I am having issues getting data from a website.
So I want android studio to show the html in the logcat.
When I am entering the app,the screen become white and unresponsive.
I am getting no errors.
every time I try using AsyncTask and it just refusing to work.
Thanks for the help.
btw,I allowed the INTERNET permission on "Android Manifest".
public class MainActivity extends AppCompatActivity {
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 (Exception e) {
e.printStackTrace();
return null;
}
}
}
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
DownloadTask download = new DownloadTask();
String result = null;
try {
result = download.execute("https://www.usmagazine.com/celebrities/a/").get();
Log.d("WORKING?", result);
}catch (Exception e){
}
}
}
Your
return result;
in doInBackground returns result to a method called onPostExecute in your AsyncTask. Please override that method, and perform the task there.
Related
Here I'm trying to read an HTML file and log it but the problem is every time i check the logs I see hundreds of numbers instead of the actual code of the HTML.
I added the Internet permission in case you asked
public class MainActivity extends AppCompatActivity {
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 += data;
data = reader.read();
}
return result;
} catch (Exception e) {
e.printStackTrace();
return "Failed";
}
}
#Override
protected void onPostExecute(String s) {
super.onPostExecute(s);
Log.i("Result is:", s);
}
}
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
downloadTask task = new downloadTask();
task.execute("https://samples.openweathermap.org/data/2.5/weather?id=2172797&appid=439d4b804bc8187953eb36d2a8c26a02");
}
}
the response of API is in JSON format.
You must parse JSON response before getting data.
Here an example of JSON parsing in java.
Good luck!
I am trying to send data to url from where i am parsing json data and i want to know can we edit json data in url if we created random json store from myjson.com or we have to maintain our own server to edit json data.Here i created random json store and i am parsing data from that url and i also wanted to edit the data in url thats the problem i was not able to do .Its not working.please help???
This was structure
[{"name":"pavan","hit":true}]
this was mainactivity code from where fetchdata executes in background
public class MainActivity extends AppCompatActivity {
Button click;
public static TextView data;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
click=(Button)findViewById(R.id.button);
data=(TextView)findViewById(R.id.fetcheddata);
click.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
fetchdata process=new fetchdata();
process.execute();
}
});
}
}
This is fetchdata class from where fetching data from url and displaying in text view of mainactivity
public class fetchdata extends AsyncTask<Void,Void,Void> {
String data="";
String dataparsed="";
String singleparsed="";
boolean flag=false;
#Override
protected Void doInBackground(Void... params) {
try {
URL url=new URL("https://api.myjson.com/bins/1854yb");
HttpURLConnection httpURLConnection=(HttpURLConnection) url.openConnection();
InputStream inputStream=httpURLConnection.getInputStream();
BufferedReader bufferedReader=new BufferedReader(new InputStreamReader(inputStream));
String line="";
while (line!=null)
{
line=bufferedReader.readLine();
data=data+line;
}
JSONArray JA=new JSONArray(data);
for(int i=0;i<JA.length();i++)
{
JSONObject JO= (JSONObject) JA.get(i);
singleparsed="Name:"+JO.get("name")+"\n"+"Feed key:"+JO.get("hit");
dataparsed=dataparsed+singleparsed;
}
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} catch (JSONException e) {
e.printStackTrace();
}
return null;
}
#Override
protected void onPostExecute(Void result) {
super.onPostExecute(result);
MainActivity.data.setText(this.dataparsed);
JSONObject postData = new JSONObject();
try {
postData.put("name","sai");
postData.put("hit", false);
new senddata().execute("https://api.myjson.com/bins/1854yb", postData.toString());
} catch (JSONException e) {
e.printStackTrace();
}
}
}
This is senddata to url code from postexecute of fetchdata this was executing and nothing is happening in url please help i am working on this from 3 days
public class senddata extends AsyncTask<String,Void, String> {
String data="";
String dataparsed="";
String singleparsed="";
boolean flag=false;
#Override
protected String doInBackground(String... params) {
String data = "";
HttpURLConnection httpURLConnection = null;
try {
httpURLConnection = (HttpURLConnection) new URL(params[0]).openConnection();
httpURLConnection.setRequestMethod("POST");
httpURLConnection.setDoOutput(true);
DataOutputStream wr = new DataOutputStream(httpURLConnection.getOutputStream());
wr.writeBytes("PostData=" + params[1]);
wr.flush();
wr.close();
InputStream in = httpURLConnection.getInputStream();
InputStreamReader inputStreamReader = new InputStreamReader(in);
int inputStreamData = inputStreamReader.read();
while (inputStreamData != -1) {
char current = (char) inputStreamData;
inputStreamData = inputStreamReader.read();
data += current;
}
dataparsed=data;
} catch (Exception e) {
e.printStackTrace();
} finally {
if (httpURLConnection != null) {
httpURLConnection.disconnect();
}
}
return data;
}
#Override
protected void onPostExecute(String result) {
super.onPostExecute(result);
Log.e("TAG", result);
}
}
This api doesn't accept any paramter after its url.
