Question

我很熟悉REST API。这是我得到的JSON响应，任何人都可以告诉我如何循环这个JSON阵列打印关键字＆amp; listView中的Creation_date？

{"result": "ok", 
"keywords":
    [ 
    {"keyword_id":"3",
     "keyword":"keyword1",
     "creation_date":"2015-03-12 15:45:12",
     "description":"",
     "tags":"",
     "followers_count":0,
     "feedbacks_count":0
     }, 
     {"keyword_id":"4",
      "keyword":"keyword2",
      "creation_date":"2015-03-12 15:45:34",
      "description":"",
      "tags":"",
      "followers_count":0,
      "feedbacks_count":0
     } 
     ], 
      "error":"" 
}

这就是我想要做的事情。

protected void onPostExecute(String result) {
            Toast.makeText(getBaseContext(), result, Toast.LENGTH_LONG).show();
            keyWord = new ArrayList<FollowingKeywords>();
            keywordlist = new ArrayList<String>();
            try {
                JSONObject json = new JSONObject(result);
                String Result = json.getString("result");

                if (Result.equals("ok")) {
                    JSONArray jarray = new JSONArray("keywords");
                    for (int i = 0; i < jarray.length(); i++) {

                        FollowingKeywords keywords = new FollowingKeywords();
                        keywords.setKeyword(JSONObject.optString("keyword"));
                        keywords.setTimestamp(JSONObject.optString("creation_date"));
                        keyWord.add(keywords);

                    }
                    count = jarray.length();
                }
            } catch (JSONException e) {
                e.printStackTrace();
            }
        }

Answer 1

您几乎就在那里，只需将此行JSONObject keywordsObject = jarray.getJSONObject(i);添加到您的for循环中，以便您可以从JSONArray中获取每个单独的对象。我已经更新了下面的完整代码段代码。

protected void onPostExecute(String result) {
            Toast.makeText(getBaseContext(), result, Toast.LENGTH_LONG).show();
            keyWord = new ArrayList<FollowingKeywords>();
            keywordlist = new ArrayList<String>();
            try {
                JSONObject json = new JSONObject(result);
                String Result = json.getString("result");

                if (Result.equals("ok")) {
                    JSONArray jarray = new JSONArray("keywords");
                    for (int i = 0; i < jarray.length(); i++) {

                        JSONObject keywordsObject = jarray.getJSONObject(i);

                        FollowingKeywords keywords = new FollowingKeywords();
                        keywords.setKeyword(keywordsObject.optString("keyword"));
                        keywords.setTimestamp(keywordsObject.optString("creation_date"));
                        keyWord.add(keywords);

                    }
                    count = jarray.length();
                }
            } catch (JSONException e) {
                e.printStackTrace();
            }
        }

Answer 2

如果你想要的只是在列表视图上显示值，你可以使用SimpleAdapter

listview = (ListView) findViewById(R.id.listview);

    ArrayList<HashMap<String, Object>> items = new ArrayList<HashMap<String, Object>>();
    HashMap<String, Object> listItem;

    for (int i = 0; i < jarray.length(); i++) {
        listItem = new HashMap<String, Object>();
        listItem.put("keyword", keywordsObject.optString("keyword"));
        listItem.put("creation_date", keywordsObject.optString("creation_date"));
        items.add(listItem);
        }

    adapter = new SimpleAdapter(getApplicationContext(), items,R.layout.yourlistviewlayout,
                            new String[] { "keyword", "creation_date" },
                            new int[] { R.id.textViewKeyword, R.id.textViewCreationDate });

    listview.setAdapter(adapter);

并在布局文件夹中创建yourlistviewlayout，其中包含两个textview，textViewKeyword和textViewCreationDate

Answer 3

将android.R.layout.simple_list_item_2用作ListView中的行项目。您需要创建自定义适配器，以便在ListView中显示这两个文本。在getView()方法中设置两个文本。另外，使用ViewHolder模式在ListView上进行平滑滚动。

protected void onPostExecute(String result) {
        JSONObject json = null;
        try {
            json = new JSONObject(result);
        } catch (JSONException e) {
            e.printStackTrace();
        }

        ArrayList<FollowingKeywords> keyWord = new ArrayList<FollowingKeywords>();
        JSONArray keywordArray = json.optJSONArray("keywords");
        if(keywordArray != null) {
            for (int i = 0; i < keywordArray.length(); i++) {
                JSONObject keywordObject = keywordArray.optJSONObject(i);
                if(keywordObject != null) {
                     FollowingKeywords keywords = new FollowingKeywords();
                     keywords.setKeyword(keywordObject.optString("keyword"));
                     keywords.setTimestamp(keywordObject.optString("creation_date"));
                     keyWord.add(keywords);
                }
            }
        }

        MyAdapter myAdapter = new MyAdapter(this, android.R.layout.simple_list_item_2, keyWord);
        ListView listView1 = (ListView) findViewById(R.id.listView1);
        listView1.setAdapter(myAdapter);
    }

<强> MyAdapter.java

public class MyAdapter extends ArrayAdapter<FollowingKeywords>{

    Context context;
    List<FollowingKeywords> keywordList;

    public MyAdapter(Context context, int resource, ArrayList<FollowingKeywords> keywordList) {
        super(context, resource, keywordList);
        this.context = context;
        this.keywordList = keywordList;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        View row = convertView;
        ViewHolder holder;
        if(row == null){
            LayoutInflater inflater = (LayoutInflater)context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            row = (View)inflater.inflate(android.R.layout.simple_list_item_2, null);      

            holder = new ViewHolder();
            holder.keywordText = (TextView)row.findViewById(android.R.id.text1);
            holder.creationText = (TextView)row.findViewById(android.R.id.text2);

            row.setTag(holder);
        } else{
            holder = (ViewHolder) row.getTag();
        }

        holder.keywordText.setText(keywordList.get(position).getKeyword());
        holder.creationText.setText(keywordList.get(position).getTimestamp());

        return row;
    }

    static class ViewHolder {
        TextView keywordText;
        TextView creationText;
    }

}

如何循环JSON数组并在Listview中打印值？ ANDROID

3 个答案: