Question

我有一个Android应用程序，并使用PHP脚本和JSON对象建立了与MySql数据库的连接。如何根据当前的“ Android客户端”用户名检查结果？如果该用户名位于列中（例如receiver或sender），我只想显示当前用户名的消息。我该怎么解决？如何检查在某些列中是否存在进行连接的用户名（并使用JSON对象获取结果）？有人有主意吗？

在php脚本中查询。我认为无法将当前用户名发送到php脚本以查看某列中是否存在

$sql = "SELECT users.username, `message` FROM users, messages
WHERE msg_fk_user_id = users.id";

机器人活动-下载php脚本并使用JSON对象对结果进行编码。

public class ViewDbMessages extends AppCompatActivity {

    ListView listView;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_view_db_messages);

        listView = (ListView) findViewById(R.id.listView);
        downloadJSON("http://192.168.00.00/socketIO/examples/chat/public/android_db_connection.php");
    }


    private void downloadJSON(final String urlWebService) {

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

            @Override
            protected void onPreExecute() {
                super.onPreExecute();
            }


            @Override
            protected void onPostExecute(String s) {
                super.onPostExecute(s);
//                Toast.makeText(getApplicationContext(), s, Toast.LENGTH_SHORT).show();
                try {
                    loadIntoListView(s);
                } catch (JSONException e) {
                    e.printStackTrace();
                }
            }

            @Override
            protected String doInBackground(Void... voids) {
                try {
                    URL url = new URL(urlWebService);
                    HttpURLConnection con = (HttpURLConnection) url.openConnection();
                    StringBuilder sb = new StringBuilder();
                    BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(con.getInputStream()));
                    String json;
                    while ((json = bufferedReader.readLine()) != null) {
                        sb.append(json + "\n");
                    }
                    return sb.toString().trim();
                } catch (Exception e) {
                    return null;
                }
            }
        }
        DownloadJSON getJSON = new DownloadJSON();
        getJSON.execute();
    }

    private void loadIntoListView(String json) throws JSONException {
        JSONArray jsonArray = new JSONArray(json);
        String[] stocks = new String[jsonArray.length()];
        for (int i = 0; i < jsonArray.length(); i++) {
            JSONObject obj = jsonArray.getJSONObject(i);
            stocks[i] = obj.getString("username") + ": " + obj.getString("message");
        }
        ArrayAdapter<String> arrayAdapter = new ArrayAdapter<>(this, android.R.layout.simple_list_item_1, stocks);
        listView.setAdapter(arrayAdapter);
    }
}

如何从数据库显示特定“ android-client”用户名的数据

0 个答案: