App Crashes on OCR

[Yoda-Man]

Future _read() async {
List texts = [];
try {
texts = await FlutterMobileVision.read(
waitTap: true,
flash: _torchOcr,
autoFocus: _autoFocusOcr,
multiple: _multipleOcr,
showText: _showTextOcr,
preview: _previewOcr,
camera: _ocrCamera,
fps: 2.0,
);
setState(() {
currentLogItem.washOption = texts[0].value;
});
} on Exception {
texts.add(OcrText('Failed to recognize text'));
}
}
}

[Vylwyn]

same issue

[Yoda-Man]

I resolved the issue by adding the OCR activity to my AndroidManifest.xml after other activity nodes

[Yoda-Man]

<activity android:name="io.github.edufolly.fluttermobilevision.ocr.OcrCaptureActivity" />

[Vylwyn]

I already have it - however I still face the issue -
java.lang.RuntimeException: Unable to destroy activity {{packagename}/io.github.edufolly.fluttermobilevision.ocr.OcrCaptureActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.Thread$State java.lang.Thread.getState()' on a null object reference

[akulkarni9]

Yes, even I've same issue...

E/AndroidRuntime(24295): Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.Thread$State java.lang.Thread.getState()' on a null object reference
E/AndroidRuntime(24295): at io.github.edufolly.fluttermobilevision.ui.CameraSource$FrameProcessingRunnable.release(CameraSource.java:1142)
E/AndroidRuntime(24295): at io.github.edufolly.fluttermobilevision.ui.CameraSource$FrameProcessingRunnable.access$900(CameraSource.java:1119)
E/AndroidRuntime(24295): at io.github.edufolly.fluttermobilevision.ui.CameraSource.release(CameraSource.java:334)
E/AndroidRuntime(24295): at io.github.edufolly.fluttermobilevision.ui.CameraSourcePreview.release(CameraSourcePreview.java:85)
E/AndroidRuntime(24295): at io.github.edufolly.fluttermobilevision.util.AbstractCaptureActivity.onDestroy(AbstractCaptureActivity.java:124)
E/AndroidRuntime(24295): at android.app.Activity.performDestroy(Activity.java:8251)
E/AndroidRuntime(24295): at android.app.Instrumentation.callActivityOnDestroy(Instrumentation.java:1364)
E/AndroidRuntime(24295): at android.app.ActivityThread.performDestroyActivity(ActivityThread.java:5290)

This is my code:
`class OCRPage extends StatefulWidget {
@OverRide
_OCRPageState createState() => _OCRPageState();
}

class _OCRPageState extends State {
int _ocrCamera = FlutterMobileVision.CAMERA_BACK;
String _text = "TEXT";

Future _read() async {
List texts = [];
try {
texts = await FlutterMobileVision.read(
camera: _ocrCamera,
waitTap: true,
);

  setState(() {
    _text = texts[0].value;
  });
} on Exception {
  texts.add(OcrText('Failed to recognize text'));
}

}

@OverRide
Widget build(BuildContext context) {
// TODO: implement build
return SingleChildScrollView(
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: [
Lottie.asset('assets/scan-some-words.json', repeat: true),
SizedBox(height: 20),
Text(
_text,
style: GoogleFonts.orbitron(
textStyle: TextStyle(
color: Colors.white,
fontSize: 20,
fontWeight: FontWeight.w500)),
textAlign: TextAlign.center,
),
SizedBox(height: 10),
Text(
Morse(_text).encode(),
style: GoogleFonts.orbitron(
textStyle: TextStyle(
color: Colors.white,
fontSize: 20,
fontWeight: FontWeight.w500)),
textAlign: TextAlign.center,
),
SizedBox(height: 30),
ElevatedButton(
onPressed: _read,
child: new Text('Start Scanning'),
// color: Color(0xFFFF16CD),
// splashColor: Colors.orangeAccent,
),
SizedBox(height: 10),
Text(
'Tap on the text to convert into Morse Code',
style: TextStyle(color: Color(0xffE6BBFC)),
)
]));
}
}`

[Oranji-Aka]

found in a other camera thread, it fixed this issue
replace with this in CameraSource.java from the library.

this is my path but you can adjust for yours
D:\flutter.pub-cache\hosted\pub.dartlang.org\flutter_mobile_vision-0.1.4+1\android\src\main\java\io\github\edufolly\fluttermobilevision\ui

@SuppressLint("Assert")
private void release() {
assert (processingThread == null || processingThread.getState() == State.TERMINATED);
if (mDetector != null) {
mDetector.release();
mDetector = null;
}
}

[RohitLuthra19]

Same for me.

