SSH服务器与Android通信(2)--Android客户端接收数据

基本原理是Android客户端通过HttpClient向服务器发出请求，服务器向Android客户端返回JSON字符串，Android客户端解析JSON字符串获得数据。

1. 新建一个Android项目，主要文件如下：

其中MainActivity是UI，CommThread是通信线程，负责和服务器通信，Util是工具类，Var存放变量。

2. Var.java:

package com.hzhi.school.util;import java.util.ArrayList;import java.util.List;public class Var {        // 访问的URL    public static String strHost = new String("http://192.168.1.100:8080/School/");    public static String strAct = new String("aclasquery");    public static String strURL = strHost + strAct;        // 列表    public static List lstId = new ArrayList();    public static List lstName = new ArrayList();    public static List lstComm = new ArrayList();        // 屏幕的尺寸    public static int wid_scr;    public static int hei_scr;        // 消息类型    public static final int msg_connect = 1;    public static final int msg_error = 2;    public static final int msg_con_start = 3;    public static final int msg_con_stop = 4;}

3. Util.java:

package com.hzhi.school.util;import java.io.BufferedReader;import java.io.InputStream;import java.io.InputStreamReader;import org.json.JSONArray;import org.json.JSONException;import org.json.JSONObject;import android.util.Log;public class Util {        // 构造类    public Util(){            }        // 将InputStream格式转化为StringBuilder格式    public static StringBuilder is2sb (InputStream is) {                String ln = "";        StringBuilder sb = new StringBuilder();        BufferedReader br = new BufferedReader(new InputStreamReader(is));        try{            while ((ln=br.readLine()) != null){                sb.append(ln);            }                    }catch(Exception e){            e.printStackTrace();        }        return sb;            }        // JSON转换成List    public static void json2list(String strJson) throws JSONException {        JSONObject jsonObject = new JSONObject(strJson);        JSONArray jsonClas = jsonObject.getJSONArray("Classes");        for (int i=0; i<jsonClas.length(); i++){            Var.lstId.add(i, jsonClas.getJSONObject(i).getString("id"));            Var.lstName.add(i, jsonClas.getJSONObject(i).getString("name"));            Var.lstComm.add(i, jsonClas.getJSONObject(i).getString("comment"));        }    }}

4.CommThread.java：

package com.hzhi.school.comm;import java.io.InputStream;import java.util.ArrayList;import java.util.List;import org.apache.http.HttpResponse;import org.apache.http.client.HttpClient;import org.apache.http.client.methods.HttpGet;import org.apache.http.impl.client.DefaultHttpClient;import android.os.Bundle;import android.os.Message;import android.util.Log;import com.hzhi.school.MainActivity;import com.hzhi.school.util.Util;import com.hzhi.school.util.Var;public class CommThread extends Thread{        // 消息变量    private Message msg;    private Bundle bdl;        // 构造函数    public void run(){                InputStream resIS;        StringBuilder resSB;        String resStr;                resIS = getIS(Var.strURL);        if (resIS == null)        {            return;        }        else        {            resSB = Util.is2sb(resIS);            resStr = resSB.toString();            try{                Util.json2list(resStr);                sendMessage(Var.msg_connect,"");            }catch (Exception e){                e.printStackTrace();                sendMessage(Var.msg_error,e.toString());            }        }     }        // 通过GET方法获取信息    public InputStream getIS (String url){                InputStream is=null;                try{            // 取得默认HttpClient实例            HttpClient hc = new DefaultHttpClient();            // 连接到服务器            HttpResponse hr = hc.execute(new HttpGet(url));            // 获取数据内容            is = hr.getEntity().getContent();                    }catch (Exception e){            e.printStackTrace();            sendMessage(Var.msg_error,e.toString());        }                return is;            }        // 发送消息(用于更新UI)    public void sendMessage(int x, String s){                msg = new Message();        bdl = new Bundle();            bdl.putString("1",s);        msg.what = x;        msg.setData(bdl);            MainActivity.mainHandler.sendMessage(msg);            }    }

