Develop Reference

Slideshow code seems correct, but app does nothing when executing in emulator

I'm trying to build an app for school that queries a website full of random cat pictures and displays them on an emulated android TV. My code looks right, but when I run it I get the spinning wheel showing it's loading and nothing else. I'm not sure what exactly is missing, but hoping someone can point me in the right direction. Code is below:
package com.example.lab2;
import androidx.appcompat.app.AppCompatActivity;
import androidx.loader.content.AsyncTaskLoader;
import android.content.Context;
import android.content.ContextWrapper;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.media.Image;
import android.os.AsyncTask;
import android.os.Bundle;
import android.os.Handler;
import android.os.Looper;
import android.provider.MediaStore;
import android.widget.ImageView;
import android.widget.ProgressBar;
import org.json.JSONException;
import org.json.JSONObject;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;
import java.sql.Array;
import java.util.ArrayList;
import java.util.concurrent.Executor;
import java.util.concurrent.Executors;
public class MainActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
ArrayList<String> ids = new ArrayList<String>();
class CatImages extends AsyncTask<String, Integer, String> {
ContextWrapper cw = new ContextWrapper(getApplicationContext());
Bitmap images;
String id;
ImageView imageView = findViewById(R.id.imageView);
ProgressBar progressBar = findViewById(R.id.progressBar);
File directory = cw.getDir("imageDir", Context.MODE_PRIVATE);
boolean on = true;
#Override
protected String doInBackground(String... strings) {
while(on == true) {
try {
URL url = new URL("https://cataas.com/cat?json=true");
HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();
InputStream response = urlConnection.getInputStream();
BufferedReader reader = new BufferedReader(new InputStreamReader(response, "UTF-8"), 8);
StringBuilder builder = new StringBuilder();
String line = null;
while ((line = reader.readLine()) != null)
{
builder.append(line + "\n");
}
String result = builder.toString();
JSONObject image = new JSONObject(result);
id = image.getString("id");
for (String element : ids) {
if (element.contains(id)) {
return null;
} else {
images = BitmapFactory.decodeStream(response);
File path = new File(directory, id + ".jpg");
FileOutputStream outputStream = new FileOutputStream(path);
images.compress(Bitmap.CompressFormat.PNG, 100, outputStream);
outputStream.flush();
outputStream.close();
ids.add(id);
}
}
for (int i = 0; i < 100; i++) {
try {
publishProgress(i);
Thread.sleep(30);
} catch (Exception e) {
e.printStackTrace();
}
}
} catch (IOException | JSONException e) {
return null;
}
}
return null;
}
#Override
protected void onProgressUpdate(Integer... values) {
super.onProgressUpdate(values);
for(String element : ids) {
if(element.contains(id)) {
File openedPic = new File(directory, id + ".jpg");
try {
Bitmap opener = BitmapFactory.decodeStream(new FileInputStream(openedPic));
imageView.setImageBitmap(opener);
} catch (FileNotFoundException e) {
e.printStackTrace();
}
}
}
}
#Override
protected void onPostExecute(String s) {
super.onPostExecute(s);
}
}
}

Late-enabling -Xcheck:jni Android studio logs

I am trying to run a simple app that extracts html from a page and displays it in the logs.
Here is the Java code:
package com.example.khkr.jsondemo;
import android.os.AsyncTask;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import org.json.JSONException;
import org.json.JSONObject;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;
public class MainActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
public class DownloadTask extends AsyncTask<String,Void,String>
{
#Override
protected String doInBackground(String... params) {
URL url;
String result = "";
try {
url = new URL(params[0]);
HttpURLConnection urlConnection = (HttpURLConnection)url.openConnection();
urlConnection.connect();
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 (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);
} catch (JSONException e) {
e.printStackTrace();
}
}
}
}
The problem is I don't see any errors in the code , but when I try to run the app, I get the following Logs which never make sense to me. Here are the logs:
https://gist.github.com/khkr/d96396ff6f8e34b3e9a430a805b735a7

