I don't know where exactly the problem lies, the app crashes anytime I log.i the info from the api.
This is the code. I don't know whether the code is out dated, I am running the newest version of Android Studio.
public class DownloadTask extends AsyncTask<String, Void, String> {
#Override
protected String doInBackground(String... urls) {
String result = "";
URL url;
HttpURLConnection urlConnection = null;
try {
url = new URL(urls[0]);
urlConnection = (HttpURLConnection) url.openConnection();
InputStream in = urlConnection.getInputStream();
InputStreamReader reader = new InputStreamReader(in);
int data = reader.read();
while (data != -1) {
char current = (char) data;
result += current;
data = reader.read();
}
return result;
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
return null;
}
#Override
protected void onPostExecute(String result) {
super.onPostExecute(result);
try {
JSONObject jsonObject = new JSONObject(result);
String weatherInfo = jsonObject.getString("weather");
Log.i("Weather content", weatherInfo);
JSONArray arr = new JSONArray(weatherInfo);
for (int i = 0; i < arr.length(); i++) {
JSONObject jsonPart = arr.getJSONObject(i);
Log.i("main", jsonPart.getString("main"));
Log.i("description", jsonPart.getString("description"));
}
} catch (JSONException e) {
e.printStackTrace();
}
}
}
If you could help me out that would be awesome, I'm quite excited to make my own weather app!
You don't convert a single byte and convert to a char like this:
char current = (char) data;
Your result string will end up with lots of strange characters
Instead you wrap your InputStreamReader to a BufferedReader, read line by line and collect your JSON.
Another easier way is to use JSONObject to read your stream:
JSONParser jsonParser = new JSONParser();
JSONObject jsonObject = (JSONObject)jsonParser.parse(
new InputStreamReader(urlConnection.getInputStream(), "UTF-8"));
Then change your AsyncTask to return JSONObject directly
public class DownloadTask extends AsyncTask<String, Void, JSONObject> {
#Override
protected String doInBackground(String... urls) {
String result = "";
URL url;
HttpURLConnection urlConnection = null;
try {
url = new URL(urls[0]);
urlConnection = (HttpURLConnection) url.openConnection();
InputStream in = urlConnection.getInputStream();
InputStreamReader reader = new InputStreamReader(in, "UTF-8");
JSONParser jsonParser = new JSONParser();
return (JSONObject)jsonParser.parse(reader);;
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
return null;
}
#Override
protected void onPostExecute(JSONObject result) {
}
}
Related
I wrote this code to make a connection and I used AsyncTask class BufferedReader with JSON object and JSON Array, but the bufferedReader return null every time, I tried the API by Fiddler (HTTP debugging server) and it is worked correctly.
//class AsyncTask
class GetUserList extends AsyncTask<String, Void, String> {
String status= null;
public GetUserList(){
}
protected void onPreExecute(){
}
#SuppressLint("WrongThread")
protected String doInBackground(String... connUrl){
HttpURLConnection conn=null;
BufferedReader reader;
final URL url;
int result;
InputStream in;
String line;
try{
url=new URL(connUrl[0]);
conn=(HttpURLConnection) url.openConnection();
conn.addRequestProperty("Content-Type", "application/json; charset=utf-8");
conn.setRequestMethod("GET");
result = conn.getResponseCode();
if(result == 200){
in=new BufferedInputStream(conn.getInputStream());
reader = new BufferedReader(new InputStreamReader(in));
StringBuilder sb=new StringBuilder();
line = null;
while((line=reader.readLine())!=null){
status=line;
}
}
}catch(Exception ex){
ex.printStackTrace();
}
return status;
}
protected void onPostExecute(String result){
super.onPostExecute(result);
JSONArray jsonArray;
JSONObject object;
String User;
int i =0;
if(result!=null){
try{
jsonArray = new JSONArray(result);
for( i=0; i<jsonArray.length(); i++){
object = jsonArray.getJSONObject(i);
User= object.getString("User");
}//end for
}//end try
catch (Exception ex){
ex.printStackTrace();
}//end catch
}//end if
}
}
I'm trying to make a mobile app that downloads info from the openweathermap.org apis. For example, if you feed that app this link: http://api.openweathermap.org/data/2.5/weather?q=Boston,us&appid=fed33a8f8fd54814d7cbe8515a5c25d7 you will get the information about the weather in Boston, MA. My code seems to work up to the point where I have to convert the input stream to a string variable. When I do that, I get garbage. Is there a particular way to do this seemingly simple task in a proper way? Here is my code so far...
private class DownloadWebpageTask extends AsyncTask<String, Void, String> {
#Override
protected String doInBackground(String... urls) {
// params comes from the execute() call: params[0] is the url.
try {
return downloadUrl(urls[0]);
} catch (IOException e) {
return null;
}
}
// onPostExecute displays the results of the AsyncTask.
