Document scanner with ML Kit on Android
Use the ML Kit document scanner API to easily add a document scanner feature to your app.
| Feature | Details |
|---|---|
| Sdk name | play-services-mlkit-document-scanner |
| Implementation | The models, scanning logic and UI flow are dynamically downloaded by Google Play services. |
| App size impact | ~300KB download size increase. |
| Initialization time | Users might have to wait for the models, logic and UI flow to download before first use. |
Try it out
Play around with the sample app to see an example usage of this API.
Before you begin
-
In your project-level
build.gradlefile, make sure to include Google's Maven repository in both your buildscript and allprojects sections. -
Add the dependency for the ML Kit document scanner library to your module's app-level gradle file, which is usually app/build.gradle:
dependencies
{
// …
implementation
'
com
.
google
.
android
.
gms
:
play
-
services
-
mlkit
-
document
-
scanner
:
16.0.0
'
}
Document Scanner configuration
The document scanner user flow (which includes a dedicated viewfinder screen and preview screen) is provided by the SDK. The viewfinder and preview screen supports the following customizable controls:
- importing from the photo gallery
- setting a limit to the number of pages scanned
- scanner mode (to control the feature sets in the flow)
You can retrieve both PDF and JPEG files for your scanned documents.
Instantiate GmsDocumentScannerOptions
to configure the scanner options:
Kotlin
val options = GmsDocumentScannerOptions.Builder()
.setGalleryImportAllowed(false)
.setPageLimit(2)
.setResultFormats(RESULT_FORMAT_JPEG, RESULT_FORMAT_PDF)
.setScannerMode(SCANNER_MODE_FULL)
.build()
Java
GmsDocumentScannerOptions options = new GmsDocumentScannerOptions.Builder()
.setGalleryImportAllowed(false)
.setPageLimit(2)
.setResultFormats(RESULT_FORMAT_JPEG, RESULT_FORMAT_PDF)
.setScannerMode(SCANNER_MODE_FULL)
.build();
Scan documents
After creating your GmsDocumentScannerOptions
, get an
instance of GmsDocumentScanner
. You can then start the scanner activity
following Activity Result APIs
introduced in AndroidX.
When the document scanning is complete, a GmsDocumentScanningResult
object will give access to the number of pages scanned, the URIs of the
images in JPEG format and PDF accordingly to what was defined via setResultFormats
:
Kotlin
val scanner = GmsDocumentScanning . getClient ( options ) val scannerLauncher = registerForActivityResult ( StartIntentSenderForResult ()) { result - > { if ( result . resultCode == RESULT_OK ) { val result = GmsDocumentScanningResult . fromActivityResultIntent ( result . data ) result . getPages () ? . let { pages - > for ( page in pages ) { val imageUri = pages . get ( 0 ). getImageUri () } } result . getPdf () ? . let { pdf - > val pdfUri = pdf . getUri () val pageCount = pdf . getPageCount () } } } } scanner . getStartScanIntent ( activity ) . addOnSuccessListener { intentSender - > scannerLauncher . launch ( IntentSenderRequest . Builder ( intentSender ). build ()) } . addOnFailureListener { ... }
Java
GmsDocumentScanner scanner = GmsDocumentScanning . getClient ( options ); ActivityResultLauncher<IntentSenderRequest> scannerLauncher = registerForActivityResult ( new StartIntentSenderForResult (), result - > { if ( result . getResultCode () == RESULT_OK ) { GmsDocumentScanningResult result = GmsDocumentScanningResult . fromActivityResultIntent ( result . getData ()); for ( Page page : result . getPages ()) { Uri imageUri = pages . get ( 0 ). getImageUri (); } Pdf pdf = result . getPdf (); Uri pdfUri = pdf . getUri (); int pageCount = pdf . getPageCount (); } }); scanner . getStartScanIntent ( activity ) . addOnSuccessListener ( intentSender - > scannerLauncher . launch ( new IntentSenderRequest . Builder ( intentSender ). build ())) . addOnFailureListener (...);
Tips to improve performance
Consider that generating document files takes time and requires processing power, so only request the output formats (JPEG, or PDF, or both) you actually need.
