Question

我一直在研究如何从服务器查询JSON数据并解析它以便在我的应用程序中使用。但是，我发现了许多不同的方法来做同样的事情。我意识到有不同的JSON解析器，所以让我们假设我坚持使用标准解析器。我的主要问题与服务器请求有关。这是我目前的MapActivity代码

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

    @Override
    protected void onPreExecute() {
        super.onPreExecute();
        // Create a Progress Dialog
        mProgressDialog = new ProgressDialog(MapActivity.this);
        mProgressDialog.setTitle("Downloading Data");
        mProgressDialog.setMessage("Loading...");
        mProgressDialog.setIndeterminate(false);
        mProgressDialog.show();
    }

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

        try {
            // Retrieve JSON Objects from the given URL address
            jsonarray = JSONFunctions.getJSONfromURL("myurl");

            for (int i = 0; i < jsonarray.length(); i++) {
                HashMap<String, String> map = new HashMap<String, String>();
                JSONObject obj = jsonarray.getJSONObject(i);

                // Retrieve JSON Objects
                map.put("id",  String.valueOf(i));
                map.put("name", obj.getString("name"));

                // 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) {
        // Do something with data
        mProgressDialog.dismiss();
    }
}

如果我的JSON数据的结构看起来很奇怪，那是因为它存储在一个未命名的数组中，所以我不必先创建一个对象。无论如何......我基本上是基于this tutorial。但是，他们有更多的代码。这一切真的有必要吗？我不这么认为。我搜索了更多，发现其他使用一半代码的例子，基本上做了同样的事情。所以我的问题，作为Android程序员的开始，处理JSON数据的最佳做法是什么？谢谢！

JSON文件示例：

[
    {
        "name": "test",
        "lat": "42.01108",
        "long": "93.679196"
    },
    {
        "name": "test",
        "lat": "42.01108",
        "long": "93.679196"
    }
]

Answer 1

@leerob您好，有一段时间我发现自己处于两难境地，但最近我使用了基本类来使Android处理json并且相当不错，我推荐您的一个好习惯就是声明常量json的关键，我有一个例子：

 public void insertMovieTypeFromJson(String movieTypeJsonStr) throws JSONException {
            final String ID = "id";
            final String TYPE = "type";
            final String DESCRIPTION = "description";

            if (movieTypeJsonStr == null)
                    return;

            try {
                    JSONArray movieTypeArrayJson = new JSONArray(movieTypeJsonStr);

                    Vector<ContentValues> cVVector = new Vector<>(movieTypeArrayJson.length());

                    for (int i = 0; i < movieTypeArrayJson.length(); i++) {

                            long id;
                            String type;
                            String description;

                            JSONObject movie = movieTypeArrayJson.getJSONObject(i);

                            id = movie.getLong(ID);
                            type = movie.getString(TYPE);
                            description = movie.getString(DESCRIPTION);

                            ContentValues movieTypeValues = new ContentValues();

                            movieTypeValues.put(MovieContract.MovieTypeEntry._ID, id);
                            movieTypeValues.put(MovieContract.MovieTypeEntry.COLUMN_TYPE, type);
                            movieTypeValues.put(MovieContract.MovieTypeEntry.COLUMN_DESCRIPTION, description);
                            cVVector.add(movieTypeValues);
                    }

                    int inserted = 0;

                    if (cVVector.size() > 0) {
                            ContentValues[] cvArray = new ContentValues[cVVector.size()];
                            cVVector.toArray(cvArray);
                            inserted = getContext().getContentResolver().bulkInsert(MovieContract.MovieTypeEntry.CONTENT_URI, cvArray);
                    }

                    Log.d(LOG_TAG, "MovieTask Complete. " + inserted + " MovieType Inserted");

            } catch (JSONException e) {
                    Log.e(LOG_TAG, e.getMessage(), e);
                    e.printStackTrace();
            }
    }

JSON：

[
    {
        "id": "1",
        "type": "Action & Adventure",
        "description": "Action & Adventure"
    },
    {
        "id": "2",
        "type": "Animation",
        "description": "Animation"
    },
    {
        "id": "3",
        "type": "Comedy",
        "description": "Comedy"
    },
    {
        "id": "4",
        "type": "Terror",
        "description": "Terror"
    }
]

我希望你觉得它很有用。

Answer 2

试试这个......

private class TestJSONParsing extends AsyncTask<JSONArray, Void, JSONArray>
{
    ArrayList<HashMap<String, String>> arraylist;
    HashMap<String, String> map;

    @Override
    protected void onPreExecute()
    {
        super.onPreExecute();
        mProgressDialog = new ProgressDialog(MapActivity.this);
        mProgressDialog.setTitle("Downloading Data");
        mProgressDialog.setMessage("Loading...");
        mProgressDialog.setIndeterminate(false);
        mProgressDialog.show();

    }

    @Override
    protected JSONArray doInBackground(JSONArray... params)
    {
        return JSONFunctions.getJSONfromURL("myurl");

    }

    @Override
    protected void onPostExecute(JSONArray resultArray)
    {
        super.onPostExecute(resultArray);
        mProgressDialog.dismiss();
        if (null != resultArray)
        {
            int resultLength = resultArray.length();
            if (resultLength > 0)
            {
                try
                {
                    for (int i = 0; i < resultLength; i++)
                    {
                        JSONObject jsonObject = resultArray
                                .getJSONObject(i);
                        map.put("id", String.valueOf(i));
                        map.put("name", jsonObject.getString("name"));
                        arraylist.add(map);
                    }
                } catch (Exception e)
                {
                    // TODO: handle exception
                    e.printStackTrace();
                }

                if (arraylist.size() > 0)
                {
                    SimpleAdapter adapter = new SimpleAdapter(
                            MapActivity.this, arraylist,
                            R.layout.your_simple_row, new String[]
                            { "id", "name" }, new int[]
                            { R.id.nameId, R.id.name });
                    // bind adapter to your components
                    listView.setAdapter(adapter);
                }
            }
        } else
        {
            Toast.makeText(getApplicationContext(), "No data",
                    Toast.LENGTH_SHORT).show();
        }

    }

}

快乐的编码......

Android：处理JSON数据的最佳实践

2 个答案: