如何使用json在android中使用post方法

Question

我创建了一个 android 应用程序，使用 json 从 ror 网站获取并显示在列表视图中，现在我想从我们的应用程序中添加数据，它也必须显示在我们应用程序的列表视图中，然后它必须显示在网站也是。如何在我们的应用程序中使用发布方法和显示。

获取我使用的方法

public class MainActivity extends ListActivity implements FetchDataListener
{
    private ProgressDialog dialog;

    @Override
    protected void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        //setContentView(R.layout.activity_list_item);   
        initView();
    }

    private void initView()
    {
        // show progress dialog
        dialog = ProgressDialog.show(this, "", "Loading...");
        String url = "http://floating-wildwood-1154.herokuapp.com/posts.json";
        FetchDataTask task = new FetchDataTask(this);
        task.execute(url);
    }

    @Override
    public void onFetchComplete(List<Application> data)
    {
        // dismiss the progress dialog
        if ( dialog != null )
            dialog.dismiss();
        // create new adapter
        ApplicationAdapter adapter = new ApplicationAdapter(this, data);
        // set the adapter to list
        setListAdapter(adapter);
    }

    @Override
    public void onFetchFailure(String msg)
    {
        // dismiss the progress dialog
        if ( dialog != null )
            dialog.dismiss();
        // show failure message
        Toast.makeText(this, msg, Toast.LENGTH_LONG).show();
    }
}

fetchdatatask.java

public class FetchDataTask extends AsyncTask<String, Void, String>
{
    private final FetchDataListener listener;
    private String msg;

    public FetchDataTask(FetchDataListener listener)
    {
        this.listener = listener;
    }

    @Override
    protected String doInBackground(String... params)
    {
        if ( params == null )
            return null;
        // get url from params
        String url = params[0];
        try
        {
            // create http connection
            HttpClient client = new DefaultHttpClient();
            HttpGet httpget = new HttpGet(url);
            // connect
            HttpResponse response = client.execute(httpget);
            // get response
            HttpEntity entity = response.getEntity();
            if ( entity == null )
            {
                msg = "No response from server";
                return null;
            }
            // get response content and convert it to json string
            InputStream is = entity.getContent();
            return streamToString(is);
        }
        catch ( IOException e )
        {
            msg = "No Network Connection";
        }
        return null;
    }

    @Override
    protected void onPostExecute(String sJson)
    {
        if ( sJson == null )
        {
            if ( listener != null )
                listener.onFetchFailure(msg);
            return;
        }
        try
        {
            // convert json string to json object
            JSONObject jsonObject = new JSONObject(sJson);
            JSONArray aJson = jsonObject.getJSONArray("post");
            // create apps list
            List<Application> apps = new ArrayList<Application>();
            for ( int i = 0; i < aJson.length(); i++ )
            {
                JSONObject json = aJson.getJSONObject(i);
                Application app = new Application();
                app.setContent(json.getString("content"));
                // add the app to apps list
                apps.add(app);
            }
            //notify the activity that fetch data has been complete
            if ( listener != null )
                listener.onFetchComplete(apps);
        }
        catch ( JSONException e )
        {
            e.printStackTrace();
            msg = "Invalid response";
            if ( listener != null )
                listener.onFetchFailure(msg);
            return;
        }
    }

    /**
     * This function will convert response stream into json string
     * 
     * @param is
     *            respons string
     * @return json string
     * @throws IOException
     */
    public String streamToString(final InputStream is) throws IOException
    {
        BufferedReader reader = new BufferedReader(new InputStreamReader(is));
        StringBuilder sb = new StringBuilder();
        String line = null;
        try
        {
            while ( (line = reader.readLine()) != null )
            {
                sb.append(line + "\n");
            }
        }
        catch ( IOException e )
        {
            throw e;
        }
        finally
        {
            try
            {
                is.close();
            }
            catch ( IOException e )
            {
                throw e;
            }
        }
        return sb.toString();
    }
}

像这样我正在使用 get 方法并显示，出于同样的目的，我想将 post 方法添加到在 android listview 中显示并在网站中显示。

如果我在单击菜单按钮（如添加）时创建一个按钮，在该按钮中将显示一页，在该页面中我必须添加数据并单击保存，它必须在列表视图中显示和也可以在网站上发帖

我怎样才能做到这一点。

Answer 1

你可以使用HttpPost

    @Override
protected String doInBackground(String... params)
{
    if ( params == null )
        return null;
    // get url from params
    String url = params[0];
    try
    {
        // create http connection
        HttpClient client = new DefaultHttpClient();
        HttpPost request = new HttpPost(url);
        try{
    StringEntity s = new StringEntity(json.toString()); //json is ur json object
    s.setContentEncoding("UTF-8");
    s.setContentType("application/json");
    request.setEntity(s);
    request.addHeader("Accept", "text/plain"); //give here your post method return type

    HttpResponse response = client.execute(request);
        // get response
        HttpEntity entity = response.getEntity();
        if ( entity == null )
        {
            msg = "No response from server";
            return null;
        }
        // get response content and convert it to json string
        InputStream is = entity.getContent();
        return streamToString(is);

Answer 2

您必须采取的主要步骤如下：

在您的 Android 应用中添加代码以将数据发布到您的服务器。
你可以在网上找到很多关于如何做到这一点的例子。这是一个例子： How to send POST request in JSON using HTTPClient?

拥有可以处理您发送的 JSON 数据的网络服务。
如何执行此操作取决于您使用的服务器端技术。

更新与您的 ListView 关联的列表

Answer 3

          public void postData() {
// Create a new HttpClient and Post Header
HttpClient httpclient = new DefaultHttpClient();
HttpPost httppost = new      
HttpPost("http://abcd.wxyz.com/");

try {
     List <NameValuePair> nameValuePairs = new ArrayList<NameValuePair>();
    nameValuePairs.add(new BasicNameValuePair("IDToken1", "username"));
    nameValuePairs.add(new BasicNameValuePair("IDToken2", "password"));


    httppost.setEntity(new UrlEncodedFormEntity(nameValuePairs));

    // Execute HTTP Post Request
    HttpResponse response = httpclient.execute(httppost);

    if(response != null) {

      int statuscode = response.getStatusLine().getStatusCode();

       if(statuscode==HttpStatus.SC_OK) {
        String strResponse = EntityUtils.toString(response.getEntity());

      }
   }

 } catch (ClientProtocolException e) {
  // TODO Auto-generated catch block
  } catch (IOException e) {
    // TODO Auto-generated catch block
  }
 }