i know my question seems very similar to others according to a buffer-clear issue... but here is a detailed description:
I have an motorolla handheld (bar-code scanner) which is reading barcodes over an tray tool.
The code is scanned by the traytool und is casted as an keystroke like a normal press on a key on a keyboard.
so i have an app in vb which should read a barcode and after that a second and than proceed the inputs.
after reading 12 chars/numbers my textfield should set the focus to an other textfield (2. barcode) so i check onChange the length and than set the focus to the next textfield.
if there is a malicous barcode or a barcode which contains more than 12 characters/numbers the second textfield will be filled with all chars after the 12. char from textfield 1.
i have no control over the scan behaviour or the keydown event of the scanner trigger... nothing possible.
also there is no termination symbol in the input data which signals me that one block is ending here.
so how is it possible to clear the buffer of the virtual keyboard of the scanner ?!
any suggestions?
I suggest downloading the manual for your scanner to find the configuration codes. They are typically a set of special barcodes that can be scanned to set properties such as allowed symbologies. What you will want to do is set the scanner so that it appends a CRLF, Tab, or other terminator for your data. That way you can act upon the end of the barcode.
You can use TWAIN to handle the scanning thought i am not sure whether it supports Motorola. Try to download some TWAIN libraries and in-cooperate them with your project.
Related
I'm trying to implement the transfer of a one-time code from SMS to the field above the keyboard, as in the image.
But for some reason the field above the keyboard is not displayed.
Code:self.valueTextField.textContentType = UITextContentTypeOneTimeCode;
UI hierarchy:
+UIView
CustomContentView
UIImageView
UITextField - valueTextField
UITextFieldContentView
I have read these materials:soQuestion and apple docs , and I saw a warning:
If you use a custom input view for a security code input text field, iOS cannot display the necessary AutoFill UI.
... but I do not understand what is meant by custom input view.
Also I have category for UITextField. Can it affect the work?
I will be glad to any ideas, thanks!
Okay. This is what I could find out. Regarding the code, it is enough that I described above. Additional settings on the client is not required. But you need to pay attention to the text of the SMS message. As an example, I attached two messages.
In the first message, our code is defined by the system as a phone number. We can even call it if we click on it. But why do we need to call a one-time code? :)
In the second image, the code is defined as one-time, just what we need. If we click on it, the system will offer to copy it to the clipboard.
What is the difference? Unfortunately, it is not completely clear by what rule the text is parsed in SMS. But we can check your text in the following way:
If you set a property textContentType to your text field and nothing works for you, the first thing you need to check is whether the operating system determines the code correctly. To do this, simply go to the message application and check the code:
blue font color with underscore - the system did not recognize
one-time code.
black font color (as default) with a gray underscore - it's okay!
At the end, in the first case, you should check the text of the message for the contents of incorrect characters.
PS Just a couple of examples of correct and incorrect SMS:
SMS-code: 12345 £ correct
SMS-code: 12345 $ correct
SMS-code: 12345 № correct
SMS-code №1: 12345 incorrect
I got caught out by the fact "Autofill PAsswords" was turned off on the phone.
It seems that it needs to be on for this functionaility to work.
I'm dealing with a barcode scanner that acts as a keyboard emulation.
I print my barcode labels with a custom heading character (pipe) .
In my main form, I listen to the keypress event and as soon as I see the custom header character, I start receiving the scan and than do my stuffs.
This method works pretty well if my application is focused but can't do nothing if the application is minimized or unfocused.
I tried to setup a keyboard hotkey. It partialli works: my application get focused on the first character but is not fast enought to capture the subsequent characters spitted very fast from the scanner.
Any idea on how to capture this keystrokes with the application unfocused?
Obviously if the heading char id detected the subsequent characters must be suppressed until the sequence is completed with a vbcr or a timeout is reached.
Note that the scanner spits a sequence of 15 characters in less than a tenth of a second
This is how Windows works, only the active application will handle keyboard input. Thus, when your application is minimized, it will not receive or handle any keyboard input.
As Bradley Uffner commented, you need a global keyboard handler, I've used this in the past and it works quite well. Basically a system wide listener that will handle keyboard input even while minimized.
I am creating a system that when the user uses the barcode scanner, it will automatically fill into a specific field.
Example: The cursor is in the textfield4, when I click the barcode scanner, the input should be placed in textfield1.
Thanks in advance for the help.
I have downloaded the SDK but I'm having a compatibility issue. I am using symbol barcode scanner LS2208. The SDK Provided by motorola isn't working.
I tried catching the time of input when enter is pressed. 1st scan is good, after that it leaves out the 1st few characters behind.
I have a Windows Application in VB.NET. I want to know if a value is entered by a user via the keyboard, or if it is coming from a barcode reader. I want to store values that come from
the keyboard in a different database than the ones the come from the barcode reader.
Option 1:
Get a barcode-scanner that is connected to a serial-port (raw serial device read by a COM port). As most barcode-scanners emulate keyboard strokes there is no way to directly distinguish a barcode scanner input from a keyboard input (see next option) without going low-level (see last update).
One connected to a serial port (or emulated one via USB as serial-ports are not so common anymore) gives you full control on where the input comes from.
Option 2:
Count number of chars typed by time. Barcode-scanners inject a sequence (line) pretty fast compared to typing. Measuring the time used in the textbox by counting key-presses (use CR+LF as a measure point as these are sent by the scanner as well) can give you one method to distinguish if a human is typing (unless there is one typing fast as f) or the content was injected. If timed-out just reject/clear the input.
In addition the checksum of the barcode (if you use one that contains that) can be used to do an extra validation in addition to time measurement.
(you can detect pasting by overriding the ctrl + v as in the next option).
Option 3:
Combine option 2 but instead of measure in the textbox tap into the ProcessCmdKey() function (by overriding it) and measure there if textbox has focus. This way you can first buffer input, measure time and if within a set time-out value, inject the line into the textbox.
Option 4:
This might be a good option as well:
http://nicholas.piasecki.name/blog/2009/02/distinguishing-barcode-scanners-from-the-keyboard-in-winforms/
Option 5: a non-technical approach -
Usability improvements: make it visually very clear that bar-codes must be entered with a scanner and not typed. I am including as an option as it is simple and if made correct also effective (there's no right answer of what is correct unfortunately).
Approached could include f.ex. a watermark in the textbox ("Don't type, scan!" or something in that order). Give it a different color, border, size etc. to distinguish it from normal textboxes, and have a help text associated and available at all time that improves clarity.
I have a USB bar code scanner that is acting as an HID keyboard emulation device. I want a web page that, for testing purposes, pops up a JavaScript alert when a scan is done. I don't want to tie the event to any visible control such as a textbox so thus, I won't have focus on any control to capture the scan input. Can this be done? I'm using VS 2010 with .NET 4.0 and VB.NET with a Symbol USB bar code scanner. Thanks ... Bob
Different bar code scanners can output different control characters like tab and line feeds. You should read the manual for your scanner.
You should be able to pick those up with a key press event handler.