Develop Reference

OutOfMemory Exception in Android-Java. Allocation failed due to fragmentation

So I developed an Android application which acts as a server for my Android game(two separated apps), both applications were written in Java.
Previously I got messages on the Log like: "Skipped 2000 frames. The main thread could be overworking".
This is the code of my app, it's made of only the MainActivity:
I tried to introduce concurrent Threads in order to make the main thread lighter. Now the skipped n frames message isn't showed anymore but messages such like the followings are shown anyways.
"Alloc concurrent copying GC freed", "Starting a blocking GC alloc", "Waiting for a blocking GC alloc", "WaitForGcToComplete blocked alloc on HeapTrim" and all of this ends with
Throwing OutOfMemoryError "Failed to allocate a 32 byte allocation with 15604408 free bytes and 14MB until OOM, target footprint 268435456, growth limit 268435456; failed due to fragmentation (largest possible contiguous allocation 0 bytes)" (VmSize 5539048 kB).
I tried to deallocate some objects (lines of code which contains "x = null") but it didn't solve. Furthermore I checked with a log if there is some sort of endless loop but it doesn't seem to be the case.
public class MainActivity extends AppCompatActivity {
private static ActivityMainBinding binding;
private WSocServer server;
private int port = 8080;
private boolean isOnline = false;
private static ArrayList<String> logs = new ArrayList<>();
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
binding = ActivityMainBinding.inflate(getLayoutInflater());
setContentView(binding.getRoot());
setSupportActionBar(binding.toolbar);
binding.openConnection.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
if(!isOnline) {
isOnline = true;
server = new WSocServer(port);
server.start();
Toast toast = Toast.makeText(view.getContext(),"Server is on", Toast.LENGTH_LONG);
toast.show();
Log.i("WebSocket Server", "Started on port " + server.getPort());
}
else{
Snackbar snack = Snackbar.make(view ,"We are already online!", Snackbar.LENGTH_INDEFINITE);
snack.setAction("Got it", new View.OnClickListener() {
#Override
public void onClick(View view) {
snack.dismiss();
}
});
snack.show();
}
}
});
binding.closeConnection.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
if(isOnline) {
isOnline = false;
logs.clear();
Toast toast = Toast.makeText(view.getContext(),"Server is off", Toast.LENGTH_LONG);
toast.show();
try {
server.stop();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
else{
Snackbar snack = Snackbar.make(view ,"We are already offline!", Snackbar.LENGTH_INDEFINITE);
snack.setAction("Got it", new View.OnClickListener() {
#Override
public void onClick(View view) {
snack.dismiss();
}
});
snack.show();
}
}
});
}
private static void addOnView(){
ConstraintLayout cl = binding.logsView;
Handler h = new Handler(Looper.getMainLooper());
for(int i = 0; i < logs.size(); i++){
TextView tv = new TextView(binding.getRoot().getContext());
tv.setTextSize(16);
tv.setTextAlignment(View.TEXT_ALIGNMENT_CENTER);
tv.setPadding(40,180*(i+1),40,0);
tv.setText(logs.get(i));
Runnable r = new Runnable() {
#Override
public void run() {
cl.addView(tv);
}
};
h.post(r);
}
}
#Override
protected void onDestroy() {
super.onDestroy();
try {
server.stop();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
public static class WSocServer extends WebSocketServer {
private List<String> matchUsers;
private Integer timerSeconds;
private UUID matchId;
//a key represents a match to which an array of extracted numbers is associated
private Hashtable<String,Integer[]> matchExtractedNumbers = new Hashtable<>();
private Hashtable<String, Collection<WebSocket>> matchClients = new Hashtable<>();
private Hashtable<String,Hashtable<String,ArrayList<String>>> users_scorePerMatch = new Hashtable<>();
private Hashtable<String,WebSocket> clientConnection = new Hashtable<>();
private void initTimer(){
timerSeconds = 60;
Timer timer = new Timer();
TimerTask task = new TimerTask() {
public void run() {
if(timerSeconds > 0) timerSeconds--;
else {
timerSeconds = 60; timer.cancel(); timer.purge();
}
}
};
timer.schedule(task,0L,1000L);
}
private String UsersListToString(List list){
return list.toString().replace("[","").replace("]","");
}
private Integer[] generateExtractedNumbers(){
