[IONIC-5]: unable to pass amount to gpay in ionic 5 using webintent

Unable to pass amount to gpay in ionic 4 using webintent.
Here is my code:

pay() {
     this.payeeVPA = '******';
    this.payeeName = '*****';
    this.payAmount = 1;
    this.transactionReference = '#123456'; 
    this.currency = 'INR';
    this.transactionNote = 'Payment for Groceries';
    const url = 'upi://pay?pa=' + this.payeeVPA + '&pn=' + this.payeeName + '&tr=' + this.transactionReference + 'tn=' + this.transactionNote + '&am=' + this.payAmount + '&cu=' + this.currency;
    const options = {
      action: this.webIntent.ACTION_VIEW,
      url
    };
    this.webIntent.startActivityForResult(options).then(success => {
      console.log(success);
      if(success.extras.Status == 'SUCCESS') {
        // SUCCESS RESPONSE
        alert(JSON.stringify(success))
      } else if(success.extras.Status == 'SUBMITTED') {
        alert(JSON.stringify(success))
        // SUBMITTED RESPONSE
      } else if(success.extras.Status == 'Failed' || success.extras.Status == 'FAILURE') {
        alert(JSON.stringify(success))
        // FAILED RESPONSE
      } else {
        alert(JSON.stringify(success))
        // FAILED RESPONSE
      }
    }, error => {
      alert(JSON.stringify(error))
      console.log(error);
    }).catch((e)=>{
      alert(JSON.stringify(e))
    });
  }

This will open gpay and ask user to enter amount.
i need to pass the amount to gpay and set amount readonly. How to achieve this?