Here is the code
Variable declared
public String gpu2dcurent = "1234567";
Asynctask, after finished it should update variable gpu2dcurent, but it doesnt
private class readgpu2d extends AsyncTask<String, Void, String> {
protected String doInBackground(String... args) {
Log.i("MyApp", "Background thread starting");
String aBuffer = "";
try {
File myFile = new File("/sys/devices/platform/kgsl-2d0.0/kgsl/kgsl-2d0/gpuclk");
FileInputStream fIn = new FileInputStream(myFile);
BufferedReader myReader = new BufferedReader(
new InputStreamReader(fIn));
String aDataRow = "";
//String aBuffer = "";
while ((aDataRow = myReader.readLine()) != null) {
aBuffer += aDataRow + "\n";
}
;
myReader.close();
} catch (Exception e) {
Toast.makeText(getBaseContext(), e.getMessage(),
Toast.LENGTH_SHORT).show();
}
return aBuffer.trim();
}
protected void onPostExecute(String result) {
// Pass the result data back to the main activity
gpu2dcurent = result;
//Toast.makeText(getBaseContext(), result,
//Toast.LENGTH_SHORT).show();
gpu.this.data = result;
if (gpu.this.pd != null) {
//gpu.this.pd.dismiss();
}
}
}
Test to see if a variable has a new value. It doesn't, it displays 1234567
TextView tx = (TextView)findViewById(R.id.textView3);
tx.setText(gpu2dcurent);
Am i missing something? When i update textView from inside onPostExecute method it works fine but when Asynctask finishes variable value resets to default
public class gpu extends Activity{
public String gpu2dcurent = "1234567";
I have a doubt you are trying to set text of TextView before completion of your Asynctask.
Yes, either make it, static public String gpu2dcurent = "1234567";
Or, set Text of TextView in onPostExecute()
protected void onPostExecute(String result) {
// Pass the result data back to the main activity
gpu2dcurent = result;
//Toast.makeText(getBaseContext(), result,
//Toast.LENGTH_SHORT).show();
gpu.this.data = result;
if (gpu.this.pd != null) {
//gpu.this.pd.dismiss();
}
tx.setText(gpu2dcurent);
}
}
Update:
After update your code in question,
change this line,
new readgpu2d().execute("blablabla");
to
new readgpu2d().execute("blablabla").get();
try to put setText into onPostExecute
protected void onPostExecute(String result) {
TextView tx = (TextView)findViewById(R.id.textView3);
tx.setText(result);
// Pass the result data back to the main activity
gpu2dcurent = result;
//Toast.makeText(getBaseContext(), result,
//Toast.LENGTH_SHORT).show();
gpu.this.data = result;
if (gpu.this.pd != null) {
//gpu.this.pd.dismiss();
}
}
In gpu class declare it as followin:
public String gpu2dcurent = "1234567";
In AsyncTask class readgpu2d, use it as following:
gpu.gpu2dcurent = result;
Update your UI=User Interface means TextView in
onProgressUpdate()
method of AsyncTask.
And check where have you declared gpu2dcurent variable???
Here is the whole code
package rs.pedjaapps.DualCore;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.List;
import java.util.concurrent.TimeoutException;
import android.app.Activity;
import android.app.ProgressDialog;
import android.os.AsyncTask;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.Spinner;
import android.widget.AdapterView.OnItemSelectedListener;
import android.widget.TextView;
import android.widget.Toast;
import com.stericson.RootTools.RootTools;
import com.stericson.RootTools.RootToolsException;
public class gpu extends Activity{
public String gpu2dcurent = "1234567";
private ProgressDialog pd = null;
private Object data = null;
private class readgpu2d extends AsyncTask<String, Void, String> {
protected String doInBackground(String... args) {
Log.i("MyApp", "Background thread starting");
String aBuffer = "";
try {
File myFile = new File("/sys/devices/platform/kgsl-2d0.0/kgsl/kgsl-2d0/gpuclk");
FileInputStream fIn = new FileInputStream(myFile);
BufferedReader myReader = new BufferedReader(
new InputStreamReader(fIn));
String aDataRow = "";
//String aBuffer = "";
while ((aDataRow = myReader.readLine()) != null) {
aBuffer += aDataRow + "\n";
}
//gpu2dcurent = aBuffer.trim();
myReader.close();
} catch (Exception e) {
Toast.makeText(getBaseContext(), e.getMessage(),
Toast.LENGTH_SHORT).show();
}
return aBuffer.trim();
}
protected void onPostExecute(String result) {
// Pass the result data back to the main activity
gpu2dcurent = result;
//Toast.makeText(getBaseContext(), result,
//Toast.LENGTH_SHORT).show();
gpu.this.data = result;
if (gpu.this.pd != null) {
gpu.this.pd.dismiss();
}
}
}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.gpu);
this.pd = ProgressDialog.show(this, "Working..", "Loading...", true, false);
new readgpu2d().execute("blablabla");
TextView tx = (TextView)findViewById(R.id.textView3);
tx.setText(gpu2dcurent);
}
}
Related
So whenever I Enter a city name in the EditText and press the button my app just crashes and does not show a toast
shows this error in logcat : used by: java.lang.NullPointerException: Can't toast on a thread that has not called Looper.prepare()
Does anyone know who to fix this error?
