<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
 android:layout_width="match_parent"
 android:layout_height="match_parent">

 <me.dm7.barcodescanner.zxing.ZXingScannerView
 android:id="@+id/scannerView"
 android:layout_width="match_parent"
 android:layout_height="match_parent" />

 <Button
 android:id="@+id/light"
 android:layout_width="wrap_content"
 android:layout_height="wrap_content"
 android:layout_alignParentBottom="true"
 android:layout_centerHorizontal="true"
 android:text="开/关灯" />

</RelativeLayout>

package zhangphil.mgscanner;

import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.widget.Toast;

import com.google.zxing.Result;

import me.dm7.barcodescanner.zxing.ZXingScannerView;

public class MainActivity extends Activity {
 private boolean mFlash;
 private ZXingScannerView mScannerView;

 private ZXingScannerView.ResultHandler mResultHandler = new ZXingScannerView.ResultHandler() {
 @Override
 public void handleResult(Result result) {
  mScannerView.resumeCameraPreview(mResultHandler); //重新进入扫描二维码

  Toast.makeText(getApplicationContext(), "内容=" + result.getText() + ",格式=" + result.getBarcodeFormat().toString(), Toast.LENGTH_SHORT).show();
 }
 };

 @Override
 public void onCreate(Bundle state) {
 super.onCreate(state);
 setContentView(R.layout.activity_main);

 mScannerView = (ZXingScannerView) findViewById(R.id.scannerView);
 mScannerView.setResultHandler(mResultHandler);

 findViewById(R.id.light).setOnClickListener(new View.OnClickListener() {
  @Override
  public void onClick(View view) {
  toggleFlash();
  }
 });
 }

 @Override
 public void onResume() {
 super.onResume();
 mScannerView.setResultHandler(mResultHandler);
 mScannerView.startCamera();
 }

 @Override
 public void onPause() {
 super.onPause();
 mScannerView.stopCamera();
 }

 private void toggleFlash() {
 mFlash = !mFlash;
 mScannerView.setFlash(mFlash);
 }
}

<uses-permission android:name="android.permission.CAMERA" />
<uses-permission android:name="android.permission.FLASHLIGHT" />