How to disable button with multiple edit text using Textwatcher?

Question

I am trying to disable my button if my input edit texts are empty. I am using text watcher for this. To test it out , i have only tried with only two edit texts to start. However, my button stays enabled no matter what.

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

    fnameInput = findViewById(R.id.et_firstname);
    lnameInput = findViewById(R.id.et_lastname);
    numberInput = findViewById(R.id.et_phone);
    emailInput = findViewById(R.id.et_email);
    nextBtn = findViewById(R.id.btn_next);

    fnameInput.addTextChangedListener(loginTextWatcher);
    lnameInput.addTextChangedListener(loginTextWatcher);


    nextBtn.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            launchNextActivity();
        }
    });
}

Text watcher method

private TextWatcher loginTextWatcher = 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 firstNameInput =firstNameInput.getText().toString().trim();
        String lastNameInput = lastNameInput.getText().toString().trim();


        // tried doing it this way 
        nextBtn.setEnabled(!firstNameInput.isEmpty() && !lastNameInput.isEmpty());

        //What i've also tried 
        if(firstNameInput.length()> 0 &&
                lastNameInput.length()>0){
            nextBtn.setEnabled(true);
        } else{
            nextBtn.setEnabled(false);
        }
    }

    @Override
    public void afterTextChanged(Editable s) {

    }
};

I expect the button to be disabled if one or all inputs are empty and enabled when all input fields are filled out.

Answer 1

create a method check all condition there like

private void checkTheConditions(){
  if(condition1 && condition2)
  nextBtn.setEnabled(true)
  else
  nextBtn.setEnabled(false)
}

call this method from afterTextChanged(Editable s) method

Answer 2

Let us consider this case for 2 EditTexts only as for now. define 2 global CharSequence as below

CharSequence fName="";
CharSequence lName="";
Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_create_profile);

        fnameInput = findViewById(R.id.et_firstname);
        lnameInput = findViewById(R.id.et_lastname);
        numberInput = findViewById(R.id.et_phone);
        emailInput = findViewById(R.id.et_email);
        nextBtn = findViewById(R.id.btn_next);

        fnameInput.addTextChangedListener(textWatcher);
        lnameInput.addTextChangedListener(textWatcher2);


        nextBtn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                launchNextActivity();
            }
        });
    }

then you have to define different textwatcher for each of your Edittext

then inside each of these textWatcher assign values to CharSequence defined above

private TextWatcher textWatcher = 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) {

      fName=s;
      validate();  //method to enable or disable button (find method below)

    }

    @Override
    public void afterTextChanged(Editable s) {

    }
};

now textWatcher2

private TextWatcher textWatcher2 = 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) {

      lName=s;
      validate();  //method to enable or disable button (find method below)

    }

    @Override
    public void afterTextChanged(Editable s) {

    }
};

now write validate method

void validate(){
        if (fName.length()>0 && lName.length()>0){
            nextBtn.setEnabled(true);

        }else {
            nextBtn.setEnabled(false);

        }
    }

Answer 3

Oh! You did a small mistake. Use OR condition instead of AND . So your code should be

nextBtn.setEnabled(!firstNameInput.isEmpty() || !lastNameInput.isEmpty());

And TextWatcher will only notify when you will manually change the inputs of EditText . So TextWatcher will not wark at starting. So at first in onCreate method you should manually check those EditText feilds.

Edit: Android new DataBinding library is best suitable for this purpose.