人工智能原理课程（5金币）

ethan · 发表于 2021-10-28 08:34

public class MainActivity extends AppCompatActivity {

private static final int WHAT_SUCCESS = 1;
private static final int WHAT_FAIL = 2;

private ListView lv_main;
private LinearLayout ll_main_loading;
private List<ShopInfo> data;
private ShopInfoAdapter adapter;

private Handler handler = new Handler() {
      @Override
      public void handleMessage(@NonNull Message msg) {
         switch (msg.what) {
            case WHAT_SUCCESS:
                  ll_main_loading.setVisibility(View.GONE);
                  // 显示列表
                  lv_main.setAdapter(adapter);
                  break;
            case WHAT_FAIL:
                  ll_main_loading.setVisibility(View.GONE);
                  Toast.makeText(MainActivity.this, "加载数据失败！", (int) 1).show();
                  break;
            default:
         }
      }
};

@Override
protected void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.activity_main);

      lv_main = findViewById(R.id.lv_main);
      ll_main_loading = findViewById(R.id.ll_main_loading);
      adapter = new ShopInfoAdapter();

      // 1.主线程，显示提示视图
      ll_main_loading.setVisibility(View.VISIBLE);
      // 2.分线程，联网请求
      // 启动分线程请求服务器动态加载数据并显示
      new Thread(() -> {
         try {
            String jsonStr = requestJson();
            System.out.println(jsonStr);
            Gson gson = new Gson();
            Log.e("gson:", gson + "");
            data = gson.fromJson(jsonStr, new TypeToken<List<ShopInfo>>() {
            }.getType());
            Log.e("json:", data + "");
            // 3.主线程，更新界面
            // 发送请求成功的消息
            handler.sendEmptyMessage(WHAT_SUCCESS);
         } catch (Exception e) {
            e.printStackTrace();
            // 发送请求失败的消息
            handler.sendEmptyMessage(WHAT_FAIL);
         }
      }).start();
}

/**
   * 联网请求得到json字符串
   *
   * @return
   */
private String requestJson() throws Exception {
      String result = "";
      // 192.168.124.4
      // 192.168.0.103
      String path = "http://192.168.124.4:9999/vod/gets";
      // 1.得到连接对象
      URL url = new URL(path);
      HttpURLConnection connection = (HttpURLConnection) url.openConnection();
      //（4）设置连接超时，读取数据超时
      connection.setConnectTimeout(5000);
      connection.setReadTimeout(5000);
      //（5）连接服务器
      connection.connect();
      int responseCode = connection.getResponseCode();
      if (responseCode == 200) {
         //（6）发请求，得到响应数据
         InputStream is = connection.getInputStream();
         ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
         byte[] buffer = new byte[1024];
         int len = -1;
         while ((len = is.read(buffer)) != -1) {
            byteArrayOutputStream.write(buffer, 0, len);
         }
         byteArrayOutputStream.close();
         is.close();
         result = byteArrayOutputStream.toString();
         // （7）断开连接
         connection.disconnect();
      } else {
         // 也可以抛出异常
      }
      return result;
}

class ShopInfoAdapter extends BaseAdapter {

      @Override
      public int getCount() {
         return data.size();
      }

      @Override
      public Object getItem(int position) {
         return data.get(position);
      }

      @Override
      public long getItemId(int position) {
         return 0;
      }

      @Override
      public View getView(int position, View convertView, ViewGroup parent) {
         if (convertView == null) {
            convertView = View.inflate(MainActivity.this, R.layout.item_main, null);
         }
         // 得到当前行的数据对象
         ShopInfo shopInfo = data.get(position);
         // 得到当前行的子view
         TextView name = convertView.findViewById(R.id.tv_item_name);
         TextView id = convertView.findViewById(R.id.tv_item_content);
         ImageView imageView = convertView.findViewById(R.id.iv_item_icon);
         // 设置数据显示
         name.setText(shopInfo.getVideoName());
         id.setText(shopInfo.getId());
         // 根据图片路径启动分线程动态请求服务加载图片并显示
         return convertView;
      }
}
}