I'm trying to get it so my app can read the words from my textfile separated by a carriage enter and spit them back out from a String array. My app starts up then just gives me a blank page which is pretty frustrating. Here is my code:
import java.io.BufferedReader;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.LinkedList;
import java.util.List;
import java.util.Timer;
import java.util.Vector;
import android.os.Bundle;
import android.app.Activity;
import android.widget.TextView;
public class MainActivity extends Activity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
TextView helloTxt= (TextView)findViewById(R.id.hellotxt);
ArrayList<String> list = new ArrayList<String>();
try {
InputStream is = getResources().openRawResource(R.raw.test);
if (is != null) {
InputStreamReader isr = new InputStreamReader(is);
BufferedReader buffythevampireslayer = new BufferedReader(isr);
String line;
do {
line = buffythevampireslayer.readLine();
list.add(line);
} while (line != null);
}
is.close();
} catch (Exception ex) {
}
String[] wordsArray=new String[list.size()];
list.toArray(wordsArray);
Thread timer=new Thread(); {
for (int c=0;c<list.size();c++){
helloTxt.setText(wordsArray[c]);
System.out.println("TEXTSET");
try {
Thread.sleep(5000);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
};
timer.start();
}
}
I'd really appreciate it if anyone could help, thanks so much!!!
EDIT::::
After getting some help in this post, I now have the working app! Thanks so much! Here is the new code:
import java.io.BufferedReader;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.UnsupportedEncodingException;
import java.util.ArrayList;
import java.util.LinkedList;
import java.util.List;
import java.util.Timer;
import java.util.Vector;
import android.os.AsyncTask;
import android.os.Bundle;
import android.os.SystemClock;
import android.app.Activity;
import android.content.res.AssetManager;
import android.widget.TextView;
public class MainActivity extends Activity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
ReadAndUpdateTextTask readAndUpdateTextTask = new ReadAndUpdateTextTask();
readAndUpdateTextTask.execute();
}
class ReadAndUpdateTextTask extends AsyncTask<Void, String, String> {
public String currentString = "";
String line="";
InputStream isr;
#Override
protected void onPreExecute() {
isr = getResources().openRawResource(R.raw.test);
}
#Override
protected String doInBackground(Void... params) {
try {
BufferedReader reader = new BufferedReader(new InputStreamReader(isr));
while ((line = reader.readLine())!= null) {
currentString += line + "\n";
publishProgress(currentString);
// I don't think you really need this but you want a sleep for 5000 ms
SystemClock.sleep(5000);
}
isr.close();
} catch (Exception ex) {
}
return currentString;
}
#Override
protected void onProgressUpdate(String... currentString) {
TextView helloTxt= (TextView)findViewById(R.id.hellotxt);
helloTxt.setText(currentString[0]);
}
#Override
protected void onPostExecute(String result) {
TextView helloTxt= (TextView)findViewById(R.id.hellotxt);
helloTxt.setText(result);
}
}
}
I don't know if this will solve anything, but you can try declaring your List as shown in Oracle's documentation. I will look further in a bit.
List<String> list = new ArrayList<String>();
if it's not a typo, your problem is here:
String[] wordsArray=new String[list.size()];
list.toArray(wordsArray);
it should be:
String[] wordsArray = list.toArray( new String[0] );
otherwise the array is filled with nulls
First, you need to store your text file in the assets folder
then you need to call the AssetManager to get the assets in your assets folder
AssetManager assetManager = getAssets();
InputStream inputStream = null;
surround these statements with a try block, in case the file is not found in the stated path
inputStream = assetManager.open("texts/sample.txt"); // path is relative to the assets folder
ByteArrayOutputStream bytesOutputStream = new ByteArrayOutputStream();
byte[] bytes = new byte[4096];
int length = 0;
read the the bytes and write them in an output stream
while((length = inputStream.read(bytes)) > 0)
bytesOutputStream.write(bytes,0,length);
create a new String, use the constructor with the byteOutputStream
encode it with UTF8(assuming there wont be any chinese, japanese, etc characters)
See this for more details about UTF Details
String yourString = new String(bytesOutputStream.toByteArray(), "UTF8");
Java String class has a method "split", which takes a regex as a parameter
it splits the string and stores it into a single element in an array everytime it encounters a new line
in your case, use '\n' which stands for new line
String[] yourStringArray = yourString.split("\n");
Surround everything with a try-catch clause (IOException), which is thrown in case file is not found
you can now use yourStringArray as
textView.setText(yourStringArray[index]);
You got a blank screen because you have a sleep at your main UI thread. Do reading the file in an AsyncTask and publish its process.
