which is used to get and set data and a MyCustomAdapter.java file which extends ArrayAdapter for listview functioning.

The checkbox is clicked but value is not added in the arraylist(named data; type String).

1. DisplayStudentName.java

     public class DisplayStudentNames extends AppCompatActivity { String myJSON; private static final String TAG_RESULTS = "result"; private static final String TAG_ROLL = "RollNo"; private static final String TAG_NAME = "Name"; JSONArray peoples = null; ListView list; ArrayList<String> checkedValue; Button b1; MyCustomAdapter dataAdapter = null; ArrayList<Student> personList=null; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_display_student_names); final Spinner sbranch = (Spinner) findViewById(R.id.branch); final Spinner ssemester = (Spinner) findViewById(R.id.semester); final Spinner ssubject = (Spinner) findViewById(R.id.edit_subject); //String branch=sbranch.getSelectedItem().toString(); //String semester=ssemester.getSelectedItem().toString(); //String subject=ssubject.getSelectedItem().toString(); String branch = "cs"; String semester = "7"; String subject = "Soft Computing"; b1 = (Button) findViewById(R.id.submit); list = (ListView) findViewById(R.id.listView); new DataFetch().execute(branch, semester, subject); list.setOnItemClickListener(new AdapterView.OnItemClickListener() { @Override public void onItemClick(AdapterView<?> parent, View view, int position, long id) { Student student = (Student) parent.getItemAtPosition(position); String Name = student.getName(); //String s=(String) ((TextView) view.findViewById(R.id.roll)).getText(); Toast.makeText(getApplicationContext(), "Clicked: " + Name, Toast.LENGTH_SHORT).show(); } }); //submitAttendance(); } class DataFetch extends AsyncTask<String, String, String> { ArrayList<NameValuePair> params; private ProgressDialog pDialog; private String url_fetch_data = "http://192.168.1.4/AttendanceApp/fetch_data.php"; InputStream is = null; String res = ""; protected void onPreExecute() { super.onPreExecute(); } protected String doInBackground(String... args) { String branch = args[0]; String semester = args[1]; String subject1 = args[2]; try { DefaultHttpClient httpClient = new DefaultHttpClient(); HttpPost httpPost = new HttpPost(url_fetch_data); params = new ArrayList<NameValuePair>(3); params.add(new BasicNameValuePair("branch", branch)); params.add(new BasicNameValuePair("semester", semester)); params.add(new BasicNameValuePair("subject", subject1)); httpPost.setEntity(new UrlEncodedFormEntity(params)); HttpResponse httpResponse = httpClient.execute(httpPost); HttpEntity httpEntity = httpResponse.getEntity(); is = httpEntity.getContent(); BufferedReader br = new BufferedReader(new InputStreamReader(is, "utf-8"), 8); StringBuilder total = new StringBuilder(); String line; while ((line = br.readLine()) != null) { total.append(line); } String result = total.toString(); return result; } catch (Exception e1) { res = "error:" + e1.getMessage().toString(); e1.printStackTrace(); } return res; } protected void onPostExecute(String httpResponse) { myJSON = httpResponse; showList(); } } protected void showList() { try { JSONObject jsonObj = new JSONObject(myJSON); peoples = jsonObj.getJSONArray("result"); personList = new ArrayList<Student>(); for (int i = 0; i < peoples.length(); i++) { Student student = new Student(); JSONObject c = peoples.getJSONObject(i); String roll = c.getString(TAG_ROLL); String name = c.getString(TAG_NAME); student.setName(name); student.setRollNo(roll); personList.add(student); } dataAdapter = new MyCustomAdapter(this, R.layout.list_item, personList); list.setAdapter(dataAdapter); } catch (JSONException e) { e.printStackTrace(); } } 

2. MyCustomAdapter.java

    public class MyCustomAdapter extends ArrayAdapter { public ArrayList<Student> personList=null; private Context context=null; private static LayoutInflater inflater=null; private ArrayList<String> data=null; private View vi; ViewHolder holder=null; public MyCustomAdapter(Context context, int resource, ArrayList<Student> personList) { super(context, resource, personList); this.context=context; this.personList=personList; } private class ViewHolder{ TextView roll; TextView name; CheckBox check; } public View getView(int position, View convertView, ViewGroup parent){ Log.v("ConvertView", String.valueOf(position)); if(convertView==null){ LayoutInflater vi = (LayoutInflater)context.getSystemService( Context.LAYOUT_INFLATER_SERVICE); convertView = vi.inflate(R.layout.list_item, null); holder=new ViewHolder(); holder.roll=(TextView)convertView.findViewById(R.id.roll); holder.name=(TextView)convertView.findViewById(R.id.name); holder.check=(CheckBox)convertView.findViewById(R.id.checkBox); convertView.setTag(holder); } else{ holder=(ViewHolder)convertView.getTag(); } Student student=personList.get(position); holder.roll.setText(student.getRollno()); holder.name.setText(student.getName()); holder.check.setTag(student); holder.check.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() { @Override public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) { if (isChecked) { data.add(holder.check.getText().toString()); } else { data.remove(holder.check.getText().toString()); } } }); return convertView; } 

}

3. Student.java -Model class

    public class Student { String rollno; String name; Boolean checkbox; public Student(){ } public Student(String rollno, String name, Boolean status){ super(); this.rollno=rollno; this.name=name; this.checkbox=status; } public String getRollno(){ return rollno; } public void setRollNo(String rollno){ this.rollno=rollno; } public String getName(){ return name; } public void setName(String name){ this.name=name; } public Boolean isCheckbox(){ return checkbox; } public void setCheckbox(boolean checkbox) { this.checkbox= checkbox; } 

Please tell me what is wrong with my code? }

Answer 1

Whenever you are making any change in the dataset, call notifyDataSetChanged() .

Thus it will be like this:

@Override
public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
    if (isChecked) {
        data.add(holder.check.getText().toString());
    } else {
        data.remove(holder.check.getText().toString());
    }
    notifyDataSetChanged();
}