[安卓] 9、线程、VIEW、消息实现从TCP服务器获取数据动态加载显示

一、前言：

一般情况下从TCP服务器读取数据是放在一个线程里读的，但是刷新界面又不得不放在线程外面，所以需要用消息传递把线程里从TCP里获得的数据传送出来，然后根据数据对页面进行相应的刷新。

二、业务逻辑：

 

这里包含2个layout,第一个用于登陆的（即输入服务器对应的IP和端口号），点击确定进行跳转到相应的监控界面，监控界面包括加热、关闭、和显示温度3个按钮，以及一个用于绘制温度的SurfaceView。

三、详细介绍：

3-1、2个activity介绍：

登陆页面对应的activity,从上面的代码可以看出：29~31行使用intent进行页面跳转,然后所有逻辑均在ControlActivity里实现了。

 public class MainActivity extends ActionBarActivity
 {
     private final String TAG = "MainActivity";
     private EditText et01;
     private EditText et02;
     private Button btOK;
     private Button btCancel;
     public static String userIP = "192.168.1.130";            //IP和端口号
     public static int userPort = 8000;
     public static int wen_du;            //当前温度
     public static int shui_wei;            //当前水位
     public static int state;            //当前状态0关闭；1烧水；2保温
     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.activity_main);
         et01 = (EditText)findViewById(R.id.et_01);
         et02 = (EditText)findViewById(R.id.et_02);
         btOK = (Button)findViewById(R.id.bt_OK);
         btCancel = (Button)findViewById(R.id.bt_Cancel);

         btOK.setOnClickListener(new OnClickListener(){
             public void onClick(View v)
             {
                 //userIP = et01.getText().toString();
                 //userPort = Integer.parseInt(et02.getText().toString());
                 //跳到控制界面
                 Intent intent = new Intent(MainActivity.this,ControlActivity.class);
                 Log.i(TAG, "跳转前");
                 startActivity(intent);
             }
         });
         btCancel.setOnClickListener(new OnClickListener(){
             public void onClick(View v)
             {
                 et01.setText("");
                 et02.setText("");
             }
         });

     }

     @Override
     public boolean onCreateOptionsMenu(Menu menu) {
         // Inflate the menu; this adds items to the action bar if it is present.
         getMenuInflater().inflate(R.menu.main, menu);
         return true;
     }

     @Override
     public boolean onOptionsItemSelected(MenuItem item) {
         // Handle action bar item clicks here. The action bar will
         // automatically handle clicks on the Home/Up button, so long
         // as you specify a parent activity in AndroidManifest.xml.
         int id = item.getItemId();
         if (id == R.id.action_settings) {
             return true;
         }
         return super.onOptionsItemSelected(item);
     }
 }

另一个activity的框架如下图：主要的有①、②、③三个函数，另外三个是Callback附带要实现的。其主要逻辑为：在onCreate中实例化按钮和surfaceView，然后对按钮进行事件绑定；每当按钮事件触发，则启动线程和TCP服务器进行通信；线程将处理的结果通过msg传给Handler,Handler根据相应消息来更新页面。

 public class ControlActivity extends Activity implements Callback {

     private final String TAG = "ControlActivity";
     private final String mAddress = MainActivity.userIP;
     private final int mPort = MainActivity.userPort;
     private Socket socket = null;
     private Button btHeat,btShut,btUpdata;
     private SurfaceView mSurface; //绘图区
     private SurfaceHolder mHolder;
     //消息句柄(线程里无法进行界面更新，所以要把消息从线程里发送出来在消息句柄里进行处理)
     public Handler myHandler = new Handler() {
         @Override
         public void handleMessage(Message msg)
         {
             Bundle bundle = msg.getData();
             String now = bundle.getString("msg");
             //SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");//设置日期格式
             if (msg.what == 0x01)
             {
                 toast_show("饮水机开始加热!");
             }
             else if (msg.what == 0x02)
             {
                 toast_show("饮水机关闭!");
             }
             else if (msg.what == 0x03)
             {
                 toast_show("饮水机实时状态更新!"+"  "+MainActivity.wen_du+"  "+MainActivity.shui_wei);
                 draw(MainActivity.wen_du);
             }
             else
             {
                 toast_show("出现错误!");
             }
         }
         //toast显示用
         private void toast_show(String msg) {
             Toast toast = Toast.makeText(getApplicationContext(),
                      msg, Toast.LENGTH_LONG);
             toast.setGravity(Gravity.CENTER, 0, 0);
             toast.show();
         }
         //画图像
         private void draw(int wen_du) {
             int y = 260 - wen_du * 2;
             Canvas canvas = mHolder.lockCanvas();
             Paint mPaint = new Paint();
             mPaint.setColor(Color.WHITE);
             canvas.drawRect(40, 50, 60, 280, mPaint);
             Paint paintCircle = new Paint();
             paintCircle.setColor(Color.RED);
             Paint paintLine = new Paint();
             paintLine.setColor(Color.BLUE);
             canvas.drawRect(40, y, 60, 280, paintCircle);
             canvas.drawCircle(50, 300, 25, paintCircle);
             int ydegree = 260;
             int tem = 0;//刻度0~100
             while (ydegree > 55) {
                 canvas.drawLine(60, ydegree, 67, ydegree, mPaint);
                 if (ydegree % 20 == 0) {
                     canvas.drawLine(60, ydegree, 72, ydegree, paintLine);
                     canvas.drawText(tem + "", 70, ydegree + 4, mPaint);
                     tem+=10;
                 }
                 ydegree = ydegree - 2;
             }
             mHolder.unlockCanvasAndPost(canvas);// 更新屏幕显示内容
         }
     };

     protected void onCreate(Bundle savedInstanceState)
     {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.control_activity);
         btHeat = (Button)findViewById(R.id.bt_heat);
         btShut = (Button)findViewById(R.id.bt_shut);
         btUpdata = (Button)findViewById(R.id.bt_updata);
         mSurface = (SurfaceView) findViewById(R.id.surface);
         mHolder = mSurface.getHolder();
         mHolder.addCallback(this);  

         btHeat.setOnClickListener(new OnClickListener() {
             @Override
             public void onClick(View v)
             {
                 String orderMsg="Heat";
                 //启动线程 向服务器发送和接收信息
                 Log.i(TAG, "Start thread");
                 new MyThread(orderMsg).start();
             }
         });

         btHeat.setOnClickListener(new OnClickListener() {
             @Override
             public void onClick(View v)
             {
                 String orderMsg="Heat";
                 //启动线程 向服务器发送和接收信息
                 Log.i(TAG, "Start thread");
                 new MyThread(orderMsg).start();
             }
         });

         btShut.setOnClickListener(new OnClickListener() {
             @Override
             public void onClick(View v)
             {
                 String orderMsg="Shut";
                 //启动线程 向服务器发送和接收信息
                 Log.i(TAG, "Start thread");
                 new MyThread(orderMsg).start();
             }
         });

         btUpdata.setOnClickListener(new OnClickListener() {
             @Override
             public void onClick(View v)
             {
                 String orderMsg="Updata";
                 //启动线程 向服务器发送和接收信息
                 Log.i(TAG, "Start thread");
                 new MyThread(orderMsg).start();
             }
         });
     }

     class MyThread extends Thread
     {
         String orderMsg;
         MyThread(String str)
         {
             orderMsg=str;
         }
         @SuppressLint("SimpleDateFormat")
         public void run()
         {
             OutputStream out = null;
             InputStream in = null;
             DataInputStream DataIn = null;//数据传输输入输出流
             DataOutputStream DataOut = null;
             byte data_of_get_server = 0;//从服务器返回的数据
             Message msg = new Message();//消息
             Bundle bundle = new Bundle();
             bundle.clear();
             try
             {
                 socket = new Socket();
                 socket.connect(new InetSocketAddress(mAddress, mPort), 8000);

