Android Question RequestFocus issue when using barcode scanner

Andrew King · Nov 10, 2024

I am programming an inventory taking app that has 2 edittext input fields: barcode and quantity.
I am not using the soft keyboard as I am using my own UI keyboard made of buttons for the numbers as for my needs.
After entering in the barcode and pressing enter the program should focus the quantity edittext.

Here is the Issue:
When I key in the barcode using self created keys, upon hitting my self created enter key the next code line is to request focus to the quantity edittext. This works fine this way.
However, when I scan the barcode, instead of the focus going to the quantity edittext as intended, the focus goes to a random button.

The only difference in the code is that when keying in the numbers the enter button calls a Sub to requestfocus whereas when scanning I use the EnterPressed event of the Barcode editText to call that same sub.

The barcode scanner is programmed to append a CR at the end of each scan. I have checked to make sure it is also not sending TAB.

I've seen similar posts about this issue but still don't quite understand how the IME library would solve this.

I'm unsure how to solve this issue, any feedback would be greatly appreciated.

drgottjr · Nov 22, 2024

attached is how things work for me.

hid and ime keyboards follow a different logic (as you have seen).
having more than 1 edittext is a problem. fortunately, it is not necessary.
both buttons and edittext views can receive focus. when you unset their
focusability, they do not behave in the same way. fortunately, in your
case, we can unset the buttons' focusability. that is what we do.

the barcode is scanned and decoded and output to the edittext view. after
that, there is no reason to switch focus. we simply wait for the user to tap
a quantiy button or a done button. if a quantity button is tapped, its value
appears in a label, not an edittext. a second edittext serves no purpose, since
there is no softkeyboard for input...

Erel · Nov 12, 2024

If I understood correctly, you need to use IME AddHandleActionEvent: https://www.b4x.com/android/forum/t...-keyboard-with-the-ime-library.14832/#content

This allows you to keep the focus on the current EditText.

Andrew King · Nov 15, 2024

Erel said:
If I understood correctly, you need to use IME AddHandleActionEvent: https://www.b4x.com/android/forum/t...-keyboard-with-the-ime-library.14832/#content

This allows you to keep the focus on the current EditText.

Ok so I have the IME library included. Do I use the HandleAction event? And if so how can I tell if enter was pressed?

Andrew King · Nov 15, 2024

Ok so I see the IME_HandleAction event is called when an CRLF character is sent to the edittext. Instead of using EditText_EnterPressed to request focus I use the IME_HandleAction. It still has the same result. A random button will get the focus instead of the next edit text I am requesting.

Edit: So I see that I needed to add return true. This keeps the focus on the same edit text. I want to move the focus to the next edit text.

drgottjr · Nov 18, 2024

it's relatively easy to force the focus from a given view to a specific view. i've tested with 4 edittext views. when i finish entering some text in edittext1 and press the enter/return key, i can shift the focus to, eg, edittext4 instead of edittext2, which might be the logical "next" view. this sounds like what you are trying to do. i haven't tested with my barcode scanner, but i'm optimistic. in the meantime, post a screen capture of your layout to give me an idea of what i'm looking at.

Andrew King · Nov 21, 2024

drgottjr said:
it's relatively easy to force the focus from a given view to a specific view. i've tested with 4 edittext views. when i finish entering some text in edittext1 and press the enter/return key, i can shift the focus to, eg, edittext4 instead of edittext2, which might be the logical "next" view. this sounds like what you are trying to do. i haven't tested with my barcode scanner, but i'm optimistic. in the meantime, post a screen capture of your layout to give me an idea of what i'm looking at.

It is relatively easy without a barcode scanner indeed. But with a barcode scanner things start going haywire.

I know that the barcode scanner sends a CRLF at the end of the read. This calls the enterpressed function. I don't understand what is going on that the focus gets redirected to the button even though you have code that requests focus to the edittext2 in the enterpressed function.

I've attached a screenshot of an example where there are two edittexts. The goal is to scan a barcode in one edittext and have the focus shift to the next edittext. So far I've been unable to do it using requestfocus and the IME library.

