[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

标签：

 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。

 1 public class MainActivity extends ActionBarActivity 
 2 {
 3     private final String TAG = "MainActivity";
 4     private EditText et01;
 5     private EditText et02;
 6     private Button btOK;
 7     private Button btCancel;
 8     public static String userIP = "192.168.1.130";            //IP和端口号
 9     public static int userPort = 8000;
10     public static int wen_du;            //当前温度
11     public static int shui_wei;            //当前水位
12     public static int state;            //当前状态0关闭；1烧水；2保温
13     @Override
14     protected void onCreate(Bundle savedInstanceState) {
15         super.onCreate(savedInstanceState);
16         setContentView(R.layout.activity_main);
17         et01 = (EditText)findViewById(R.id.et_01);
18         et02 = (EditText)findViewById(R.id.et_02);
19         btOK = (Button)findViewById(R.id.bt_OK);
20         btCancel = (Button)findViewById(R.id.bt_Cancel);
21         
22             
23         btOK.setOnClickListener(new OnClickListener(){
24             public void onClick(View v)
25             {
26                 //userIP = et01.getText().toString();
27                 //userPort = Integer.parseInt(et02.getText().toString());
28                 //跳到控制界面
29                 Intent intent = new Intent(MainActivity.this,ControlActivity.class);
30                 Log.i(TAG, "跳转前");
31                 startActivity(intent);
32             }
33         });
34         btCancel.setOnClickListener(new OnClickListener(){
35             public void onClick(View v)
36             {
37                 et01.setText("");
38                 et02.setText("");
39             }
40         });
41         
42     }
43 
44     
45     @Override
46     public boolean onCreateOptionsMenu(Menu menu) {
47         // Inflate the menu; this adds items to the action bar if it is present.
48         getMenuInflater().inflate(R.menu.main, menu);
49         return true;
50     }
51 
52     @Override
53     public boolean onOptionsItemSelected(MenuItem item) {
54         // Handle action bar item clicks here. The action bar will
55         // automatically handle clicks on the Home/Up button, so long
56         // as you specify a parent activity in AndroidManifest.xml.
57         int id = item.getItemId();
58         if (id == R.id.action_settings) {
59             return true;
60         }
61         return super.onOptionsItemSelected(item);
62     }
63 }