                 //输入输出流实例化
                 out=socket.getOutputStream();
                 in=socket.getInputStream();
                 DataIn = new DataInputStream(in);
                 DataOut=new DataOutputStream(out);

                 //读取服务器的返回数据
                 //服务器采用单byte数据进行发送
                 /*
                 TCP客户端:输入命令从服务器获得数据
                 PS：服务器只接受1个char,返回也是一个char,上述数据均为16进制
                 */
                 if(orderMsg.equals("Heat"))//加热命令
                 {
                     msg.what = 0x01;//消息类别
                     DataOut.writeByte('0');
                     Log.i(TAG, "flush 前");
                     out.flush();
                     Log.i(TAG, "flush 后");
                     data_of_get_server=DataIn.readByte();
                     Log.i(TAG, "读取数据后");
                 }
                 else if(orderMsg.equals("Shut"))
                 {
                     msg.what = 0x02;//消息类别
                     DataOut.writeByte('0');//停止加热
                     out.flush();
                     data_of_get_server=DataIn.readByte();
                 }
                 else if(orderMsg.equals("Updata"))
                 {
                     msg.what = 0x03;//消息类别
                     DataOut.writeByte('w');//刷新温度信息
                     out.flush();
                     data_of_get_server=DataIn.readByte();
                     MainActivity.wen_du=data_of_get_server;

                     DataOut.writeByte('s');//刷新深度信息
                     out.flush();
                     data_of_get_server=DataIn.readByte();
                     MainActivity.shui_wei=data_of_get_server;
                 }
                 //将消息发送给UI刷新消息句柄处
                 bundle.putByte("msg",data_of_get_server);
                 msg.setData(bundle);
                 myHandler.sendMessage(msg);
             }
             catch(Exception e){
                 e.printStackTrace();
                 //Intent intent = new Intent(ControlActivity.this,MainActivity.class);
                 //Log.i(TAG, "跳转前");
                 //startActivity(intent);
                 //将消息发送给UI刷新消息句柄处
                 msg.what = 0x04;//消息类别
                 bundle.putByte("msg",data_of_get_server);
                 msg.setData(bundle);
                 myHandler.sendMessage(msg);
             }finally{
                 try{
                     if(in!=null)in.close();Log.i(TAG, "读取数据后1");
                     if(out!=null)out.close();Log.i(TAG, "读取数据后2");
                     if(DataOut!=null)DataOut.close();Log.i(TAG, "读取数据后3");
                     if(DataIn!=null)DataIn.close();Log.i(TAG, "读取数据后4");
                     if(socket!=null)socket.close();Log.i(TAG, "读取数据后5");
                 }catch(Exception e){}
             }
         }
     }

     @Override
     public void surfaceCreated(SurfaceHolder holder) {
         // TODO Auto-generated method stub

     }

     @Override
     public void surfaceChanged(SurfaceHolder holder, int format, int width,
             int height) {
         // TODO Auto-generated method stub

     }

     @Override
     public void surfaceDestroyed(SurfaceHolder holder) {
         // TODO Auto-generated method stub

     }
 }

全部代码：

3-2、消息传递详细介绍：

如下，第9-10行要加入回调函数；12-21、23-32、34-43以及45-54分别是几个按钮的点击监听函数，其中对于不同的情况，通过设置orderMsg进行区别，然后启动相应的线程和服务器通信。

 protected void onCreate(Bundle savedInstanceState)
 {
     super.onCreate(savedInstanceState);
     setContentView(R.layout.control_activity);
     btHeat = (Button)findViewById(R.id.bt_heat);
     btShut = (Button)findViewById(R.id.bt_shut);
     btUpdata = (Button)findViewById(R.id.bt_updata);
     mSurface = (SurfaceView) findViewById(R.id.surface);
     mHolder = mSurface.getHolder();
     mHolder.addCallback(this);  