E/AndroidRuntime(21923): java.lang.RuntimeException: Unable to destroy activity {com.uhs.vehicollate2021/io.github.edufolly.fluttermobilevision.ocr.OcrCaptureActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.Thread$State java.lang.Thread.getState()' on a null object reference
E/AndroidRuntime(21923): at android.app.ActivityThread.performDestroyActivity(ActivityThread.java:4521)
E/AndroidRuntime(21923): at android.app.ActivityThread.handleDestroyActivity(ActivityThread.java:4539)
E/AndroidRuntime(21923): at android.app.servertransaction.DestroyActivityItem.execute(DestroyActivityItem.java:39)
E/AndroidRuntime(21923): at android.app.servertransaction.TransactionExecutor.executeLifecycleState(TransactionExecutor.java:145)
E/AndroidRuntime(21923): at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:70)
E/AndroidRuntime(21923): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1831)
E/AndroidRuntime(21923): at android.os.Handler.dispatchMessage(Handler.java:106)
E/AndroidRuntime(21923): at android.os.Looper.loop(Looper.java:201)
E/AndroidRuntime(21923): at android.app.ActivityThread.main(ActivityThread.java:6810)
E/AndroidRuntime(21923): at java.lang.reflect.Method.invoke(Native Method)
E/AndroidRuntime(21923): at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:547)
E/AndroidRuntime(21923): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:873)
E/AndroidRuntime(21923): Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.Thread$State java.lang.Thread.getState()' on a null object reference
E/AndroidRuntime(21923): at io.github.edufolly.fluttermobilevision.ui.CameraSource$FrameProcessingRunnable.release(CameraSource.java:1142)
E/AndroidRuntime(21923): at io.github.edufolly.fluttermobilevision.ui.CameraSource$FrameProcessingRunnable.access$900(CameraSource.java:1119)
E/AndroidRuntime(21923): at io.github.edufolly.fluttermobilevision.ui.CameraSource.release(CameraSource.java:334)
E/AndroidRuntime(21923): at io.github.edufolly.fluttermobilevision.ui.CameraSourcePreview.release(CameraSourcePreview.java:85)
E/AndroidRuntime(21923): at io.github.edufolly.fluttermobilevision.util.AbstractCaptureActivity.onDestroy(AbstractCaptureActivity.java:124)
E/AndroidRuntime(21923): at android.app.Activity.performDestroy(Activity.java:7524)
E/AndroidRuntime(21923): at android.app.Instrumentation.callActivityOnDestroy(Instrumentation.java:1307)
E/AndroidRuntime(21923): at android.app.ActivityThread.performDestroyActivity(ActivityThread.java:4506)
E/AndroidRuntime(21923): ... 11 more

[Gustavoo44]

Same issue.. Does someone fixed that or know other way to do same OCR text recognition?

Thanks

[Huntler]

I got the same issue as well. Error message:

E/AndroidRuntime( 5573): java.lang.RuntimeException: Unable to destroy activity {com.example.receipt_scanner/io.github.edufolly.fluttermobilevision.ocr.OcrCaptureActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.Thread$State java.lang.Thread.getState()' on a null object reference

Seems like a basic Nullpointer exception which causes
unable to destroy activity {com.example.receipt_scanner/io.github.edufolly.fluttermobilevision.ocr.OcrCaptureActivity}.

I think I located the cause at this position. Here, the code
processingThread.getState() causes a Nullpointer exception because processingThread is a null object. In my opinion, the processingThread was released, before this method is executed.

[rguerra712]

I have found that this bug looks to be tied to the gradle version.

When I upgrade my build.grade to classpath to version com.android.tools.build:gradle:4.1.0 or greater in conjunction to the gradle-wrapper.properties distribution to distributionUrl=https\://services.gradle.org/distributions/gradle-6.5-all.zip or greater, this is what causes this library to crash.

I have been able to fix this problem by tying my app to older versions com.android.tools.build:gradle:3.5.0 and distributionUrl=https\://services.gradle.org/distributions/gradle-5.6.2-all.zip respectively.

Although it is not ideal nor a good long-term solution, it at least is a temporary workaround I have found in case it helps anyone else.