我已经完全更新了这个问题:
这是我在 PHP 中的 json_encode 示例:
print(json_encode($row));
导致{"AverageRating":"4.3"}，这很好。
但是在Java中，我似乎无法获取这个4.3值。这是(对于 Android 项目)我编辑了不相关的数据。
public class Rate extends ListActivity {
JSONArray jArray;
String result = null;
InputStream is = null;
StringBuilder sb = null;
String Item, Ratings, Review, starAvg;
RatingBar ratingsBar;
ArrayList<NameValuePair> param;
public void onCreate(Bundle savedInstanceState) {
starAvg = "0";
new starRatingTask().execute();
ratingsBar = (RatingBar) findViewById(R.id.theRatingBar);
class starRatingTask extends AsyncTask<String, String, Void> {
InputStream is = null;
String result = "";
@Override
protected Void doInBackground(String... params) {
String url_select = "http://www.---.com/---/average_stars.php";
ArrayList<NameValuePair> param = new ArrayList<NameValuePair>();
param.add(new BasicNameValuePair("item", Item));
HttpClient httpClient = new DefaultHttpClient();
HttpPost httpPost = new HttpPost(url_select);
try {
httpPost.setEntity(new UrlEncodedFormEntity(param));
HttpResponse httpResponse = httpClient.execute(httpPost);
HttpEntity httpEntity = httpResponse.getEntity();
// read content
is = httpEntity.getContent();
} catch (Exception e) {
Log.e("log_tag", "Error in http connection " + e.toString());
}
try {
BufferedReader br = new BufferedReader(
new InputStreamReader(is));
StringBuilder sb = new StringBuilder();
String line = "";
while ((line = br.readLine()) != null) {
sb.append(line + "\n");
}
is.close();
result = sb.toString();
} catch (Exception e) {
Log.e("log_tag", "Error converting result " + e.toString());
}
return null;
}
protected void onPostExecute(Void v) {
try {
jArray = new JSONArray(result);
JSONObject json_data = null;
for (int i = 0; i < jArray.length(); i++) {
json_data = jArray.getJSONObject(i);
starAvg = json_data.getString("AverageRating");
}
} catch (JSONException e1) {
Toast.makeText(getBaseContext(), "No Star Ratings!",
Toast.LENGTH_LONG).show();
} catch (ParseException e1) {
e1.printStackTrace();
}
Toast.makeText(getBaseContext(), starAvg,
Toast.LENGTH_LONG).show();
ratingsBar.setRating(Float.valueOf(starAvg));
}
}
第二个 toast 评级产生“0”，如一开始所设置的那样。
最佳答案
为什么不以 JSON 形式传回“整个”行？
print(json_encode($row));
JSON 旨在表示对象，如果您只是传回一个数字，那么将其作为数字字符串传递不是更好吗？不过，我知道想要使用 JSON，因此它是通用的，这就是为什么您应该将整行传回。然后它将是一个包含平均值的数组(只有一个元素)。
关于java - 从 PHP/MySQL 到 Java/JSON，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/11149197/