如何在 flutter 中使用文本识别？

Question

I want to create a text ocr app and I've used flutter and firebase ml vision.

I've faced an exception when I want to read the text.

I've migrated my app to androidx and checked firebase and Gradle version.

I can build the app without any Gradle issue and the app starts as well.

but as I've mentioned above the problem starts when reading text.

You can see below my code and the error.

please help me because I tried to fix it for more than 6 hours.

My Code:

Future pickImage() async {
    File pickedImage = await ImagePicker.pickImage(
      source: ImageSource.gallery,
    );
    setState(() {
      fileImage = pickedImage;
      isImageLoaded = true;
    });
  }

  Future readText() async {
    FirebaseVisionImage ourImage = FirebaseVisionImage.fromFile(fileImage);
    TextRecognizer recognizeText = FirebaseVision.instance.textRecognizer();
    VisionText readText = await recognizeText.processImage(ourImage);

     for (TextBlock block in readText.blocks) {
      for (TextLine line in block.lines) {
        for (TextElement word in line.elements) {
          print(word.text);
        }
      }
    }
  }

The Error:

[ERROR:flutter/lib/ui/ui_dart_state.cc(148)] Unhandled Exception: PlatformException(textRecognizerError, Waiting for the text recognition model to be downloaded. Please wait., null)
E/flutter (14595): #0      StandardMethodCodec.decodeEnvelope (package:flutter/src/services/message_codecs.dart:569:7)
E/flutter (14595): #1      MethodChannel.invokeMethod (package:flutter/src/services/platform_channel.dart:316:33)
E/flutter (14595): <asynchronous suspension>
E/flutter (14595): #2      MethodChannel.invokeMapMethod (package:flutter/src/services/platform_channel.dart:344:48)
E/flutter (14595): <asynchronous suspension>
E/flutter (14595): #3      TextRecognizer.processImage (package:firebase_ml_vision/src/text_recognizer.dart:40:38)
E/flutter (14595): <asynchronous suspension>
E/flutter (14595): #4      _MyHomePageState.readText (package:text_ocr/main.dart:57:47)
E/flutter (14595): <asynchronous suspension>
E/flutter (14595): #5      _MyHomePageState.build.<anonymous closure> (package:text_ocr/main.dart:100:25)
E/flutter (14595): <asynchronous suspension>
E/flutter (14595): #6      _InkResponseState._handleTap (package:flutter/src/material/ink_well.dart:654:14)
E/flutter (14595): #7      _InkResponseState.build.<anonymous closure> (package:flutter/src/material/ink_well.dart:729:32)
E/flutter (14595): #8      GestureRecognizer.invokeCallback (package:flutter/src/gestures/recognizer.dart:182:24)
E/flutter (14595): #9      TapGestureRecognizer._checkUp (package:flutter/src/gestures/tap.dart:365:11)
E/flutter (14595): #10     TapGestureRecognizer.handlePrimaryPointer (package:flutter/src/gestures/tap.dart:275:7)
E/flutter (14595): #11     PrimaryPointerGestureRecognizer.handleEvent (package:flutter/src/gestures/recognizer.dart:455:9)
E/flutter (14595): #12     PointerRouter._dispatch (package:flutter/src/gestures/pointer_router.dart:75:13)
E/flutter (14595): #13     PointerRouter.route (package:flutter/src/gestures/pointer_router.dart:102:11)
E/flutter (14595): #14     GestureBinding.handleEvent (package:flutter/src/gestures/binding.dart:218:19)
E/flutter (14595): #15     GestureBinding.dispatchEvent (package:flutter/src/gestures/binding.dart:198:22)
E/flutter (14595): #16     GestureBinding._handlePointerEvent (package:flutter/src/gestures/binding.dart:156:7)
E/flutter (14595): #17     GestureBinding._flushPointerEventQueue (package:flutter/src/gestures/binding.dart:102:7)
E/flutter (14595): #18     GestureBinding._handlePointerDataPacket (package:flutter/src/gestures/binding.dart:86:7)
E/flutter (14595): #19     _rootRunUnary (dart:async/zone.dart:1136:13)
E/flutter (14595): #20     _CustomZone.runUnary (dart:async/zone.dart:1029:19)
E/flutter (14595): #21     _CustomZone.runUnaryGuarded (dart:async/zone.dart:931:7)
E/flutter (14595): #22     _invoke1 (dart:ui/hooks.dart:263:10)
E/flutter (14595): #23     _dispatchPointerDataPacket (dart:ui/hooks.dart:172:5)
E/flutter (14595): 

Answer 1

Add this to your android/app/AndroidManifest.xml file:

<application ...>
  ...
  <meta-data
    android:name="com.google.firebase.ml.vision.DEPENDENCIES"
    android:value="ocr" />
  <!-- To use multiple models: android:value="ocr,label,barcode,face" -->
</application>

It will download the resources you are currently missing, while the app installs.