FormValidation

Hello friends today we are learn about how to validate android form.

Create new android project and see below code.

activity_main.xml  

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:padding="5dp"
    >


    <FrameLayout
        android:id="@+id/FragContainer"
        android:layout_width="match_parent"
        android:layout_height="match_parent"></FrameLayout>



</RelativeLayout>

ActivityMain.java

public class MainActivity extends AppCompatActivity implements OnCustomclickListener{

    Stack<String> stringStack;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        stringStack=new Stack<>();
       

//      add first fragment in stack
        FragmentManager fragmentManager = getSupportFragmentManager();
        FragmentTransaction transaction = fragmentManager.beginTransaction();
        Fragment fragment = new LoginFragment();

        String tag = fragment.toString();
        stringStack.add(tag);
        transaction.add(R.id.FragContainer, fragment, tag);
        transaction.addToBackStack(tag);
        transaction.commit();

    }

    @Override
    public void OnClick(String tag)
    {
        if (tag.equalsIgnoreCase("login"))
        {
            LoginFragment loginFragment=new LoginFragment();
            beginTransction(loginFragment);
        }else if (tag.equalsIgnoreCase("registration"))
        {
            RegistratinFragment fragment=new RegistratinFragment();
            beginTransction(fragment);
        }
    }

    private void beginTransction(Fragment fragment)
    {
        Bundle args = new Bundle();
        String tag = fragment.toString();
        fragment.setArguments(args);
        FragmentTransaction transaction = getSupportFragmentManager().beginTransaction();

        Fragment currentFragment = getSupportFragmentManager().findFragmentByTag(stringStack.peek());
        transaction.hide(currentFragment);
        transaction.add(R.id.FragContainer, fragment, fragment.toString());
        // This is important, we must addToBackStack so we can pull it out later.
        transaction.addToBackStack(tag);

        stringStack.add(tag);
        transaction.commit();
    }

    @Override
    public void onBackPressed() {
        // from the stack we can get the latest fragment
        Fragment fragment = getSupportFragmentManager().findFragmentByTag(stringStack.peek());
        // If its an instance of Fragment1 I don't want to finish my activity, so I launch a Toast instead.
        if (fragment instanceof LoginFragment){
            Toast.makeText(getApplicationContext(), "YOU ARE AT THE TOP FRAGMENT",                Toast.LENGTH_SHORT).show();
        }
        else{
            // Remove the framg
            removeFragment();
            super.onBackPressed();
        }
    }

    private void removeFragment(){
        // remove the current fragment from the stack.
        stringStack.pop();
        FragmentTransaction transaction = getSupportFragmentManager().beginTransaction();
        Fragment fragment = getSupportFragmentManager().findFragmentByTag(stringStack.peek());

        transaction.show(fragment);
        transaction.commit();
    }


}

loginfragment.xml

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.samset.validationloginform.fragments.LoginFragment">
    <TextView
        android:layout_centerHorizontal="true"
        android:padding="10dp"
        android:textSize="20dp"
        android:textStyle="bold"
        android:textColor="@color/colorAccent"
        android:text="Login"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />
    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_centerInParent="true"
        android:orientation="vertical"
        android:paddingLeft="40dp"
        android:paddingRight="40dp">


        <android.support.design.widget.TextInputLayout
            android:id="@+id/text_input_email"
            android:layout_width="match_parent"
            android:layout_height="wrap_content">

            <EditText
                android:id="@+id/input_email"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:hint="@string/hint_email"
                android:inputType="textEmailAddress" />
        </android.support.design.widget.TextInputLayout>

        <android.support.design.widget.TextInputLayout
            android:id="@+id/text_input_password"
            android:layout_width="match_parent"
            android:layout_height="wrap_content">

