Android Tutorial B4A-Bridge a new way to connect to your device

There are several options to develop with B4A:
- Android emulator or a VM.
- Connect to a real device in USB debugging mode
- Connect to a real device with B4A-Bridge.

I recommend starting with B4A-Bridge, which is the simplest connection method.

USB Debug Mode

You will need to first configure your device to support USB debugging (Settings - Developer - USB debugging).

In order to reveal the developer settings you should follow these instructions:
- Choose Settings - About Phone
- Find the Build Number entry and click on it 7 times.
- On many devices you need to set the USB connection type to MTP or PTP.

Not all devices support USB debugging.

B4A-Bridge

B4A-Bridge is made of two components. One component runs on the device and allows the second component which is part of the IDE to connect and communicate with the device.
The connection is done over the local network or with a Bluetooth connection.

Once connected, B4A-Bridge supports all of the IDE features which include: installing applications, viewing the logs, debugging and the visual designer (taking screenshots is not supported).

Android doesn't allow applications to quietly install other applications, therefore when you run your application using B4A-Bridge you will see a dialog asking you to approve the installation.

Getting started with B4A-Bridge
1. First you need to install B4A-Bridge on your device.
B4A-Bridge can be downloaded from Google Play: https://play.google.com/store/apps/details?id=anywheresoftware.b4a.b4abridge

Note that you need to allow installation of applications from "Unknown sources". This is done by choosing Settings from the Home screen - Manage Applications.


2. Run B4A-Bridge on your device. It will display a screen similar to:

3. Connect the IDE to the device

Go to Tools -> B4A-Bridge -> Connection -> New IP

You will be asked to enter the device IP address. The IP is displayed on the device.

The status bar at the bottom of the screen shows the current status:

That's it.

When B4A-Bridge gets connected it first checks if the designer application needs to be updated. In that case it will first install the designer application.

B4A-Bridge keeps running as a service until you press on the Stop button.
You can always reach it by opening the notifications screen.


As mentioned above, when you run an application you are required to approve the installation. You will usually see the following screens:

Note that the Internet permission is automatically added in debug mode.

In the above dialog you should choose Open to start the application.
If you try to install an existing application signed with a different key, the install will fail (without any meaningful message). You should first uninstall the existing application. Go to the home screen - Settings - Applications - Manage applications - choose the application - Uninstall.

Once you finished developing you should press on the Stop button in order to save battery.

Logs

With B4A-Bridge the logs will only appear in release mode if you add this line to the main module:

#BridgeLogger: True

It is better to comment this line before submitting your app to Google Play.


B4A-Bridge source code is available here: http://www.b4x.com/forum/basic4andr...ls/8153-b4a-bridge-source-code.html#post45854

Tip

You can click on the B4A-Bridge status in the IDE to connect or disconnect the bridge.

 

[Erel]

It writes the temporary APK file to File.DirDefaultExternal.

 

[Charlie]

The stack trace says there's a FileNot Found Exception looking for /mnt/sdcard/Android/data/anywheresoftware.b4a.b4abridge/files/temp2.apk

I'm sure my external SD card mounts as /mnt/extsd/.. Is it possible that file.DirDefaultExternal points to /mnt/extsd/.., but something tries to write directly to /mnt/sdcard/..? There is no /Android/Data under /extsd/, and the version under /sdcard/ does not contain a /anywheresoftware.b4a.b4abridge/ sub directory.

 

[Erel]

There are several "external storages". B4A-Bridge always writes to File.DirDefaultExternal, which is probably pointing to /mnt/sdcard/...

 

[Charlie]

Did some poking... I opened a terminal window, then started SU access.

Attempts to create anything under /mnt/sdcard returns an error - read only file system. I can create anything I like under /mnt/extsd.

 

[Erel]

Which device are you using? Note that B4A-Bridge checks for a writable storage when it starts with File.ExternalWritable.

 

[Charlie]

The device is a low end "no-name" from China. From its "about tablet" page:

Model number is TWD_MID
Android 4.04
Kernel 3.0.8+
It's Intel Atom based.

I know it's not mainstream, but with a price tag about $50 US including shipping, I suspect there are going to be a lot of them in developer hands before too long.

It ships with 802.11G, webcam, gravity sensor, HD-video capability, 800x480 screen and root access is enabled. The only things missing is Bluetooth, and I'm also having trouble finding a proper set of USB drivers. And of course B4A

I'd say about 85% of apps tried to date work well.

 

[Erel]

The source code of B4A-Bridge is available. You can modify it and set the path to the second external storage.

B4A-Bridge source code

 

[Charlie]

That's an excellent idea! If that is truly the only issue, I'll create a version that is configurable and make it available. I'll let you know how it goes.

 

[Charlie]

Just a quick update... I made the changes. I still get the failure, but there are no Android logs now to help chase it. I got busied out on another project, and have had to park this for a couple weeks, so I have not figured out why. Stay tuned, and any suggestions are most welcome.

 

[Gaver Powers]

B4ABridge needs external storage to load the apk to before installation. On modern high end devices this is built in. Low end and older devices often need an SD card to provide this. Storage Options | Android Developers

How can I check my Samsung Tab to determine if I need to purchase an SD card to enable b4aBridge, or if it will support the application in it's current configuration?

 

[Erel]

You do not need to purchase an SD card. Samsung Tab (like almost all devices) includes an internal storage that is treated as an external storage.

 

[vecino]

Hello, with B4A Bridge can connect via wireless or bluetooth, to choose from, however, is there a way to connect via LAN?

Thanks and regards.

 

[Erel]

Yes. You should choose Connect Wireless and enter the device ethernet IP address. It will be different than the value that appears in the app. You can find it in the device settings.

 

[vecino]

Hello, how do I do?, Is that when I choose the wireless connection shows the message "connecting to wifi" and stay there.

Thanks and regards.

 

[Erel]

How is the device connected to the computer?

 

[vecino]

It is connected via a standard RJ45.
The device is a POS system that consists of a android tablet and ticket printer.

 

[Erel]

Try to ping the device LAN ip address from the computer. If it is reachable then it should work.

 

[vecino]

Hello, the tablet has fixed IP device.
I can ping from windows to the tablet.
I do not know how to connect, because B4A not connect.

Thanks and regards.

 

[vecino]

Hello, I have gotten it to work.

Thanks and regards

 

[Torby]

I use it. It's quite handy, but what's with all the buzzing?