im using android studio
package com.example.whatstheweather;
import androidx.appcompat.app.AppCompatActivity;
import android.content.Context;
import android.os.AsyncTask;
import android.os.Bundle;
import android.os.Looper;
import android.util.Log;
import android.view.View;
import android.view.inputmethod.InputMethodManager;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;
import org.json.JSONArray;
import org.json.JSONObject;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;
import java.net.URLEncoder;
public class MainActivity extends AppCompatActivity {
EditText editText;
TextView resultTextView;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
editText = findViewById(R.id.editTextTextPersonName);
resultTextView = findViewById(R.id.resultTextView);
}
public void getWeather(View view){
try {
DownloadTask task = new DownloadTask();
String encodedCityName = URLEncoder.encode(editText.getText().toString(), "UTF-8");
task.execute("http://openweathermap.org/data/2.5/weather?q=" + encodedCityName + "&APPID=9eebb30a9664baf113136d98e764ffb5");
InputMethodManager mgr = (InputMethodManager) getSystemService(Context.INPUT_METHOD_SERVICE);
mgr.hideSoftInputFromWindow(editText.getWindowToken(), 0);
}catch (Exception e){
e.printStackTrace();
Toast.makeText(getApplicationContext(),"Could not find weather :(",Toast.LENGTH_SHORT).show();
}
}
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();;
Toast.makeText(getApplicationContext(),"Could not find weather :(",Toast.LENGTH_SHORT).show();
return null;
}
}
#Override
protected void onPostExecute(String s) {
super.onPostExecute(s);
try {
JSONObject jsonObject = new JSONObject(s);
String weatherInfo = jsonObject.getString("weather");
JSONArray arr = new JSONArray(weatherInfo);
String message = "";
for (int i = 0; i< arr.length(); i++){
JSONObject jsonPart =arr.getJSONObject(i);
String main = jsonPart.getString("main");
String description = jsonPart.getString("description");
if (!main.equals("") && !description.equals("")) {
message += main + ": " + description + "\r\n";
}
}
if (!message.equals("")){
resultTextView.setText(message);
}else{
Toast.makeText(getApplicationContext(),"Could not find weather :(",Toast.LENGTH_SHORT).show();
}
}catch (Exception e){
e.printStackTrace();
Toast.makeText(getApplicationContext(),"Could not find weather :(",Toast.LENGTH_SHORT).show();
}
}
}
}
try {
//add her code
} catch (java.text.ParseException e) {
runOnUiThread(new Runnable(){
public void run() {
Toast.makeText(getApplicationContext(),"Please key in
the correct input",
Toast.LENGTH_LONG).show();
}
});
e.printStackTrace();
return true; // attention here
}
Method in onCreate :
private void toastPublic(final String message){
Handler handler = new Handler(Looper.getMainLooper());
handler.post(new Runnable() {
public void run() {
Toast.makeText(getBaseContext(),""+message,
4 /*Toast.LENGTH_SHORT*/).show();
}});
}
Next : use in inside asyncTask or Thread
This question already has answers here:
What arguments are passed into AsyncTask<arg1, arg2, arg3>?
(5 answers)
Closed 3 years ago.
I am working on an Android app in which I am making a weather app. The application opens api data from a JSON and displays this information. More specifically it takes the user input of a city or zip code and adds this info to the URL for the API and then executes the URL.
