[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
        
    }
}

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

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 工程链接：http://pan.baidu.com/s/1i3zhMVr 

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