stripPaymentGateWay.java

 implementation 'com.stripe:stripe-android:7.0.0'
   
   
public class MainActivity extends AppCompatActivity {

    public static final String PUBLISHABLE_KEY = "pk_test_RDj9RzgYggpcUuVoLoqBKWWl";
    private Card card;
    private ProgressDialog progress;
    private Button purchase;


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

        card = new Card(
                "4242424242424242", //card number
                12, //expMonth
                2030,//expYear
                "123"//cvc
        );

        progress = new ProgressDialog(this);
        purchase = (Button) findViewById(R.id.purchase);
        purchase.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                Log.d("click", "clicked");
                buy();
            }
        });
    }

    private void buy() {
        boolean validation = card.validateCard();
        if (validation) {
            startProgress("Validating Credit Card");
            new Stripe(this).createToken(
                    card,
                    PUBLISHABLE_KEY,
                    new TokenCallback() {
                        @Override
                        public void onError(Exception error) {
                            Toast.makeText(MainActivity.this,
                                    "Stripe -" + error.toString(),
                                    Toast.LENGTH_LONG).show();
                        }

                        @Override
                        public void onSuccess(Token token) {
                            finishProgress();
                            charge(token);
                        }
                    });
        } else if (!card.validateNumber()) {
            Toast.makeText(MainActivity.this,
                    "Stripe - The card number that you entered is invalid",
                    Toast.LENGTH_LONG).show();
        } else if (!card.validateExpiryDate()) {
            Toast.makeText(MainActivity.this,
                    "Stripe - The expiration date that you entered is invalid",
                    Toast.LENGTH_LONG).show();
        } else if (!card.validateCVC()) {
            Toast.makeText(MainActivity.this,
                    "Stripe - The CVC code that you entered is invalid",
                    Toast.LENGTH_LONG).show();
        } else {
            Toast.makeText(MainActivity.this,
                    "Stripe - The card details that you entered are invalid",
                    Toast.LENGTH_LONG).show();
        }
    }

    private void charge(Token cardToken){
        HashMap<String, Object> params = new HashMap<String, Object>();
        params.put("ItemName", "test");
        params.put("cardToken", cardToken.getId());
        params.put("name","Dominic Wong");
        params.put("email","dominwong4@gmail.com");
        params.put("address","HIHI");
        params.put("zip","99999");
        params.put("city_state","CA");
        startProgress("Purchasing Item");

        Log.d("token ", cardToken.getId());
       /* ParseCloud.callFunctionInBackground("purchaseItem", params, new FunctionCallback<Object>() {
            public void done(Object response, ParseException e) {
                finishProgress();
                if (e == null) {
                    Log.d("Cloud Response", "There were no exceptions! " + response.toString());
                    Toast.makeText(getApplicationContext(),
                            "Item Purchased Successfully ",
                            Toast.LENGTH_LONG).show();
                } else {
                    Log.d("Cloud Response", "Exception: " + e);
                    Toast.makeText(getApplicationContext(),
                            e.getMessage().toString(),
                            Toast.LENGTH_LONG).show();
                }
            }
        });*/
    }

    private void finishProgress(){
        progress.dismiss();
    }


    private void startProgress(String title) {
        progress.setTitle(title);
        progress.setMessage("Please Wait");
        progress.show();
    }

}



xml layout added:
----------------
<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <LinearLayout
        android:id="@+id/activity_main"
        android:layout_width="0dp"
        android:layout_height="0dp"
        android:orientation="vertical"
        android:paddingBottom="@dimen/activity_vertical_margin"
        android:paddingLeft="@dimen/activity_horizontal_margin"
        android:paddingRight="@dimen/activity_horizontal_margin"
        android:paddingTop="@dimen/activity_vertical_margin"
        android:weightSum="1"
        tools:layout_constraintTop_creator="1"
        tools:layout_constraintRight_creator="1"
        tools:layout_constraintBottom_creator="1"
        android:layout_marginStart="9dp"
        app:layout_constraintBottom_toBottomOf="parent"
        android:layout_marginEnd="9dp"
        app:layout_constraintRight_toRightOf="parent"
        android:layout_marginTop="8dp"
        tools:layout_constraintLeft_creator="1"
        android:layout_marginBottom="8dp"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        android:layout_marginLeft="9dp"
        android:layout_marginRight="9dp">

        <Button
            android:id="@+id/purchase"
            android:layout_width="365dp"
            android:layout_height="60dp"
            android:text="Purchase Button"
            android:visibility="visible"
            android:layout_marginTop="5dp"
            android:layout_marginLeft="5dp"
            tools:layout_editor_absoluteX="11dp"
            tools:layout_editor_absoluteY="5dp" />

    </LinearLayout>


</android.support.constraint.ConstraintLayout>