I am making an app, where a server in java sends a Place Array and other stuff in other activities. so I create a service to connect to the server from different activities. I have not implement server connection yet but I am simulating the server response, which I pass as parameter to an adapter (the adapter is tested), that I create to show this places in a ListView. so I got my Place array in my activity and I set it to the return object from a method in the service, but when I run the app it crashes and I got this error message:
java.lang.NullPointerException: Attempt to invoke virtual method 'com.remedialguns.smartourist.Place[] com.remedialguns.smartourist.ConnectionService.getPlaces()' on a null object.
UPDATE now is te same error but in myAdapter class when name.setText... so this is my service.
package com.remedialguns.smartourist;
import android.app.Service;
import android.content.Intent;
import android.os.Binder;
import android.os.IBinder;
import android.util.Log;
import android.widget.Toast;
import java.io.IOException;
import java.io.PrintStream;
import java.net.InetSocketAddress;
import java.net.Socket;
import java.net.SocketAddress;
import java.util.Locale;
public class ConnectionService extends Service {
Socket s;
PrintStream os;
private static final String TAG="com.remedialguns.smartourist";
private final IBinder myBinder = new LocalBinder();
@Override
public IBinder onBind(Intent intent) {
return myBinder;
}
public void sendProfileData(){
//send profile data to server
}
public Place[] getPlaces(){
Place[] PlacesToShow = new Place[10];
//F̶a̶k̶e̶ ̶d̶a̶t̶a̶ Test data
PlacesToShow[0]= new Place("MUSEO","Museo Nacional Agropecuario", 0.15, 0.4, 0.12);
PlacesToShow[1]= new Place("MUSEO","Museo Arqueológico Junín",0.10, 0.78, 0.44);
PlacesToShow[2]= new Place("MUSEO","Museo Botero", 0.2, 0.8, 0.08);
PlacesToShow[3]= new Place("MUSEO","Museo de Zea", 0.3, 0.65, 0.23);
PlacesToShow[4]= new Place("MUSEO","MUSEO DEL ORO", 0.13, 0.56, 0.12);
PlacesToShow[5]= new Place("MUSEO","MUSEO DE ARTE COLONIAL", 0.3, 0.67, 0.14);
PlacesToShow[6]= new Place("MUSEO","MUSEO HISTORICO DE LA POLICIA NACIONAL", 0.34, 0.3, 0.33);
PlacesToShow[8]= new Place("MUSEO","MUSEO DE LOS NIÑOS", 0.05, 0.65, 0.03);
PlacesToShow[7]= new Place("MUSEO","Museo Nacional", 0.15, 0.4, 0.12);
PlacesToShow[9]= new Place("MUSEO","MUSEO MILITAR", 0.07, 0.5, 0.6);
return PlacesToShow;
}
public class LocalBinder extends Binder {
ConnectionService getService(){
return ConnectionService.this;
}
}
}
this is my activity with my ListView and adapter.(UPDATE)
package com.remedialguns.smartourist;
import android.content.ComponentName;
import android.content.Context;
import android.os.Bundle;
import android.support.design.widget.Snackbar;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.ListAdapter;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;
import android.os.IBinder;
import android.content.Context;
import android.content.Intent;
import android.content.ServiceConnection;
import com.remedialguns.smartourist.ConnectionService.LocalBinder;
import com.google.android.gms.location.places.Places;
public class ListActivity extends AppCompatActivity {
ConnectionService tcpService;
boolean isBound=false;
//Place[] PlacesToShow=tcpService.getPlaces();
Place[] PlacesToShow=new Place[10];
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_list);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
Intent i = new Intent(this, ConnectionService.class);
bindService(i, myConnection, Context.BIND_AUTO_CREATE);
// PlacesToShow=tcpService.getPlaces();
if (isBound) {
PlacesToShow = tcpService.getPlaces();
}
//Place[] PlacesToShow=tcpService.getPlaces();
ListAdapter MyAdapter = new MyAdapter(this, PlacesToShow);
ListView ListPlaces=(ListView) findViewById(R.id.MyList);
ListPlaces.setAdapter(MyAdapter);
ListPlaces.setOnItemClickListener(
new AdapterView.OnItemClickListener(){
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
Context context = view.getContext();
TextView textViewItem = ((TextView)view.findViewById(R.id.name));
String name =textViewItem.getText().toString();
TextView textViewItem2 = (TextView)findViewById(R.id.description);
String descripcion=textViewItem2.getText().toString();