使用HttpClient向服务器发出请求，服务器返回的是一个InputStream，调用Util里面的函数将InputStream转换成StringBuilder，获得JSON字符串，再解析JSON字符串，获得数据。

5. MainActivity.java:

package com.hzhi.school;import java.util.ArrayList;import java.util.List;import android.app.ListActivity;import android.app.ProgressDialog;import android.content.Context;import android.graphics.Typeface;import android.os.Bundle;import android.os.Handler;import android.os.Message;import android.util.Log;import android.view.Gravity;import android.view.View;import android.view.View.OnClickListener;import android.view.ViewGroup;import android.widget.BaseAdapter;import android.widget.Button;import android.widget.LinearLayout;import android.widget.ListView;import android.widget.TextView;import android.widget.Toast;import com.hzhi.school.comm.CommThread;import com.hzhi.school.util.Var;public class MainActivity extends ListActivity{        static list_clas_adaptor myAdaptor;    static Context mCtx;    static ProgressDialog progressDialog;    static Toast toast;    CommThread myThread;    static int numGet = 0;    ListView lv;    int id;    item_clas it;        @Override    protected void onCreate(Bundle savedInstanceState) {                super.onCreate(savedInstanceState);        setContentView(R.layout.activity_list_clas);        mCtx = getApplicationContext();                getScreen();                myAdaptor = new list_clas_adaptor(this);        progressDialog = ProgressDialog.show(MainActivity.this,                 "连接", "正在连接服务器:" + Var.strURL, true, false);        setListAdapter(myAdaptor);                myThread = new CommThread();        myThread.start();            }        protected void onListItemClick(ListView l, View v, int position, long id) {          id = Integer.parseInt((String) myAdaptor.list_data.get(position).txtNum.getText());                it = (item_clas) myAdaptor.getItem((int)id);super.onListItemClick(l, v, position, id);      }          // 获得课程列表    public static void getData(){            myAdaptor.list_data.clear();        if (Var.lstId.size()>0){                for (int i=0; i<Var.lstId.size(); i++){                myAdaptor.addItem(Var.lstId.get(i).toString(),                         Var.lstName.get(i).toString(), Var.lstComm.get(i).toString(), 1);            }        }        numGet++;    }        // 消息处理Handler    public static Handler mainHandler = new Handler() {          public void handleMessage(Message msg) {                switch (msg.what)              {                                     // 出错                 case  Var.msg_error:                     toast = Toast.makeText(mCtx,                             "错误:" + msg.getData().getString("1"), Toast.LENGTH_LONG);                     toast.show();                     break;                 // 已连接成功                 case Var.msg_connect:                     progressDialog.dismiss();                     getData();                     myAdaptor.notifyDataSetChanged();                     toast = Toast.makeText(mCtx,                              "连接服务器并返回数据成功!", Toast.LENGTH_LONG);                      toast.show();                     break;                              }                super.handleMessage(msg);           }      };            // 获得屏幕尺寸    public void getScreen(){                Var.wid_scr = getWindowManager().getDefaultDisplay().getWidth();        Var.hei_scr = getWindowManager().getDefaultDisplay().getHeight();            }    }//课程列表class list_clas_adaptor extends BaseAdapter implements OnClickListener{        public Context ctx;    public List<item_clas> list_data;    public String s1, s2;    public list_clas_adaptor(Context context){                ctx =context;        list_data = new ArrayList<item_clas>();            }            @Override    public int getCount() {        // TODO Auto-generated method stub        return list_data.size();    }    @Override    public Object getItem(int id) {        // TODO Auto-generated method stub         s2 = String.valueOf(id);        for (int i=0; i<list_data.size(); i++){            s1 = (String) list_data.get(i).txtNum.getText();            if (s1.equals(s2))                return list_data.get(i);        }                return null;            }    @Override    