     btHeat.setOnClickListener(new OnClickListener() {
         @Override
         public void onClick(View v)
         {
             String orderMsg="Heat";
             //启动线程 向服务器发送和接收信息
             Log.i(TAG, "Start thread");
             new MyThread(orderMsg).start();
         }
     });

     btHeat.setOnClickListener(new OnClickListener() {
         @Override
         public void onClick(View v)
         {
             String orderMsg="Heat";
             //启动线程 向服务器发送和接收信息
             Log.i(TAG, "Start thread");
             new MyThread(orderMsg).start();
         }
     });

     btShut.setOnClickListener(new OnClickListener() {
         @Override
         public void onClick(View v)
         {
             String orderMsg="Shut";
             //启动线程 向服务器发送和接收信息
             Log.i(TAG, "Start thread");
             new MyThread(orderMsg).start();
         }
     });

     btUpdata.setOnClickListener(new OnClickListener() {
         @Override
         public void onClick(View v)
         {
             String orderMsg="Updata";
             //启动线程 向服务器发送和接收信息
             Log.i(TAG, "Start thread");
             new MyThread(orderMsg).start();
         }
     });
 }

从上面知道，我们必须有一个MyThread的类：构造函数就是把上面说的用于区分命令的orderMsg赋值给MyThread成员变量，然后在run函数中：11-14行来定义用于和TCP服务器通信的输入输出流；第15行的变量是记录从服务器返回的数据（这里服务器每次只返回一个byte类，这个取决于通信协议的约定！）；第16-18行实例化的msg、bundle用于传送消息，对应的第77-80行，想要发送消息要：①首先设置消息类别（这里出错消息类别为0x04:msg.what = 0x04;加热为0x01;停止加热为0x02等）②然后用bundle将信息合成bundle.putByte("msg",data_of_get_server);其中第一个string为key,第二个为value ③然后将msg的信息设置为handle,即：msg.setData(bundle); ④最后用myHandler将消息发出：myHandler.sendMessage(msg);

 class MyThread extends Thread
 {
     String orderMsg;
     MyThread(String str)
     {
         orderMsg=str;
     }
     @SuppressLint("SimpleDateFormat")
     public void run()
     {
         OutputStream out = null;
         InputStream in = null;
         DataInputStream DataIn = null;//数据传输输入输出流
         DataOutputStream DataOut = null;
         byte data_of_get_server = 0;//从服务器返回的数据
         Message msg = new Message();//消息
         Bundle bundle = new Bundle();
         bundle.clear();
         try
         {
             socket = new Socket();
             socket.connect(new InetSocketAddress(mAddress, mPort), 8000);

             //输入输出流实例化
             out=socket.getOutputStream();
             in=socket.getInputStream();
             DataIn = new DataInputStream(in);
             DataOut=new DataOutputStream(out);

             //读取服务器的返回数据
             //服务器采用单byte数据进行发送
             /*
             TCP客户端:输入命令从服务器获得数据
             PS：服务器只接受1个char,返回也是一个char,上述数据均为16进制
             */
             if(orderMsg.equals("Heat"))//加热命令
             {
                 msg.what = 0x01;//消息类别
                 DataOut.writeByte('0');
                 Log.i(TAG, "flush 前");
                 out.flush();
                 Log.i(TAG, "flush 后");
                 data_of_get_server=DataIn.readByte();
                 Log.i(TAG, "读取数据后");
             }
             else if(orderMsg.equals("Shut"))
             {
                 msg.what = 0x02;//消息类别
                 DataOut.writeByte('0');//停止加热
                 out.flush();
                 data_of_get_server=DataIn.readByte();
             }
             else if(orderMsg.equals("Updata"))
             {
                 msg.what = 0x03;//消息类别
                 DataOut.writeByte('w');//刷新温度信息
                 out.flush();
                 data_of_get_server=DataIn.readByte();
                 MainActivity.wen_du=data_of_get_server;