#Override
protected void onPostExecute(String result) {
TextView test = (TextView) findViewById(R.id.test);
if(result!=null) test.setText(result);
else{
Log.i(DEBUG_TAG, "returned result is null");}
}
}
private String downloadUrl(String myurl) throws IOException {
InputStream is = null;
try {
URL url = new URL(myurl);
HttpURLConnection conn = (HttpURLConnection) url.openConnection();
conn.setReadTimeout(10000 /* milliseconds */);
conn.setConnectTimeout(15000 /* milliseconds */);
conn.setRequestMethod("GET");
conn.setDoInput(true);
// Starts the query
conn.connect();
int response = conn.getResponseCode();
Log.i(DEBUG_TAG, "The response is: " + response);
is = conn.getInputStream();
String text = getStringFromInputStream(is);
//JSONObject json = new JSONObject(text);
//try (Scanner scanner = new Scanner(is, StandardCharsets.UTF_8.name())) {
//text = scanner.useDelimiter("\\A").next();
//}
//Bitmap bitmap = BitmapFactory.decodeStream(is);
return text;
}catch(Exception e) {
Log.i(DEBUG_TAG, e.toString());
}finally {
if (is != null) {
is.close();
}
}
return null;
}
private static String getStringFromInputStream(InputStream is) {
BufferedReader br = null;
StringBuilder sb = new StringBuilder();
String line;
try {
br = new BufferedReader(new InputStreamReader(is));
while ((line = br.readLine()) != null) {
sb.append(line);
}
} catch (IOException e) {
e.printStackTrace();
} finally {
if (br != null) {
try {
br.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
return sb.toString();
}
Check this library . Is An asynchronous callback-based Http client for Android built on top of Apache’s HttpClient libraries.
I've been following a tutorial which provided an example website to use in the json request, however when i put in my own website to scrape data from, nothing happens.
Here is my code;
private TextView tvData;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
tvData = (TextView) findViewById(R.id.tvJsonItem);
new JSONTask().execute("http://jsonparsing.parseapp.com/jsonData/moviesDemoItem.txt");
}
public class JSONTask extends AsyncTask<String,String, String>{
#Override
protected String doInBackground(String ... params) {
HttpURLConnection connection = null;
BufferedReader reader = null;
try {
URL url = new URL(params[0]);
connection = (HttpURLConnection) url.openConnection();
connection.connect();
InputStream stream = connection.getInputStream();
reader = new BufferedReader(new InputStreamReader(stream));
StringBuffer buffer = new StringBuffer();
String line = "";
while ((line = reader.readLine()) != null) {
buffer.append(line);
}
String finalJson = buffer.toString();
JSONObject parentObject = new JSONObject(finalJson);
JSONArray parentArray = parentObject.getJSONArray("movies");
JSONObject finalObject = parentArray.getJSONObject(0);
String ChampionName = finalObject.getString("movie");
String mostGames = finalObject.getString("year");
return ChampionName + mostGames;
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} catch (JSONException e) {
e.printStackTrace();
} finally {
if (connection != null) {
connection.disconnect();
}
try {
if (reader != null) {
reader.close();
}
} catch (IOException e) {
e.printStackTrace();
}
}
return null;
}
#Override
protected void onPostExecute(String result){
super.onPostExecute(result);
tvData.setText(result);
}
}
}
Screen of when it works on left and screen when it doesnt work on right.
So yeah, this is what i know i have to change
new JSONTask().execute("http://api.champion.gg/champion/Ekko");
and
JSONObject parentObject = new JSONObject(finalJson);
JSONArray parentArray = parentObject.getJSONArray("WHAT DO I PUT HERE");
JSONObject finalObject = parentArray.getJSONObject(0);
String ChampionName = finalObject.getString("WHAT DO I PUT HERE");
String mostGames = finalObject.getString("WHAT DO I PUT HERE");
From this URL - http://api.champion.gg/champion/Ekko/ , i want to get lets say the first two fields "key":"Ekko","role":"Top", so if anyone could give me a hand, that would be great!
According to the JSON returned form your link http://api.champion.gg/champion/Ekko/
You have to start to parse your string response as JSONArray
JSONArray parentObject = new JSONArray(finalJson);
then start to loop through this array to get JSONObject
JSONObject jsonObject = parentObject.getJSONObject(yourLoopIndex);
Inside each JSONObject you can get any value. by using the key in the original JSON string.
i would like to write data in an external mysql database with my android app.
