OCRActivity.java

package hu.autsoft.androidapidemos;

import android.Manifest;
import android.annotation.SuppressLint;
import android.app.Activity;
import android.app.AlertDialog;
import android.app.Dialog;
import android.content.Context;
import android.content.DialogInterface;
import android.content.Intent;
import android.content.IntentFilter;
import android.content.pm.PackageManager;
import android.hardware.Camera;
import android.speech.tts.TextToSpeech;
import android.support.annotation.NonNull;
import android.support.v4.app.ActivityCompat;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.GestureDetector;
import android.view.MotionEvent;
import android.view.ScaleGestureDetector;
import android.view.View;
import android.widget.TextView;
import android.widget.Toast;

import com.google.android.gms.common.ConnectionResult;
import com.google.android.gms.common.GoogleApiAvailability;
import com.google.android.gms.vision.text.TextBlock;
import com.google.android.gms.vision.text.TextRecognizer;

import java.io.IOException;
import java.util.Locale;

import butterknife.BindView;
import butterknife.ButterKnife;
import hu.autsoft.androidapidemos.ocr.CameraSource;
import hu.autsoft.androidapidemos.ocr.CameraSourcePreview;
import hu.autsoft.androidapidemos.ocr.GraphicOverlay;
import hu.autsoft.androidapidemos.ocr.OcrDetectorProcessor;
import hu.autsoft.androidapidemos.ocr.OcrGraphic;

public class OCRActivity extends AppCompatActivity {

    private static final int RC_HANDLE_GMS = 9001;

    private static final String TAG = "OcrCaptureActivity";

    private static final int RC_HANDLE_CAMERA_PERM = 2;

    public static final String AutoFocus = "AutoFocus";
    public static final String UseFlash = "UseFlash";
    public static final String TextBlockObject = "String";

    private CameraSource mCameraSource;
    private CameraSourcePreview mPreview;
    private GraphicOverlay<OcrGraphic> mGraphicOverlay;

    private ScaleGestureDetector scaleGestureDetector;
    private GestureDetector gestureDetector;

    @BindView(R.id.tvOcrResult)
    TextView tvOcrResult;

    @Override
    public void onCreate(Bundle bundle) {
        super.onCreate(bundle);
        setContentView(R.layout.activity_ocr);

        ButterKnife.bind(this);

        mPreview = (CameraSourcePreview) findViewById(R.id.preview);
        mGraphicOverlay = (GraphicOverlay<OcrGraphic>) findViewById(R.id.graphicOverlay);

        boolean autoFocus = true;
        boolean useFlash = false;

        int rc = ActivityCompat.checkSelfPermission(this, Manifest.permission.CAMERA);
        if (rc == PackageManager.PERMISSION_GRANTED) {
            createCameraSource(autoFocus, useFlash);
        } else {
            requestCameraPermission();
        }

        scaleGestureDetector = new ScaleGestureDetector(this, new ScaleListener());

        Toast.makeText(this, "Tap to Speak. Pinch/Stretch to zoom",Toast.LENGTH_LONG).show();
    }

    private void requestCameraPermission() {
        Log.w(TAG, "Camera permission is not granted. Requesting permission");

        final String[] permissions = new String[]{Manifest.permission.CAMERA};

        if (!ActivityCompat.shouldShowRequestPermissionRationale(this,
                Manifest.permission.CAMERA)) {
            ActivityCompat.requestPermissions(this, permissions, RC_HANDLE_CAMERA_PERM);
            return;
        }

        final Activity thisActivity = this;

        View.OnClickListener listener = new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                ActivityCompat.requestPermissions(thisActivity, permissions,
                        RC_HANDLE_CAMERA_PERM);
            }
        };
    }

    @Override
    public boolean onTouchEvent(MotionEvent e) {
        boolean b = scaleGestureDetector.onTouchEvent(e);


        return b || super.onTouchEvent(e);
    }

    @SuppressLint("InlinedApi")
    private void createCameraSource(boolean autoFocus, boolean useFlash) {
        Context context = getApplicationContext();
        TextRecognizer textRecognizer = new TextRecognizer.Builder(context).build();
        textRecognizer.setProcessor(new OcrDetectorProcessor(mGraphicOverlay, tvOcrResult));

        if (textRecognizer.isOperational()) {
            mCameraSource =
                    new CameraSource.Builder(getApplicationContext(), textRecognizer)
                            .setFacing(CameraSource.CAMERA_FACING_BACK)
                            .setRequestedPreviewSize(1280, 1024)
                            .setRequestedFps(2.0f)
                            .setFlashMode(useFlash ? Camera.Parameters.FLASH_MODE_TORCH : null)
                            .setFocusMode(autoFocus ? Camera.Parameters.FOCUS_MODE_CONTINUOUS_PICTURE : null)
                            .build();
        }
    }


    @Override
    protected void onResume() {
        super.onResume();
        startCameraSource();
    }

    @Override
    protected void onPause() {
        super.onPause();
        if (mPreview != null) {
            mPreview.stop();
        }
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        if (mPreview != null) {
            mPreview.release();
        }
    }

    @Override
    public void onRequestPermissionsResult(int requestCode,
                                           @NonNull String[] permissions,
                                           @NonNull int[] grantResults) {
        if (requestCode != RC_HANDLE_CAMERA_PERM) {
            Log.d(TAG, "Got unexpected permission result: " + requestCode);
            super.onRequestPermissionsResult(requestCode, permissions, grantResults);
            return;
        }

        if (grantResults.length != 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
            Log.d(TAG, "Camera permission granted - initialize the camera source");
            // we have permission, so create the camerasource
            boolean autoFocus = getIntent().getBooleanExtra(AutoFocus,false);
            boolean useFlash = getIntent().getBooleanExtra(UseFlash, false);
            createCameraSource(autoFocus, useFlash);
            return;
        }

        Log.e(TAG, "Permission not granted: results len = " + grantResults.length +
                " Result code = " + (grantResults.length > 0 ? grantResults[0] : "(empty)"));

        DialogInterface.OnClickListener listener = new DialogInterface.OnClickListener() {
            public void onClick(DialogInterface dialog, int id) {
                finish();
            }
        };

        AlertDialog.Builder builder = new AlertDialog.Builder(this);
        builder.setTitle(R.string.app_name)
                .setMessage(R.string.txt_no_camera_permission)
                .setPositiveButton(R.string.btn_ok, listener)
                .show();
    }

    private void startCameraSource() throws SecurityException {
        // check that the device has play services available.
        int code = GoogleApiAvailability.getInstance().isGooglePlayServicesAvailable(
                getApplicationContext());
        if (code != ConnectionResult.SUCCESS) {
            Dialog dlg =
                    GoogleApiAvailability.getInstance().getErrorDialog(this, code, RC_HANDLE_GMS);
            dlg.show();
        }

        if (mCameraSource != null) {
            try {
                mPreview.start(mCameraSource, mGraphicOverlay);
            } catch (IOException e) {
                Log.e(TAG, "Unable to start camera source.", e);
                mCameraSource.release();
                mCameraSource = null;
            }
        }
    }

    private class ScaleListener implements ScaleGestureDetector.OnScaleGestureListener {

        @Override
        public boolean onScale(ScaleGestureDetector detector) {
            return false;
        }

        @Override
        public boolean onScaleBegin(ScaleGestureDetector detector) {
            return true;
        }

        @Override
        public void onScaleEnd(ScaleGestureDetector detector) {
            if (mCameraSource != null) {
                mCameraSource.doZoom(detector.getScaleFactor());
            }
        }
    }
}