ScreenExtender/MobileDroid/ScrExtDroid/MainActivity.cs

using Android.App;
using Android.Graphics;
using Android.OS;
using Android.Views;
using Android.Widget;
using System;
using System.IO;
using System.Net.Sockets;
using System.Threading.Tasks;

namespace ScrExtDroid
{
    [Activity(Label = "ScrExtDroid", MainLauncher = true, Icon = "@drawable/icon")]
    public class MainActivity : Activity
    {
        private FlushView _view;

        private bool _isRunning;

        private string _target;

        private string ConfigFilePath
        {
            get
            {
                var dataPath = Application.FilesDir.AbsolutePath;
                if (Directory.Exists(dataPath) == false) Directory.CreateDirectory(dataPath);
                return System.IO.Path.Combine(dataPath, "sxd_config.txt");
            }
        }

        private void AskAndConnect()
        {
            EditText et = new EditText(this);

            et.Text = File.Exists(ConfigFilePath) ? File.ReadAllText(ConfigFilePath) : "192.168.233.233:61234";

            AlertDialog.Builder ad = new AlertDialog.Builder(this);
            ad.SetTitle("Connect");
            ad.SetView(et);
            ad.SetPositiveButton("OK", delegate
            {
                _target = et.Text;
                StartDisplay();
            });
            ad.SetNegativeButton("Cancel", delegate
            {
                Finish();
            });
            ad.Show();
        }

        private void StartDisplay(bool askAgainOnFail = false)
        {
            _isRunning = true;
            Task.Run(() =>
            {
                var client = new Socket(SocketType.Stream, ProtocolType.Tcp);
                try
                {
                    var parts = _target.Split(':');
                    var port = int.Parse(parts[1]);

                    RunOnUiThread(delegate
                    {
                        Toast.MakeText(this, "Connecting...", ToastLength.Short).Show();
                    });

                    var wait = client.BeginConnect(parts[0], port, null, null);

                    wait.AsyncWaitHandle.WaitOne(2000, true);  //等待2秒
                    if (!wait.IsCompleted) throw new TimeoutException("Time out");

                    RunOnUiThread(delegate
                    {
                        Toast.MakeText(this, "Connected", ToastLength.Short).Show();
                    });

                    File.WriteAllText(ConfigFilePath, _target);
                }
                catch (Exception e)
                {
                    RunOnUiThread(delegate
                    {
                        Toast.MakeText(this, "Connect fail:" + e.Message, ToastLength.Short).Show();
                    });

                    RunOnUiThread(delegate
                    {
                        if (askAgainOnFail)
                        {
                            AskAndConnect();
                        }
                        else
                        {
                            System.Threading.Thread.Sleep(1000);
                            StartDisplay(true);
                        }
                    });
                    return;
                }

                client.Send(new byte[1]);
                client.ReceiveTimeout = 1000;

                var ns = new NetworkStream(client);
                ns.ReadTimeout = 1000;

                var r = new BinaryReader(ns);

                try
                {
                    do
                    {
                        var l = r.ReadInt32();
                        if (l == 0)
                        {
                            RunOnUiThread(() => Finish());
                            break;
                        }
                        var b = r.ReadBytes(l);
                        var ms = new MemoryStream(b);
                        var bm = BitmapFactory.DecodeStream(ms);
                        RunOnUiThread(() => { _view.DrawBitmap(bm); });
                        askAgainOnFail = false;
                    } while (_isRunning);
                }
                catch (Exception e)
                {
                    RunOnUiThread(delegate
                    {
                        Toast.MakeText(this, "Lost Connection:" + e.Message, ToastLength.Short).Show();
                        if (askAgainOnFail)
                        {
                            AskAndConnect();
                        }
                        else
                        {
                            System.Threading.Thread.Sleep(1000);
                            StartDisplay(true);
                        }
                    });
                }
                client.Close();
            });
        }

        //

        protected override void OnCreate(Bundle bundle)
        {
            base.OnCreate(bundle);
            RequestWindowFeature(WindowFeatures.NoTitle);
            Window.AddFlags(WindowManagerFlags.KeepScreenOn);

            _view = new FlushView(this);
            SetContentView(_view);
        }

        protected override void OnResume()
        {
            base.OnResume();
            AskAndConnect();
        }

        protected override void OnPause()
        {
            base.OnPause();
            _isRunning = false;
        }

        private class FlushView : View
        {
            private readonly MainActivity context;
            private Bitmap _bmp;

            public FlushView(MainActivity context)
                : base(context)
            {
                this.context = context;
            }

            public void DrawBitmap(Bitmap bmp)
            {
                _bmp = bmp;
                Invalidate();
            }

            public override void Draw(Canvas canvas)
            {
                var b = _bmp;
                if (b != null)
                {
                    canvas.DrawBitmap(b, 0, 0, new Paint());
                    _bmp = null;
                    b.Dispose();
                }
            }
        }
    }
}