java - Android - 如何从 URL/JSON 获取特定数据？

Question

所以我有这个代码，这是一个带有 ListView 搜索字段和一个确认搜索的按钮的页面，当按下按钮时 ListView 被填充来自烂番茄 API 的电影名称，问题是有人帮助我编写了这段代码，我希望有人帮助我分解它并逐句理解它，我的主要目标是获取“标题”，“在列表中单击的电影的“概要”和“url 图像”，并将其传递给我的其他 Activity ，但整个 JSON 并获取特定的数据内容，让我非常困惑。

Link to Rotten Tomatoes API documentation ，这是我的代码:

public class MovieAddFromWeb extends Activity implements View.OnClickListener,
        OnItemClickListener {

    private TextView searchBox;
    private Button bGo, bCancelAddFromWeb;
    private ListView moviesList;
    public List<String> movieTitles;
    static final int ACTIVITY_WEB_ADD = 3;

    // the Rotten Tomatoes API key
    private static final String API_KEY = "8q6wh77s65aw435cab9rbzsq";

    // the number of movies to show in the list
    private static final int MOVIE_PAGE_LIMIT = 8;

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

        InitializeVariables();

    }

    /*
     * Initializing the variables and creating the bridge between the views from
     * the xml file and this class
     */

    private void InitializeVariables() {

        searchBox = (EditText) findViewById(R.id.etSearchBox);
        bGo = (Button) findViewById(R.id.bGo);
        bCancelAddFromWeb = (Button) findViewById(R.id.bCancelAddFromWeb);
        moviesList = (ListView) findViewById(R.id.list_movies);

        bGo.setOnClickListener(this);
        bCancelAddFromWeb.setOnClickListener(this);
        moviesList.setOnItemClickListener(this);
    }

    @Override
    public void onClick(View v) {
        switch (v.getId()) {

        case R.id.bGo:
            new RequestTask()
                    .execute("http://api.rottentomatoes.com/api/public/v1.0/movies.json?apikey="
                            + API_KEY
                            + "&q="
                            + searchBox.getText()
                            + "&page_limit=" + MOVIE_PAGE_LIMIT);
            break;

        case R.id.bCancelAddFromWeb:
            finish();
            break;

        }

    }

    private void refreshMoviesList(List<String> movieTitles) {
        moviesList.setAdapter(new ArrayAdapter<String>(this,
                android.R.layout.simple_list_item_1, movieTitles
                        .toArray(new String[movieTitles.size()])));
    }

    private class RequestTask extends AsyncTask<String, String, String> {
        // make a request to the specified url
        @Override
        protected String doInBackground(String... uri) {
            HttpClient httpclient = new DefaultHttpClient();
            HttpResponse response;
            String responseString = null;
            try {
                // make a HTTP request
                response = httpclient.execute(new HttpGet(uri[0]));
                StatusLine statusLine = response.getStatusLine();
                if (statusLine.getStatusCode() == HttpStatus.SC_OK) {
                    ByteArrayOutputStream out = new ByteArrayOutputStream();
                    response.getEntity().writeTo(out);
                    out.close();
                    responseString = out.toString();
                } else {
                    // close connection
                    response.getEntity().getContent().close();
                    throw new IOException(statusLine.getReasonPhrase());
                }
            } catch (Exception e) {
                Log.d("Test", "Couldn't make a successful request!");
            }
            return responseString;
        }

        @Override
        protected void onPostExecute(String response) {
            super.onPostExecute(response);

            try {
                // convert the String response to a JSON object
                JSONObject jsonResponse = new JSONObject(response);

                // fetch the array of movies in the response
                JSONArray jArray = jsonResponse.getJSONArray("movies");

                // add each movie's title to a list
                movieTitles = new ArrayList<String>();
                for (int i = 0; i < jArray.length(); i++) {
                    JSONObject movie = jArray.getJSONObject(i);
                    movieTitles.add(movie.getString("title"));

                }
                // refresh the ListView
                refreshMoviesList(movieTitles);
            } catch (JSONException e) {
                Log.d("Test", "Couldn't successfully parse the JSON response!");
            }
        }
    }

    @Override
    public void onItemClick(AdapterView<?> av, View view, int position, long id) {

        Intent openMovieEditor = new Intent(this, MovieEditor.class);
        openMovieEditor.putExtra("movieTitle", movieTitles.get(position));
        openMovieEditor.putExtra("callingActivity", ACTIVITY_WEB_ADD);
        startActivityForResult(openMovieEditor, ACTIVITY_WEB_ADD);

    }
}

Answer 1

请参阅下面修改后的代码..

public class MovieAddFromWeb extends Activity implements View.OnClickListener, OnItemClickListener {

private TextView searchBox;
private Button bGo, bCancelAddFromWeb;
private ListView moviesList;
public List<String> movieTitles;

//added new variables
public List<String> movieSynopsis;
public List<String> movieImgUrl;


static final int ACTIVITY_WEB_ADD = 3;

// the Rotten Tomatoes API key
private static final String API_KEY = "8q6wh77s65aw435cab9rbzsq";

// the number of movies to show in the list
private static final int MOVIE_PAGE_LIMIT = 8;

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

    InitializeVariables();

}

/*
 * Initializing the variables and creating the bridge between the views from
 * the xml file and this class
 */

private void InitializeVariables() {

    searchBox = (EditText) findViewById(R.id.etSearchBox);
    bGo = (Button) findViewById(R.id.bGo);
    bCancelAddFromWeb = (Button) findViewById(R.id.bCancelAddFromWeb);
    moviesList = (ListView) findViewById(R.id.list_movies);

    bGo.setOnClickListener(this);
    bCancelAddFromWeb.setOnClickListener(this);
    moviesList.setOnItemClickListener(this);
}

@Override
public void onClick(View v) {
    switch (v.getId()) {

    case R.id.bGo:
        new RequestTask()
                .execute("http://api.rottentomatoes.com/api/public/v1.0/movies.json?apikey="
                        + API_KEY
                        + "&q="
                        + searchBox.getText()
                        + "&page_limit=" + MOVIE_PAGE_LIMIT);
        break;

    case R.id.bCancelAddFromWeb:
        finish();
        break;

    }

}

private void refreshMoviesList(List<String> movieTitles) {
    moviesList.setAdapter(new ArrayAdapter<String>(this,
            android.R.layout.simple_list_item_1, movieTitles
                    .toArray(new String[movieTitles.size()])));
}

private class RequestTask extends AsyncTask<String, String, String> {
    // make a request to the specified url
    @Override
    protected String doInBackground(String... uri) {
        HttpClient httpclient = new DefaultHttpClient();
        HttpResponse response;
        String responseString = null;
        try {
            // make a HTTP request
            response = httpclient.execute(new HttpGet(uri[0]));
            StatusLine statusLine = response.getStatusLine();
            if (statusLine.getStatusCode() == HttpStatus.SC_OK) {
                ByteArrayOutputStream out = new ByteArrayOutputStream();
                response.getEntity().writeTo(out);
                out.close();
                responseString = out.toString();
            } else {
                // close connection
                response.getEntity().getContent().close();
                throw new IOException(statusLine.getReasonPhrase());
            }
        } catch (Exception e) {
            Log.d("Test", "Couldn't make a successful request!");
        }
        return responseString;
    }

    @Override
    protected void onPostExecute(String response) {
        super.onPostExecute(response);

        try {
            // convert the String response to a JSON object
            JSONObject jsonResponse = new JSONObject(response);

            // fetch the array of movies in the response
            JSONArray jArray = jsonResponse.getJSONArray("movies");

            // add each movie's title to a list
            movieTitles = new ArrayList<String>();

            //newly added
            movieSynopsis = new ArrayList<String>();
            movieImgUrl= new ArrayList<String>();

            for (int i = 0; i < jArray.length(); i++) {
                JSONObject movie = jArray.getJSONObject(i);
                movieTitles.add(movie.getString("title"));


                movieSynopsis.add(movie.getString(#add the synopsis var name returned by the JSON));
                movieImgUrl.add(movie.getString(#add the urlvar name returned by the JSON));


            }
            // refresh the ListView
            refreshMoviesList(movieTitles);
        } catch (JSONException e) {
            Log.d("Test", "Couldn't successfully parse the JSON response!");
        }
    }
}

@Override
public void onItemClick(AdapterView<?> av, View view, int position, long id) {

    Intent openMovieEditor = new Intent(this, MovieEditor.class);
    openMovieEditor.putExtra("movieTitle", movieTitles.get(position));

    //newly added
    openMovieEditor.putExtra("movieSynopsis", movieSynopsis.get(position));
    openMovieEditor.putExtra("movieImgUrl", movieImgUrl.get(position));


    openMovieEditor.putExtra("callingActivity", ACTIVITY_WEB_ADD);
    startActivityForResult(openMovieEditor, ACTIVITY_WEB_ADD);

}