Andrew King · Nov 21, 2024

code:

#Region  Project Attributes
    #ApplicationLabel: B4A Example
    #VersionCode: 1
    #VersionName:
    'SupportedOrientations possible values: unspecified, landscape or portrait.
    #SupportedOrientations: unspecified
    #CanInstallToExternalStorage: False
#End Region

#Region  Activity Attributes
    #FullScreen: False
    #IncludeTitle: True
#End Region

Sub Process_Globals
    'These global variables will be declared once when the application starts.
    'These variables can be accessed from all modules.
    Private xui As XUI
   
End Sub

Sub Globals
    Private IME As IME
   
    'These global variables will be redeclared each time the activity is created.
    Private EditText2 As EditText
    Private EditText1 As EditText
End Sub

Sub Activity_Create(FirstTime As Boolean)
    Activity.LoadLayout("Layout")
    IME.Initialize("IME")
    IME.AddHandleActionEvent(EditText1)
End Sub

Sub Activity_Resume

End Su

Sub Activity_Pause (UserClosed As Boolean)

End Sub

Sub Button1_Click
    xui.MsgboxAsync("Hello world!", "B4X")
End Sub

Sub IME_HandleAction As Boolean
    Dim e As EditText
    e = Sender
    'the code below can be exchanged for the line in EditText1_EnterPressed comment or uncomment
    EditText1.requestfocus
    Return True 'if true this results in the focus remaining on the edittext1. If false, this results in button1 receiving focus
End Sub

Private Sub EditText1_EnterPressed
    'the code below can be exchanged for the line in IME_Handleaction comment or uncomment
    'EditText2.RequestFocus
   
End Sub

drgottjr · Nov 21, 2024

i believe it works with my netum scanner. i want to mimic your setup. will revert later

drgottjr · Nov 21, 2024

that picture is not the layout you described. that's what i want to see. i've already done what you did with a couple views (that's how i know it works). i want to understand what your layout looks like. android uses an algorithm when dealing with a grid of views. that's why you get random focus.

Andrew King · Nov 21, 2024

drgottjr said:
that picture is not the layout you described. that's what i want to see. i've already done what you did with a couple views (that's how i know it works). i want to understand what your layout looks like. android uses an algorithm when dealing with a grid of views. that's why you get random focus.

Ok attached below is the original. I just made a simple b4a project to isolate the problem. For me with the simple project it still is acting goofy. I figured if I could get the simple project to work correctly, I could get my original project to work right.

Andrew King · Nov 21, 2024

drgottjr said:
that picture is not the layout you described. that's what i want to see. i've already done what you did with a couple views (that's how i know it works). i want to understand what your layout looks like. android uses an algorithm when dealing with a grid of views. that's why you get random focus.

Can you upload the project you got to work with a couple of views? I'd like to test to see if it works for me too. Thanks.

drgottjr · Nov 21, 2024

Andrew King said:
Ok attached below is the original. I just made a simple b4a project to isolate the problem. For me with the simple project it still is acting goofy. I figured if I could get the simple project to work correctly, I could get my original project to work right.

yes, that's what i'm looking for.
the txtInputBarcode edittext is single line, yes? you have that attribute set, yes? is the forceDone attribute set?
when the scanner decodes the barcode and displays it in txtInputBarcode, the next thing that is to happen
always is txtInputQuantity receives the focus? is it an edittext also? if so, why? and why does it receive
the focus (if that's what's supposed to happen)? after the barcode has been scanned, there is no reason for any
view to receive the focus since you have no idea what the user is going to do. so exactly what is happening? and
please clarify why txtinputQuantity would be an edittext.

am i correct in assuming the screen with the edittext views and buttons is on a panel? and when you make the panel
visible, you set the focus to txtInputBarcode? does the softkeyboard pop up any any time?

Mark Stuart · Nov 21, 2024

Hi Andrew,
I see you're building a Barcode scanning app, and so I wanted to see if I can help you out with what I built a few years ago and has been in use for that long at multiple company locations.

This demo app was built from code and layouts that I used in the above app. It just covers the scanning part of the app. And so I hope that it can help in some way.
I kept this demo app as fundamental as possible for the demonstration of scanning, entering a quantity, and adding the scanned info into a CustomListView. From there you can add the data to a local database. Then later - as I did - upload that scanned data to the remote server.
In my working company app, they use connected/wired barcode readers that are setup, on the scanner, to send a CR on each scan.
This sends the FocusChanged event to the txtBarcode EditText. The code in that event does the saving work.

See the app in the attached ZIP file.

HTH,
Mark Stuart

drgottjr · Nov 22, 2024

attached is how things work for me.

hid and ime keyboards follow a different logic (as you have seen).
having more than 1 edittext is a problem. fortunately, it is not necessary.
both buttons and edittext views can receive focus. when you unset their
focusability, they do not behave in the same way. fortunately, in your
case, we can unset the buttons' focusability. that is what we do.

the barcode is scanned and decoded and output to the edittext view. after
that, there is no reason to switch focus. we simply wait for the user to tap
a quantiy button or a done button. if a quantity button is tapped, its value
appears in a label, not an edittext. a second edittext serves no purpose, since
there is no softkeyboard for input. the buttons serve that purpose, and they
don't need an edittext to display the quantity selected.

once you turn off the buttons' focusability, there is no "next" focusing -
random or algorithmic.

