android - 如何将 url 传递给 json 并在 android 中显示对 listview 的响应，我如何在 listview 中显示

Question

//如何将url传递给json并在android中显示对listview的响应，我如何在listview中显示 public class MainActivity extends Activity {

    @SuppressLint("NewApi")
    @TargetApi(Build.VERSION_CODES.GINGERBREAD)
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder().permitAll().build();
         InputStream is = null;
        StrictMode.setThreadPolicy(policy); 
         InputStream inputStream = null;
            String result = "";
        DefaultHttpClient httpclient = new DefaultHttpClient();
        HttpPost httppost = new HttpPost("http://api.learn2crack.com/android/jsonos/");
        try {
            HttpResponse httpresponse = httpclient.execute(httppost);
             HttpEntity httpEntity = httpresponse.getEntity();
              is = httpEntity.getContent();
        } catch (ClientProtocolException e) {
            // TODO Auto-generated catch blockt
            e.printStackTrace();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }


}

Answer 1

您需要解析来自服务器的响应，然后使用它来显示 ListView。

最好的方法是解析 JSON 数据并创建一个 ArrayList，稍后可以将其传递给 ListView 的适配器。

有一个关于这个主题的优秀教程（带有完整的工作代码） 。

教程中的片段：

private class GetContacts extends AsyncTask<Void, Void, Void> {

        @Override
        protected void onPreExecute() {
            super.onPreExecute();
            // Showing progress dialog
            pDialog = new ProgressDialog(MainActivity.this);
            pDialog.setMessage("Please wait...");
            pDialog.setCancelable(false);
            pDialog.show();

        }

        @Override
        protected Void doInBackground(Void... arg0) {
            // Creating service handler class instance
            ServiceHandler sh = new ServiceHandler();

            // Making a request to url and getting response
            String jsonStr = sh.makeServiceCall(url, ServiceHandler.GET);

            Log.d("Response: ", "> " + jsonStr);

            if (jsonStr != null) {
                try {
                    JSONObject jsonObj = new JSONObject(jsonStr);

                    // Getting JSON Array node
                    contacts = jsonObj.getJSONArray(TAG_CONTACTS);

                    // looping through All Contacts
                    for (int i = 0; i < contacts.length(); i++) {
                        JSONObject c = contacts.getJSONObject(i);

                        String id = c.getString(TAG_ID);
                        String name = c.getString(TAG_NAME);
                        String email = c.getString(TAG_EMAIL);
                        String address = c.getString(TAG_ADDRESS);
                        String gender = c.getString(TAG_GENDER);

                        // Phone node is JSON Object
                        JSONObject phone = c.getJSONObject(TAG_PHONE);
                        String mobile = phone.getString(TAG_PHONE_MOBILE);
                        String home = phone.getString(TAG_PHONE_HOME);
                        String office = phone.getString(TAG_PHONE_OFFICE);

                        // tmp hashmap for single contact
                        HashMap<String, String> contact = new HashMap<String, String>();

                        // adding each child node to HashMap key => value
                        contact.put(TAG_ID, id);
                        contact.put(TAG_NAME, name);
                        contact.put(TAG_EMAIL, email);
                        contact.put(TAG_PHONE_MOBILE, mobile);

                        // adding contact to contact list
                        contactList.add(contact);
                    }
                } catch (JSONException e) {
                    e.printStackTrace();
                }
            } else {
                Log.e("ServiceHandler", "Couldn't get any data from the url");
            }

            return null;
        }

        @Override
        protected void onPostExecute(Void result) {
            super.onPostExecute(result);
            // Dismiss the progress dialog
            if (pDialog.isShowing())
                pDialog.dismiss();
            /**
             * Updating parsed JSON data into ListView
             * */
            ListAdapter adapter = new SimpleAdapter(
                    MainActivity.this, contactList,
                    R.layout.list_item, new String[] { TAG_NAME, TAG_EMAIL,
                            TAG_PHONE_MOBILE }, new int[] { R.id.name,
                            R.id.email, R.id.mobile });

            setListAdapter(adapter);
        }

    }