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。

  1 public class ControlActivity extends Activity implements Callback {
  2     
  3     private final String TAG = "ControlActivity";
  4     private final String mAddress = MainActivity.userIP;
  5     private final int mPort = MainActivity.userPort;
  6     private Socket socket = null;
  7     private Button btHeat,btShut,btUpdata;
  8     private SurfaceView mSurface; //绘图区
  9     private SurfaceHolder mHolder;  
 10     //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)
 11     public Handler myHandler = new Handler() {
 12         @Override
 13         public void handleMessage(Message msg) 
 14         {
 15             Bundle bundle = msg.getData();
 16             String now = bundle.getString("msg");
 17             //SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");//设置日期格式
 18             if (msg.what == 0x01) 
 19             {
 20                 toast_show("饮水机开始加热!");
 21             }
 22             else if (msg.what == 0x02) 
 23             {
 24                 toast_show("饮水机关闭!");
 25             }
 26             else if (msg.what == 0x03) 
 27             {
 28                 toast_show("饮水机实时状态更新!"+"  "+MainActivity.wen_du+"  "+MainActivity.shui_wei);
 29                 draw(MainActivity.wen_du);
 30             }
 31             else
 32             {
 33                 toast_show("出现错误!");
 34             }
 35         }
 36         //toast显示用
 37         private void toast_show(String msg) {
 38             Toast toast = Toast.makeText(getApplicationContext(),
 39                      msg, Toast.LENGTH_LONG);
 40             toast.setGravity(Gravity.CENTER, 0, 0);
 41             toast.show();
 42         }
 43         //画图像
 44         private void draw(int wen_du) {  
 45             int y = 260 - wen_du * 2;  
 46             Canvas canvas = mHolder.lockCanvas();  
 47             Paint mPaint = new Paint();  
 48             mPaint.setColor(Color.WHITE);  
 49             canvas.drawRect(40, 50, 60, 280, mPaint);  
 50             Paint paintCircle = new Paint();  
 51             paintCircle.setColor(Color.RED);  
 52             Paint paintLine = new Paint();  
 53             paintLine.setColor(Color.BLUE);  
 54             canvas.drawRect(40, y, 60, 280, paintCircle);  
 55             canvas.drawCircle(50, 300, 25, paintCircle);  
 56             int ydegree = 260;  
 57             int tem = 0;//刻度0~100
 58             while (ydegree > 55) {  
 59                 canvas.drawLine(60, ydegree, 67, ydegree, mPaint);  
 60                 if (ydegree % 20 == 0) {  
 61                     canvas.drawLine(60, ydegree, 72, ydegree, paintLine);  
 62                     canvas.drawText(tem + "", 70, ydegree + 4, mPaint);  
 63                     tem+=10;  
 64                 }  
 65                 ydegree = ydegree - 2;  
 66             }  
 67             mHolder.unlockCanvasAndPost(canvas);// 更新屏幕显示内容  
 68         }  
 69     };
 70     
 71     protected void onCreate(Bundle savedInstanceState) 
 72     {
 73         super.onCreate(savedInstanceState);
 74         setContentView(R.layout.control_activity);
 75         btHeat = (Button)findViewById(R.id.bt_heat);
 76         btShut = (Button)findViewById(R.id.bt_shut);
 77         btUpdata = (Button)findViewById(R.id.bt_updata);
 78         mSurface = (SurfaceView) findViewById(R.id.surface);  
 79         mHolder = mSurface.getHolder();  
 80         mHolder.addCallback(this);  
 81         
 82         btHeat.setOnClickListener(new OnClickListener() {
 83             @Override
 84             public void onClick(View v) 
 85             {
 86                 String orderMsg="Heat";
 87                 //启动线程 向服务器发送和接收信息
 88                 Log.i(TAG, "Start thread");
 89                 new MyThread(orderMsg).start();
 90             }
 91         });
 92         
 93         btHeat.setOnClickListener(new OnClickListener() {
 94             @Override
 95             public void onClick(View v) 
 96             {
 97                 String orderMsg="Heat";
 98                 //启动线程 向服务器发送和接收信息
 99                 Log.i(TAG, "Start thread");
100                 new MyThread(orderMsg).start();
101             }
102         });
103         
104         btShut.setOnClickListener(new OnClickListener() {
105             @Override
106             public void onClick(View v) 
107             {
108                 String orderMsg="Shut";
109                 //启动线程 向服务器发送和接收信息
110                 Log.i(TAG, "Start thread");
111                 new MyThread(orderMsg).start();
112             }
113         });
114         
115         btUpdata.setOnClickListener(new OnClickListener() {
116             @Override
117             public void onClick(View v) 
118             {
119                 String orderMsg="Updata";
120                 //启动线程 向服务器发送和接收信息
121                 Log.i(TAG, "Start thread");
122                 new MyThread(orderMsg).start();
123             }
124         });
125     }
126     
127     class MyThread extends Thread 
128     {
129         String orderMsg;
130         MyThread(String str)
131         {
132             orderMsg=str;
133         }
134         @SuppressLint("SimpleDateFormat")
135         public void run()
136         {
137             OutputStream out = null;
138             InputStream in = null;
139             DataInputStream DataIn = null;//数据传输输入输出流
140             DataOutputStream DataOut = null;
141             byte data_of_get_server = 0;//从服务器返回的数据
142             Message msg = new Message();//消息
143             Bundle bundle = new Bundle();
144             bundle.clear();
145             try
146             {
147                 socket = new Socket();
148                 socket.connect(new InetSocketAddress(mAddress, mPort), 8000);
149         
150                 //输入输出流实例化
151                 out=socket.getOutputStream();
152                 in=socket.getInputStream();
153                 DataIn = new DataInputStream(in);
154                 DataOut=new DataOutputStream(out);
155                 
156                 //读取服务器的返回数据
157                 //服务器采用单byte数据进行发送
158                 /*
159                 TCP客户端:输入命令从服务器获得数据
160                 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
161                 */
162                 if(orderMsg.equals("Heat"))//加热命令
163                 {
164                     msg.what = 0x01;//消息类别
165                     DataOut.writeByte(‘0‘);    
166                     Log.i(TAG, "flush 前");
167                     out.flush();
168                     Log.i(TAG, "flush 后");
169                     data_of_get_server=DataIn.readByte();
170                     Log.i(TAG, "读取数据后");
171                 }
172                 else if(orderMsg.equals("Shut"))
173                 {
174                     msg.what = 0x02;//消息类别
175                     DataOut.writeByte(‘0‘);//停止加热
176                     out.flush();
177                     data_of_get_server=DataIn.readByte();
178                 }
179                 else if(orderMsg.equals("Updata"))
180                 {
181                     msg.what = 0x03;//消息类别
182                     DataOut.writeByte(‘w‘);//刷新温度信息
183                     out.flush();
184                     data_of_get_server=DataIn.readByte();
185                     MainActivity.wen_du=data_of_get_server;
186                     
187                     DataOut.writeByte(‘s‘);//刷新深度信息
188                     out.flush();
189                     data_of_get_server=DataIn.readByte();
190                     MainActivity.shui_wei=data_of_get_server;
191                 }
192                 //将消息发送给UI刷新消息句柄处
193                 bundle.putByte("msg",data_of_get_server);
194                 msg.setData(bundle);
195                 myHandler.sendMessage(msg);
196             }
197             catch(Exception e){
198                 e.printStackTrace();
199                 //Intent intent = new Intent(ControlActivity.this,MainActivity.class);
200                 //Log.i(TAG, "跳转前");
201                 //startActivity(intent);
202                 //将消息发送给UI刷新消息句柄处
203                 msg.what = 0x04;//消息类别
204                 bundle.putByte("msg",data_of_get_server);
205                 msg.setData(bundle);
206                 myHandler.sendMessage(msg);
207             }finally{
208                 try{
209                     if(in!=null)in.close();Log.i(TAG, "读取数据后1");
210                     if(out!=null)out.close();Log.i(TAG, "读取数据后2");    
211                     if(DataOut!=null)DataOut.close();Log.i(TAG, "读取数据后3");
212                     if(DataIn!=null)DataIn.close();Log.i(TAG, "读取数据后4");
213                     if(socket!=null)socket.close();Log.i(TAG, "读取数据后5");
214                 }catch(Exception e){}
215             }
216         }
217     }
218 
219     @Override
220     public void surfaceCreated(SurfaceHolder holder) {
221         // TODO Auto-generated method stub
222         
223     }
224 
225     @Override
226     public void surfaceChanged(SurfaceHolder holder, int format, int width,
227             int height) {
228         // TODO Auto-generated method stub
229         
230     }
231 
232     @Override
233     public void surfaceDestroyed(SurfaceHolder holder) {
234         // TODO Auto-generated method stub
235         
236     }
237 }