MainActivity.java
package com.shanehampcsci3660.weather;
import androidx.appcompat.app.AppCompatActivity;
import android.content.Intent;
import android.os.Bundle;
import android.text.Editable;
import android.text.TextWatcher;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
//import static com.shanehampcsci3660.weather.GetJsonData.*;
public class MainActivity extends AppCompatActivity
{
public static TextView tempTV, jsonTV;
public EditText cityORZipET;
private Button getWeather;
public String zip, cityOrZip;
#Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
tempTV = (TextView) findViewById(R.id.tempTV);
jsonTV = (TextView) findViewById(R.id.jsonFeedTV);
cityORZipET = (EditText) findViewById(R.id.cityORZipET);
getWeather = (Button) findViewById(R.id.getWeatherButton);
//cityOrZip = cityORZipET.getText().toString();
getWeather.setOnClickListener(new View.OnClickListener()
{
#Override
public void onClick(View view)
{
GetJsonData getJsonData = new GetJsonData();
//getJsonData.execute();
cityOrZip = cityORZipET.getText().toString();
getJsonData.execute("https://api.openweathermap.org/data/2.5/weather?q=" + cityOrZip +"&appid=x");
jsonTV.setText(cityOrZip);
/*if(cityOrZip.equals(""))
{
getJsonData.execute("https://api.openweathermap.org/data/2.5/weather?q=" + cityOrZip +"&appid=x");
}
else
{
zip = "30528";
getJsonData.execute("https://api.openweathermap.org/data/2.5/weather?q=" + zip + "&appid=x");
}*/
}
});
}
}
GetJsonData.java
package com.shanehampcsci3660.weather;
import android.os.AsyncTask;
import android.util.Log;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
public class GetJsonData extends AsyncTask<Void, Void, Void>
{
public String data= "", line = "", name = "";
double temp, minTemp, maxTemp;
#Override
protected Void doInBackground(Void... voids)
{
try
{
URL url = new URL("https://api.openweathermap.org/data/2.5/weather?q=30528&appid=id");
HttpURLConnection httpURLConnection = (HttpURLConnection) url.openConnection();
InputStream inputStream = httpURLConnection.getInputStream();
BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(inputStream));
while(line != null)
{
line = bufferedReader.readLine();
data = data + line;
}
JSONObject jsonObject = new JSONObject(data);
JSONObject main = jsonObject.getJSONObject("main");
name = jsonObject.getString("name");
temp = main.getDouble("temp");
minTemp = main.getDouble("min_temp");
maxTemp = main.getDouble("max_temp");
/*JSONObject jsonObject = new JSONObject(result);
JSONObject jsonData = new JSONObject(jsonObject.getString("main"));
String weatherInfo = jsonObject.getString("weather");
JSONArray jsonArray = new JSONArray(weatherInfo);
String description, icon, iconURI;
for(int i = 0; i < jsonArray.length(); i++)
{
JSONObject jsonData1 = jsonArray.getJSONObject(i);
description = jsonData1.getString("description");
MainActivityController.description.setText(description);
icon = jsonData1.getString("icon");
iconURI = "http://openweathermap.org/img/w/" + icon + ".png";
Picasso.get().load(iconURI).into(MainActivityController.conditionImageView);
}*/
}
catch(MalformedURLException e)
{
e.printStackTrace();
}
catch(IOException e)
{
e.printStackTrace();
}
catch (JSONException e)
{
e.printStackTrace();
}
return null;
}
#Override
protected void onPostExecute(Void aVoid)
{
super.onPostExecute(aVoid);
//MainActivity.jsonTV.setText(data);
MainActivity.tempTV.setText("City:\t" + name + "\tTemp:\t" + temp);
Log.d("Json Feed", name + "Temp: " + temp);
}
public static void execute(String s) {
}
}
My issue is that no matter where I put...
if(cityOrZip.equals(""))
{
getJsonData.execute("https://api.openweathermap.org/data/2.5/weather?q=" + cityOrZip +"&appid=id");
}
else
{
zip = "30528";
getJsonData.execute("https://api.openweathermap.org/data/2.5/weather?q=" + zip + "&appid=id");
}
...It will only show the data of the default Url opened in GetJsonData.java. My question is what am I doing wrong and what should I correct in order to make my app work with the user input like it should.
you are calling an GetJsonData.execute with the url that contains the client data, but it has no code in it. Looking at your current code the zip that the client inputs does not get stored into the worker class.
