java - 从 PHP 编码的 JSON 数据中获取 Null，输出到 Java

Question

我在 PHP 中的 JSON 输出是这样完成的:

 print json_encode(array('rate' => $topcat, 'hometown' => $hometown, 'talk' => $talk));

我的 JSON 输出在浏览器中如下所示:

{"rate":"电影","hometown":"华盛顿州西雅图","talk":"电影"}

在 Java/Android 中我这样做:

protected void onPostExecute(Void v) {

    try {
        JSONArray jArray = new JSONArray(result);
        JSONObject json_data = null;
        for (int i = 0; i < jArray.length(); i++) {
            json_data = jArray.getJSONObject(i);


            Hometown = json_data.getString("hometown");
            FavCategory = json_data.getString("rate");              
            Talk = json_data.getString("talk");



        }
    } catch (JSONException e1) {

    } catch (ParseException e1) {
        e1.printStackTrace();
    }

    if (Hometown.equals("")) {
        Hometown = "Not Specified";
    }

    tvHometown.setText(Hometown);
    tvRate.setText(FavCategory);
    tvTalk.setText(Talk);

    Log.d("Log: ", Hometown + " " + FavCategory + " " + Talk);

}

}

在该日志上，我得到:西雅图，华盛顿州，null，null

有人能明白为什么吗？

编辑:新的 Java 代码，仍然出现错误:

String homeTown = "", favCategory = "", favTalk = "";
        try {
            JSONObject jsonData = new JSONObject(result);

            homeTown = jsonData.getString("hometown");
            favCategory = jsonData.getString("rate");
            favTalk = jsonData.getString("talk");


            tvHometown.setText(homeTown);
            tvRate.setText(favCategory);
            tvTalk.setText(favTalk);




} catch (JSONException e1) {

    } catch (ParseException e1) {
        e1.printStackTrace();
    }

我遇到异常:

02-05 08:51:48.078: E/log_tag(22958): Error in http connection org.json.JSONException: Value null of type org.json.JSONObject$1 cannot be converted to JSONArray

Answer 1

尽管the PHP vocabulary ，此 JSON 的顶级元素:

{"rate":"Movies","hometown":"Seattle, WA","talk":"Movies"}

是 an object (a key-value mapping), not an array 。 {} 是一个致命的赠品。

改变这个

JSONArray jArray = new JSONArray(result);

对此:

JSONObject jsonData = new JSONObject(result);

然后从那里开始:

String hometown = jsonData.getString("hometown");
String favCategory = jsonData.getString("rate");              
String talk = jsonData.getString("talk");

注意如何，as a matter of good Java style ，我使用 lowerCamelCased 变量名称。