在Android中读取Json文件并在ListView中填充 [英] Read Json file in Android and Populate in ListView

问题描述

我编写了这段代码来读取json文件，并在listview中显示它，但返回空列表.如果有人建议我，我将不胜感激.谢谢

I write this piece of code for reading json file and show it in listview but it return empty list . I would appreciate if anybody advise me. Thanks

eventList.json:

eventList.json:

    {
"events": [
{
"event": "Taste of day"
},
{
"event": "House Party at Park"
},
{
"event": "Farmers Markets"
},
{
"event": "Blues Festival Preview Events"
},
{
"event": "Cultural Alliance - Heritage and Fashion"
}
]
}

这是一个用于读取和解析json文件的活动:

and this an Activity for reading and parsing json file :

     public class EventSelectActivity extends Activity {




@Override


protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_event_select);


    // Reading json file from assets folder
    StringBuffer sb = new StringBuffer();
    BufferedReader br = null;
    try {
        br = new BufferedReader(new InputStreamReader(getAssets().open(
                "eventList.json")));
        String temp;
        while ((temp = br.readLine()) != null)
            sb.append(temp);
    } catch (IOException e) {
        e.printStackTrace();
    } finally {
        if ((br != null)) {
            try {
                br.close(); // stop reading
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }

    try {
        JSONObject jsonObjMain = new JSONObject();
        JSONArray jsonArray = jsonObjMain.getJSONArray("events");

        ArrayList<String> messages = new ArrayList<String>();
        for (int i = 0; i < jsonArray.length(); i++) {

            // Creating JSONObject from JSONArray
            JSONObject jsonObj = jsonArray.getJSONObject(i);

            // Getting data from individual JSONObject
            String message = jsonObj.getString("msg");
            messages.add(message);

        }

        ArrayAdapter<String> adapter = new ArrayAdapter<String>(EventSelectActivity.this,
                android.R.layout.simple_list_item_1, messages);
        ListView list=(ListView)findViewById(R.id.eventList);
        list.setAdapter(adapter);
        list.setOnItemClickListener(new AdapterView.OnItemClickListener()
        {

            @Override
            public void onItemClick(AdapterView<?> parent, View view,
                                    int position, long id) {
                Toast.makeText(EventSelectActivity.this, "TEST List View", Toast.LENGTH_SHORT).show();

            }
        });

    } catch (JSONException e) {
        e.printStackTrace();
    }


}

}

推荐答案

变量sb保存已使用的JSON数据.

The variable sb holds the consumed JSON data.

没有引用实际的JSON对象，因为它是空的.

There was no reference to actual JSON object as it was empty.

JSONObject jsonObjMain = new JSONObject();

更改代码块:

try {
   JSONObject jsonObjMain = new JSONObject(sb.toString());
   JSONArray jsonArray = jsonObjMain.getJSONArray("events");
   // ... 

对JSON字段"msg"有未定义的引用，也许应该是事件"?

There is a undefined reference to the JSON field, "msg", maybe it should be "event"?

// Getting data from individual JSONObject
String message = jsonArray.getString(i);
messages.add(message);

这篇关于在Android中读取Json文件并在ListView中填充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！