This is because you always use the same URL in GetJsonData class. According to question What arguments are passed into AsyncTask? your class declaration should look like:
public class GetJsonData extends AsyncTask<String, Void, YourPojo> {
#Override
protected YourPojo doInBackground(String... urls)
{
try
{
URL url = new URL(urls[0]);
...
} catch (Exception e) {
handle(e);
}
}
}
where YourPojo is a class you need to create to store all properties you need to read from JSON payload:
class YourPojo {
private String data;
private String line;
private String name;
private double temp;
private double minTemp
private double maxTemp;
// getters, setters
}
When setting a value in setData the value is OK in String returnDataTab1, but when getId() states it's null. Is the issue staring me in the face.
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLEncoder;
import android.app.AlertDialog;
import android.content.Context;
import android.content.Intent;
import android.content.SharedPreferences;
import android.os.AsyncTask;
import android.widget.Toast;
public class BackgroundTask extends AsyncTask<String,Void,String>
{
Context context;
String dataResponse = "";
String returnDataTab1;
//getter
public String getId()
{
//The system out below shows a value of null although the setData method set it ok.
System.out.println("zzzzzzzzzzzzzzzzzzzzzzzzzzzzz : "+returnDataTab1);
return returnDataTab1;
}
public void setData(String newResult)
{
returnDataTab1=newResult;
System.out.println("zzzzzzzzzzzzzzzzzzzzzzzzzzzzz : "+returnDataTab1);
/// the returnDataTab value is set ok
}
BackgroundTask(Context ctx)
{
this.context = ctx;
}
#Override
protected String doInBackground(String... params)
{
String urlLogin = "";
String task = params[0];
String loginusername="";
String loginpassword="";
if (task.equals("login"))
{
urlLogin = "http://domain/LoginAndRegister-login.php";
loginusername = params[1];
loginpassword = params[2];
//
try
{
URL url = new URL(urlLogin);
HttpURLConnection httpURLConnection = (HttpURLConnection) url.openConnection();
httpURLConnection.setRequestMethod("POST");
httpURLConnection.setDoOutput(true);
httpURLConnection.setDoInput(true);
//send the driver number to the database
OutputStream outputStream = httpURLConnection.getOutputStream();
OutputStreamWriter outputStreamWriter = new OutputStreamWriter(outputStream,"UTF-8");
BufferedWriter bufferedWriter = new BufferedWriter(outputStreamWriter);
String myDatalogin = URLEncoder.encode("identifier_loginEmail","UTF-8")+"="+URLEncoder.encode(loginusername,"UTF-8")
+"&"+URLEncoder.encode("identifier_loginPassword","UTF-8")+"="+URLEncoder.encode(loginpassword,"UTF-8");
bufferedWriter.flush();
bufferedWriter.write(myDatalogin);
bufferedWriter.close();
outputStream.close();
//get response from the database
InputStream inputStream = httpURLConnection.getInputStream();
InputStreamReader inputStreamReader = new InputStreamReader(inputStream,"UTF-8");
BufferedReader bufferedReader = new BufferedReader(inputStreamReader);
//String dataResponse = "";
String inputLine = "";
while((inputLine = bufferedReader.readLine()) != null)
{
dataResponse += inputLine;
}
bufferedReader.close();
inputStream.close();
httpURLConnection.disconnect();
return dataResponse;
}
catch (MalformedURLException e)
{
e.printStackTrace();
}
catch (IOException e)
{
e.printStackTrace();
}
}//end if statement
#Override
protected void onPreExecute()
{
super.onPreExecute();
}
#Override
protected void onProgressUpdate(Void... values)
{
super.onProgressUpdate(values);
}
/// gets value OK from background task
#Override
protected void onPostExecute(String result)
{
this.setData(result);
}
}
Would appreciate if you guys could take a look and point out the obvious mistake.
This is the code called from a tab
BackgroundTask backgroundTaskLogin = new BackgroundTask(Tab1Activity.this);
backgroundTaskLogin.execute(task,username,password);
String x;
x=backgroundTaskLogin.getId();
Toast.makeText(getApplicationContext(), "Data Response : "+x, Toast.LENGTH_SHORT).show();
The values are set from
protected void onPostExecute(String result)
{
this.setData(result);
// gets result value fine
}
I tried to Download and Unzip files if there is an update on a server and all works perfect. But I want to open the next Activity only after all files have been downloaded and unzipped, not when it started downloading.