this class works for that:
public class SendingData extends AppCompatActivity {
Intent intent = null;
private class LoadingDataURL extends AsyncTask<String, String, JSONArray> {
#Override
protected JSONArray doInBackground(String... params) {
URL url;
HttpURLConnection urlConnection = null;
JSONArray response = new JSONArray();
try {
url = new URL(params[0]);
urlConnection = (HttpURLConnection) url.openConnection();
int responseCode = urlConnection.getResponseCode();
String responseString = readStream(urlConnection.getInputStream());
intent = new Intent(SendingData.this, Overview.class);
startActivity(intent);
response = new JSONArray(responseString);
} catch (Exception e) {
e.printStackTrace();
} finally {
if (urlConnection != null)
urlConnection.disconnect();
}
return response;
}
private String readStream(InputStream in) {
BufferedReader reader = null;
StringBuffer response = new StringBuffer();
try {
reader = new BufferedReader(new InputStreamReader(in, "UTF-8"));
String line = "";
while ((line = reader.readLine()) != null) {
response.append(line);
}
} catch (IOException e) {
e.printStackTrace();
} finally {
if (reader != null) {
try {
reader.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
return response.toString();
}
}
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.loading_data);
String firstname = "Max";
String secondname= "Mustermann";
LoadingDataURL client = new LoadingDataURL();
client.execute("https://domain.com/index.php?"+
"fristname="+fristname+
"&secondname="+secondname);
}
}
My Problem is, that if in my strings (fristname, secondname) is an & or ? or any special characters, the entry will not be save correctly.
any ideas? :)
Use the URLEncoder class.
Try this please
String fn = URLEncoder.encode(fristname, "utf-8");
String sn = URLEncoder.encode(secondname, "utf-8");
LoadingDataURL client = new LoadingDataURL();
client.execute("https://domain.com/index.php?"+
"fristname=" + fn + "&secondname=" + sn);
Note: Don't encode the full url, just the parameter values.
I am trying to parse some JSON data, but my app doesn't do anything because i can't seem to get any response from URL, i tried to open URL connection in few different ways, but it's still the same. for Example :
urlMy=new URL(string);
URLConnection tc = urlMy.openConnection();
BufferedReader in = new BufferedReader(new InputStreamReader(
tc.getInputStream()));
String line=in.readLine();
doesn't return anything, it even dismisses everything in my function written below that code.
Or
urlMy=new URL(examp);
InputStream inputStream = urlMy.openConnection().getInputStream();
InputStreamReader reader = new InputStreamReader(inputStream);
BufferedReader bR = new BufferedReader(reader);
the same thing. This function is called and like it never happend, every function after this one executes, so it's not in the endless loop, but every bit of code in this function after this example code is ignored. if i remove this code for reading url, everthing else works.
Try to use AsyncTask,try something like:
class MyAsyncTask extends AsyncTask<String, String, Void> {
private ProgressDialog progressDialog = new ProgressDialog(MainActivity.this);
InputStream inputStream = null;
String result = "";
protected void onPreExecute() {
progressDialog.setMessage("Downloading your data...");
progressDialog.show();
progressDialog.setOnCancelListener(new OnCancelListener() {
public void onCancel(DialogInterface arg0) {
MyAsyncTask.this.cancel(true);
}
});
}
#Override
protected Void doInBackground(String... params) {
String url_select = "http://yoururlhere.com"
ArrayList<NameValuePair> param = new ArrayList<NameValuePair>();
try {
// Set up HTTP post
// HttpClient is more then less deprecated. Need to change to URLConnection
HttpClient httpClient = new DefaultHttpClient();
HttpPost httpPost = new HttpPost(url_select);
httpPost.setEntity(new UrlEncodedFormEntity(param));
HttpResponse httpResponse = httpClient.execute(httpPost);
HttpEntity httpEntity = httpResponse.getEntity();
// Read content & Log
inputStream = httpEntity.getContent();
} catch (UnsupportedEncodingException e1) {
Log.e("UnsupportedEncodingException", e1.toString());
e1.printStackTrace();
} catch (ClientProtocolException e2) {
Log.e("ClientProtocolException", e2.toString());
e2.printStackTrace();
} catch (IllegalStateException e3) {
Log.e("IllegalStateException", e3.toString());
e3.printStackTrace();
} catch (IOException e4) {
Log.e("IOException", e4.toString());
e4.printStackTrace();
}
// Convert response to string using String Builder
try {
BufferedReader bReader = new BufferedReader(new InputStreamReader(inputStream, "iso-8859-1"), 8);
StringBuilder sBuilder = new StringBuilder();
String line = null;
while ((line = bReader.readLine()) != null) {
sBuilder.append(line + "\n");
}
inputStream.close();
result = sBuilder.toString();
} catch (Exception e) {
Log.e("StringBuilding & BufferedReader", "Error converting result " + e.toString());
}
} // protected Void doInBackground(String... params)
protected void onPostExecute(Void v) {
//parse JSON data
try{
JSONArray jArray = new JSONArray(result);
for(i=0; i < jArray.length(); i++) {
JSONObject jObject = jArray.getJSONObject(i);
String name = jObject.getString("name");
String tab1_text = jObject.getString("tab1_text");
int active = jObject.getInt("active");
} // End Loop
this.progressDialog.dismiss();
} catch (JSONException e) {
Log.e("JSONException", "Error: " + e.toString());
} // catch (JSONException e)
} // protected void onPostExecute(Void v)
} //class MyAsyncTask extends AsyncTask<String, String, Void>
In the last Google I/O, Google released a new library called Volley. It's fast for HTTP requests, very easy to use and you can set it up to return JSONObjects ready for parsing. https://developers.google.com/events/io/sessions/325304728