Your onCreate method should look like this:
public class MainActivity extends Activity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
ReadAndUpdateTextTask readAndUpdateTextTask = new ReadAndUpdateTextTask();
readAndUpdateTextTask.execute();
}
class ReadAndUpdateTextTask extends AsyncTask<Void, String, String> {
InputStream isr;
#Override
protected void onPreExecute() {
isr = getResources().openRawResource(R.raw.test);
}
#Override
protected String doInBackground(Void... params) {
try {
String currentString = "";
BufferedReader reader = new BufferedReader(new InputStreamReader(isr));
while ((line = reader.readLine())!= null) {
currentString += line + "\n";
publishProgress(currentString);
// I don't think you really need this but you want a sleep for 5000 ms
SystemClock.sleep(5000);
}
isr.close();
} catch (Exception ex) {
}
return currentString;
}
#Override
protected void onProgressUpdate(String... currentString) {
TextView helloTxt= (TextView)findViewById(R.id.hellotxt);
helloTxt.setText(currentString[0]);
}
#Override
protected void onPostExecute(String result) {
TextView helloTxt= (TextView)findViewById(R.id.hellotxt);
helloTxt.setText(result);
}
}
}
Related
So I've been cracking my brain with this issues. I'm trying to validate if the an user credentials on a app connected to mysql are valid. The thing is that wherever I try to compare the result of the query with a string all I get is the else statement.
Here's the Fragment for the Login
package com.example.pablorjd.CheckThisOut;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
public class Login extends AppCompatActivity {
EditText etUsername;
EditText etPassword;
Button btnLogin;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_login);
etUsername = (EditText)findViewById(R.id.etUsername);
etPassword = (EditText)findViewById(R.id.etPassword);
btnLogin = (Button)findViewById(R.id.btnLogin);
}
public void onLogin(View view){
String username = etUsername.getText().toString();
String password = etPassword.getText().toString();
String type = "login";
BackgroundWorker backgroundWorker = new BackgroundWorker(this);
backgroundWorker.execute(type,username,password);
}
}
I'm using a background class to make the connection to mysql
package com.example.pablorjd.CheckThisOut;
import android.app.AlertDialog;
import android.content.Context;
import android.os.AsyncTask;
import android.widget.Toast;
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;
public class BackgroundWorker extends AsyncTask<String, Void, String> {
Context context;
AlertDialog alertDialog;
BackgroundWorker(Context ctx){
context = ctx;
}
#Override
protected String doInBackground(String... params) {
String type = params[0];
String login_url = "http://10.20.13.31/checkthisout/login.php";
if (type.equals("login")){
try {
String user_name = params[1];
String password = params[2];
URL url = new URL(login_url);
HttpURLConnection httpURLConnection = (HttpURLConnection) url.openConnection();
httpURLConnection.setRequestMethod("POST");
httpURLConnection.setDoOutput(true);
httpURLConnection.setDoInput(true);
OutputStream outputStream = httpURLConnection.getOutputStream();
BufferedWriter bufferedWriter = new BufferedWriter(new OutputStreamWriter(outputStream, "UTF-8"));
String post_data = URLEncoder.encode("user_name", "UTF-8")+"="+URLEncoder.encode(user_name,"UTF-8")+"&"
+URLEncoder.encode("password", "UTF-8")+"="+URLEncoder.encode(password,"UTF-8");
bufferedWriter.write(post_data);
bufferedWriter.flush();
bufferedWriter.close();
outputStream.close();
InputStream inputStream = httpURLConnection.getInputStream();
BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(inputStream, "UTF-8"));
String result = "";
String line = "";
while ((line = bufferedReader.readLine())!=null){
result += line;
}
bufferedReader.close();
inputStream.close();
httpURLConnection.disconnect();
return result;
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
return null;
}
#Override
protected void onPreExecute() {
}
#Override
protected void onPostExecute(String result) {
if (result.equals("true")){
Toast.makeText(context, "If is working", Toast.LENGTH_SHORT).show();
}else{
Toast.makeText(context,result, Toast.LENGTH_SHORT).show();
}
}
#Override
protected void onProgressUpdate(Void... values) {
super.onProgressUpdate(values);
}
}
I know the DB connections is working because I'm actually receiving the message that I set on the php file.
