Android开发学习——android与服务器端数据交互

1.首先搭建服务器端。

使用MyEclipse开发工具

public class MyServlet extends HttpServlet {    @Override    protected void doGet(HttpServletRequest req, HttpServletResponse resp)            throws ServletException, IOException {                ArrayList food = new ArrayList();        Gson g = new Gson();                        Food f1 = new Food(1,"1111","1111","/cinema_1.jpg");        Food f2 = new Food(2,"2222","22222","/cinema_2.jpg");        Food f3 = new Food(3,"3333","33333","/food_1.jpg");        Food f4 = new Food(4,"44444","4444","/food_2.jpg");        Food f5 = new Food(5,"55555","5555","/hotel_1.jpg");                food.add(f1);        food.add(f2);        food.add(f3);        food.add(f4);        food.add(f5);                boolean  isNextPage = false;        Map map = new HashMap();                map.put("foodList", food);        map.put("isNextPage", isNextPage);                resp.setContentType("text/html;charset=utf-8");                PrintWriter  out = resp.getWriter();        out.print(g.toJson(map));        out.close();}}

上述代码所需的Food实体如下：

public class Food implements Serializable{    private int id;        private String name;    private String desc;        private String imgPath;        public Food(int id, String name, String desc, String imgPath) {        super();        this.id = id;        this.name = name;        this.desc = desc;        this.imgPath = imgPath;    }    public int getId() {        return id;    }    public void setId(int id) {        this.id = id;    }    public String getName() {        return name;    }    public void setName(String name) {        this.name = name;    }    public String getDesc() {        return desc;    }    public void setDesc(String desc) {        this.desc = desc;    }    public String getImgPath() {        return imgPath;    }    public void setImgPath(String imgPath) {        this.imgPath = imgPath;    }}

我们在浏览器中访问

Android开发学习——android与服务器端数据交互_第1张图片

可以获取到结果，说明服务器端是正常的。

2.服务器端搭建好了之后，我们搭建android端

public class MainActivity extends Activity {    private ListView lv;        private List  data = new ArrayList();        private MyAdapter mAdapter;        private ProgressDialog  pd;        private boolean isNextPage;        @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);                lv = (ListView) findViewById(R.id.lv);            pd = new ProgressDialog(this);                mAdapter = new MyAdapter(this, data);                lv.setAdapter(mAdapter);                new MyFoodTask().execute();                    }        private class MyFoodTask extends AsyncTask>{        @Override        protected void onPreExecute() {                        pd.setMessage("Loading...");                    }                @Override        protected Map doInBackground(String... params) {                    String path  = "http://10.0.2.2:8080/TestWeb/bbb";            HttpClient client = new DefaultHttpClient();            HttpGet get = new HttpGet(path);                        try {                HttpResponse resp = client.execute(get);                if(resp.getStatusLine().getStatusCode()==200){                                        HttpEntity entity = resp.getEntity();                    String result = EntityUtils.toString(entity);                    Log.i("111", "result="+result);                    Map map =  parseJson(result);                    return map;                                    }                        } catch (Exception e) {                // TODO Auto-generated catch block                e.printStackTrace();            }                                                return null;        }                        @Override        protected void onPostExecute(Map result) {                            pd.dismiss();            isNextPage =  (Boolean) result.get("isNextPage");            data.addAll(  (List) result.get("foodList")  );            mAdapter.notifyDataSetChanged();                        for(int i = 0;i){                                Food f = data.get(i);                                new MyImgTask().execute(f);                    }        }            private Map parseJson(String json) throws Exception{                Map result = new HashMap();        List lists = new ArrayList();        JSONObject  bigObj = new JSONObject(json);        result.put("isNextPage",  bigObj.getBoolean("isNextPage"));        JSONArray array = bigObj.getJSONArray("foodList");        Food  f = null;        for(int i =0 ;i){            f = new Food();            JSONObject smallObj = array.getJSONObject(i);                        f.setId( smallObj.getInt("id") );            f.setName( smallObj.getString("name") );            f.setDesc(smallObj.getString("desc"));            f.setImgPath( smallObj.getString("imgPath") );            lists.add(f);        }        result.put("foodList", lists);        return result;                    }            private class MyImgTask extends AsyncTask{        @Override        protected Food doInBackground(Food... params) {                    Food f =  params[0];            String imgPath = "http://10.0.2.2:8080/TestWeb"+f.getImgPath();                        HttpClient client = new DefaultHttpClient();            HttpGet get = new HttpGet(imgPath);                try {                HttpResponse resp = client.execute(get);                if(resp.getStatusLine().getStatusCode()==200){                                        HttpEntity entity = resp.getEntity();                    byte img [] = EntityUtils.toByteArray(entity);                                    f.setImgData(img);                            }                            } catch (Exception e) {                e.printStackTrace();            }            return f;                }        @Override        protected void onPostExecute(Food result) {            mAdapter.notifyDataSetChanged();        }            }    }}

所需的Food实体：

public class Food implements Serializable{    private int id;        private String name;        private String desc;        private String imgPath;        private byte imgData [];                public int getId() {        return id;    }    public void setId(int id) {        this.id = id;    }    public String getName() {        return name;    }    public void setName(String name) {        this.name = name;    }    public String getDesc() {        return desc;    }    public void setDesc(String desc) {        this.desc = desc;    }    public String getImgPath() {        return imgPath;    }    public void setImgPath(String imgPath) {        this.imgPath = imgPath;    }    public byte[] getImgData() {        return imgData;    }    public void setImgData(byte[] imgData) {        this.imgData = imgData;    }}

所需的适配器：

public class MyAdapter  extends BaseAdapter{    private Context context;        private List  data ;            public MyAdapter(Context context, List data) {        this.context = context;        this.data = data;    }    @Override    public int getCount() {        // TODO Auto-generated method stub        return data.size();    }    @Override    public Object getItem(int position) {        // TODO Auto-generated method stub        return data.get(position);    }    @Override    public long getItemId(int position) {        // TODO Auto-generated method stub        return position;    }            @Override    public View getView(int position, View convertView, ViewGroup parent) {        if(convertView==null){                        convertView = LayoutInflater.from(context).inflate(R.layout.item, null);                    }        ImageView iv_img = (ImageView) convertView.findViewById(R.id.iv_img);        TextView tv_name = (TextView) convertView.findViewById(R.id.tv_name);        TextView tv_desc = (TextView) convertView.findViewById(R.id.tv_desc);                Food food = data.get(position);                if(food.getImgData()==null){            iv_img.setImageResource(R.drawable.cinema_1);        }else{            byte [] imgData = food.getImgData();            Bitmap bm  = BitmapFactory.decodeByteArray(imgData, 0, imgData.length);            iv_img.setImageBitmap(bm);        }                tv_name.setText( food.getName());        tv_desc.setText( food.getDesc());                return convertView;    }}

我们启动模拟器，得到运行结果：

Android开发学习——android与服务器端数据交互_第2张图片

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