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Barcode Scanner Plugin

Tested Version: 1.3.0
This plugin provides a scanning barcode feature. Detect barcode or QR Code[^1] by device's camera and returns extracted strings.

Plugin ID

@monaca/monaca-plugin-barcode-scanner

Adding the Plugin in Monaca

In order to use this plugin, please enable Barcode Scanner plugin in Monaca Cloud IDE.

Supported Platforms

Build Environments

  • Cordova 11.0.0 or later
  • Android Platform 10.1.2 or later
  • iOS Platform 6.2.0 or later

Operating Environments

  • Android 5.1 or later (9 or later recommended)
  • iOS 11 or later (13 or later recommended)

Supported Barcode Types

  • QR_CODE
  • EAN_8
  • EAN_13
  • ITF
See here for the caution of detection.
Some devices may fail to detect barcodes. See here for details.

Features

Scanning mode

  • Normal mode (since v1.0.0) The detected code is displayed on screen and selected by tapping(clicking).
  • One Shot mode (since v1.1.0) The first detected code is selected and screen closed automatically.

Detection timeout message (since v1.1.0)

A Specified message can be displayed if no code is detected for a certain period.

API Reference

monaca.BarcodeScanner.scan()

monaca.BarcodeScanner.scan(successCallback, failCallback[, options])
  • Calling scan () will transition to the scanner screen.
  • When the barcode is detected, the extracted character string is displayed below the frame.(Normal mode)
  • Tap the string to return to the original screen and the string and barcode type will be returned to successCallback.
  • In the case of One Shot mode, the first detected code is returned and screen is closed automatically.
  • When returned to the original screen without selecting the string, the detection will be cancelled. In order to return to the original screen, click the "Close" (X on the screen) button for iOS and the "Back" button for Android.

successCallback

successCallback(result)
result: following data
{
data: {
"text": "xxxxxxxx" // detected string
"format": "QR_CODE" // barcode type
},
cancelled: false // detection cancelled(true) or not(false)
}

failCallback

failCallback(error)
error: error message(string)
message
description
"permission denied"
camera permission is not granted.

options

{
"oneShot" : true,
"timeoutPrompt" : {
"show" : true,
"timeout" : 5,
"prompt" : "Not detected"
},
"debug" : {
"preview" : 0
}
}
parameter
type
default value
description
oneShot
boolean
false
Enable or disable One Shot mode.
timeoutPrompt.show
boolean
false
Show or hide detection timeout message.
timeoutPrompt.timeout
int
-
Period(in seconds) from when the barcode not detected until the message is displayed.
timeoutPrompt.prompt
string
"Barcode not detected"
Timeout message.
debug.preview (android only)
int
0
Debug Preview Mode(Android only) Displays camera preview bitmap(before sending to MLKit) on screen. 0: OFF(default) 1: Inside detection area 2: Whole camera image

Example

monaca.BarcodeScanner.scan((result) => {
if (result.cancelled) {
// scan cancelled
} else {
// scan
const detected_text = result.data.text;
const detected_format = result.data.format;
}
}, (error) => {
// permission error
const error_message = error;
}, {
"oneShot" : true,
"timeoutPrompt" : {
"show" : true,
"timeout" : 5,
"prompt" : "Not detected"
}
});

iOS Quirks

Since iOS 10, it's mandatory to provide a usage description in the info.plist. The description string is displayed in the permission dialog box.
This plugin requires the following usage descriptions:
  • NSCameraUsageDescription specifies the reason for your app to access the device's camera.
To add these entries to the info.plist, you can use the <edit-config> tag in the config.xml file like this:
<platform name="ios">
<edit-config target="NSCameraUsageDescription" file="*-Info.plist" mode="merge">
<string>need camera access to scan barcode</string>
</edit-config>
</platform>

Android Quirks

compileSDKVersion

The library androidx.camera:camera-view used internally requires compileSDKVersion>=31. So Target SDK Version of Android Application setting in Monaca Cloud IDE should be set 31 or above.

Barcode detection problem due to device model dependency

This plugin detects barcodes by processing the image captured by the camera (ImageProxy) and passing it to the barcode detection library (MLKit). ImageProxy can store images in a variety of formats, and it depends on the device what format the camera captures. Some devices may fail to detect barcodes because they are captured in a format not supported by the plugin.

Supported format

version
supported format
before ver.1.2.1
- Support JPEG or YUV_420_888 - Support only when plane buffer's rowStride is same as ImageWidth
ver.1.3.0
- Support when plane buffer's rowStride is different from ImageWidth

How to check for unsupported image formats

You can check the device compatibility by using the debug preview feature added in ver.1.3.0.
  • Enable debug preview in options
monaca.BarcodeScanner.scan((result) => {
if (result.cancelled) {
// scan cancelled
} else {
// scan
}
}, (error) => {
// permission error
const error_message = error;
}, {
"debug" : {
"preview" : 1
}
});
  • Thumbnail of the image before barcode detection are displayed on the scan screen.
If this thumbnail image is displayed distorted, it will be a device that does not support.
​
​

About detecting barcode

ITF code (since ver.1.2.0)

  • For iOS, only ITF-14 (14 digits ITF) is supported.
  • For Android, various digits ITF is supported.
    • Because ITF code standard is prone to cause missdetection, requiring the barcode to be exactly positioned within the detection area.
[^1]: QR Code is a registered trademark of DENSO WAVE INCORPORATED in Japan and in other countries.
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