Use Fast Checkout with Your Android App

The SDK provides 2 main routes for invoking checkout:

1. Checkout with a List of Products
2. Checkout with a Cart ID

All required fields are explained below:

fastCheckoutButton.setOnClickListener {

  // Checkout with products
	fastCheckout.checkoutWithProducts { options ->
    options.products = ...
  }

  // Or, checkout with cart id
  fastCheckout.checkoutWithCartId { options ->
    options.cartId = "..."
  }
}

Checkout with a List of Products

You can instantiate the options object by passing each new Product to its .addProduct() method. Passing in couponCode is optional (the coupon code defaults to null so you can skip it if the buyer hasn't provided a coupon).

fastCheckoutButton.setOnClickListener {
	fastCheckout.checkoutWithProducts { options ->

    // use .addProduct() to start building list of products
    options.addProduct(
      Product(
        // An identifier for the product being ordered.
        id = "FAST_PLATFORM_PRODUCT_ID",

        // A unique sub-identifier for this product. These are sometimes used to denote size / color, etc.
        variantId = "FAST_PLATFORM_VARIANT_ID"

        // Configurable properties of this product (e.g. color, size, etc.)
        options = listOf(
          ProductOption(id: "color", value: "blue"),
          ProductOption(id: "size", value: "large"),
          ProductOption(...)
        ),

        // The number of this item that should be purchased.
        quantity = 1
      )
    )

    // add another product
    options.addProduct(...)

    // Optionally, add other configuration, like adding a coupon:
    options.couponCode = "10OFF"
  }
}

Product Breakdown

Each Product has a product ID (id), a variant ID (variantId), and a set of optional product configurations (or product options) that are used to describe the exact product being ordered.

Describe your products in a manner that can be processed by your backend, as this data will be structured as outlined below.

ProductOption Breakdown

A ProductOption is a configuration that further describes the product being ordered (e.g. ProductOption(id: "color", value: "blue")).

Checkout with a Cart ID

You can also start checkout by by instantiating the options object with a cartId. In this case, Fast's APIs will reach out to your store to fetch products, coupons, etc., from the cart.

fastCheckoutButton.setOnClickListener {
	fastCheckout.checkoutWithCartId { options ->
    options.cartId = "123"
  }
}

Initialize Theme

The options objects for both checkoutWithProducts and checkoutWithCartId accept an optional theme value. This is set to FastTheme.AUTO by default, which will match the system's current light/dark theme setting. You can manually set it to FastTheme.LIGHT or FastTheme.DARK if you need to override this (e.g. if your app provides a setting to override the system's current theme).