All I know is that for some reason the if statement is not working for this.
please if someone could shed a light for me that'd be great.
OK so, for some reason, the validation just wouldn't take the string comparison and instead jumped to the else statement showing in this case a Toast. What I had to do was to modify the string given to me by the php file so it would be just a number (0 or 1 in this case). then I parsed the string into an int and the if worked like a charm.
This is the resulting code
#Override
protected void onPostExecute(String result) {
int val = Integer.parseInt(result.replaceAll("[\\D]",""));
if (val == 0){
Intent intent = new Intent(context,MainActivity.class);
context.startActivity(intent);
Toast.makeText(context,"Login exitoso",Toast.LENGTH_SHORT).show();
}else{
Toast.makeText(context,"Login erroneo",Toast.LENGTH_SHORT).show();
}
}
I still don't know why the if statement wouldn't work with strings.
I am trying to get a JSON Array from this local server for five days:
localhost/match_picture/service.php?action=read
and i can't do it !!
I search it in google and read too many documentations !
here is my code:
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;
public class WebService {
public static String readUrl(String server_url) {
BufferedReader bufferedReader = null;
try {
URL url = new URL(server_url);
HttpURLConnection con = (HttpURLConnection) url.openConnection();
StringBuilder sb = new StringBuilder();
bufferedReader = new BufferedReader(new InputStreamReader(con.getInputStream()));
String json;
while ((json = bufferedReader.readLine()) != null) {
sb.append(json+"\n");
}
return sb.toString();
}catch (Exception e) {
e.printStackTrace();
}
return null;
}
}
and it's Main_Activity:
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.Toast;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import java.util.ArrayList;
public class Activity_main extends AppCompatActivity {
private ArrayList<StructAcount> netAcount = new ArrayList<StructAcount>();
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
String result= WebService.readUrl("http://localhast/match_picture/service.php?action=read");
if (result != null) {
try {
JSONArray tasks = new JSONArray(result);
for (int i=0; i<tasks.length(); i++) {
StructAcount acount= new StructAcount();
JSONObject object = tasks.getJSONObject(i);
acount.id = object.getLong("user_id");
acount.name = object.getString("user_name");
acount.email = object.getString("user_email");
netAcount.add(acount);
}
} catch (JSONException e) {
e.printStackTrace();
}
}
for (StructAcount acount: netAcount) {
Toast.makeText(Activity_main.this, "username: " + acount.name + "\n" + "useremail: " + acount.email , Toast.LENGTH_SHORT).show();
}
}
}
it is runing on emulator and crashes in this line:
bufferedReader = new BufferedReader(new InputStreamReader(con.getInputStream()));
and i dont know why ...
I am Searching for five days!!!!
I can do it with HttpClient
but i want to be update
I saw a vidoe in youtube that create a class in Main_Activity extends AsyncTask and make connenction in doInBackground(String... params). I try that and that works correcly. but because I want to do it in anoder class (WebService) and I dont know how can i sent result to Main_Activity , I remove that class extended from AsyncTask.
thank's for your help
sorry for my poor english
You have a NetworkOnMainThreadException to begin with.
And your app crashes.
Google how to solve it.
i am trying to implement sample JSON data App that Gets JSON data from server
i am Getting complete JSON file whats wrong with my coding ?
