Changing the ListView TextView Strings/Text before loading of the listview

Question

Don't know how to ask the question or maybe the title is wrong too . I have tried to find the answer everywhere but didn't get . Help . I am getting data from SQLite database in a ListView which contains four TextViews .

final String[] from = new String[] { DatabaseHelper._ID, DatabaseHelper.TITLE, DatabaseHelper.USERNAME, DatabaseHelper.PASSWORD };
final int[] to = new int[] { R.id.id, R.id.dataTitle, R.id.dataUsername, R.id.dataPassword };

DBManager dbManager = new DBManager(this);
dbManager.open();

Cursor cursor = dbManager.fetch();

ListView dataList = findViewById(R.id.dataList);
dataList.setEmptyView(findViewById(R.id.emptyData));

SimpleCursorAdapter adapter = new SimpleCursorAdapter(this, R.layout.contents, cursor, from, to, 0);
adapter.notifyDataSetChanged();
dataList.setAdapter(adapter);

Where fetch() is :

public Cursor fetch() {
            String[] columns = new String[] {
                    DatabaseHelper._ID,
                    DatabaseHelper.TITLE,
                    DatabaseHelper.USERNAME ,
                    DatabaseHelper.PASSWORD
            };
    Cursor cursor = database.query(DatabaseHelper.TABLE_NAME, columns, null, null, null, null, null);
    if (cursor != null) {
        cursor.moveToFirst();
    }
    return cursor;
}

Now the problem is I have stored String data in database in encrypted format. I want to decrypt the Strings before showing in the ListView . Please help me . Thanks .

Did you try custom adapter? you can refer this link https://stackoverflow.com/questions/8166497/custom-adapter-for-list-view — Jack, Jul 02 '18 at 11:28
I could not understand how to implement it here . Can you guide me ? @Jack — Sudipta Basak, Jul 02 '18 at 11:34

Arpit bandil · Accepted Answer · 2018-07-02T12:18:02.183

you should use AysncTask for retrieving data from database because if data is larger then UI may be unresponsive and hang and decrypt the string in fetch() method.

You should Load listview in onPostExecute method()

Example:

private class GetData extends AsyncTask<Void, Void, Void> {
    ArrayList<YourModel> youArray=null;

    @Override
    protected Void doInBackground(Void... voids) {
        youArray=dbManager.fetch() // Return decrypted array from fetch method.
        return null;
    }

    @Override
    protected void onPreExecute() {
        super.onPreExecute();
    }

    @Override
    protected void onPostExecute(Void result) {
      // Load your listview here...
       SimpleCursorAdapter adapter = new SimpleCursorAdapter(this, R.layout.contents, cursor, from, to, 0);
       dataList.setAdapter(adapter);
       adapter.notifyDataSetChanged();
    }
}

Your ListView Adapter

public class LazyAdapter extends BaseAdapter {

private Context context=null;
 ArrayList<YourModel> data=new ArrayList<>;
private static LayoutInflater inflater=null;

public LazyAdapter(Context context, ArrayList<YourModel> data) {
    this.context = a;
    this.data=data;
    inflater = (LayoutInflater)activity.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
}

public int getCount() {
    return data.size();
}

public Object getItem(int position) {
    return position;
}

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

public View getView(int position, View convertView, ViewGroup parent) {
    View vi=convertView;
    if(convertView==null)
        vi = inflater.inflate(R.layout.your_view, null);

    // Your subviews which needed to be initialized and set.
    TextView email = (TextView)vi.findViewById(R.id.email); // email
    TextView password = (TextView)vi.findViewById(R.id.password); // password



    User user = data.get(position);

    // Setting all values in listview
    email.setText(user.getEmail());
    password.setText(user.getPassword());

    return vi;
}}

I am very new in android development . Can you guide me step by step please ? — Sudipta Basak, Jul 02 '18 at 12:01
Alright i will, can you use recyclerView or it has specific requirement for listview? — Arpit bandil, Jul 02 '18 at 12:05
Just add your model and get data from cursor to your array and set adapter and its completed. — Arpit bandil, Jul 02 '18 at 12:20
Refer this link https://www.simplifiedcoding.net/custom-listview-android/ for custom listview and see below link for convert cursor to ArrayList https://stackoverflow.com/questions/1354006/how-can-i-create-a-list-array-with-the-cursor-data-in-android — Arpit bandil, Jul 03 '18 at 04:04

score 0 · Answer 2 · answered Jul 02 '18 at 11:47

0

if i have understood your point correctly you can add encrypted data to ArrayList then encrypt in array list and next add to listview

answered Jul 02 '18 at 11:47

Mehrdad

1,477
15
17

How can I decrypt the data in arraylist ? – Sudipta Basak Jul 02 '18 at 12:04
String encryptedString = encrypt("My String","MySecretKey") for encryption ... And String decryptedString = decrypt(encryptedString,"MySecretKey") for decryption – Sudipta Basak Jul 02 '18 at 12:59
there is a separate class for this two methods – Sudipta Basak Jul 02 '18 at 13:02
test a code like this: `final String[] from = new String[] { decrypt(DatabaseHelper.TITLE,"MySecretKey") , ......... }` – Mehrdad Jul 03 '18 at 12:51

Changing the ListView TextView Strings/Text before loading of the listview

2 Answers2