android - 必须先用 setProcessor 设置检测器处理器才能接收检测结果

Question

我正在使用 Mobile Vision API 来扫描二维码。
我在activity中有这个方法使用摄像头捕捉代码:

private void createCameraSource() {
    final BarcodeDetector barcodeDetector = new BarcodeDetector.Builder(this).build();
    if(!barcodeDetector.isOperational()){
        Toast.makeText(this,
                "No se puede utilizar el detector de códigos de barra", Toast.LENGTH_LONG).show();
        this.finish();
    }
    else {
        final CameraSource cameraSource = new CameraSource.Builder(this, barcodeDetector)
                .setAutoFocusEnabled(true)
                .setRequestedPreviewSize(1600, 1024)
                .build();
        cameraPreview.getHolder().addCallback(new SurfaceHolder.Callback() {
            @Override
            public void surfaceCreated(SurfaceHolder surfaceHolder) {
                if (ActivityCompat.checkSelfPermission(RegisterActivity.this, Manifest.permission.CAMERA) == PackageManager.PERMISSION_GRANTED) {
                    try {
                        cameraSource.start(cameraPreview.getHolder());
                    } catch (IOException e) {
                        e.printStackTrace();
                    }
                }
            }

            @Override
            public void surfaceChanged(SurfaceHolder surfaceHolder, int i, int i1, int i2) {

            }

            @Override
            public void surfaceDestroyed(SurfaceHolder surfaceHolder) {
                cameraSource.stop();
            }
        });

        barcodeDetector.setProcessor(new Detector.Processor<Barcode>() {
            @Override
            public void release() {

            }

            @Override
            public void receiveDetections(Detector.Detections<Barcode> detections) {
                final SparseArray<Barcode> barcodes = detections.getDetectedItems();
                if (!RegisterActivity.this.isProcessing() && barcodes.size() > 0) {
                    barcodeDetector.release();
                    RegisterActivity.this.setProcessing(true);
                    Intent intent = new Intent(RegisterActivity.this, ResultActivity.class);
                    intent.putExtra("code", codigo);
                    intent.putExtra("data", barcodes.valueAt(0));
                    setResult(CommonStatusCodes.SUCCESS, intent);
                    startActivity(intent);
                    RegisterActivity.this.setProcessing(false);
                    finish();
                }

            }
        });
    }
}

当检测到并读取代码时，我需要将该代码传递给其他 Activity 。这就是为什么我有这个代码:

                if (!RegisterActivity.this.isProcessing() && barcodes.size() > 0) {
                    barcodeDetector.release();
                    RegisterActivity.this.setProcessing(true);
                    Intent intent = new Intent(RegisterActivity.this, ResultActivity.class);
                    intent.putExtra("code", codigo);
                    intent.putExtra("data", barcodes.valueAt(0));
                    setResult(CommonStatusCodes.SUCCESS, intent);
                    startActivity(intent);
                    RegisterActivity.this.setProcessing(false);
                    finish();
                }

当我运行应用程序时，这个异常显示在 logcat 中:

2020-08-27 18:19:53.894 11076-11746/com.company.myapp E/CameraSource: Exception thrown from receiver.
    java.lang.IllegalStateException: Detector processor must first be set with setProcessor in order to receive detection results.
        at com.google.android.gms.vision.Detector.receiveFrame(com.google.android.gms:play-services-vision-common@@19.1.2:17)
        at com.google.android.gms.vision.CameraSource$zza.run(com.google.android.gms:play-services-vision-common@@19.1.2:47)
        at java.lang.Thread.run(Thread.java:929)
2020-08-27 18:19:53.956 11076-11746/com.company.myapp E/CameraSource: Exception thrown from receiver.
    java.lang.IllegalStateException: Detector processor must first be set with setProcessor in order to receive detection results.
        at com.google.android.gms.vision.Detector.receiveFrame(com.google.android.gms:play-services-vision-common@@19.1.2:17)
        at com.google.android.gms.vision.CameraSource$zza.run(com.google.android.gms:play-services-vision-common@@19.1.2:47)
        at java.lang.Thread.run(Thread.java:929)

该应用程序工作正常，因为新 Activity 已打开，我可以在那里接收读取的代码，但是，如果我在该 Activity 中设置断点并开始调试，调试器 session 将在几秒钟后结束，不再出现错误。
那个代码有什么问题？

Answer 1

调试有时会改变代码的行为。尤其是当您的框架与许多线程(如 android)一起工作时。
来自堆栈跟踪 at java.lang.Thread.run(Thread.java:929)我想说，在调用 setProcessor 之前，线程中的某些代码(当前未处于调试状态)想要使用解码器。
在 Java 中，只有正在调试的线程会在断点处停止，其他线程不会被触及，并且在到达断点时也不会停止。