It is a get method Api url not post method . Try running it in post method in postman , it will give error.
If u run in get method ,it will produce same output ,even if u add something after url :-"https://api.myjson.com/bins/1854yb"
I think you have some issue with myJson in creating api. If you are a beginner in android your can also try with Link for ready made Api for Android
They have created different kind of Apis for understanding the json concept.
also get some update about PostMan Link for postman
I am New to the android studio and want to something more. Actually, I am trying to pass the string that I got from the spinner in onCreateMethod and pass to the onPostExecute function. I will be grateful for the help. Bellow is my code.
I tried making a global variable called First and store the string from spinner and pass it on the onPostExecute function.
public class Convert extends AppCompatActivity implements LocationListener
{
Spinner dropdown;
Button btn;
String text;
String first;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_convert);
dropdown = (Spinner) findViewById(R.id.spinner1);
btn = (Button)findViewById(R.id.btn);
String[] items = new String[]{"United States,USD", "Nepal,NPR", "Bangladesh,BDT","Brazil,BRL"};
ArrayAdapter<String> adapter = new ArrayAdapter<>(this, android.R.layout.simple_spinner_dropdown_item, items);
dropdown.setAdapter(adapter);
btn.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
text = dropdown.getSelectedItem().toString();
first = text.substring(text.length()-3);
Log.i("her", first);
}
});
new DownloadTask().execute("http://openexchangerates.org/api/latest.json?
app_id=XXXXXXXXXX");
}
public class DownloadTask extends AsyncTask<String, Void, String> {
#Override
protected String doInBackground(String... urls) {
String result = "";
URL url;
HttpURLConnection httpURLConnection = null;
try {
url = new URL(urls[0]);
httpURLConnection = (HttpURLConnection) url.openConnection();
InputStream in = httpURLConnection.getInputStream();
InputStreamReader reader = new InputStreamReader(in);
int data = reader.read();
while (data != -1) {
char counter = (char) data;
result += counter;
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);
JSONObject curr = jsonObject.getJSONObject("rates");
String npr = curr.getString(first);
Log.i("money", npr );
} catch (JSONException e) {
e.printStackTrace();
}
}
}
What I want is to pass the string first on the onPostExecute function.
When you will call your DownloadTask, asyncTask fires with method execute, just pass param though him. Example:
How to pass url
new DownloadTask().execute("url for download");
How to receive url
protected String doInBackground(String... urls) {
String url = urls[0]; // url for download
}
Also you could send and array of params. Also be careful with AsyncTask, do not pass your context/view variable, it could arise memory leaks, read docs.
I am trying to download web content using a multi thread approach. I am following an online android development tutorial service so I know believe my code is correct (The complete android web developer course Chapter 5). However, after displaying part of the web page in the log as requested, I get the message:
"I/Choreographer: Skipped 743 frames! The application may be doing too much work on its main thread."
I am using the AsynTask but still no luck.
public class MainActivity extends AppCompatActivity {
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(Exception e) {
e.printStackTrace();
return "Failed";
}
}
}
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
DownloadTask task = new DownloadTask();
String result = null;
try {
result = task.execute("http://www.w3schools.com/html/tryit.asp?filename=tryhtml_basic_document").get();
} catch (InterruptedException e) {
e.printStackTrace();
} catch (ExecutionException e) {
e.printStackTrace();
}
Log.i("Contents of URL", result);
}
}
Well, if you do call the AsyncTask.get() method directly in your onCreate() method, then you're kinda cheating, because the code is actually executed in the UI Thread !
You really must not call get(), because this will wait for the result, and thus block the UI Thread (which is precisely what you want to avoid)
I guess you did this because you wanted to have the result in your onCreate() method, but you can't.
Generally, you need to show the result in an UI field (like a TextView). In that case, you should use an Handler instance to be able to use its value from the UI Thread again.
Corrected code :
public class MainActivity extends AppCompatActivity {
public class DownloadTask extends AsyncTask<String, Void, String> {
#Override
protected void onPostExecute(Result result) {
Log.i("Contents of URL", result);
}
#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(Exception e) {
e.printStackTrace();
return "Failed";
}
}
}
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
DownloadTask task = new DownloadTask();
task.execute("http://www.w3schools.com/html/tryit.asp?filename=tryhtml_basic_document");
}
}
public class MainActivity extends AppCompatActivity {
Where I set up the url and HttpUrlConnection which allows the program to read the contents of the url.
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(Exception e){
e.printStackTrace();
}
return null;
}
}
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
DownloadTask task = new DownloadTask();
String result = null;
try {
result = task.execute("http://www.historyplace.com/specials/").get();
Log.i("Contents of URL", result);
} catch (InterruptedException e) {
e.printStackTrace();
} catch (ExecutionException e) {
e.printStackTrace();
}
}
}
I believe my code is written correctly because the logCat does display a few lines of code. Unfortunately it does not display all of it. I am trying to first retrieve all of the code so I can use Regex to extract certain pictures and names for an educational school project.