B4J Tutorials

The next service you can use in WebApps using ABMaterial 1.20: Storage. With storage you can upload/download files with ease. Here is an example using it together with the new ABMFileInput...

 

This is the first of a two part tutorial on some big changes I'm making to ABMaterial in 1.09. It should be fully backwards compatible so no (or very, very little) changes will be needed from...

 

What is a ESP8266?

It's a small Basic programmabe microcontroller with Wifi, TCP/IP stack plus server, GPIO's and... it's unbelievable cheap. For about 3€ you get it as a bulk version which you...

 

When working with WebSocket handlers the client maintains an online connection. The connection is expected to be kept alive for as long as needed.

However there are cases where the connection can...

 

Edit: Web Apps tutorial: http://www.b4x.com/android/forum/threads/webapp-web-apps-overview.39811/

The server implementation is based on a popular and powerful Java server library...

 

B4x Object Browser supports B4J and is free.

https://www.b4x.com/android/forum/t...r-api-documentation-b4x-object-browser.25682/

 

I added a couple of new methods to the CRUD generator that allows code generation for an overview (similar to what you see in this feedback app):

' some new properties...

 

Building a headless app that I will wrap into an exe and run as a service, all is well compiling in debug mode, but when switching to release I want to compile to .jar but NOT run it. Workaround...

 

ABMTimeline is a component to present a time line of events. Using the ABMTimeLineElement you can create events, with some assets like images.

Update: Ignore this, I've found a more recent...

 

I've had some questions about inline editing of tables in ABMaterial. There is one way to do this, however it has its limitations and will only work in certain cases. It only works for 'String'...

 

I would like to share my experience with creating push-enabled android-apps for blackberry-devices. Many thanks to Erel, who supports my efforts decisively.

I have tried a lot of things to enable...

 

It's not directly related to B4J but I find it very useful for new RaspBerry owners.

Just installed my 3rd RaspBerry. The ones I have are controlled via Putty (remote) so no keyboard is needed...

 

Using a Raspberry to handle a lot of data will definetly corrupt/destroy the SD card after a while (e.g. if you use it as a webserver). SD cards are slow (in comparison to a hd or sdd). The best...

 

I use some Windows *.bat files to do backups, etc. Some things are quite difficult or crap to do (like error handling, messaging, etc.) so I decided to convert one of my scripts to a non-ui B4J...

 

This code is based on Erel's Screen Capture tutorial - https://www.b4x.com/android/forum/threads/server-screen-capture-server.37292/#content

Using the jAWTRobot lib for a simple screen...

 

This is a simple server that takes a screenshot of the current desktop screen and returns the image as the response.

For example if you call it from the device browser:

The handler...

 

This example uses one ABM page to handle all tables listed under "Configure App".
In an effort to reduce code size (and maintenance), number of pages and duplicate methods, I am...

 

I took Ilan's challenge and implemented a minimum spanning tree algorithm.

You can see the solution online: https://b4x.com:51041/mst/index.html

The algorithm used is Prim's...

 

There are many Linux based, embedded boards available. Most or all of them support Java which means that they also support B4J.

In order to start development we need to install Java JRE 7+ (JDK...

 

A new component for ABMaterial in the next version (1.08): ABMPDFViewer. It allows viewing, printing, downloading, localizing, a side view to show pages and more.

Completely materialized...