How to access a TextView located in a Table Layout

Issue

I made a TableLayout 3x3 in "Activity A"(Chose a Table Layout, because I thought it suits my needs) 7 of the 9 cells are clickable and open "Activity B" which is a custom number picker I made. I used an intent to pass an array and other data to activity B The idea of my number picker is to set a value in the cell I just clicked in Activity A(I wanted something like the calendarDatePicker) In "Activity B" I have a method to update the values from "Activity A" and finish() "Activity B" when an image View is clicked which works very fine except that it does not set the value for the clicked Text View

How can I set the TextValue from another activity when the TextValue is contained in a Table Layout?

I don't use intent, because honestly I don't know how to handle it when the "Activity B" is closed. I mean where in "Activity A" should I handle this intent from "Activity B"

Using the debugger I found out that trying to set the text using the TextView Id does not works as it shows a "null" object in the debugger.

Activity A

package com.example.racu.threebythree;


public class threebythree extends AppCompatActivity {

    public static ArrayList<Integer> ColumnA = new ArrayList<Integer>();
    public static ArrayList<Integer> ColumnB = new ArrayList<Integer>();
    public static ArrayList<Integer> ColumnC = new ArrayList<Integer>();


    @Override
    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_three_by_three);

        for (int i = 1; i < 28; i++) {
            if (i > 0 && i < 10)
                ColumnA.add(i);
            if (i > 10 && i < 19)
                ColumnB.add(i);
            if (i > 19 && i < 28)
                ColumnC.add(i);
        }

    }

    public void openNumberPicker(View v) {

//      I used this to "guess" the location of the cell in the table layout as I could not find a way to do it.

        String cellName = v.getResources().getResourceName(v.getId());
        String cellLetter = cellName.substring(cellName.lastIndexOf("/") + 1);

//      Send intent

        Intent intent = new Intent(this, NumberPicker.class);
        intent.putExtra("Id", (cellLetter.substring(0, 1) + cellLetter.substring(2)).toUpperCase());

        switch (cellLetter.substring(0, 1)) {
            case ("a"):
                intent.putIntegerArrayListExtra("Column", ColumnA);
                break;
            case ("b"):
                intent.putIntegerArrayListExtra("Column", ColumnB);
                break;
            case ("c"):
                intent.putIntegerArrayListExtra("Column", ColumnC);
                break;
        }
        intent.putExtra("Cell ID", v.getId());

        startActivity(intent);
    }

}

Avtivity B

package com.example.racu.threebythree;

public class NumberPicker extends AppCompatActivity {

    GridView numberPicker;
    ArrayList<Integer> numbersToDisplay;
    TextView viewToDisplay;

    ImageView ok, cancel;


    @Override
    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_number_picker);
        numberPicker = (GridView) findViewById(R.id.arrayNumbers);
        viewToDisplay = (TextView) findViewById(R.id.number_to_select);
        ok = (ImageView) findViewById(R.id.add_number_to_card);
        ok.setClickable(false);

        Intent intent = getIntent();
        String idFromIntent = intent.getStringExtra("Id");
        numbersToDisplay = intent.getIntegerArrayListExtra("Letter");
        TextView numberPosition = (TextView) findViewById(R.id.numberPosition);
        numberPosition.setText(idFromIntent);
        final TextView chosenNumber = (TextView) findViewById(R.id.chosenNumber);

        ArrayAdapter<Integer> adapter = new ArrayAdapter<Integer>(this, R.layout.number_for_picker, numbersToDisplay);
        numberPicker.setAdapter(adapter);

        numberPicker.setOnItemClickListener(new AdapterView.OnItemClickListener() {

            public void onItemClick(AdapterView<?> parent, View v, int position, long id) {

                chosenNumber.setText(((TextView) v).getText());
                ok.setImageResource(R.drawable.ok_blue);
                ok.setClickable(true);
            }
        });

    }

    public void updateThreByThree(View v) {

        Intent intent = getIntent();
        int currentCell = intent.getIntExtra("Cell ID", 0);
        String idFromIntent = intent.getStringExtra("Id").substring(0, 1);

        TextView chosenNumber = (TextView) findViewById(R.id.chosenNumber);

// Here I try to Set the text to the cell in Activity A, using its R.id, but in the debugger I get a null reference, therefore my app crashes
        TextView currentCellToEdit = (TextView) findViewById(currentCell);
        currentCellToEdit.setText(chosenNumber.getText());

        int temp = Integer.parseInt(chosenNumber.getText().toString());


        switch (idFromIntent) {
            case "A":
                threebythree.ColumnA.remove(Integer.valueOf(temp));
                break;
            case "B":
                threebythree.ColumnB.remove(Integer.valueOf(temp));
                break;
            case "C":
                threebythree.ColumnC.remove(Integer.valueOf(temp));
                break;
        }
        finish();
    }

    public void cancel(View view) {

        finish();
    }
}

Thanks to Pavan for the hint I found two more very helpful post here and this one was EXACTLY what I was looking for.

Solution

Like that ( make sure you give the TableLayout an id ):

TableLayout tl = (TableLayout)findViewById( R.id.tableLayout );
TextView tv = (TextView)tl.findViewById( R.id.textView );

Answered By - RonTLV