Whatsapp auto send message without clicking the send button on android

I've been searching the internet for quite a while now and still couldn't find a way to send a message automatically. So far what my app can does is open up the Whatsapp to a certain contact and write down the message I want to send. Here is my code :

This code is to check if Whatsapp is installed on the device

private boolean checkWA(String uri) {
        PackageManager packageManager = getPackageManager();
        boolean appInstalled;

        try {
            packageManager.getPackageInfo(uri, PackageManager.GET_ACTIVITIES);
            appInstalled = true;
        }
        catch (PackageManager.NameNotFoundException e) {
            appInstalled = false;
        }
        return  appInstalled;
    }

This code is to intent to Whatsapp (couldn't auto send message)

public void onClickWhatsApp() {

        boolean installed = checkWA("com.whatsapp");
        if (installed){
            String url = "https://api.whatsapp.com/send/?phone=6282167975500&text=" + "ADDON ERROR";
            Intent i = new Intent(Intent.ACTION_VIEW);
            i.setPackage("com.whatsapp");
            i.setData(Uri.parse(url));
            startActivity(i);
        }
        else {
            String url = "https://api.whatsapp.com/send/?phone=6282167975500&text=" + "ADDON ERROR";
            Intent i = new Intent(Intent.ACTION_VIEW);
            i.setData(Uri.parse(url));
            startActivity(i);
        }
    }

Does anyone know how to do the auto send part? Thanks.