Whats_app.java

 private void openWhatsAppForFeedback() {

        boolean isWhatsAppInstalled = whatsappInstalled("com.whatsapp");
        if (isWhatsAppInstalled) {
            String smsNumber = "966535550107"; //without '+'

            StringBuffer stringBuffer = new StringBuffer();
            stringBuffer.append("User ID: " + mCipherUserId);
            stringBuffer.append("User account: " + mSessionManager.getStringPreference(SessionManager.USER_EMAIL));

            try {
                Intent sendIntent = new Intent("android.intent.action.MAIN");
                sendIntent.setComponent(new ComponentName("com.whatsapp", "com.whatsapp.Conversation"));
                sendIntent.setAction(Intent.ACTION_SEND);
                sendIntent.setType("text/plain");
                sendIntent.putExtra(Intent.EXTRA_TEXT, stringBuffer.toString());
                sendIntent.putExtra("jid", smsNumber + "@s.whatsapp.net"); //phone number without "+" prefix
                sendIntent.setPackage("com.whatsapp");
                startActivity(sendIntent);
            } catch (Exception e) {
                Toast.makeText(getActivity(), "Error/n" + e.toString(), Toast.LENGTH_SHORT).show();
            }
        }
    }