I created a simple application using the tesseract library:
File manifest:
<?xml version="1.0" encoding="utf-8"?> <manifest xmlns:android="http://schemas.android.com/apk/res/android" package="com.example.skolos.sum"> <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/> <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" /> <uses-permission android:name="android.permission.CAMERA" /> <uses-feature android:name="android.hardware.camera" android:required="true" /> <application android:allowBackup="true" android:icon="@mipmap/ic_launcher" android:label="@string/app_name" android:supportsRtl="true" android:theme="@style/AppTheme"> <activity android:name=".MainActivity"> <intent-filter> <action android:name="android.intent.action.MAIN" /> <category android:name="android.intent.category.LAUNCHER" /> </intent-filter> </activity> </application> </manifest> Main Activity Code:
import android.content.Context; import android.content.Intent; import android.os.Environment; import android.provider.MediaStore; import android.support.v7.app.AppCompatActivity; import android.os.Bundle; import android.view.View; import android.widget.EditText; import android.widget.ImageView; import com.googlecode.tesseract.android.TessBaseAPI; import android.app.AlertDialog; import android.content.DialogInterface; import android.content.res.AssetManager; import android.graphics.Bitmap; import android.graphics.BitmapFactory; import android.util.Log; import android.widget.TextView; import java.io.File; import java.io.FileNotFoundException; import java.io.FileOutputStream; import java.io.IOException; import java.io.InputStream; import java.io.OutputStream; public class MainActivity extends AppCompatActivity { private ImageView imageView; private TessBaseAPI mTess; Bitmap imageBitmap; Bitmap image; String datapath = ""; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); imageView = (ImageView) findViewById(R.id.imageView); Context context = MainActivity.this; //init image image = BitmapFactory.decodeResource(getResources(), R.drawable.test_image); //initialize Tesseract API String language = "eng"; datapath = context.getFilesDir()+ "/tesseract/"; mTess = new TessBaseAPI(); checkFile(new File(datapath + "tessdata/")); mTess.init(datapath, language); } public boolean init(String datapath, String language) { if (datapath == null) { throw new IllegalArgumentException("Data path must not be null!"); } if (!datapath.endsWith(File.separator)) { datapath += File.separator; } File tessdata = new File(datapath + "tessdata"); if (!tessdata.exists() || !tessdata.isDirectory()) { throw new IllegalArgumentException("Data path must contain subfolder tessdata!"); } return init(datapath, language); } static final int REQUEST_IMAGE_CAPTURE = 1; public void getImage(View view) { Intent takePictureIntent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE); if (takePictureIntent.resolveActivity(getPackageManager()) != null) { startActivityForResult(takePictureIntent, REQUEST_IMAGE_CAPTURE); } } @Override protected void onActivityResult(int requestCode, int resultCode, Intent data) { if (requestCode == REQUEST_IMAGE_CAPTURE && resultCode == RESULT_OK) { Bundle extras = data.getExtras(); Bitmap imageBitmap = (Bitmap) extras.get("data"); imageView.setImageBitmap(imageBitmap); String OCRresult = null; mTess.setImage(imageBitmap); OCRresult = mTess.getUTF8Text(); EditText OCRTextView = (EditText) findViewById(R.id.OCRTextView); OCRTextView.setText(OCRresult); } } private void checkFile(File dir) { if (!dir.exists() && dir.mkdirs()) { copyFiles(); } if (dir.exists()) { String datafilepath = datapath + "/tessdata/eng.traineddata"; File datafile = new File(datafilepath); if (!datafile.exists()) { copyFiles(); } } } private void copyFiles() { try { String filepath = datapath + "/tessdata/eng.traineddata"; AssetManager assetManager = getAssets(); InputStream instream = assetManager.open("tessdata/eng.traineddata"); OutputStream outstream = new FileOutputStream(filepath); byte[] buffer = new byte[1024]; int read; while ((read = instream.read(buffer)) != -1) { outstream.write(buffer, 0, read); } outstream.flush(); outstream.close(); instream.close(); File file = new File(filepath); if (!file.exists()) { throw new FileNotFoundException(); } } catch (FileNotFoundException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } } } The code works in an emulator with API 24:
Does not work with API 22 and below:
I have an assumption that the cant can be in this piece of code in the main activity:
//initialize Tesseract API String language = "eng"; datapath = context.getFilesDir()+ "/tesseract/"; mTess = new TessBaseAPI(); checkFile(new File(datapath + "tessdata/")); mTess.init(datapath, language); Obviously, it crashes on initialization, apparently, the library cannot open the language file at datapath. Attention, experts! Question: What could be the difference in different versions of Android and how to make it work in older versions of the firmware?
