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> food = new ArrayList<Food>();
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<String,Object> map = new HashMap<String,Object>();
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
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<Food> data = new ArrayList<Food>();
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<String, Void, Map<String,Object>>{
@Override
protected void onPreExecute() {
pd.setMessage("Loading...");
}
@Override
protected Map<String, Object> 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<String,Object> map = parseJson(result);
return map;
}
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return null;
}
@Override
protected void onPostExecute(Map<String, Object> result) {
pd.dismiss();
isNextPage = (Boolean) result.get("isNextPage");
data.addAll( (List<Food>) result.get("foodList") );
mAdapter.notifyDataSetChanged();
for(int i = 0;i<data.size();i++){
Food f = data.get(i);
new MyImgTask().execute(f);
}
}
private Map<String,Object> parseJson(String json) throws Exception{
Map<String ,Object> result = new HashMap<String,Object>();
List<Food> lists = new ArrayList<Food>();
JSONObject bigObj = new JSONObject(json);
result.put("isNextPage", bigObj.getBoolean("isNextPage"));
JSONArray array = bigObj.getJSONArray("foodList");
Food f = null;
for(int i =0 ;i<array.length();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<Food, Void, Food>{
@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<Food> data ;
public MyAdapter(Context context, List<Food> 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：
有兴趣的同学， 可以尝试自己做一下。