I'm really confused, i'm trying to develop a simple function that allow me to send and receive data from a server.
The operation is as follows:
In an activity I execute an HTTP POST to a PHP file on a server, the "PHP file" gets the data that i send (tipically a string), and executes a query using the parameters sent over http.
Example:
My android app send a string with this value "PIPPO", in the PHP file there is a query, for example:
$value = PIPPO /* data received from android app*/ Select * from characters where(characters.name=".$value.")
p.s. all data use JSON format
The problem is: i always used a function (that works fine) but now all methods are deprecated, I can't find an alternative to the methods for the newest API.
This is my code:
public class ReadServer extends Activity {
String result;
public String readserver(String id_data, String data){
try{
HttpClient httpclient = new DefaultHttpClient();
HttpPost httpPost = new HttpPost("myurl/queryMobile.php");
StringBuilder builder = new StringBuilder();
String json = "";
//Build jsonObject
JSONObject jsonObject = new JSONObject();
jsonObject.accumulate(id_data, data);
//Convert JSONObject to JSON to String
json = jsonObject.toString();
//Set json to StringEntity
StringEntity se = new StringEntity(json);
//Set httpPost Entity
httpPost.setEntity(se);
//Set some headers to inform server about the type of the content
httpPost.setHeader("Accept", "application/json");
httpPost.setHeader("Content-type", "application/json");
//Execute POST request to the given URL
HttpResponse httpResponse = httpclient.execute(httpPost);
//Receive response as inputStream
StatusLine statusLine = httpResponse.getStatusLine();
int statusCode = statusLine.getStatusCode();
//Convert input stream to string
AlertDialog.Builder alertDialog;
switch(statusCode){
case 200:
HttpEntity entity = httpResponse.getEntity();
InputStream content = entity.getContent();
BufferedReader reader = new BufferedReader(new InputStreamReader(content));
String line="";
try{
while ((line = reader.readLine()) != null) {
builder.append(line);
result = builder.toString();
}
}catch(Exception e){
alertDialog = new AlertDialog.Builder(this);
alertDialog.setTitle("400 Bad Request");
alertDialog.setMessage("Non è stato possibile soddisfare la tua richiesta, riprova più tardi.");
alertDialog.show();
}
break;
Just try this code. :)
public class MainActivity extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
new Test().execute();
}
//AsyncTask
class Test extends AsyncTask < String, Void, String > {
@Override
protected String doInBackground(String...params) {
InputStream in = null;
String queryResult = "";
URL url = new URL("http://www.android.com/");
HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();
//add parameters
urlConnection.setReadTimeout(10000);
urlConnection.setConnectTimeout(15000);
urlConnection.setRequestMethod("POST");
urlConnection.setDoInput(true);
urlConnection.setDoOutput(true);
List<NameValuePair> params = new ArrayList<NameValuePair>();
params.add(new BasicNameValuePair("firstParam", paramValue1));
params.add(new BasicNameValuePair("secondParam", paramValue2));
params.add(new BasicNameValuePair("thirdParam", paramValue3));
try {
//write OutputStream
OutputStream os = urlConnection.getOutputStream();
BufferedWriter writer = new BufferedWriter(
new OutputStreamWriter(os, "UTF-8"));
writer.write(getQuery(params));
writer.flush();
writer.close();
os.close();
InputStream in = new BufferedInputStream(urlConnection.getInputStream());
queryResult = readStream( in );
} finally {
urlConnection.disconnect();
}
return queryResult;
}
private String readStream(InputStream iStream) throws IOException {
//Buffered reader allows us to read line by line
try (BufferedReader bReader =
new BufferedReader(new InputStreamReader(iStream))) {
StringBuilder builder = new StringBuilder();
String line;
while ((line = bReader.readLine()) != null) { //Read till end
builder.append(line);
}
return builder.toString();
}
}
private String getQuery(List<NameValuePair> params) throws UnsupportedEncodingException
{
StringBuilder result = new StringBuilder();
boolean first = true;
for (NameValuePair pair : params)
{
if (first)
first = false;
else
result.append("&");
result.append(URLEncoder.encode(pair.getName(), "UTF-8"));
result.append("=");
result.append(URLEncoder.encode(pair.getValue(), "UTF-8"));
}
return result.toString();
}
protected void onPostExecute(String data) {
// do further things
Toast toast = Toast.makeText(getApplicationContext(), data,
Toast.LENGTH_SHORT);
toast.show();
}
}
}
Maybe its the time you start using volley. It's a great library and made just for to solve your purpose.
Don't know anything about volley. Well don't worry. Here is a perfect video to tell you what volley is capable of. It includes all the steps to include it in your project (although it is nothing more than mentioning gradle dependency)
I am also mentioning a sample example of how you can use it in your code.
public class MainActivity extends Activity {
private TextView txtDisplay;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
txtDisplay = (TextView) findViewById(R.id.txtDisplay);
RequestQueue queue = Volley.newRequestQueue(this);
String url = "myurl/queryMobile.php";
JSONObject params = new JSONObject();
params.put("name", "Dexter");
JsonObjectRequest jsObjRequest =
new JsonObjectRequest(Request.Method.POST,
url,
param,
new Response.Listener<JSONObject>() {
@Override
public void onResponse(JSONObject response) {
// TODO Auto-generated method stub
txtDisplay.setText("Response => "+response.toString());
findViewById(R.id.progressBar1).setVisibility(View.GONE);
}},
new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
// TODO Auto-generated method stub
}
});
queue.add(jsObjRequest);
}
}
The original code (and tutorial) is available here.
Believe me someday you will have to move to volley, why not today!
来源：https://stackoverflow.com/questions/35535257/send-and-receive-data-from-server-using-6-0-api-android