Toast.makeText(context,"lugar: "+name+", descripcion: "+descripcion,Toast.LENGTH_SHORT).show();
}
});
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_main, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
private ServiceConnection myConnection=new ServiceConnection() {
@Override
public void onServiceConnected(ComponentName name, IBinder service) {
LocalBinder binder = (LocalBinder) service;
tcpService = binder.getService();
PlacesToShow = tcpService.getPlaces();
isBound = true;
}
@Override
public void onServiceDisconnected(ComponentName name) {
isBound=false;
}
};
}
this is my activity.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
android:paddingBottom="@dimen/activity_vertical_margin"
app:layout_behavior="@string/appbar_scrolling_view_behavior"
tools:showIn="@layout/activity_list"
tools:context="com.remedialguns.smartourist.ListActivity">
<!-- <TextView
android:id="@+id/answer"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="these are the places that our smart monkeys had find for you."/>
-->
<ListView
android:id="@+id/MyList"
android:layout_width="match_parent"
android:layout_height="match_parent">
</ListView>
</LinearLayout>
this is my manifest
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.remedialguns.smartourist" >
<application
android:allowBackup="true"
android:icon="@mipmap/ic_launcher"
android:label="@string/app_name"
android:supportsRtl="true"
android:theme="@style/AppTheme" >
<activity
android:name=".LoginActivity"
android:label="@string/app_name"
android:theme="@style/AppTheme.NoActionBar" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<meta-data
android:name="com.google.android.gms.version"
android:value="@integer/google_play_services_version" />
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.GET_ACCOUNTS" />
<uses-permission android:name="android.permission.USE_CREDENTIALS" />
<activity
android:name=".MainActivity"
android:label="@string/app_name"
android:theme="@style/AppTheme.NoActionBar" >
</activity>
<activity
android:name=".RealMainActivity"
android:label="@string/app_name"
android:theme="@style/AppTheme.NoActionBar" >
</activity>
<activity
android:name=".ListActivity"
android:label="@string/app_name"
android:parentActivityName=".RealMainActivity"
android:theme="@style/AppTheme.NoActionBar" >
<meta-data
android:name="android.support.PARENT_ACTIVITY"
android:value="com.remedialguns.smartourist.RealMainActivity" />
</activity>
<service
android:name=".ConnectionService"
android:enabled="true"
android:exported="true" >
</service>
</application>
</manifest>
this is my adapter class
package com.remedialguns.smartourist;
import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.ImageView;
import android.widget.TextView;
public class MyAdapter extends ArrayAdapter<Place> {
MyAdapter(Context context, Place[] places){
super(context, R.layout.visual_place, places);
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
LayoutInflater MyInflater = LayoutInflater.from(getContext());
View placeView = MyInflater.inflate(R.layout.visual_place, parent, false);
Place singlePlaceItem=getItem(position);
TextView name=(TextView) placeView.findViewById(R.id.name);
ImageView icon =(ImageView) placeView.findViewById(R.id.icon);
TextView description = (TextView) placeView.findViewById(R.id.description);
name.setText(singlePlaceItem.getName().toString());
icon.setImageResource(R.mipmap.ic_launcher);
description.setText("Cost "+singlePlaceItem.getCost()+", distance "+singlePlaceItem.getDistance()+", rate "+singlePlaceItem.getRate()+" *");
return placeView;
}
}
please help me.
Here:
bindService(i, myConnection, Context.BIND_AUTO_CREATE);
Place[] PlacesToShow=new Place[10];
PlacesToShow=tcpService.getPlaces();
tcpService is null probably using is to call getPlaces() method before onServiceConnected method is called.
Use isBound to check onServiceConnected is called or not before using tcpService object:
if(isBound){
//
PlacesToShow=tcpService.getPlaces();
}
and also use onServiceConnected method as:
@Override
public void onServiceConnected(ComponentName name, IBinder service) {
LocalBinder binder = (LocalBinder) service;
tcpService = binder.getService();
PlacesToShow=tcpService.getPlaces();
isBound=true;
}
Also make sure added ConnectionService in AndroidManifest.xml as service.