                 DataOut.writeByte('s');//刷新深度信息
                 out.flush();
                 data_of_get_server=DataIn.readByte();
                 MainActivity.shui_wei=data_of_get_server;
             }
             //将消息发送给UI刷新消息句柄处
             bundle.putByte("msg",data_of_get_server);
             msg.setData(bundle);
             myHandler.sendMessage(msg);
         }
         catch(Exception e){
             e.printStackTrace();
             //Intent intent = new Intent(ControlActivity.this,MainActivity.class);
             //Log.i(TAG, "跳转前");
             //startActivity(intent);
             //将消息发送给UI刷新消息句柄处
             msg.what = 0x04;//消息类别
             bundle.putByte("msg",data_of_get_server);
             msg.setData(bundle);
             myHandler.sendMessage(msg);
         }finally{
             try{
                 if(in!=null)in.close();Log.i(TAG, "读取数据后1");
                 if(out!=null)out.close();Log.i(TAG, "读取数据后2");
                 if(DataOut!=null)DataOut.close();Log.i(TAG, "读取数据后3");
                 if(DataIn!=null)DataIn.close();Log.i(TAG, "读取数据后4");
                 if(socket!=null)socket.close();Log.i(TAG, "读取数据后5");
             }catch(Exception e){}
         }
     }
 }

接下来就是myHandler了：第6-7行是取消息的过程，其和放消息有种逆过程的感觉，首先用bundle取出消息：Bundle bundle = msg.getData(); 然后通过String now = bundle.getString("msg");获得键值为“msg”的value,然后分类处理即可。其中toast_show是自己封装的用于显示toast消息的函数，draw是用来绘制那个温度计的函数。

 //消息句柄(线程里无法进行界面更新，所以要把消息从线程里发送出来在消息句柄里进行处理)
 public Handler myHandler = new Handler() {
     @Override
     public void handleMessage(Message msg)
     {
         Bundle bundle = msg.getData();
         String now = bundle.getString("msg");
         //SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");//设置日期格式
         if (msg.what == 0x01)
         {
             toast_show("饮水机开始加热!");
         }
         else if (msg.what == 0x02)
         {
             toast_show("饮水机关闭!");
         }
         else if (msg.what == 0x03)
         {
             toast_show("饮水机实时状态更新!"+"  "+MainActivity.wen_du+"  "+MainActivity.shui_wei);
             draw(MainActivity.wen_du);
         }
         else
         {
             toast_show("出现错误!");
         }
     }
     //toast显示用
     private void toast_show(String msg) {
         Toast toast = Toast.makeText(getApplicationContext(),
                  msg, Toast.LENGTH_LONG);
         toast.setGravity(Gravity.CENTER, 0, 0);
         toast.show();
     }
     //画图像
     private void draw(int wen_du) {
         int y = 260 - wen_du * 2;
         Canvas canvas = mHolder.lockCanvas();
         Paint mPaint = new Paint();
         mPaint.setColor(Color.WHITE);
         canvas.drawRect(40, 50, 60, 280, mPaint);
         Paint paintCircle = new Paint();
         paintCircle.setColor(Color.RED);
         Paint paintLine = new Paint();
         paintLine.setColor(Color.BLUE);
         canvas.drawRect(40, y, 60, 280, paintCircle);
         canvas.drawCircle(50, 300, 25, paintCircle);
         int ydegree = 260;
         int tem = 0;//刻度0~100
         while (ydegree > 55) {
             canvas.drawLine(60, ydegree, 67, ydegree, mPaint);
             if (ydegree % 20 == 0) {
                 canvas.drawLine(60, ydegree, 72, ydegree, paintLine);
                 canvas.drawText(tem + "", 70, ydegree + 4, mPaint);
                 tem+=10;
             }
             ydegree = ydegree - 2;
         }
         mHolder.unlockCanvasAndPost(canvas);// 更新屏幕显示内容
     }
 };

本文链接：http://www.cnblogs.com/zjutlitao/p/4230360.html

更多精彩：http://www.cnblogs.com/zjutlitao/

工程链接：http://pan.baidu.com/s/1i3zhMVr

GitHub链接：https://github.com/beautifulzzzz/SmartDrink