I cant use list view in android with json more than one result

Hi every one I have a problem
i want to get data from site with json and show it in my android list view
but in my program i can only see the first result of json and dont
show me the all result of the json.
please help me.
this is my code
mainactivity code:
package com.example.delta.travel;
import android.app.ListActivity;
import android.app.ProgressDialog;
import android.os.AsyncTask;
import android.os.Bundle;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.View;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.ListAdapter;
import android.widget.SimpleAdapter;
import android.widget.Toast;
import org.apache.http.NameValuePair;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
public class MainActivity extends ListActivity {
private ProgressDialog pd;
JSONParser jParser=new JSONParser();
ArrayList<HashMap<String,String>> P;
JSONArray s=null;
private final String url="http://192.168.1.3/upload/travel.php";
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
P = new ArrayList<>();
new travel().execute();
}
class travel extends AsyncTask<String,Void,String>{
#Override
protected void onPreExecute() {
super.onPreExecute();
pd=new ProgressDialog(MainActivity.this);
pd.setMessage("login");
pd.show();
}
#Override
protected String doInBackground(String... params) {
List<NameValuePair> parms=new ArrayList<>();
JSONObject json=jParser.makeHTTPRequest(url,"GET");
try {
int t=json.getInt("t");
if(t==1){
s=json.getJSONArray("travel");
for(int i=0;i<s.length();i++){
JSONObject c=s.getJSONObject(i);
String companyname=c.getString("companyname");
String cod=c.getString("cod");
String bign=c.getString("bign");
String stop=c.getString("stop");
String date=c.getString("date");
String time=c.getString("time");
String price=c.getString("price");
HashMap<String,String>map=new HashMap<String,String>();
map.put("companyname",companyname);
map.put("cod",cod);
map.put("bign",bign);
map.put("stop",stop);
map.put("date",date);
map.put("time",time);
map.put("price",price);
P.add(map);
}
}else {
Toast.makeText(MainActivity.this,"No Data Found",Toast.LENGTH_SHORT).show();
}
} catch (JSONException e) {
e.printStackTrace();
}
return null;
}
#Override
protected void onPostExecute(String s) {
super.onPostExecute(s);
pd.dismiss();
runOnUiThread(new Runnable() {
#Override
public void run() {
ListAdapter adapter = new SimpleAdapter(MainActivity.this, P, R.layout.item_list,
new String[]{"companyname", "cod", "bign", "stop", "date", "time", "price"},
new int[]{R.id.companyname, R.id.cod, R.id.bign, R.id.stop, R.id.date, R.id.time1, R.id.price});
setListAdapter(adapter);
}
});
}
}
}
and my json parser code:
package com.example.delta.travel;
import android.net.http.HttpResponseCache;
import android.util.Log;
import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.NameValuePair;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.client.utils.URLEncodedUtils;
import org.apache.http.impl.client.DefaultHttpClient;
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.io.UnsupportedEncodingException;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.ProtocolException;
import java.net.URL;
import java.util.Date;
import java.util.List;
/**
* Created by delta on 5/28/2016.
*/
public class JSONParser {
static InputStream is=null;
static JSONObject jObj=null;
static String json="";
// constructor
public JSONParser(){
}
// function get json from url
// by making HTTP POST or GET method
public JSONObject makeHTTPRequest(String urlString, String method) {
if(method.equals("POST")){
URL url = null;
try {
url = new URL(urlString);
HttpURLConnection conn = (HttpURLConnection) url.openConnection();
conn.setRequestMethod("POST");
conn.setRequestProperty("Accept", "application/json");
BufferedReader br = new BufferedReader(new InputStreamReader(
(conn.getInputStream())));
String output;
StringBuilder sb = new StringBuilder();
while ((output = br.readLine()) != null) {
sb.append(output);
}
conn.disconnect();
json = sb.toString();
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (ProtocolException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}else if(method.equals("GET")){
URL url = null;
try {
url = new URL(urlString);
HttpURLConnection conn = (HttpURLConnection) url.openConnection();
conn.setRequestMethod("GET");
conn.setRequestProperty("Accept", "application/json");
BufferedReader br = new BufferedReader(new InputStreamReader(
(conn.getInputStream())));
String output;
StringBuilder sb = new StringBuilder();
while ((output = br.readLine()) != null) {
sb.append(output);
}
conn.disconnect();
json = sb.toString();
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (ProtocolException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
try {
jObj = new JSONObject(json);
} catch (JSONException e) {
e.printStackTrace();
}
return jObj;
}
}
and my php code:
<?php
$con=mysqli_connect("localhost","root","","travels");
mysqli_set_charset($con,"utf8");
$response=array();
$result=mysqli_query($con,"select * from travel");
if(mysqli_num_rows($result)>0){
while($row=mysqli_fetch_array($result)){
$temp=array();
$temp["companyname"]=$row["companyname"];
$temp["cod"]=$row["cod"];
$temp["bign"]=$row["bign"];
$temp["stop"]=$row["stop"];
$temp["date"]=$row["date"];
$temp["time"]=$row["time"];
$temp["price"]=$row["price"];
$response["travel"]=array();
array_push($response["travel"],$temp);
$response["t"]=1;
echo json_encode($response);
}
}
else{
$response["t"]=0;
$response["message"]="Not Found";
echo json_encode($response);
}
?>

How to import class from another file in java in Android Studio?