This is my Activity:
package com.example;
import android.app.ProgressDialog;
import android.content.Context;
import android.content.Intent;
import android.os.AsyncTask;
import android.os.Bundle;
import android.os.Environment;
import android.os.PowerManager;
import android.os.StrictMode;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import android.view.WindowManager;
import android.widget.Toast;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.URL;
import java.util.ArrayList;
import java.util.List;
public class Update extends AppCompatActivity {
private ProgressDialog ringProgressDialog;
private static Boolean finished = false;
private String read(String fileName) {
StringBuilder retString = new StringBuilder();
String zeilenumbruch = "\n";
BufferedReader reader = null;
try {
File file = new File(fileName);
FileInputStream in = new FileInputStream(Environment.getExternalStorageDirectory().toString() + "/.example/Anleitungen/.data/Versions/" + fileName);
reader = new BufferedReader(new InputStreamReader(in));
String zeile;
while ((zeile = reader.readLine()) != null) {
retString.append(zeile);
}
reader.close();
} catch (IOException ex) {
Log.e(getPackageName(), ex.getMessage());
}
return retString.toString();
}
public static String getTextOfUrl(String uri) throws Exception {
StringBuilder result = new StringBuilder();
URL url = new URL(uri);
String line = null;
BufferedReader reader = null;
finished = false;
try {
reader = new BufferedReader(new InputStreamReader(url.openStream()));
while ((line = reader.readLine()) != null) {
result.append(line);
}
return result.toString();
} finally {
if (reader != null) {
reader.close();
}
finished = true;
}
}
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_update);
if (android.os.Build.VERSION.SDK_INT > 9) {
StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder().permitAll().build();
StrictMode.setThreadPolicy(policy);
}
PowerManager pm = (PowerManager) getSystemService(Context.POWER_SERVICE);
final PowerManager.WakeLock wl = pm.newWakeLock(PowerManager.SCREEN_DIM_WAKE_LOCK, "Updating");
wl.acquire();
getWindow().addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);
AsyncTaskRunner runner = new AsyncTaskRunner();
runner.execute();
}
private void downloadAndUnzipContent(String path, String urlPath) {
String url = urlPath;
DownloadFileAsync download = new DownloadFileAsync(path, this, new DownloadFileAsync.PostDownload() {
#Override
public void downloadDone(File file) {
Log.i(getPackageName(), "file download completed");
// check unzip file now
Decompress unzip = new Decompress(Update.this, file, true);
unzip.unzip();
Log.i(getPackageName(), "File unzip completed");
}
});
download.execute(url);
}
private void downloadContent(String path, String urlPath) {
DownloadFileAsync download = new DownloadFileAsync(path, this, new DownloadFileAsync.PostDownload() {
#Override
public void downloadDone(File file) {
Log.i(getPackageName(), "file download completed");
}
});
download.execute(urlPath);
}
private class AsyncTaskRunner extends AsyncTask<String, String, String> {
private String resp;
#Override
protected String doInBackground(String... params) {
try {
List<String> files = new ArrayList<String>();
files.add("Archiv");
files.add("Funkempfaenger");
files.add("Funkhandsender");
files.add("Funksender");
files.add("Funksensoren");
files.add("Hausautomatisierung");
files.add("Jalousieantriebe");
files.add("Rohrantriebe");
files.add("SensorenKabelgebunden");
files.add("Sonderantriebe");
files.add("Torantriebe");
files.add("Torsteuerungen");
files.add("WandgeraeteKabelgebunden");
for (int uI = 0; uI < files.size(); uI++) {
try {
String newVersion = getTextOfUrl("http://www.example.com/zip/Versions/" + files.get(uI) + ".txt");
int nV = Integer.parseInt(newVersion);
String readString = files.get(uI) + ".txt";
String oldVersion = read(readString);
int iV = Integer.parseInt(oldVersion);
if (iV < nV) {
while (!finished) {
Log.i(getPackageName(), "Finished = False");
}
String dlPath = Environment.getExternalStorageDirectory() + "/.example/Anleitungen/.data/" + files.get(uI) + ".zip";
String dlPath2 = Environment.getExternalStorageDirectory() + "/.example/Anleitungen/.data/Versions/" + files.get(uI) + ".txt";
downloadAndUnzipContent(dlPath, "http://www.example.com/zip/Versions/" + files.get(uI) + ".zip");
