怎么在Android中利用orc实现一个文字识别功能

public class MainActivity extends AppCompatActivity implements View.OnClickListener {

private TextView mTvInfo;
private TessBaseAPI mBaseAPI;
private ProgressBar mProbar;
private String path;
private RadioGroup mRadioGroup;
private RadioButton mRbtnIdCard;
private RadioButton mRbtnBankNumber;
private RadioButton mRbtnTxt;

@Override
protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_main);
  findViewById(R.id.btn_start).setOnClickListener(this);
  mProbar = (ProgressBar) findViewById(R.id.pb);
  mTvInfo = (TextView) findViewById(R.id.tv_info);
  mRadioGroup = (RadioGroup) findViewById(R.id.rg);
  mRbtnIdCard = (RadioButton) findViewById(R.id.rb_idCard);
  mRbtnBankNumber = (RadioButton) findViewById(R.id.rb_bankNumber);
  mRbtnTxt = (RadioButton) findViewById(R.id.rb_txt);
  mRadioGroup.check(0);

  path = Environment.getExternalStorageDirectory().getAbsoluteFile().getAbsolutePath();
}

@Override
public void onClick(View v) {
  mTvInfo.setText("");
  switch (v.getId()) {
    case R.id.btn_start:
      if (Build.VERSION.SDK_INT >= 23) {
        if (ActivityCompat.checkSelfPermission(this, Manifest.permission.WRITE_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED) {
          // 没有权限
          if(ActivityCompat.shouldShowRequestPermissionRationale(this, Manifest.permission.CALL_PHONE)){
            //如果没勾选“不再询问”，向用户发起权限请求
            ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.CALL_PHONE}, 0);
          }else{
            Toast.makeText(this,"请前往设置——>存储卡权限——>允许",Toast.LENGTH_SHORT).show();
          }
        } else {
          // 有权限,接着你要干的活
          startReadText();
        }
      }else{
        startReadText();
      }
      break;
  }
}


private Handler mHandler = new Handler() {
  @Override
  public void handleMessage(Message msg) {
    switch (msg.what) {
      case 0:
        String s = (String) msg.obj;
        if (!TextUtils.isEmpty(s)) {
          mProbar.setVisibility(View.GONE);
          mTvInfo.setText(s);
          //释放bitmap
          mBaseAPI.clear();
        } else {
          mProbar.setVisibility(View.GONE);
          Toast.makeText(MainActivity.this, "识别图片内容失败", Toast.LENGTH_SHORT).show();
        }

        break;
      case 1:
        Toast.makeText(MainActivity.this, "读取图片失败", Toast.LENGTH_SHORT).show();
        break;
    }
  }
};

private Bitmap getBitmap(int id) {
  Bitmap bitmap = null;
  try {
    bitmap = BitmapFactory.decodeResource(getResources(), id);
  } catch (Exception e) {
    return null;
  }
  return bitmap;
}

/**
 * 开始识别文字
 */
private void startReadText() {

  File f = new File(path+"/tessdata") ;
  if(!f.exists()){
    Toast.makeText(this,"请先下载好语言包置于sd/tessdata目录",Toast.LENGTH_SHORT).show();
    return;
  }

  final int btnId = mRadioGroup.getCheckedRadioButtonId();
  final int resId ;
  if(R.id.rb_idCard==btnId){
    resId = R.drawable.idcard;
  }else if(R.id.rb_bankNumber==btnId){
    resId = R.drawable.bank_number;
  }else{
    resId = R.drawable.tet_info;
  }

  mProbar.setVisibility(View.VISIBLE);
  new Thread() {
    @Override
    public void run() {
      mBaseAPI = new TessBaseAPI();//初始化需要耗时，可以启动时程序时，预初始化
      mBaseAPI.init(path + File.separator, "chi_sim");
      Bitmap bitmap = getBitmap(resId);
      if (bitmap == null) {
        mHandler.sendEmptyMessage(1);
      } else {
        mBaseAPI.setImage(bitmap);
        //根据Init的语言，获得ocr后的字符串
        String t = mBaseAPI.getUTF8Text();//耗时操作
        Message obtain = Message.obtain();
        obtain.what = 0;
        obtain.obj = t;
        mHandler.sendMessage(obtain);
      }
    }
  }.start();
}
}