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I'm looking for a way to send POST data to a PHP script and display the result.I want to send POST data of $username to php. This is my php file:

<?php ...// connect $username = $_POST['txtUsername'];// this data $mysqli->query("SET NAMES 'utf8'"); $sql="SELECT * FROM $username"; $result=$mysqli->query($sql); while($e=mysqli_fetch_assoc($result)){ $output[]=$e; } print(json_encode($output)); $mysqli->close(); ?>

My activities:
DataParser.class

public class DataParser extends AsyncTask<Void,Void,Integer>{ Context c; ListView lv; String jsonData; ProgressDialog pd; ArrayList<Spacecraft> spacecrafts = new ArrayList<>(); public DataParser(Context c, ListView lv, String jsonData) { this.c = c; this.lv = lv; this.jsonData = jsonData; } @Override protected void onPreExecute() { super.onPreExecute(); pd= new ProgressDialog(c); pd.setTitle("Parse"); pd.setMessage("Parsing..Please wait"); pd.show(); } @Override protected Integer doInBackground(Void... voids) { return this.parseData(); } @Override protected void onPostExecute(Integer result) { super.onPostExecute(result); pd.dismiss(); if (result==0){ Toast.makeText(c,"Unable to parse",Toast.LENGTH_SHORT).show(); } else { CustomAdapter adapter = new CustomAdapter(c,spacecrafts); lv.setAdapter(adapter); } } private int parseData(){ try { JSONArray ja = new JSONArray(jsonData); JSONObject jo = null; spacecrafts.clear(); Spacecraft s=null; for (int i=0;i<ja.length();i++){ jo=ja.getJSONObject(i); int id = jo.getInt("id"); String name =jo.getString("name"); String send =jo.getString("send"); String comment =jo.getString("comment"); String date =jo.getString("date"); s=new Spacecraft(); s.setId(id); s.setName(name); s.setSend(send); s.setComment(comment); s.setDate(date); spacecrafts.add(s); } return 1; } catch (JSONException e) { e.printStackTrace(); } return 0; }}

MainActivity: 

public class MainActivity extends AppCompatActivity implements AsyncResponse { String urlAddress="http://mysite/myphp.php"; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); final ListView lv = (ListView) findViewById(R.id.lv) ; Intent intent = getIntent(); final String username = intent.getStringExtra("location"); Downloader d = new Downloader(MainActivity.this,urlAddress,lv); d.execute();

And Downloader.class:

public class Downloader extends AsyncTask<Void,Void,String> { Context c; String urlAddress; ListView lv; ProgressDialog pd; public Downloader(Context c, String urlAddress, ListView lv) { this.c = c; this.urlAddress = urlAddress; this.lv = lv; } @Override protected void onPreExecute() { super.onPreExecute(); pd = new ProgressDialog(c); pd.setTitle("Fetch"); pd.setMessage("Fetching...Please wait"); pd.show(); } @Override protected String doInBackground(Void... voids) { return this.downloadData(); } @Override protected void onPostExecute(String s) { super.onPostExecute(s); pd.dismiss(); if(s==null){ Toast.makeText(c,"Unsuccessful,Null,returned",Toast.LENGTH_SHORT).show(); } else { DataParser parser = new DataParser(c,lv,s); parser.execute(); } } private String downloadData(){ HttpURLConnection con = Connector.connect(urlAddress); if (con==null){ return null; } InputStream is=null; try { is=new BufferedInputStream(con.getInputStream()); BufferedReader br = new BufferedReader(new InputStreamReader(is)); String line = null; StringBuffer response = new StringBuffer(); if (br!=null){ while ((line=br.readLine())!=null){ response.append(line+"\n"); } br.close(); } else {return null;} return response.toString(); } catch (IOException e) { e.printStackTrace(); } finally { if(is != null){ try { is.close(); } catch (IOException e) { e.printStackTrace(); } } } return null; }}

Please help me, Thank you!

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  • where is the problem? in your java codes or in PHP codes ? Commented Jul 1, 2016 at 23:54
  • Use retrofit square.github.io/retrofit for http requests. Commented Jul 2, 2016 at 4:40

1 Answer 1

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Based on the code you've provided, it looks like you are downloading data, but it doesn't seem like you are posting any data.

There are a few ways you can send data via HTTP POST. You could try using the Google IO Volley API, which takes care of a lot of the logic of network calls for you.

For example:

RequestQueue queue = Volley.newRequestQueue(this); String url = "https://myurl.com"; JsonRequest postRequest = new StringRequest(Request.Method.POST, url, new Response.Listener<String>() { @Override public void onResponse(JSONObject response) { Log.d(TAG, response.toString()); } }, new Response.ErrorListener() { @Override public void onErrorResponse(VolleyError error) { Log.e(TAG, error.toString()); } }) { @Override protected Map<String, String> getParams() { Map<String, String> params = new HashMap<String, String>(); params.put("txtUsername", "mUsername"); return params; } @Override public Map<String, String> getHeaders() throws AuthFailureError { Map<String, String> headers = new HashMap<String, String>(); headers.put("Content-Type", "application/x-www-form-urlencoded"); return headers; } }; queue.add(postRequest);

You could also write your own AsyncTask to perform the post. Here is an example:

public class PostRequestAsyncTask extends AsyncTask<Void, Void, String { Context context; Map<String, String> postParams; /** * Overridden constructor */ public PostRequestAsyncTask(Context context, Map<String, String> postParams) { this.context = context; this.postParams = new LinkedHashMap<String, String>(postParams); } /** * Default constructor */ public PostRequestAsyncTask() {} public byte[] generatePostData() { StringBuilder postData = new StringBuilder(); for (Map.Entry<String, String> dParam : postParams.entrySet()) { if (postData.length() != 0) postData.append('&'); try { postData.append(URLEncoder.encode(dParam.getKey(), "UTF-8")); postData.append('='); postData.append(URLEncoder.encode(String.valueOf(dParam.getValue()), "UTF-8")); } catch (UnsupportedEncodingException e) { e.printStackTrace(); } } byte[] postDataBytes = null; try { postDataBytes = postData.toString().getBytes("UTF-8"); } catch (UnsupportedEncodingException e) { e.printStackTrace(); } return postDataBytes; } @Override protected String doInBackground(Void... params) { /* Set params */ byte[] postDataBytes = generatePostData(); /* Set headers and write */ URL url = null; HttpURLConnection conn = null; try { url = new URL("https://myurl.com"); conn = (HttpURLConnection) url.openConnection(); conn.setRequestMethod("POST"); conn.setRequestProperty("Content-Type", "application/x-www-form-urlencoded"); conn.setRequestProperty("Content-Length", String.valueOf(postDataBytes.length)); conn.setDoOutput(true); conn.getOutputStream().write(postDataBytes); } catch (MalformedURLException | IOException e) { e.printStackTrace(); } /* Retrieve response */ Reader in = null; String response = new String(); try { in = new BufferedReader(new InputStreamReader(conn.getInputStream(), "UTF-8")); response = ""; for (int c = in.read(); c != -1; c = in.read()) { response += (char) c; } } catch (IOException e) { e.printStackTrace(); } return response; } @Override protected void onPostExecute(String resp) { super.onPostExecute(resp); JSONObject jsonResponse = null; try { jsonResponse = new JSONObject(resp); //do something with your json response } catch (JSONException e) { e.printStackTrace(); } } }

Then execute your AsyncTask like so:

Map<String, String> postParams = new LinkedHashMap<>(); postParams.put("txtUserName", "mUsername"); new PostRequestAsyncTask(MyActivity.this, postParams).execute();
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