Gregory's Blog

Kendo Responsive Panel

While working on the mobile site, I had a few challenges with the Kendo responsive panel that I solved with the blog today, and wanted to make a post about it as I could not find any other solution on the web. I ran into someone posting the same scrolling question as I was looking to solve on stack overflow, but could not find anything else on the web.

The responsive panel is used to provide a slide-out menu on mobile devices when you click on what is commonly known as a 'hamburger. The panel is used in responsive web design and is triggered when the device reaches a certain minimum screen width. Here is the code that I developed for this blog:

view plain about
1<nav id="sidebarPanel" class="k-content">
2    <!---Suppply the sideBarType argument before loading the side bar--->
3    <cfset sideBarType = "panel">
4    <cfinclude template="includes/layers/sidebar.cfm">
5</nav><!---<nav id="sidebar">--->
6            
7<!--- This script must be placed underneath the layer that is being used in order to effectively work as a flyout menu.--->
8Javascript
9    $("#sidebarPanel").kendoResponsivePanel({
10        breakpoint: 1280,
11        orientation: "left",
12        autoClose: true
13        })
14        .on("click", "a", function(e) {
15            $("#sidebarPanel").kendoResponsivePanel("close");
16    });

There were several challenges that I ran into when developing this.

First, I tried to use the same div element that I use on the right side of the page to hold the various widgets, such as the calendar, subscribe, recent posts, etc. However, I noticed that if I tried to use the same div for the responsive menu, I could no longer apply certain css properties to the panel, and it was stuck at the top of the page.

To solve this, I used a different div at the end of the application to serve as the responsive panel, duplicated the logic from the right column, and put it into the new panel at the end of the page. I also created a script to show the new responsive panel when the screen size hit the breakpoint setting (1280 pixels), and hid the original div that is on the right column. Here is the relevant portions of the code:

view plain about
1// Handle the sidebar and the sideBarPanels
2    if (windowWidth <= 1280){
3        // Hide the sidepanel (the responsive panel will takeover here).
4        $( "#sidebar" ).hide();
5        // Show the responsive panel
6        $( "#sidebarPanel" ).show();
7    } else {
8        // Show the sidebar, and hide the responsive panel
9        $( "#sidebar" ).show();
10        $( "#sidebarPanel" ).hide();
11    }

Second, the hamburger showed up, but it closed as soon as I tried to open it. I found the following solution while searching the web:

view plain about
1// Important note: this is a workaround with a google chrome bug and mobile devices.
2// This prevents the following error: "Intervention] Unable to preventDefault inside passive event listener due to target being treated as passive."
3// See https://github.com/telerik/kendo-ui-core/issues/3556
4$(".k-rpanel-toggle").on("touchend", function(e) {
5     e.preventDefault();
6});

Third, I ran into problems where to put the resonsivePanel initiation script. I found out that it must be at underneath the actual element that it will be placed into.

It now works, however, there is a big problem. I could not scroll down the responsive panel when it was triggered. It just stayed in a fixed position and only showed the top part of the page. I looked everywhere in the Kendo site, and then on the internet, looking for some arcane argument that I could use, such as scrollable: true, but couldn't find any. I then looked at the similar jQuery UI menu, and inspected Telerik's production page which has a responsive panel and found that they both used the css declaration: position: absolute;

view plain about
1position: absolute;

Fourth. Ok, that fixed that problem, but now the div layer disappeared at the bottom of the page. I tried setting height to 100%, but that failed too. So I looked at both jQuery and Kendo's panels again, and noticed that they also used: height: auto;

view plain about
1height: auto;
Also, use the autoclose argument to be false on the responsive panel widget, otherwise you won't be able to able to keep the layer open when scrolling past the bottom of the first page. That worked! The panel can be scrolled now.

