Xamarin.Android-用ZXing实现二维码扫描以及连续扫描

public class MainFragment : Android.Support.V4.App.Fragment
    {
        MobileBarcodeScanner scanner;

        public override View OnCreateView(LayoutInflater inflater, ViewGroup p1, Bundle p2)
        {
            return inflater.Inflate(Resource.Layout.Main, null);
        }

        public override void OnViewCreated(View view, Bundle savedInstanceState)
        {
            base.OnViewCreated(view, savedInstanceState);

            scanner = new MobileBarcodeScanner(this.Activity);

            this.View.FindViewById(Resource.Id.btnDefault).Click += btnDefault_Click;
            this.View.FindViewById(Resource.Id.btnCustom).Click += btnCustom_Click;
        }

        async void btnDefault_Click(object sender, EventArgs e)
        {
            //不使用自定义界面
            scanner.UseCustomOverlay = false;

            //设置上下提示文字
            scanner.TopText = "上面的文字";
            scanner.BottomText = "下面的文字";

            var result = await scanner.Scan();

            HandleScanResult(result);
        }

        async void btnCustom_Click(object sender, EventArgs e)
        {
            View zxingOverlay;
            //使用自定义界面（可以给框内加个动画什么的，这个自由发挥）
            scanner.UseCustomOverlay = true;
            zxingOverlay = LayoutInflater.FromContext(this.Activity).Inflate(Resource.Layout.ZxingOverlay, null);
            scanner.CustomOverlay = zxingOverlay;

            var result = await scanner.Scan();

            HandleScanResult(result);
        }

        void HandleScanResult(ZXing.Result result)
        {
            string msg = "";

            if (result != null && !string.IsNullOrEmpty(result.Text))
                msg = "扫描结果: " + result.Text;
            else
                msg = "扫描取消!";

            this.Activity.RunOnUiThread(() => 
                {
                    Toast.MakeText(this.Activity, msg, ToastLength.Short).Show();
                });
        }
    }

public class ScannerFragment : Android.Support.V4.App.Fragment
    {
        ZXingScannerFragment scanFragment;
        View zxingOverlay;

        public override View OnCreateView(LayoutInflater inflater, ViewGroup p1, Bundle p2)
        {
            return inflater.Inflate(Resource.Layout.Scanner, null);
        }

        public override void OnViewCreated(View view, Bundle savedInstanceState)
        {
            base.OnViewCreated(view, savedInstanceState);

            zxingOverlay = LayoutInflater.FromContext(this.Activity).Inflate(Resource.Layout.ZxingOverlay, null);

            scanFragment = new ZXingScannerFragment(ScanResultCallback);
            scanFragment.UseCustomView = true;
            scanFragment.CustomOverlayView = zxingOverlay;

            this.Activity.SupportFragmentManager.BeginTransaction()
                .Replace(Resource.Id.fragment_container, scanFragment)
                .Commit();
        }

        private void ScanResultCallback(ZXing.Result result)
        {
            if (result == null || string.IsNullOrEmpty(result.Text))
            {
                this.Activity.RunOnUiThread(() =>
                {
                    Toast.MakeText(this.Activity, "扫描已取消！", ToastLength.Short).Show();
                    ((HomeFragment)this.FragmentManager.Fragments[0]).SetCurrentTab("Main");
                });
                return;
            }
            else
            {
                //扫描成功
                this.Activity.RunOnUiThread(() =>
                {
                    //震动
                    Vibrator vibrator = (Vibrator)Application.Context.GetSystemService(Context.VibratorService);
                    long[] pattern = { 0, 350, 220, 350 };
                    vibrator.Vibrate(pattern, -1);

                    Console.WriteLine(result.Text);

                    Toast.MakeText(this.Activity, result.Text, ToastLength.Short).Show();
                    ((HomeFragment)this.FragmentManager.Fragments[0]).SetCurrentTab("Main");
                });
                return;
            }
        }
    }