Andrew King · Nov 25, 2024

drgottjr said:
yes, that's what i'm looking for.
the txtInputBarcode edittext is single line, yes? you have that attribute set, yes? is the forceDone attribute set?
when the scanner decodes the barcode and displays it in txtInputBarcode, the next thing that is to happen
always is txtInputQuantity receives the focus? is it an edittext also? if so, why? and why does it receive
the focus (if that's what's supposed to happen)? after the barcode has been scanned, there is no reason for any
view to receive the focus since you have no idea what the user is going to do. so exactly what is happening? and
please clarify why txtinputQuantity would be an edittext.

am i correct in assuming the screen with the edittext views and buttons is on a panel? and when you make the panel
visible, you set the focus to txtInputBarcode? does the softkeyboard pop up any any time?

the txtInputBarcode edittext is single line, yes?
Yes
you have that attribute set, yes?
Yes
when the scanner decodes the barcode and displays it in txtInputBarcode, the next thing that is to happen
always is txtInputQuantity receives the focus?
Yes
is it an edittext also?
Yes
if so, why?
Two reasons:
Because the user may attach a peripheral numeric keypad or other input device, the software must accept that input as well
Because the user may scan another barcode when the quantity edittext is selected and the software will detect how many chars the input is. If it >= 6 chars then the software will assume it is a barcode and will default the quantity 1 and then add another entry with the next barcode scanned. The goal is to eliminate as many unnecessary steps as possible to make inventory taking as fast as possible.
after the barcode has been scanned, there is no reason for any
view to receive the focus since you have no idea what the user is going to do. so exactly what is happening? and
please clarify why txtinputQuantity would be an edittext.
See last above answer

Andrew King · Nov 25, 2024

drgottjr said:
attached is how things work for me.

hid and ime keyboards follow a different logic (as you have seen).
having more than 1 edittext is a problem. fortunately, it is not necessary.
both buttons and edittext views can receive focus. when you unset their
focusability, they do not behave in the same way. fortunately, in your
case, we can unset the buttons' focusability. that is what we do.

the barcode is scanned and decoded and output to the edittext view. after
that, there is no reason to switch focus. we simply wait for the user to tap
a quantiy button or a done button. if a quantity button is tapped, its value
appears in a label, not an edittext. a second edittext serves no purpose, since
there is no softkeyboard for input. the buttons serve that purpose, and they
don't need an edittext to display the quantity selected.

once you turn off the buttons' focusability, there is no "next" focusing -
random or algorithmic.

This is a nice example. Yes I am not using the soft keyboard. However the quantity input must be able to accept input from a peripheral device if the user chooses to. It is part of the requirements.

So the only way I can think to make it work and to fit everything onto one layout is to have an edittext for barcode and an edittext for quantity. Both can accept external input. Also another requirement is that if you scan a barcode and do not enter a quantity and scan the next barcode it will default the first barcode to quantity 1 and the next barcode it will await another quantity entry or the user may continue to scan barcodes only and repeat the process. So I figured the software would check the the edittext of the quantity for char length say if it is equal to greater than 6 it assumes that a quantity was not entered but a barcode was scanned, so it defaults the quantity to 1 and continues with that next scanned barcode. This keeps the user from having to hit enter every time they scan for a default quantity of 1. But remember the other requirement so the quantity must be an input as well. I could just use one edittext and use the IME library like Erel suggested to retain the focus on that edit text. But then my layout gets crowded because I need another label view to show what was just scanned.

It is frustrating that it is so difficult to simply move the focus from one edittext to the next specified edittext. How would one go about turning off the focusability of the buttons?

Andrew King · Nov 25, 2024

I was able to get it to function correctly by using reflection by using runmethod2 "setfocusable" to false on all buttons.

Thanks drgottjr for the solution and thank you all for helping me troubleshoot.

Dave G · Dec 2, 2024

Using HID mode with the scanner is a real pain. Using SPP mode directs the scan to a common routine using the Serial interface that you provide and then the routine can RequestFocus to the correct EditText field or throw away the scan if the app doesn't want a scan at this time. I posted an example awhile back. It also makes sure the scan is the correct symbology e.g. EAN vs UPC. This approach prevents scanning a UPC into a Quantity field.

Android Question RequestFocus issue when using barcode scanner

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