            <EditText
                android:id="@+id/input_password"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:inputType="textPassword"
                android:hint="@string/hint_password" />
        </android.support.design.widget.TextInputLayout>
        <Button
            android:id="@+id/btn_login"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:gravity="center"
            android:layout_gravity="center_horizontal"
            android:layout_marginTop="40dp"
            android:background="@color/colorPrimary"
            android:text="@string/btn_login"
            android:textColor="@android:color/white" />
        <TextView
            android:id="@+id/dontaccount"
            android:layout_marginTop="20dp"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textStyle="bold"
            android:gravity="center"
            android:textColor="@color/colorAccent"
            android:layout_gravity="center_horizontal"
            android:text="Don't have account?"
            android:textSize="15dp" />
    </LinearLayout>



    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentBottom="true"
        android:layout_alignParentRight="true"
        android:padding="10dp"
        android:text="By samset"
        android:textSize="10dp" />
</RelativeLayout>

LoginFragment.java

public class LoginFragment extends Fragment {

    private View view;
    Button login;
    private TextView dontHave;
    private TextInputLayout ti_email,ti_password;
    private EditText et_email,et_password;

    private OnCustomclickListener listener;
    public LoginFragment() {
        // Required empty public constructor
    }


    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        view=inflater.inflate(R.layout.fragment_login, container, false);
        dontHave= (TextView) view.findViewById(R.id.dontaccount);
        ti_email= (TextInputLayout) view.findViewById(R.id.text_input_email);
        ti_password= (TextInputLayout) view.findViewById(R.id.text_input_password);

        et_email= (EditText) view.findViewById(R.id.input_email);
        et_password= (EditText) view.findViewById(R.id.input_password);

        login= (Button) view.findViewById(R.id.btn_login);

        return view;
    }

    @Override
    public void onActivityCreated(Bundle savedInstanceState) {
        super.onActivityCreated(savedInstanceState);
        et_email.addTextChangedListener(new MyTextWatcher(et_email));
        et_password.addTextChangedListener(new MyTextWatcher(et_password));

        dontHave.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
             listener.OnClick("registration");
            }
        });
        login.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Login();
            }
        });
    }

    @Override
    public void onAttach(Activity activity) {
        super.onAttach(activity);

        try {
            listener= (OnCustomclickListener) activity;
            //mOnFragment1ClickedListener = (OnFragment1ClickedListener) activity;
        } catch (ClassCastException e) {
            e.printStackTrace();
        }
    }

    private void Login() {

        if (!validateEmail()) {
            return;
        }

        if (!validatePassword()) {
            return;
        }

        Toast.makeText(getActivity(), "sucessfully login!", Toast.LENGTH_SHORT).show();
    }
    private boolean validateEmail() {
        String email = et_email.getText().toString().trim();

        if (email.isEmpty() || !isValidEmail(email)) {
            ti_email.setError(getString(R.string.err_email));
            requestFocus(et_email);
            return false;
        } else {
            ti_email.setErrorEnabled(false);
        }

        return true;
    }

    private boolean validatePassword() {
        if (et_password.getText().toString().trim().isEmpty()) {
            ti_password.setError(getString(R.string.err_password));
            requestFocus(et_password);
            return false;
        } else {
            ti_password.setErrorEnabled(false);
        }

        return true;
    }

    private static boolean isValidEmail(String email) {
        return !TextUtils.isEmpty(email) && android.util.Patterns.EMAIL_ADDRESS.matcher(email).matches();
    }

    private void requestFocus(View view) {
        if (view.requestFocus()) {
            getActivity().getWindow().setSoftInputMode(WindowManager.LayoutParams.SOFT_INPUT_STATE_ALWAYS_VISIBLE);
        }
    }
    private class MyTextWatcher implements TextWatcher {

        private View view;

        private MyTextWatcher(View view) {
            this.view = view;
        }

        public void beforeTextChanged(CharSequence charSequence, int i0, int i1, int i2) {
        }

        public void onTextChanged(CharSequence charSequence, int i0, int i1, int i2) {
        }

        public void afterTextChanged(Editable editable) {
            switch (view.getId()) {
                case R.id.input_email:
                    validateEmail();
                    break;
                case R.id.input_password:
                    validatePassword();
                    break;
            }
        }
    }
}

Thank you.

I hope this blog helps you.

Source code

https://github.com/SamsetDev/FormValidation/tree/master

Live Sample