ChapaKt (Unofficial)

Simple api wrapper and utilities for chapa payment gateway. I know this is a hacky or not a really good solution but that's all what we got now until chapa releases an official Android-Sdk or just a rest api for everybody to use.

Api Reference

So, let's get started. The official chapa documentation states before carrying out the transaction, a user must provide required information such as full name, email address, the amount to transfer, etc. Below you will find a list of parameter needed:

Parameter	Type	Description
key	string	**
Required**. This will be your public key from Chapa. When on test mode use the test key, and when on live mode use the live key.
email	string	Required. A customer’s email. address.
amount	string	Required. The amount you will be charging your customer.
first_name	string	Required. A customer’s first name.
last_name	string	Required. Acustomer's last name.
tx_ref	string	Required. A unique reference given to each transaction.
currency	string	**
Required**. The currency in which all the charges are made. i.e ETB, USD
callback_url	string	The URL to redirect the customer to after payment is done.
customization[title]	string	The customizations field (optional) allows you to customize the look and feel of the payment modal.

note:- Since we are using redirections to check if a payment is finished return_url is a must in this library. because with out it we don't have any way of checking the current url.

Heads Up!

We use kotlin coroutines in the project and example to handle all the requests and as such so I would recommend you to read kotlin-croutines from the docs if you don't know them already. as for java developers I didn't provide any thing because I think its been a while since I have done Android development in java.

Also, I do not consider my self as an expert in kotlin so if you find anything that can be Improved please open an issue, pullrequest or just contact me. any amount of help is appreciated.

The api

In need of another solution? checkout chapa-dart or chapa-java

Installation

First add jitpack to your project

allprojects {
    repositories {
        maven { url 'https://jitpack.io' }
    }
}

Add the dependency

dependencies {
    implementation 'com.github.YohannesTz:ChapaKt:1.0.0'
}

Usage/Example

first we need to initialize the sdk by giving it your secretKey

  private val secretKey = "you-chapa-secrete-key"
  private lateinit var chapaSdk: Chapa

and then inside OnCreate method

  chapaSdk = Chapa(secretKey)

then we will create a chapa post data with the required variables

  val postData = ChapaPostData(
    55.0,
    "ETB",
    "abebe@bikila.com",
    "Abebe",
    "Bikila",
    UUID.randomUUID().toString(),
    "https://checkout.chapa.co/checkout/payment-receipt",
    "ChapaKt", //optional
    "Chapa kotlin example", //optional
    "SomeLogo" //optional
  )

After initializing the post data when we want to trigger the payment (let's say with button click) what we have to do it fist initialize a payment object using the chapa class then after you can launch the ChapaActivity. The activity expects you to pass *return_url, checkout_url , tx_ref, secretKey on the intent as an extra.

please don't pass the bare elements to ChapaActivity because you could have two or more apps using simultaneously and add your package name just to be safe

  payButton.setOnClickListener {
    CoroutineScope(Dispatchers.IO).launch {
        val initResult = async {
            chapaSdk.initialize(postData)
        }
        val chapaPayment = initResult.await()
        if (chapaPayment != null && chapaPayment.status == "success") {
            val resultIntent = Intent(applicationContext, ChapaActivity::class.java)
            resultIntent.putExtra(
                packageName + ChapaConstants.TRANSACTION_EXTRA_RETURN_URL,
                postData.returnUrl
            )
            resultIntent.putExtra(
                packageName + ChapaConstants.TRANSACTION_EXTRA_CHECKOUT_URL,
                chapaPayment.data.checkoutUrl
            )
            resultIntent.putExtra(
                packageName + ChapaConstants.TRANSACTION_EXTRA_TX_REF,
                postData.txRef
            )
            resultIntent.putExtra(
                "secreteKey",
                secretKey
            )
            paymentActivityLauncher.launch(resultIntent)
        }
    }
  }

after that you have to launch your activity but you need to get the result from it. so traditionally, this could be achived by startActivityForResult but since that api is deprecated long ago we will be using the activity lanucher. after the Activity returned the payment response is attached with the result intent. you can get the response object by doing getStringExtra( packageName + ChapaConstants.TRANSACTION_EXTRA_TX_REF) after checking the results you can update your ui based on the response.

  private var paymentActivityLauncher =
    registerForActivityResult(ActivityResultContracts.StartActivityForResult()) { result ->
        if (result.resultCode == Activity.RESULT_OK) {
            CoroutineScope(Dispatchers.IO).launch {
                val txRef =
                    result.data!!.getStringExtra(packageName + ChapaConstants.TRANSACTION_EXTRA_TX_REF)
                if (txRef != null) {
                    val trRes: ChapaResponse? = withContext(Dispatchers.Default) {
                        chapaSdk.verifyPayment(txRef)
                    }
                    if (trRes != null && trRes.status == "success") { // payment successfull, update ui here
                        this@MainActivity.runOnUiThread {
                            statusTextView.text = "Paid!"
                        }
                    }
                } else {
                    this@MainActivity.runOnUiThread {
                        statusTextView.text = "Payment failed!"
                    }
                }
            }
        }
    }

todo

• Better handling of background tasks
• Translations