Android UI Validator

A simple fields validator for Android that I created for checking mandatory fields.

Setup

1. Copy the code inside UIValidator.java file into a new class file inside your Android application and call it UIValidator.
2. Replace the following line with your actual package name

   package YOUR_PACKAGE_NAME_HERE;
   

3. Done

Usage Example

1. Create a global List<View> and call it fieldsToBeValidated (name doesn't matter)
2. Inside onCreate method in your Activity (onViewCreated method in Fragment):
   Initialize your fieldsToBeValidated list as you would initialize a List<>. for example:
   

fieldsToBeValidated = new ArrayList<>(Arrays.asList(
  			firstNameTextView,
  			lastNameTextView,
  			phoneNumberTextView,
  			emailTextView,
  			professionIdSpinner,
  			cityNameTextView,
  			zipCodeTextView,
  			streetTextView,
  			houseNumberTextView));

3. Use the validateViewFields method as follows

if (!UIValidator.validateViewFields(fieldsToBeValidated, true)) {
    YOUR CODE HERE...
}

Notes

1. The main method of this class is validateViewFields, but there are more methods that you can use on your own.
2. validateViewFields takes two arguments, the first is the list of the views you want to validate, and the second is a boolean that applies visuals on the fields you want to validate. in other words, the boolean indicates setting red error on fields or not.
3. The capabilities of UIValidator class are only for TextView (EditText as well) and Spinner views. it can be scaled to other view types, I just didn't need to for now.
4. Default values for the validator are " " (empty string) for TextView, and " " (empty string) or "Select..." for Spinner, you can change those as you wish.

Full Code Usage Example

1. Activity:

    public class AddContractActivity extends AppCompatActivity {
  
      TextView contractDescriptionTextView;
      TextView totalAmountTextView;
  
      List<View> fieldsToBeValidated;
  
      @Override
      protected void onCreate(Bundle savedInstanceState) {
          super.onCreate(savedInstanceState);
          setContentView(R.layout.activity_add_contract);
  
          contractDescriptionTextView = findViewById(R.id.contractDescriptionEditText);
          totalAmountTextView = findViewById(R.id.totalAmountText);
  
          fieldsToBeValidated = new ArrayList<>(Arrays.asList(
                  contractDescriptionTextView,
                  totalAmountTextView));
  
          saveButton.setOnClickListener(new View.OnClickListener() {
              @Override
              public void onClick(View v) {
                  if (!UIValidator.validateViewFields(fieldsToBeValidated, true)) {
                      Toast.makeText(AddContractActivity.this, "Missing Fields", Toast.LENGTH_SHORT).show();
                      mainScrollView.post(new Runnable() {
                          @Override
                          public void run() {
                              mainScrollView.smoothScrollTo(0, 0);
                          }
                      });
                      return;
                  }
              }
          });
      }
  }

2. Fragment:

  public class AddPersonFragment extends Fragment {

  TextView firstNameTextView;
  TextView lastNameTextView;
  TextView phoneNumberTextView;
  TextView emailTextView;
  Spinner professionIdSpinner;
  TextView cityNameTextView;
  TextView zipCodeTextView;
  TextView streetTextView;
  TextView houseNumberTextView;
  
  List<View> fieldsToBeValidated;
  
  @Override
  public void onViewCreated(@NonNull View view, @Nullable Bundle savedInstanceState) {
      super.onViewCreated(view, savedInstanceState);


      firstNameTextView = getView().findViewById(R.id.firstNameTextView);
      lastNameTextView = getView().findViewById(R.id.lastNameTextView);
      phoneNumberTextView = getView().findViewById(R.id.phoneNumberTextView);
      emailTextView = getView().findViewById(R.id.emailTextView);
      professionIdSpinner = getView().findViewById(R.id.professionIdSpinner);
      cityNameTextView = getView().findViewById(R.id.cityNameTextView);
      zipCodeTextView = getView().findViewById(R.id.zipCodeTextView);
      streetTextView = getView().findViewById(R.id.streetTextView);
      houseNumberTextView = getView().findViewById(R.id.houseNumberTextView);

      fieldsToBeValidated = new ArrayList<>(Arrays.asList(
              firstNameTextView,
              lastNameTextView,
              phoneNumberTextView,
              emailTextView,
              professionIdSpinner,
              cityNameTextView,
              zipCodeTextView,
              streetTextView,
              houseNumberTextView));
  }
  
  public Person getPersonFromFragment() {
      if (!UIValidator.validateViewFields(fieldsToBeValidated, true)) {
          return null;
      }

      Person person = new Person();

      person.firstName = firstNameTextView.getText().toString();
      person.lastName = lastNameTextView.getText().toString();
      person.contactInfo.phoneNumber = phoneNumberTextView.getText().toString();
      person.contactInfo.emailAddress = emailTextView.getText().toString();
      person.profession.name = professionIdSpinner.getSelectedItem().toString();
      person.contactInfo.address.city.name = cityNameTextView.getText().toString();
      person.contactInfo.address.zipCode = zipCodeTextView.getText().toString();
      person.contactInfo.address.street = streetTextView.getText().toString();
      person.contactInfo.address.number = houseNumberTextView.getText().toString();

      return person;
  }
}