downloadContent(dlPath2, "http://www.example.com/zip/Versions/" + files.get(uI) + ".txt");
}
} catch (Exception e) {
e.printStackTrace();
publishProgress(e.toString());
}
}
} catch (Exception e) {
e.printStackTrace();
}
return "HI!";
}
/*
* (non-Javadoc)
*
* #see android.os.AsyncTask#onPostExecute(java.lang.Object)
*/
#Override
protected void onPostExecute(String result) {
// execution of result of Long time consuming operation
Toast.makeText(Update.this, getString(R.string.UpdateFinished), Toast.LENGTH_LONG).show();
Intent intent = new Intent(Update.this, Home.class);
startActivity(intent);
finish();
}
/*
* (non-Javadoc)
*
* #see android.os.AsyncTask#onPreExecute()
*/
#Override
protected void onPreExecute() {
}
/*
* (non-Javadoc)
*
* #see android.os.AsyncTask#onProgressUpdate(Progress[])
*/
#Override
protected void onProgressUpdate(String... text) {
Toast.makeText(Update.this, text[0], Toast.LENGTH_SHORT).show();
}
}
#Override
public void onBackPressed() {
Log.i(getPackageName(), "Back pressed");
}
}
This is my Decompress.class:
package com.example;
import android.content.Context;
import android.util.Log;
import android.widget.Toast;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.util.zip.ZipEntry;
import java.util.zip.ZipInputStream;
public class Decompress {
private File _zipFile;
private InputStream _zipFileStream;
private Context context;
private static String ROOT_LOCATION = "/sdcard";
private static final String TAG = "UNZIPUTIL";
private Boolean pathNew;
public Decompress(Context context, File zipFile, Boolean path) {
_zipFile = zipFile;
this.context = context;
pathNew = path;
if (pathNew) {
ROOT_LOCATION = "/sdcard/.example/Anleitungen";
}
_dirChecker("");
}
public Decompress(Context context, InputStream zipFile) {
_zipFileStream = zipFile;
this.context = context;
_dirChecker("");
}
public void unzip() {
try {
Log.i(TAG, "Starting to unzip");
InputStream fin = _zipFileStream;
if(fin == null) {
fin = new FileInputStream(_zipFile);
}
ZipInputStream zin = new ZipInputStream(fin);
ZipEntry ze = null;
while ((ze = zin.getNextEntry()) != null) {
Log.v(TAG, "Unzipping " + ze.getName());
if(ze.isDirectory()) {
_dirChecker(ROOT_LOCATION + "/" + ze.getName());
} else {
FileOutputStream fout = new FileOutputStream(new File(ROOT_LOCATION, ze.getName()));
ByteArrayOutputStream baos = new ByteArrayOutputStream();
byte[] buffer = new byte[1024];
int count;
// reading and writing
while((count = zin.read(buffer)) != -1)
{
baos.write(buffer, 0, count);
byte[] bytes = baos.toByteArray();
fout.write(bytes);
baos.reset();
}
fout.close();
zin.closeEntry();
}
}
zin.close();
Log.i(TAG, "Finished unzip");
} catch(Exception e) {
Log.e(TAG, "Unzip Error", e);
Toast.makeText(context, "Error while unzipping: " + e.toString(), Toast.LENGTH_LONG).show();
}
}
private void _dirChecker(String dir) {
File f = new File(dir);
Log.i(TAG, "creating dir " + dir);
if(dir.length() >= 0 && !f.isDirectory() ) {
f.mkdirs();
}
}
}
This is my DownloadFileAsnyc.class:
package com.example;
import android.content.Context;
import android.os.AsyncTask;
import android.util.Log;
import java.io.BufferedInputStream;
import java.io.File;
import java.io.FileDescriptor;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.net.URL;
import java.net.URLConnection;
public class DownloadFileAsync extends AsyncTask<String, String, String> {
private static final String TAG ="DOWNLOADFILE";
public static final int DIALOG_DOWNLOAD_PROGRESS = 0;
private PostDownload callback;
private Context context;
private FileDescriptor fd;
private File file;
private String downloadLocation;
public DownloadFileAsync(String downloadLocation, Context context, PostDownload callback){
this.context = context;
this.callback = callback;
this.downloadLocation = downloadLocation;
}
#Override
protected void onPreExecute() {
super.onPreExecute();
}
#Override
protected String doInBackground(String... aurl) {
int count;
try {
URL url = new URL(aurl[0]);
URLConnection connection = url.openConnection();
connection.connect();
int lenghtOfFile = connection.getContentLength();
Log.d(TAG, "Length of the file: " + lenghtOfFile);
InputStream input = new BufferedInputStream(url.openStream());
file = new File(downloadLocation);