i am following an youtube tutorial but he did successfully but i am getting complete JSON File
this is JSON server side file
{
"movies" :[
{
"movie" : "Avenger",
"year" : 2012
}
]
}
and this is code from android app
package com.yog.jsonparser;
import android.os.AsyncTask;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.webkit.URLUtil;
import android.widget.Button;
import android.widget.TextView;
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.URI;
import java.net.URISyntaxException;
import java.net.URL;
import java.net.URL;
public class MainActivity extends AppCompatActivity {
TextView tvData;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Button btnHit = (Button) findViewById(R.id.btnHit);
tvData = (TextView)findViewById(R.id.tvJsonItem);
btnHit.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
new JSONTask().execute("http://myDomainName.com/getData.txt");
}
});
}
public class JSONTask extends AsyncTask<String,String,String>{
HttpURLConnection connection = null;
BufferedReader reader = null;
URI url;
StringBuffer buffer;
#Override
protected String doInBackground(String... params){
try{
//URL OF REQUESTED PAGE
url=new URI(params[0]);
connection = (HttpURLConnection) (new URL(params[0]).openConnection());
connection.connect();
InputStream stream=connection.getInputStream();
reader=new BufferedReader(new InputStreamReader(stream));
buffer=new StringBuffer();
String line;
while((line =reader.readLine())!=null){
buffer.append(line);
}
String finalJSON=buffer.toString();
JSONObject parentOject = new JSONObject(finalJSON);
JSONArray parentArray = parentOject.getJSONArray("movies");
JSONObject finalObject= parentArray.getJSONObject(0);
String movieName= finalObject.getString("movie");
int year=finalObject.getInt("year");
return movieName + "-" + year;
} catch (URISyntaxException 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 s) {
super.onPostExecute(s);
tvData.setText(buffer.toString());
}
}
}
current Output :
{"movies" :[{ "movie" : "Avenger","year" : 2012}]}
Expected output :
Avenger
2012
Change your onPostExecute method as below.
#Override
protected void onPostExecute(String s) {
super.onPostExecute(s);
tvData.setText(s);
}
Here s will be return statement of doInBackground. "movieName + "-" + year;"
You are getting {"movies" :[{ "movie" : "Avenger","year" : 2012}]} in the TextView because you are setting the buffer's output to the TextView. Change your onPostExecute like this:
#Override
protected void onPostExecute(String s) {
super.onPostExecute(s);
if(s != null){
tvData.setText(s);
}else{
//// Some error occurred
tvData.setText(buffer.toString());
}
}
I'm new to android and I hope someone could help me here. I have an activity Faculty and a button.
This is my XML layout browse_faculty:
<Button
android:onClick="searchFSTEHandler"
android:id="#+id/bFSTE"
android:layout_width="220dp"
android:layout_height="80dp"
android:layout_alignLeft="#+id/bFBE"
android:layout_below="#+id/bFBE"
android:layout_marginTop="20dp"
android:text="#string/fste" />
and this is my Faculty Activity which displays the buttons:
I use Intent to view ListView
public class Faculty extends Activity{
#Override
protected void onCreate(Bundle BrowseFaculty) {
// TODO Auto-generated method stub
super.onCreate(BrowseFaculty);
setContentView(R.layout.browse_faculty);
}
//on the XML,this is the "searchFSTEHandler" i want to use to show ListView
public void searchFSTEHandler(View target){
Intent courseList = new Intent(this, HttpActivity.class);
startActivity(courseList);
}
}
and below is the "HttpActivity" class is the class that displays my ListView. This class read a php file which gets data from a MySQL server and converts to JSON data then parses it into a array list.
