whatsapp.kt

fun whatsApp() {

        val smsNumber = "923224522526"
        val isWhatsappInstalled = whatsappInstalledOrNot("com.whatsapp")
        if (isWhatsappInstalled) {

            val sendIntent = Intent("android.intent.action.MAIN")
            sendIntent.component = ComponentName("com.whatsapp", "com.whatsapp.Conversation")
            sendIntent.putExtra("jid", PhoneNumberUtils.stripSeparators(smsNumber) + "@s.whatsapp.net")//phone number without "+" prefix
            sendIntent.putExtra(Intent.EXTRA_TEXT, "dummy text from app");

            startActivity(sendIntent)
        } else {
            val uri = Uri.parse("market://details?id=com.whatsapp")
            val goToMarket = Intent(Intent.ACTION_VIEW, uri)
            Toast.makeText(this, "WhatsApp not Installed",
                    Toast.LENGTH_SHORT).show()
            startActivity(goToMarket)
        }
    }

    private fun whatsappInstalledOrNot(uri: String): Boolean {
        val pm = packageManager
        var app_installed = false
        try {
            pm.getPackageInfo(uri, PackageManager.GET_ACTIVITIES)
            app_installed = true
        } catch (e: PackageManager.NameNotFoundException) {
            app_installed = false
        }

        return app_installed
    }



 val i = Intent(Intent.ACTION_SENDTO, Uri.parse("content://com.android.contacts/data/923224522526"))
            i.type = "text/plain"
            i.`package` = "com.whatsapp"           // so that only Whatsapp reacts and not the chooser
            i.putExtra(Intent.EXTRA_SUBJECT, "Subject")
            i.putExtra(Intent.EXTRA_TEXT, "I'm the body.")
            startActivity(i)