FileOutputStream output = new FileOutputStream(file); //context.openFileOutput("content.zip", Context.MODE_PRIVATE);
Log.d(TAG, "file saved at " + file.getAbsolutePath());
fd = output.getFD();
byte data[] = new byte[1024];
long total = 0;
while ((count = input.read(data)) != -1) {
total += count;
publishProgress(""+(int)((total*100)/lenghtOfFile));
output.write(data, 0, count);
}
output.flush();
output.close();
input.close();
} catch (Exception e) {}
return null;
}
protected void onProgressUpdate(String... progress) {
//Log.d(TAG,progress[0]);
}
#Override
protected void onPostExecute(String unused) {
if(callback != null) callback.downloadDone(file);
}
public static interface PostDownload{
void downloadDone(File fd);
}
}
Please help me. Sorry for my bad English.
Thank you.
You are starting the new Activity whenever AsyncTaskRunner finishes executing its background job. AsyncTaskRunner is basically just launching multiple DownloadFileAsync tasks.
AsyncTaskRunner won't wait for the launched tasks to complete. It will just launch them and finish the task which causes your new Activity to start.
The optimal way to fix this is to use only one AsyncTask that process each file sequentially. A dirty way would be to make AsyncTaskRunner wait for each DownloadFileAsync task to finish before launching the next. You can do this by calling the .get() method on each task:
download.execute(url).get();
But again, this defeats the purpose of AsyncTasks.
I am building an app that displays details of a book you have searched. The problem is that every time I change the orientation of my device the list view elements disappear. I want help in how to make them not disappear. I have a feeling that I need to use a Loader but I have no idea in how to implement it. Here are my activities.
MainActivity :-
package com.example.visha.booklistingapp;
import android.content.Context;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;
import android.os.AsyncTask;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.EditText;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;
import java.util.ArrayList;
import java.util.List;
public class MainActivity extends AppCompatActivity {
private BookAdapter mAdapter;
EditText searchtext;
ListView earthquakeListView;
TextView empty;
TextView authorcheck;
TextView titlecheck;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
earthquakeListView = (ListView) findViewById(R.id.listView);
mAdapter = new BookAdapter(this, new ArrayList<Book>());
earthquakeListView.setAdapter(mAdapter);
searchtext = (EditText) findViewById(R.id.editText);
empty = (TextView) findViewById(R.id.textView);
earthquakeListView.setEmptyView(empty);
}
public void searchclick(View view) {
ConnectivityManager connectivityManager = (ConnectivityManager)getSystemService(Context.CONNECTIVITY_SERVICE);
if(connectivityManager.getNetworkInfo(ConnectivityManager.TYPE_MOBILE).getState() == NetworkInfo.State.CONNECTED ||
connectivityManager.getNetworkInfo(ConnectivityManager.TYPE_WIFI).getState() == NetworkInfo.State.CONNECTED) {
String parturl = searchtext.getText().toString();
parturl = parturl.replaceAll("\\s","");
StringBuilder urlbuilder = new StringBuilder();
urlbuilder.append(" https://www.googleapis.com/books/v1/volumes?q=");
urlbuilder.append(parturl);
urlbuilder.append("&maxResults=5");
String url = urlbuilder.toString();
BookAsyncTask task = new BookAsyncTask();
task.execute(url); }
else{
Toast.makeText(getApplicationContext(), "You are not connected to the internet",
Toast.LENGTH_LONG).show();
}
}
private class BookAsyncTask extends AsyncTask<String, Void, List<Book>> {
#Override
protected List<Book> doInBackground(String... urls) {
// Don't perform the request if there are no URLs, or the first URL is null
if (urls.length < 1 || urls[0] == null) {
return null;
}
List<Book> result = QueryUtils.fetchBookData(urls[0]);
return result;
}
#Override
protected void onPostExecute(List<Book> data) {
mAdapter.clear();
if (data != null && !data.isEmpty()) {
mAdapter.addAll(data);
}
}
}
}
QueryUtils :-
package com.example.visha.booklistingapp;
import android.text.TextUtils;
import android.util.Log;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.nio.charset.Charset;
import java.util.ArrayList;
import java.util.List;
/**
* Created by visha on 14-10-2016.