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.URL;
import java.net.URLConnection;
import java.util.ArrayList;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import android.os.AsyncTask;
import android.os.Bundle;
import android.app.ListActivity;
import android.widget.ArrayAdapter;
public class HttpActivity extends ListActivity {
public String f1 = "FSTE";
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.faculty_course);
new getHttp().execute();
getHttp test =new getHttp();
String strJsonData = test.doInBackground(f1);
// Convert String JSON data to Java class
ArrayList<Courses> arrayCourse= test.parseJsonData(strJsonData);
//Create an ArrayAdapter which shows the ArrayList data
this.setListAdapter(new ArrayAdapter<Courses>(this,android.R.layout.simple_list_item_1,arrayCourse));
}
private class getHttp extends AsyncTask<String, Void, String> {
public getHttp() {
}
#Override
protected String doInBackground(String... faculty) {
InputStream is = null;
try {
URL url = new URL("http://10.0.2.2/sqlWebService.php?faculty=FSTE");
URLConnection con = url.openConnection();
con.setConnectTimeout(10000);
con.setReadTimeout(10000);
is = con.getInputStream();
BufferedReader br = new BufferedReader(
new InputStreamReader(is));
StringBuffer sb = new StringBuffer();
String str;
while ((str = br.readLine()) != null) {
sb.append(str);
}
return sb.toString();
} catch (IOException e) {
e.printStackTrace();
return "";
} finally {
try {
if (is != null)
is.close();
} catch (IOException e2) {
e2.printStackTrace();
}
}
}
//------------------------------------------------------
private ArrayList<Courses> parseJsonData(String strJson) {
ArrayList<Courses> Course = new ArrayList<Courses>();
try {
// Generate JSONArray object by JSON String data
JSONArray arr = new JSONArray(strJson);
//from the JSONArray, get one element (row) of JSONData
for (int i = 0; i < arr.length(); i++) {
//Get JSON Object which is one element of the array
JSONObject ob = arr.getJSONObject(i);
Courses exam = new Courses();
//get the value by key, and set to exam class
exam.setCode(ob.optString("code"));
//save exam class to exam array list
Course.add(exam);
}
} catch (JSONException e) {
e.printStackTrace();
}
return Course;
}
}
}
The application crashes as soon as I click on the button and gives a error:
"android.os.NetworkOnMainThreadException"
Help Please !
The problem that you are having is network operation like what you are trying to do cannot and should not be performed on the main UI thread. Doing so will lead to an ANR (Android Not Responding), which is exactly the kind of error you are getting just now. What you want to do is move your code to a separate thread or to an AsyncTask that will perform this action in the background on a different thread using the doInBackground() method which does not have access to your views on the main UI thread. For example,
private class ExampleOperation extends AsyncTask<String, Void, String> {
public ExampleOperation() { //ctor }
#Override
protected void onPreExecute() {
//things that you want to initialize and maybe show dialog to user.
}
#Override
protected String doInBackground(String... params) {
//this is where you perform that network related operation.
}
#Override
protected void onPostExecute(String result) {
//this is where get the results from the network related task.
}
#Override
protected void onProgressUpdate(Void... values) {
//you can update your progressbar if any; otherwise omit method.
}
}
Then all you have to do is call the AsyncTask where ever you want to use it: new ExampleOperation().execute();
You can't make HTTP calls in the main thread, they take too long and would make the UI unresponsive. You need to do it in an AsyncTask.
For some reason the onPreExecute isn't being called. Code:
protected void onPreExcecute() {
hook.createDialog(ticker);
}
Entire class:
package com.evandarwin.finance;
import java.io.IOException;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import android.content.Context;
import android.os.AsyncTask;
import android.widget.Toast;
public class GetTicker extends AsyncTask<String, Integer, String>{
private Context ctx;
private String ticker;
private SimpleFinanceActivity hook;
public GetTicker(Context ctx, String ticker, SimpleFinanceActivity hook) {
this.ctx = ctx;
this.ticker = ticker.toUpperCase();
this.hook = hook;
}
protected void onPreExcecute() {
hook.createDialog(ticker);
}
#SuppressWarnings("unused")
#Override
protected String doInBackground(String... params) {
try {
URL url = new URL("http://finance.yahoo.com/d/quotes.csv?s="+ticker+"&f=a");
HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();
urlConnection.setRequestMethod("GET");
urlConnection.setDoOutput(true);
urlConnection.connect();
InputStream is = urlConnection.getInputStream();
StringBuffer str = new StringBuffer();
int bufferLength = 0; //used to store a temporary size of the buffer
byte[] stream = new byte[1024];
while ( (bufferLength = is.read(stream)) > 0 ) {
str.append(stream);
}
return str.toString();
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e1) {
e1.printStackTrace();
}
return null;
}
protected void onPostExecute(String result) {
hook.destroyDialog();
Toast.makeText(ctx, result, Toast.LENGTH_LONG).show();
}
}
This is giving me a NullPointerException, I know I've had this problem before but I don't remember what I did to fix it. Please help! :P
The reason the #Override is causing a problem in Eclipse (and the reason the method isn't being called) is that you have made a typing error.
You are calling it onPreExcecute (note the 'c' after the 'x' shouldn't be there). Correct it to be onPreExecute and use #Override for that.