Enable Button when Spinner and EditText are not empty in Dialog

Question

In my AlertDialog, I have a Spinner and an EditText. I am trying to disable the positive button of the dialog if

selected item at Spinner is "Select currency" ("Select currency" is the first item in my Array and Spinner is set to return String currencyName as "") or
EditText is empty.

In the code below, if I have input in EditText before selecting item in Spinner, the positive button remains disabled. I have no idea how to make these two work together.

Any help will be much appreciated. Thanks.

private void openDialog(){
    LayoutInflater inflater = LayoutInflater.from(MainActivity.this);
    View subView = inflater.inflate(R.layout.dialog_layout, null);
    final EditText subEditTextExchangeRate = subView.findViewById(R.id.textInputExchangeRate);
    final Spinner subSpinner = subView.findViewById(R.id.spinner);

    ArrayAdapter<CharSequence> adapter = ArrayAdapter.createFromResource(this, R.array.currency, android.R.layout.simple_spinner_item);
    adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
    subSpinner.setAdapter(adapter);
    subSpinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
        @Override
        public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
            if(parent.getItemAtPosition(position).equals("Select currency")){
                currencyName = "";

            }else {
                currencyName = parent.getItemAtPosition(position).toString();
            }
        }
        @Override
        public void onNothingSelected(AdapterView<?> parent) {

        }
    });

    AlertDialog.Builder builder = new AlertDialog.Builder(this);
    builder.setView(subView);

    builder.setPositiveButton("OK", new DialogInterface.OnClickListener() {
        @Override
        public void onClick(DialogInterface dialog, int which) {
            exchangeRate = subEditTextExchangeRate.getText().toString();
            st2 = exchangeRate;
        }
    });

    builder.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
        @Override
        public void onClick(DialogInterface dialog, int which) {

        }
    });


    final AlertDialog alertDialog = builder.create();
    alertDialog.show();

    alertDialog.getButton(AlertDialog.BUTTON_POSITIVE).setEnabled(false);
    subEditTextExchangeRate.addTextChangedListener(new TextWatcher() {
        @Override
        public void beforeTextChanged(CharSequence s, int start, int count, int after) {

        }

        @Override
        public void onTextChanged(CharSequence s, int start, int before, int count) {
            String exchangeRateInput = subEditTextExchangeRate.getText().toString();
            alertDialog.getButton(AlertDialog.BUTTON_POSITIVE).setEnabled(!exchangeRateInput.isEmpty() && !currencyName.isEmpty()); 
        }//This is the logic that I am looking for but the method is watching only EditText

        @Override
        public void afterTextChanged(Editable s) {

        }
    });
}

score 0 · Answer 1 · answered Mar 14 '19 at 05:10

You should invoke button enable/disable logic Spinner.onItemSelected of your spinner. As of now you are only checking for logic in EditText.onTextChanged.

Declare your AlertDialog before setting listener on Spinner and EditText.
In Spinner.onItemSelected add your logic to enable or disable button.
In EditText.onTextChanged add your logic to enable or disable button.

score 0 · Accepted Answer · edited Mar 14 '19 at 05:33

Please try below code with only one change, put below line in subSpinner.setOnItemSelectedListener and also please declare alertDialog globally.

alertDialog.getButton(AlertDialog.BUTTON_POSITIVE).setEnabled(!exchangeRateInput.isEmpty() && !currencyName.isEmpty());

Here is Your Code.

private void openDialog(){
    LayoutInflater inflater = LayoutInflater.from(MainActivity.this);
    View subView = inflater.inflate(R.layout.dialog_layout, null);
    final EditText subEditTextExchangeRate = subView.findViewById(R.id.textInputExchangeRate);
    final Spinner subSpinner = subView.findViewById(R.id.spinner);

    ArrayAdapter<CharSequence> adapter = ArrayAdapter.createFromResource(this, R.array.currency, android.R.layout.simple_spinner_item);
    adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
    subSpinner.setAdapter(adapter);
    subSpinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
        @Override
        public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
            if(parent.getItemAtPosition(position).equals("Select currency")){
                currencyName = "";

            }else {
                currencyName = parent.getItemAtPosition(position).toString();
            }
            alertDialog.getButton(AlertDialog.BUTTON_POSITIVE).setEnabled(!exchangeRateInput.isEmpty() && !currencyName.isEmpty()); 
        }
        @Override
        public void onNothingSelected(AdapterView<?> parent) {

        }
    });

    AlertDialog.Builder builder = new AlertDialog.Builder(this);
    builder.setView(subView);

    builder.setPositiveButton("OK", new DialogInterface.OnClickListener() {
        @Override
        public void onClick(DialogInterface dialog, int which) {
            exchangeRate = subEditTextExchangeRate.getText().toString();
            st2 = exchangeRate;
        }
    });

    builder.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
        @Override
        public void onClick(DialogInterface dialog, int which) {

        }
    });


    alertDialog = builder.create();
    alertDialog.show();

    alertDialog.getButton(AlertDialog.BUTTON_POSITIVE).setEnabled(false);
    subEditTextExchangeRate.addTextChangedListener(new TextWatcher() {
        @Override
        public void beforeTextChanged(CharSequence s, int start, int count, int after) {

        }

        @Override
        public void onTextChanged(CharSequence s, int start, int before, int count) {
            String exchangeRateInput = subEditTextExchangeRate.getText().toString();
            alertDialog.getButton(AlertDialog.BUTTON_POSITIVE).setEnabled(!exchangeRateInput.isEmpty() && !currencyName.isEmpty()); 
        }//This is the logic that I am looking for but the method is watching only EditText

        @Override
        public void afterTextChanged(Editable s) {

        }
    });
}

alertDialog is not available in onItemSelected as its declared below! — Gokul Nath KP, Mar 14 '19 at 05:29
please take alert dialog gloabally. i have edited my answer. — android, Mar 14 '19 at 05:31
Thanks for the quick response. I have just tried the answer and encountered the following error: java.lang.NullPointerException: Attempt to invoke virtual method 'boolean java.lang.String.isEmpty()' on a null object reference The error is at "alertDialog.getButton(AlertDialog.BUTTON_POSITIVE).setEnabled(!exchangeRateInput.isEmpty() && !currencyName.isEmpty());" after "currencyName = parent.getItemAtPosition(position).toString();" — Tan YiLiang, Mar 14 '19 at 05:52
Solved. I declared exchangeRateInput = "" at the start. Thanks for the help! — Tan YiLiang, Mar 14 '19 at 06:04

score 0 · Answer 3 · answered Mar 14 '19 at 05:23

you can make work your code if you change your code like,

    Button button = dialog.getButton(AlertDialog.BUTTON_POSITIVE);
    button.setEnabled(false);
        subEditTextExchangeRate.addTextChangedListener(new TextWatcher() {
            @Override
            public void beforeTextChanged(CharSequence s, int start, int count, int after) {

            }

            @Override
            public void onTextChanged(CharSequence s, int start, int before, int count) {
            if(s.length>0 && !TextUtils.isEmpty(currencyName )){
            button.setEnabled(true);
            // your logic
           }else{
            button.setEnabled(false);
            // your logic
            }


            @Override
            public void afterTextChanged(Editable s) {

            }
        });

->this will do your work.

Enable Button when Spinner and EditText are not empty in Dialog

3 Answers3