I'm trying to call the function getUrlContents(string) inside my seismic_text.java file to my MainActivity.java file. How can I call the function from anywhere in the file? Any information or tip is appreciated. I include my files down below.
This is my MainActivity.java:
package bt.alfaquake;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.app.NotificationManager;
import android.content.Intent;
import android.view.View;
import android.app.PendingIntent;
import android.support.v7.app.ActionBarActivity;
import android.support.v4.app.NotificationCompat;
import bt.alfaquake.seismic_text;
public class MainActivity extends AppCompatActivity {
NotificationCompat.Builder notification;
private static final int uniqueID = 123;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
notification = new NotificationCompat.Builder(this);
}
}
This is my seismic_text.java:
package bt.alfaquake;
import java.net.*;
import java.io.*;
public class seismic_text {
public static String getUrlContents(String theUrl) {
StringBuilder content = new StringBuilder();
try
{
URL url = new URL(theUrl);
URLConnection urlConnection = url.openConnection();
BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(urlConnection.getInputStream()));
String line;
while ((line = bufferedReader.readLine()) != null)
{
content.append(line + "\n");
}
bufferedReader.close();
}
catch(Exception e)
{
e.printStackTrace();
}
return content.toString();
}
}
}

You can call seismic_text.getUrlContents(url); but it will cause NetworkOnMainThreadException
Just wrap this call to Simple AsynkTask.
class MyTask extends AsyncTask<Void, Void, String> {
#Override
protected String doInBackground(Void... params) {
try {
return seismic_text.getUrlContents(url);
} catch (InterruptedException e) {
e.printStackTrace();
}
return null;
}
#Override
protected void onPostExecute(String result) {
super.onPostExecute(result);
// TODO handle result here
}
}
And call it from your code:
new MyTask().execute();

Simply call this in your MainActivty.java:
seismic_text.getUrlContents(url);

Length Cannot be resolved or is not a field

I am new to Java and Android.
I have been getting this error in my program length cannot be resolved or is not a field I just don't understand how to solve this.
Here's the code
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.MalformedURLException;
import java.net.URL;
import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.DefaultHttpClient;
import android.os.AsyncTask;
import android.os.Environment;
public class DownloadImages extends AsyncTask {
protected Object doInBackground(Object... params) {
System.out.println("External Storage State = " + Environment.getExternalStorageState());
File directory=new File(Environment.getExternalStorageDirectory(), "/Images");
if (directory.exists()==false)
{
directory.mkdir();
}
for(int i = 0; i <URLS.length; i++) {
try {
File firstFile=new File(directory+"/" +i+ ".jpeg");
if(firstFile.exists()==false)
{
HttpClient httpClient =new DefaultHttpClient();
HttpGet httpGet =new HttpGet(URLS[i]);
HttpResponse resp = httpClient.execute(httpGet);
System.out.println("Status Code = " +resp.getStatusLine().getStatusCode());
if(resp.getStatusLine().getStatusCode()==200)
{
HttpEntity entity = resp.getEntity();
InputStream is = entity.getContent();
Boolean status = firstFile.createNewFile();
FileOutputStream foutS = new FileOutputStream(firstFile);
byte[] buffer = new byte[1024];
long total = 0;
int count;
while((count = is.read(buffer)) != -1){
total += count;
foutS.write(buffer, 0, count);
}
foutS.close();
is.close();
publishProgress(i);
}
}
}catch(MalformedURLException e){
e.printStackTrace();
}catch(ClientProtocolException e){
e.printStackTrace();
}catch(IOException e){
e.printStackTrace();
}
}
return null;
}
#SuppressWarnings("unchecked")
protected void onProgressUpdate(Object... values){
super.onProgressUpdate(values);
}
}
Getting Error in For Statement Line
for(int i = 0; i <URLS.length; i++) {
MainActivity.java
import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;
public class MainActivity extends Activity{
private static final String[] URLS = {
"http://cdn.cs76.net/2011/spring/lectures/6/imgs/img_2851.jpg",
"http://cdn.cs76.net/2011/spring/lectures/6/imgs/img_2944.jpg",
"http://cdn.cs76.net/2011/spring/lectures/6/imgs/img_2989.jpg",
"http://cdn.cs76.net/2011/spring/lectures/6/imgs/img_3005.jpg",
"http://cdn.cs76.net/2011/spring/lectures/6/imgs/img_3012.jpg",
"http://cdn.cs76.net/2011/spring/lectures/6/imgs/img_3034.jpg",
"http://cdn.cs76.net/2011/spring/lectures/6/imgs/img_3047.jpg",
"http://cdn.cs76.net/2011/spring/lectures/6/imgs/img_3092.jpg",
"http://cdn.cs76.net/2011/spring/lectures/6/imgs/img_3110.jpg",
"http://cdn.cs76.net/2011/spring/lectures/6/imgs/img_3113.jpg",
"http://cdn.cs76.net/2011/spring/lectures/6/imgs/img_3128.jpg",
"http://cdn.cs76.net/2011/spring/lectures/6/imgs/img_3160.jpg",
};
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
new DownloadImages().execute();
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.activity_main, menu);
return true;
}
}

make URLS as public
public static final String[] URLS = {
and use it as
for(int i = 0; i <MainActivity.URLS.length; i++) {
Try it..,.

An inner class is a class declared inside another class. Try putting DownloadImages inside MainActivity.