OCRTest01 MainActivyty

MainActivity.java

package org.nunocky.ocrtest01;

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

import android.app.AlertDialog;
import android.content.DialogInterface;
import android.content.res.AssetManager;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.Bundle;
import android.os.Environment;
import android.support.v7.app.ActionBarActivity;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;

import com.googlecode.tesseract.android.TessBaseAPI;

// Ref: http://gaut.am/making-an-ocr-android-app-using-tesseract/
// Ref: http://zdenop.github.io/tesseract-doc/group___advanced_a_p_i.html#ga284228c7e9d18bbbd3984d44e252d625

public class MainActivity extends ActionBarActivity {

	private static final String TAG = MainActivity.class.getSimpleName();
	
	private static final String EXSTORAGE_PATH = String.format("%s/%s", Environment.getExternalStorageDirectory().toString(), "OCRTest01/");
	private static final String TESSDATA_PATH = String.format("%s/%s", EXSTORAGE_PATH, "tessdata/");
	private static final String TRAIN_LANG = "eng";
	private static final String TRAINEDDATA = String.format("%s.traineddata", TRAIN_LANG);
	private static final String TARGET_IMAGE = "sample.jpg";

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
		
		try {
			prepareTrainedFileIfNotExist();
		} catch (Exception e) {
			Log.e(TAG, e.toString());
			
			new AlertDialog.Builder(this)
			.setTitle("Error")
			.setMessage("Asset setup failed.")
			.setPositiveButton("Close", new DialogInterface.OnClickListener() {
				@Override
				public void onClick(DialogInterface dialog, int which) {
					finish();
				}})
			.show();
		}
	}

	/**
	 * traineddataを assetsから外部ストレージにコピーする。TessBaseAPIクラスがアセットを直接扱えないため。
	 * @throws Exception アセットから外部ストレージへのコピーに失敗
	 */
	private void prepareTrainedFileIfNotExist() throws Exception {
	  
	  // MEMO : Manifestの android.permission.WRITE_EXTERNAL_STORAGEを忘れずに
	  
		String paths[] = {EXSTORAGE_PATH, EXSTORAGE_PATH + "/tessdata"};
		for (String path : paths) {
			File dir = new File(path);
			if (!dir.exists()) {
				if (!dir.mkdirs()) {
					throw new Exception("ディレクトリ生成に失敗");
				}
			}
		}
		
		String traineddata_path = String.format("%s%s", TESSDATA_PATH, TRAINEDDATA);
		
		if ( (new File(traineddata_path).exists()))
			return;
		
		try {
			InputStream   in = getAssets().open(TRAINEDDATA);
			OutputStream out = new FileOutputStream(traineddata_path);

			byte[] buf = new byte[1024];
			int len;
			while ((len = in.read(buf)) > 0) {
				out.write(buf, 0, len);
			}
			in.close();
			out.close();
		} catch (IOException e) {
			Log.e(TAG, e.toString());
			throw new Exception("アセットのコピーに失敗");
		}
	}

	@Override
	public boolean onCreateOptionsMenu(Menu menu) {
		getMenuInflater().inflate(R.menu.main, menu);
		return true;
	}

	@Override
	public boolean onOptionsItemSelected(MenuItem item) {
		int id = item.getItemId();
		if (id == R.id.action_settings) {
			return true;
		}
		return super.onOptionsItemSelected(item);
	}
	
	@Override
	protected void onResume() {
		super.onResume();
		
		try {
			// OCRの実験本体
			// * sample.jpgをロード (ARGB_8888に変換する)
			// * OCRを行う TessBaseAPIを初期化
			//  * traineddataを設定 
			//  * 画像を指定
			//  * 文字を検出する範囲を指定
			
			AssetManager assetManager = getResources().getAssets();

		    InputStream is = assetManager.open(TARGET_IMAGE);
		    Bitmap bitmap = BitmapFactory.decodeStream(is);
		    bitmap = bitmap.copy(Bitmap.Config.ARGB_8888, true);

		    TessBaseAPI baseApi = new TessBaseAPI();
		    baseApi.init(EXSTORAGE_PATH, "eng"); 
		    baseApi.setImage(bitmap);
		    baseApi.setRectangle(56, 81, 230, 22);
		    String recognizedText = baseApi.getUTF8Text();
		    baseApi.end();
		    
		    Log.d(TAG, "Recognized: " + recognizedText);
		} catch (IOException e) {
		    /* 例外処理 */
			Log.d(TAG, e.toString());
		}
	}	
}