如何将JSON转换为JAVA对象? [英] How can i convert JSON to JAVA object?

问题描述

我在以下我正在尝试将其转换为JAVA对象，但无法加载图像.

I am trying to convert it to JAVA Object but i failed to load the IMAGE.

这是我的代码

  public class MainActivity extends ActionBarActivity {
    // Declare Variables
    JSONObject jsonobject;
    JSONArray jsonarray;
    ListView listview;
    ListViewAdapter adapter;
    ProgressDialog mProgressDialog;
    ArrayList<HashMap<String, String>> arraylist;
    static String url = "https://www.googleapis.com/youtube/v3/search?part=snippet&maxResult=30&q=natok+bangla+mosharrof+karim&key=AIzaSyCR40QlsuX0aFfBV-wEPDsH_jxna1tDFRA";

    static String VIDEO_ID = "videoId";
    static String TITLE = "title";
    //static String DESCRIPTION = "description";
    static String THUMBNAILS = "http://img.youtube.com/vi/\" + videoId + \"/hqdefault.jpg\"";

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        // Get the view from listview_main.xml
        setContentView(R.layout.listview_main);
        // Execute DownloadJSON AsyncTask
        new DownloadJSON().execute();
    }

    // DownloadJSON AsyncTask
    private class DownloadJSON extends AsyncTask<Void, Void, Void> {

        @Override
        protected void onPreExecute() {
            super.onPreExecute();
            // Create a progressdialog
            mProgressDialog = new ProgressDialog(MainActivity.this);
            // Set progressdialog title
            mProgressDialog.setTitle("Your Youtube Video is");
            // Set progressdialog message
            mProgressDialog.setMessage("Loading...");
            mProgressDialog.setIndeterminate(false);
            // Show progressdialog
            mProgressDialog.show();
        }

        @Override
        protected Void doInBackground(Void... params) {
            // Create an array
            arraylist = new ArrayList<HashMap<String, String>>();

            // Retrieve JSON Objects from the given URL address

            String query = "bangla natok 2015";
            query = query.replace(" ", "+");
            try {
                query = URLEncoder.encode(query, "utf-8");
            } catch (UnsupportedEncodingException e) {
                // TODO Auto-generated catch block
                //e.printStackTrace();
            }

            jsonobject = JSONfunctions.getJSONfromURL("https://www.googleapis.com/youtube/v3/search?part=id%2Csnippet&q=natok+2015&maxResults=50&key=AIzaSyCR40QlsuX0aFfBV-wEPDsH_jxna1tDFRA");

            try {
                // Locate the array name in JSON
                JSONArray jsonarray = jsonobject.getJSONArray("items");

                for (int i = 0; i < jsonarray.length(); i++) {
                    HashMap<String, String> map = new HashMap<String, String>();
                    jsonobject = jsonarray.getJSONObject(i);
                    // Retrive JSON Objects
                    JSONObject jsonObjId = jsonobject.getJSONObject("id");
                    map.put("videoId", jsonObjId.getString("videoId"));
                    map.put ("img","http://img.youtube.com/vi/" + VIDEO_ID + "/hqdefault.jpg");

                    JSONObject jsonObjSnippet = jsonobject.getJSONObject("snippet");
                    map.put("title", jsonObjSnippet.getString("title"));

                    //map.put("description", jsonObjSnippet.getString("description"));
                    // map.put("flag", jsonobject.getString("flag"));




                    // Set the JSON Objects into the array
                    arraylist.add(map);
                }
            } catch (JSONException e) {
                Log.e("Error", e.getMessage());
                e.printStackTrace();
            }
            return null;
        }

        @Override
        protected void onPostExecute(Void args) {
            // Locate the listview in listview_main.xml
            listview = (ListView) findViewById(R.id.listview);
            // Pass the results into ListViewAdapter.java
            adapter = new ListViewAdapter(MainActivity.this, arraylist);
            // Set the adapter to the ListView
            listview.setAdapter(adapter);
            // Close the progressdialog
            mProgressDialog.dismiss();
        }
    }

我需要在此处显示的所有内容，但我无法在此处显示图像.我无法找到&遇到任何错误.将JSON转换为Java对象是否有问题?

Everything i need i receive to show here but i can not show the image here.i can not find & get any kind of error.is there any problem to converting JSON to java object?

推荐答案

在这种情况下，最好使用GSON，这样无需手动即可将json字符串转换为java对象.

Its better to use the GSON in this case it will convert your json string to java object without do manual work.

将以下行添加到gradle依赖项

add following line to gradle dependency

compile 'com.google.code.gson:gson:1.7.2'

现在使用此代码将json字符串转换为java对象

Now use this code to convert the json string to java object

POJOClass obj = gson.fromJson(json, POJOClass.class)

您还可以使用此站点将json转换为POJO类，而无需手动创建

Also you can use this site to convert your json to POJO Class without creating it manually

http://www.jsonschema2pojo.org/

如果有问题，请通知我

这篇关于如何将JSON转换为JAVA对象?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！