$ flutter pub add flutter_bkash

dependencies:
    flutter_bkash: ^0.1.3

BkashPayment(  
    // depend isSandbox (true/false)
    isSandbox: true,
    // amount of your bkash payment
    amount: '20',
    /// intent would be (sale / authorization)
    intent: 'sale',
    // accessToken: '', /// if the user have own access token for verify payment
    // currency: 'BDT',
    /// bkash url for create payment, when you implement on you project then it be change as your production create url, [when you send it on sandbox mode, send it as empty string '' or anything]
    createBKashUrl: 'https://merchantserver.sandbox.bka.sh/api/checkout/v1.2.0-beta/payment/create',
    /// bkash url for execute payment, , when you implement on you project then it be change as your production create url, [when you send it on sandbox mode, send it as empty string '' or anything]
    executeBKashUrl: 'https://merchantserver.sandbox.bka.sh/api/checkout/v1.2.0-beta/payment/execute',
    /// for script url, when you implement on production the set it live script js (https://scripts.pay.bka.sh/versions/1.2.0-beta/checkout/bKash-checkout-pay.js)
    scriptUrl: 'https://scripts.sandbox.bka.sh/versions/1.2.0-beta/checkout/bKash-checkout-sandbox.js',
    /// the return value from the package
    /// status => 'paymentSuccess', 'paymentFailed', 'paymentError', 'paymentClose'
    /// data => return value of response
     
    paymentStatus: (status, data) {
    dev.log('return status => $status');  
    dev.log('return data => $data');

    /// when payment success  
    if (status == 'paymentSuccess') {
        if (data['transactionStatus'] == 'Completed') {
            Style.basicToast('Payment Success');  
        }
    }  
      
    /// when payment failed  
    else if (status == 'paymentFailed') {
        if (data.isEmpty) {
            Style.errorToast('Payment Failed');
        } else if (data[0]['errorMessage'].toString() != 'null'){
            Style.errorToast("Payment Failed ${data[0]['errorMessage']}");
        } else {  
            Style.errorToast("Payment Failed");
        }
    }  
      
    /// when payment on error  
    else if (status == 'paymentError') {
        Style.errorToast(jsonDecode(data['responseText'])['error']);
    }  
      
    /// when payment close on demand closed the windows  
    else if (status == 'paymentClose') {
        if (data == 'closedWindow') {
            Style.errorToast('Failed to payment, closed screen');
        } else if (data == 'scriptLoadedFailed') {
            Style.errorToast('Payment screen loading failed');
        }
    }
    /// back to screen to pop()
    Navigator.of(context).pop();
    },
)