*/
public final class QueryUtils {
private static final String LOG_TAG = QueryUtils.class.getSimpleName();
private QueryUtils() {
}
public static List<Book> fetchBookData(String requestUrl) {
URL url = createUrl(requestUrl);
String jsonResponse = null;
try {
jsonResponse = makeHttpRequest(url);
} catch (IOException e) {
Log.e(LOG_TAG, "Problem making the HTTP request.", e);
}
List<Book> Books = extractFeatureFromJson(jsonResponse);
return Books;
}
private static URL createUrl(String stringUrl) {
URL url = null;
try {
url = new URL(stringUrl);
} catch (MalformedURLException e) {
Log.e(LOG_TAG, "Problem building the URL ", e);
}
return url;
}
private static String makeHttpRequest(URL url) throws IOException {
String jsonResponse = "";
if (url == null) {
return jsonResponse;
}
HttpURLConnection urlConnection = null;
InputStream inputStream = null;
try {
urlConnection = (HttpURLConnection) url.openConnection();
urlConnection.setReadTimeout(10000 /* milliseconds */);
urlConnection.setConnectTimeout(15000 /* milliseconds */);
urlConnection.setRequestMethod("GET");
urlConnection.connect();
if (urlConnection.getResponseCode() == 200) {
inputStream = urlConnection.getInputStream();
jsonResponse = readFromStream(inputStream);
} else {
Log.e(LOG_TAG, "Error response code: " + urlConnection.getResponseCode());
}
} catch (IOException e) {
Log.e(LOG_TAG, "Problem retrieving the Book JSON results.", e);
} finally {
if (urlConnection != null) {
urlConnection.disconnect();
}
if (inputStream != null) {
inputStream.close();
}
}
return jsonResponse;
}
private static String readFromStream(InputStream inputStream) throws IOException {
StringBuilder output = new StringBuilder();
if (inputStream != null) {
InputStreamReader inputStreamReader = new InputStreamReader(inputStream, Charset.forName("UTF-8"));
BufferedReader reader = new BufferedReader(inputStreamReader);
String line = reader.readLine();
while (line != null) {
output.append(line);
line = reader.readLine();
}
}
return output.toString();
}
private static List<Book> extractFeatureFromJson(String BookJSON) {
if (TextUtils.isEmpty(BookJSON)) {
return null;
}
List<Book> Books = new ArrayList<>();
try {
JSONObject baseJsonResponse = new JSONObject(BookJSON);
JSONArray BookArray = baseJsonResponse.getJSONArray("items");
for (int i = 0; i < BookArray.length(); i++) {
JSONObject currentBook = BookArray.getJSONObject(i);
JSONObject properties = currentBook.getJSONObject("volumeInfo");
String author;
if(properties.has("authors")) {
author = properties.getString("authors");
}
else {
author = "";
}
String title = properties.getString("title");
Book Book = new Book(author, title);
Books.add(Book);
}
} catch (JSONException e) {
Log.e("QueryUtils", "Problem parsing the Book JSON results", e);
}
return Books;
}
}
You need to override onSaveInstanceState and onRestoreInstanceState methods of Activity Class.
In onSaveInstanceState, save the list data into the Bundle.
In onRestoreInstanceState, restore the list with the Bundle data and re-create the list adapter.
Cheers!!!
if you do not have a different layout for the activity landscape mode then simply putting android:configChanges="orientation|screenLayout|screenSize" will do the job for you.
Example:
<activity
android:name=".MainActivity"
android:configChanges="orientation|screenLayout|screenSize" />
and if you do have different layout for landscape mode the you need to override the savedInstanceState and save and restore the list accordingly in OnCreate