The final working code is pasted below:

CSS:

view plain about
1/* The side bar panel is essentially a duplicate of the sidebar div, however, it is a responsive panel used when the screen size gets small. */
2#sidebarPanel {
3/* We are going to eliminate this sidebar for larger devices, and activate it when the screen size gets to a certain size. */
4display: none;
5/* Note: the panel will not scroll with the blog content unless there is a css position: absolute. */
6position: absolute;
7margin: 0;
8/* Apply more padding to the right to keep things uniform. */
9padding: 20px 40px 20px 20px;
10width: 45%;
11/* Note: if you don't set 'height: auto', the panel will not be displayed below the bottom of the page. */
12height: auto;
13vertical-align: top;
14overflow: visible;
15border-right: thin;
16        
17/* Put a drop shadow on the panel when it is expanded. */
18#sidebarPanel.k-rpanel-expanded {
19 box-shadow: 0 0 10px rgba(0,0,0,.3);
20 }
CFML:
view plain about
1<!---This is the sidebar responsive navigation panel that is triggered when the screen gets to a certain size. It is a duplicated of the sidebar div above, however, I can't properly style the sidebar the way that I want to within the blog content, so it is duplicated without the styles here.--->
2                        
3<!--- Side bar is to the right of the main panel container. It is also used as a responsive panel below when the screen size is small. --->
4<nav id="sidebarPanel" class="k-content">
5<!---Suppply the sideBarType argument before loading the side bar--->
6<cfset sideBarType = "panel">
7<cfinclude template="includes/layers/sidebar.cfm">
8</nav><!---<nav id="sidebar">--->
Javascript:
view plain about
1<!--- This script must be placed underneath the layer that is being used in order to effectively work as a flyout menu.--->
2    $("#sidebarPanel").kendoResponsivePanel({
3        breakpoint: 1280,
4        orientation: "left",
5        autoClose: false // set this to false if you want the layer to stay up when you want to sroll down.
6        })
7        .on("click", "a", function(e) {
8            $("#sidebarPanel").kendoResponsivePanel("close");
9    });
10
11// Important note: this is a workaround with a google chrome bug and mobile devices.
12// This prevents the following error: "Intervention] Unable to preventDefault inside passive event listener due to target being treated as passive."
13// See https://github.com/telerik/kendo-ui-core/issues/3556
14    $(".k-rpanel-toggle").on("touchend", function(e) {
15        e.preventDefault();
16    });

Comments

This entry was posted on February 9, 2019 at 10:38 PM and has received 230 views.

Needed to develop a new proxy function

Raymond's approach was typical in the mid 2000's. He posted a form to a .cfm page, and the server processed server side logic as well as performing client side operations, like setting form values on the client. However, Ajax is a different beast. Most of our Kendo HTML5 interfaces do not post to another HTML page. Instead, the UI elements, such as the Kendo window, posts limited data to a function that has to perform all of the logic without refreshing the client page. However, for several reasons, the blog.cfc component does not have all of the information that I need to do this successfully.

First, we can't get session vars in the main blog.cfc. Raymond (and et-al) had another application.cfm in the org/cambden/blog folder that prevented this component from having access to the session variables set on the /blogCfc/application.cfm template. Cfc's should have access to the session scope unless it finds another application.cfm (or cfc) template, and here, this is the case.

This poses some problems with ajax. I do not want to have to hard code authentication variables, like the isAdmin, in a javascript ajax post. This is quite insecure.

I tried in vain to get the blog.cfc component to work for my purposes. After finding and eliminating the 'other' application.cfm template which caused problems accessing the session scope, I was able to obtain session variables, but the elimination of the application.cfm template in the same directory caused new problems. One example is that the isUserInRole function is now erroring out with an 'You have attempted to dereference a scalar variable of type class java.lang.String as a structure with members.'. This new error was raised throughout the blog.cfc template.

Another issue is that I suspect that the /blogCfc/org/delmore/coldfishconfig.xml file is not working when the application.cfm template is disabled. This file most likely deals with the cfauthentication tag.

In order to have the session scope, and in order to potentially cache the code after an ajax operation, I had to develop a new template to act as a proxy. I am not using a .cfc component for ajax post operations as I need the session variables and need to perform client side operations, such as setting form values, and caching the output of the page.

