code: package me.dm7.barcodescanner.zbar.sample;
  
  import android.os.Bundle;
  import android.os.Handler;
  import android.view.ViewGroup;
  import android.widget.Toast;
  
  import me.dm7.barcodescanner.zbar.Result;
  import me.dm7.barcodescanner.zbar.ZBarScannerView;
  
  public class SimpleScannerActivity extends BaseScannerActivity implements ZBarScannerView.ResultHandler {
      private ZBarScannerView mScannerView;
  
      @Override
      public void onCreate(Bundle state) {
          super.onCreate(state);
          setContentView(R.layout.activity_simple_scanner);
          setupToolbar();
          ViewGroup contentFrame = (ViewGroup) findViewById(R.id.content_frame);
          mScannerView = new ZBarScannerView(this);
          contentFrame.addView(mScannerView);
      }
  
      @Override
      public void onResume() {
          super.onResume();
          mScannerView.setResultHandler(this);
          mScannerView.startCamera();
      }
  
      @Override
      public void onPause() {
          super.onPause();
          mScannerView.stopCamera();
      }
  
      @Override
      public void handleResult(Result rawResult) {
          Toast.makeText(this, "Contents = " + rawResult.getContents() +
                  ", Format = " + rawResult.getBarcodeFormat().getName(), Toast.LENGTH_SHORT).show();
          // Note:
          // * Wait 2 seconds to resume the preview.
          // * On older devices continuously stopping and resuming camera preview can result in freezing the app.
          // * I don't know why this is the case but I don't have the time to figure out.
          Handler handler = new Handler();
          handler.postDelayed(new Runnable() {
              @Override
              public void run() {
                  mScannerView.resumeCameraPreview(SimpleScannerActivity.this);
              }
          }, 2000);
      }
  }
  