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。

 1 protected void onCreate(Bundle savedInstanceState) 
 2 {
 3     super.onCreate(savedInstanceState);
 4     setContentView(R.layout.control_activity);
 5     btHeat = (Button)findViewById(R.id.bt_heat);
 6     btShut = (Button)findViewById(R.id.bt_shut);
 7     btUpdata = (Button)findViewById(R.id.bt_updata);
 8     mSurface = (SurfaceView) findViewById(R.id.surface);  
 9     mHolder = mSurface.getHolder();  
10     mHolder.addCallback(this);  
11     
12     btHeat.setOnClickListener(new OnClickListener() {
13         @Override
14         public void onClick(View v) 
15         {
16             String orderMsg="Heat";
17             //启动线程 向服务器发送和接收信息
18             Log.i(TAG, "Start thread");
19             new MyThread(orderMsg).start();
20         }
21     });
22     
23     btHeat.setOnClickListener(new OnClickListener() {
24         @Override
25         public void onClick(View v) 
26         {
27             String orderMsg="Heat";
28             //启动线程 向服务器发送和接收信息
29             Log.i(TAG, "Start thread");
30             new MyThread(orderMsg).start();
31         }
32     });
33     
34     btShut.setOnClickListener(new OnClickListener() {
35         @Override
36         public void onClick(View v) 
37         {
38             String orderMsg="Shut";
39             //启动线程 向服务器发送和接收信息
40             Log.i(TAG, "Start thread");
41             new MyThread(orderMsg).start();
42         }
43     });
44     
45     btUpdata.setOnClickListener(new OnClickListener() {
46         @Override
47         public void onClick(View v) 
48         {
49             String orderMsg="Updata";
50             //启动线程 向服务器发送和接收信息
51             Log.i(TAG, "Start thread");
52             new MyThread(orderMsg).start();
53         }
54     });
55 }

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);