public long getItemId(int position) {        // TODO Auto-generated method stub        return list_data.indexOf(position);    }    @Override    public View getView(int position, View convertView, ViewGroup parent) {        // TODO Auto-generated method stub        item_clas my_item;     if (convertView == null)         {              my_item = new item_clas(ctx,              (String)list_data.get(position).txtNum.getText(),              (String)list_data.get(position).txtName.getText(),              (String)list_data.get(position).txtComm.getText()              ,1);         }        else        {              my_item = (item_clas)convertView;              my_item.txtNum.setText(list_data.get(position).txtNum.getText());            my_item.txtName.setText(list_data.get(position).txtName.getText());            my_item.txtComm.setText(list_data.get(position).txtComm.getText());        }                // 点击删除按钮        my_item.btnDel.setOnClickListener(new OnClickListener() {            @Override            public void onClick(View v) {                                            }        });                // 点击修改按钮        my_item.btnMdf.setOnClickListener(new OnClickListener() {            @Override            public void onClick(View v) {                                            }
        });        return my_item;     }        public void addItem(String num, String name, String comm, int x)    {          list_data.add(new item_clas(ctx, num, name, comm, x));     }        @Override    public void onClick(View v) {            }    }// clas列表的一行class item_clas extends LinearLayout{        public TextView txtNum;      public TextView txtName;    public TextView txtComm;    public TextView txtMdf;    public TextView txtDel;    public Button btnMdf;    public Button btnDel;         public item_clas(Context ctx, String num, String name, String comm, int x)    {                 super(ctx);        this.setOrientation(HORIZONTAL);        int hei = 60;               txtNum = new TextView(ctx);        txtNum.setText(num);        txtNum.setGravity(Gravity.CENTER);        txtNum.setTypeface(Typeface.DEFAULT_BOLD, Typeface.BOLD);        addView(txtNum, new LinearLayout.LayoutParams((int)(Var.wid_scr*0.1),hei));                 txtName = new TextView(ctx);        txtName.setText(name);        txtName.setGravity(Gravity.CENTER);        txtName.setTypeface(Typeface.DEFAULT_BOLD, Typeface.BOLD);        addView(txtName, new LinearLayout.LayoutParams((int)(Var.wid_scr*0.2),hei));                 txtComm = new TextView(ctx);        txtComm.setText(comm);        Gravity g = new Gravity();        txtComm.setGravity(Gravity.LEFT);        addView(txtComm, new LinearLayout.LayoutParams((int)(Var.wid_scr*0.4),hei));                if (x==0){                        txtDel = new TextView(ctx);            txtDel.setText("删除");            txtDel.setGravity(Gravity.CENTER);            addView(txtDel, new LinearLayout.LayoutParams((int)(Var.wid_scr*0.15),hei));            Log.i("addView", txtDel.getText().toString());                        txtMdf = new TextView(ctx);            txtMdf.setText("更新 ");            txtMdf.setGravity(Gravity.CENTER);            addView(txtMdf, new LinearLayout.LayoutParams((int)(Var.wid_scr*0.15),hei));            Log.i("comm=", comm);            Log.i("addView", txtMdf.getText().toString());        }        else{                    btnDel = new Button(ctx);            btnDel.setText("删除");            btnDel.setGravity(Gravity.CENTER);            btnDel.setTypeface(Typeface.DEFAULT_BOLD, Typeface.BOLD);            btnDel.setFocusable(false);            addView(btnDel, new LinearLayout.LayoutParams((int)(Var.wid_scr*0.15),hei));                    btnMdf = new Button(ctx);            btnMdf.setText("更新");            btnMdf.setGravity(Gravity.CENTER);            btnMdf.setTypeface(Typeface.DEFAULT_BOLD, Typeface.BOLD);            btnMdf.setFocusable(false);            addView(btnMdf, new LinearLayout.LayoutParams((int)(Var.wid_scr*0.15),hei));        }    }    }

MainActivity调用CommThread访问服务器，获得数据后通过BaseAdaptor显示出来。在item_clas类中，由于点击每一行会被系统误以为是在点击Button，所以要给Button加上:

setFocusable(false);

运行结果：

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