Goals: The proxy template will use Raymond's blog.cfc to perform all database operations. Whenever possible, I will perform server side business logic using Raymonds Blog.cfc.

Comments

This entry was posted on November 9, 2018 at 10:42 PM and has received 206 views.

Introductory purpose

I am hoping to redesign Raymond Camden's BlogCfc, a blog based upon ColdFusion first introduced by Raymond, around 2003. This particular blog engine was last updated in late 2012. My purpose is to use a popular ColdFusion related blog and to convert the UI into a Telerik Kendo UI. Suffice it to say- this blog is for geeks. That said, I'll still write this with the intention of making it comfortable for the non-web developer to follow along (just in case there is a lightning bolt chance that one such non-tech will want to follow along!).

I have been using ColdFusion since 1998? It was version 2.5 I believe... I started off using ColdFusion's built in UI, and quickly became disappointed. It was fine for beginners, but problematic when using it for enterprise web applications. The ColdFusion UI was brittle, you could not expand the functionality, and you had to purchase a new version of ColdFusion in order to update it- if you could at all. The overall consensus among serious developers was to use something other than ColdFusion's built in UI.

I personally settled on using Telerik's Kendo library with jQuery. I found this UI to be powerful, and beautiful. One of the problems with current front end design is that the method in which to beautify the page requires very long and complex style sheets. Often, the style sheets are almost as complex as the server side code. I wanted to use a library that was powerful, looked really good, but did not require a lot of fuss in the UI.

Kendo offers me dozens of predefined themes that I can use for generic enterprise class web applications, and allows the front end to look really good with minimal fuss. Kendo also offers rich HTML5 web widgets, such as a beautiful grid that supports editing data sets with millions of rows. It also forces the developer to use modern HTML5 code. Kendo is not without issues though. As we will see, it is complex, and getting it to work can be tedious at times. I hope to annotate some of the challenges using Kendo, but it is in my opinion, one of the most powerful and elegant UI libraries around.

In regards to ColdFusion, another major issue with Kendo is that It is also completely absent among ColdFusion developers. I can't find any body of information to go to when things go astray. Telerik does not offer any ColdFusion wrappers, and Telerik only markets and supports its product for .Net, PHP, and JSP. If at all possible, I hope that this blog can be a resource to ColdFusion developers to use Kendo, even if exploratively.

I have admired the original author of the code base that powers this blog, and use his own blog examples of ColdFusion and code for my own professional use. Raymond Camden is a legend in the ColdFusion community. His posts on the internet have literally saved my professional bacon many times. I am happy to try to re-engineer one of his own older applications to fulfill this purpose. I'm going to make decisions with his original open source code, and hope to thoroughly rewrite it. And ironically, I will likely use his new blogging layout at https://www.raymondcamden.com/ as an example how to best re-design his older original code.

Comments

This entry was posted on October 30, 2018 at 12:13 AM and has received 166 views.




Footer Logo

Your input and contributions are welcomed!

If you have an idea, BlogCfc based code, or a theme that you have built using this site that you want to share, please contribute by making a post here or share it by contacting us! This community can only thrive if we continue to work together.

Images and Photography:

Gregory Alexander either owns the copyright, or has the rights to use, all images and photographs on the site. If an image is not part of the "Galaxie Blog" open sourced distribution package, and instead is part of a personal blog post or a comment, please contact us and the author of the post or comment to obtain permission if you would like to use a personal image or photograph found on this site.

Credits:

Portions of Galaxie Blog are powered on the server side by BlogCfc, an open source blog developed by Raymond Camden. Revitalizing BlogCfc was a part of my orginal inspiration that prompted me to design this site. Some of the major open source contributers to BlogCfc include:

  1. Peter Farrell: the author of 'Lyla Captcha' that is used on this blog.
  2. Pete Freitag: the author of the 'ColdFish' code formatter that is also used on this blog.

Version:

Galaxie Blog Version 1.45 October 9 2019














































xmlKeywords:descMetaTag getXmlKeywordValue(articles.body, 'facebookImageUrlMetaData'):