 1 class MyThread extends Thread 
 2 {
 3     String orderMsg;
 4     MyThread(String str)
 5     {
 6         orderMsg=str;
 7     }
 8     @SuppressLint("SimpleDateFormat")
 9     public void run()
10     {
11         OutputStream out = null;
12         InputStream in = null;
13         DataInputStream DataIn = null;//数据传输输入输出流
14         DataOutputStream DataOut = null;
15         byte data_of_get_server = 0;//从服务器返回的数据
16         Message msg = new Message();//消息
17         Bundle bundle = new Bundle();
18         bundle.clear();
19         try
20         {
21             socket = new Socket();
22             socket.connect(new InetSocketAddress(mAddress, mPort), 8000);
23     
24             //输入输出流实例化
25             out=socket.getOutputStream();
26             in=socket.getInputStream();
27             DataIn = new DataInputStream(in);
28             DataOut=new DataOutputStream(out);
29             
30             //读取服务器的返回数据
31             //服务器采用单byte数据进行发送
32             /*
33             TCP客户端:输入命令从服务器获得数据
34             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
35             */
36             if(orderMsg.equals("Heat"))//加热命令
37             {
38                 msg.what = 0x01;//消息类别
39                 DataOut.writeByte(‘0‘);    
40                 Log.i(TAG, "flush 前");
41                 out.flush();
42                 Log.i(TAG, "flush 后");
43                 data_of_get_server=DataIn.readByte();
44                 Log.i(TAG, "读取数据后");
45             }
46             else if(orderMsg.equals("Shut"))
47             {
48                 msg.what = 0x02;//消息类别
49                 DataOut.writeByte(‘0‘);//停止加热
50                 out.flush();
51                 data_of_get_server=DataIn.readByte();
52             }
53             else if(orderMsg.equals("Updata"))
54             {
55                 msg.what = 0x03;//消息类别
56                 DataOut.writeByte(‘w‘);//刷新温度信息
57                 out.flush();
58                 data_of_get_server=DataIn.readByte();
59                 MainActivity.wen_du=data_of_get_server;
60                 
61                 DataOut.writeByte(‘s‘);//刷新深度信息
62                 out.flush();
63                 data_of_get_server=DataIn.readByte();
64                 MainActivity.shui_wei=data_of_get_server;
65             }
66             //将消息发送给UI刷新消息句柄处
67             bundle.putByte("msg",data_of_get_server);
68             msg.setData(bundle);
69             myHandler.sendMessage(msg);
70         }
71         catch(Exception e){
72             e.printStackTrace();
73             //Intent intent = new Intent(ControlActivity.this,MainActivity.class);
74             //Log.i(TAG, "跳转前");
75             //startActivity(intent);
76             //将消息发送给UI刷新消息句柄处
77             msg.what = 0x04;//消息类别
78             bundle.putByte("msg",data_of_get_server);
79             msg.setData(bundle);
80             myHandler.sendMessage(msg);
81         }finally{
82             try{
83                 if(in!=null)in.close();Log.i(TAG, "读取数据后1");
84                 if(out!=null)out.close();Log.i(TAG, "读取数据后2");    
85                 if(DataOut!=null)DataOut.close();Log.i(TAG, "读取数据后3");
86                 if(DataIn!=null)DataIn.close();Log.i(TAG, "读取数据后4");
87                 if(socket!=null)socket.close();Log.i(TAG, "读取数据后5");
88             }catch(Exception e){}
89         }
90     }
91 }

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。

 1 //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)
 2 public Handler myHandler = new Handler() {
 3     @Override
 4     public void handleMessage(Message msg) 
 5     {
 6         Bundle bundle = msg.getData();
 7         String now = bundle.getString("msg");
 8         //SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");//设置日期格式
 9         if (msg.what == 0x01) 
10         {
11             toast_show("饮水机开始加热!");
12         }
13         else if (msg.what == 0x02) 
14         {
15             toast_show("饮水机关闭!");
16         }
17         else if (msg.what == 0x03) 
18         {
19             toast_show("饮水机实时状态更新!"+"  "+MainActivity.wen_du+"  "+MainActivity.shui_wei);
20             draw(MainActivity.wen_du);
21         }
22         else
23         {
24             toast_show("出现错误!");
25         }
26     }
27     //toast显示用
28     private void toast_show(String msg) {
29         Toast toast = Toast.makeText(getApplicationContext(),
30                  msg, Toast.LENGTH_LONG);
31         toast.setGravity(Gravity.CENTER, 0, 0);
32         toast.show();
33     }
34     //画图像
35     private void draw(int wen_du) {  
36         int y = 260 - wen_du * 2;  
37         Canvas canvas = mHolder.lockCanvas();  
38         Paint mPaint = new Paint();  
39         mPaint.setColor(Color.WHITE);  
40         canvas.drawRect(40, 50, 60, 280, mPaint);  
41         Paint paintCircle = new Paint();  
42         paintCircle.setColor(Color.RED);  
43         Paint paintLine = new Paint();  
44         paintLine.setColor(Color.BLUE);  
45         canvas.drawRect(40, y, 60, 280, paintCircle);  
46         canvas.drawCircle(50, 300, 25, paintCircle);  
47         int ydegree = 260;  
48         int tem = 0;//刻度0~100
49         while (ydegree > 55) {  
50             canvas.drawLine(60, ydegree, 67, ydegree, mPaint);  
51             if (ydegree % 20 == 0) {  
52                 canvas.drawLine(60, ydegree, 72, ydegree, paintLine);  
53                 canvas.drawText(tem + "", 70, ydegree + 4, mPaint);  
54                 tem+=10;  
55             }  
56             ydegree = ydegree - 2;  
57         }  
58         mHolder.unlockCanvasAndPost(canvas);// 更新屏幕显示内容  
59     }  
60 };

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[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

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原文地址：http://www.cnblogs.com/zjutlitao/p/4230360.html