Integer[] callerBoard = new Integer[90];
List<Integer> boardPool = new ArrayList<>();
boardPool.addAll(Arrays.asList(IntStream.rangeClosed(1,90).boxed().toArray(Integer[]::new)));
for(int i = 0; i < 90; i++){
int rng = ThreadLocalRandom.current().nextInt(0,90-i);
callerBoard[i] = boardPool.remove(rng);
}
return callerBoard;
}
private void initMatch(){
matchId = UUID.randomUUID();
Integer[] matchBoard = generateExtractedNumbers();
matchExtractedNumbers.put(matchId.toString(),matchBoard);
matchClients.put(matchId.toString(),clientConnection.values());
Hashtable<String,ArrayList<String>> matchData = new Hashtable<>();
for(String user: matchUsers) matchData.put(user,new ArrayList<>());
users_scorePerMatch.put(matchId.toString(), matchData);
}
private Integer getExtractedNumber(String match, Integer turn){
if(turn >= 90) return -1;
Integer[] thisMatchExtractedNumbers = matchExtractedNumbers.get(match);
Integer returning = thisMatchExtractedNumbers[turn];
thisMatchExtractedNumbers = null;
return returning;
}
public WSocServer(int port){
super(new InetSocketAddress(port));
}
public WSocServer(InetSocketAddress address) {
super(address);
}
#Override
public void onOpen(WebSocket conn, ClientHandshake handshake) {
Thread thread = new Thread(new Runnable() {
#Override
public void run() {
Log.i("WebSocket(open)", conn.getRemoteSocketAddress().getAddress().getHostAddress() + " entered the room!");
logs.add(conn.getRemoteSocketAddress().getAddress().getHostAddress() + " entered the room!");
matchUsers = new ArrayList<>();
matchUsers.addAll(Arrays.asList("user1","user2","user3","user4","user5"));
}
});
thread.start();
}
#Override
public void onClose(WebSocket conn, int code, String reason, boolean remote) {
Thread thread = new Thread(new Runnable() {
#Override
public void run() {
Log.i("WebSocket(close)", conn + " has left the room! Reason: " + reason);
logs.add(conn + " has left the room!");
}
});
thread.start();
}
#Override
public void onMessage(WebSocket conn, String message) {
Thread thread = new Thread(new Runnable() {
#Override
public void run() {
logs.add(message + " from " + conn.getRemoteSocketAddress().getAddress().getHostAddress());
Log.i("WebSocket(message)", conn + ": " + message);
MainActivity.addOnView();
if(message.startsWith("username")){
if(matchUsers.size() < 6){
String user = message.replace("username;","");
if(!matchUsers.contains(user)) {
matchUsers.add(user);
clientConnection.put(user,conn);
}
String sending = "matchUsers;" + UsersListToString(matchUsers);
conn.send(sending);
}
else conn.send("errorUsername");
}
else if(message.equals("timerStart")){
initTimer();
if(matchUsers.size() < 6){
String sending = "timeStarter;" + timerSeconds.toString();
conn.send(sending);
}
else conn.send("errorTimer");
}
else if(message.equals("getMatchId")){
if(!matchUsers.isEmpty()){
initMatch();
matchUsers.clear();
}
String sending = "matchId;" + matchId.toString();
conn.send(sending);
}
else if(message.startsWith("inGame")){
String[] fields = message.split(";");
String matchId = fields[1].split("=")[1];
int turn = Integer.parseInt(fields[2].split("=")[1]);
Integer extraction = getExtractedNumber(matchId,turn);
fields = null;
conn.send("extracted=" + extraction.toString());
}
else if(message.startsWith("score")){
String matchId = message.split(";")[1].split("=")[1];
String score = message.split(";")[0].split("=")[1];
WebSocket[] clients = matchClients.get(matchId).toArray(new WebSocket[0]);
String user = "";
Enumeration<String> keys = clientConnection.keys();
String key = keys.nextElement();
while(!key.isEmpty()){
if(clientConnection.get(key) == conn) {
user = key;
break;
}
key = keys.nextElement();
}
keys = null;
Hashtable<String,ArrayList<String>> tmp = users_scorePerMatch.get(matchId);
ArrayList<String> tmp_list = tmp.get(user);
tmp_list.add(score);
tmp.replace(user,tmp_list);
users_scorePerMatch.replace(matchId,tmp);
for(int i = 0; i < clients.length; i++){
clients[i].send("statement;" + user + " got " + score + " with");
}
clients = null;
}
else if(message.startsWith("endMatchData")){
String matchId = message.split(";")[1].split("=")[1];
Hashtable<String,ArrayList<String>> users_ofMatch = users_scorePerMatch.get(matchId);
ArrayList<String> users = new ArrayList<>();
Enumeration<String> e = users_ofMatch.keys();
while(e.hasMoreElements()){
Log.e("endmatchdata","a");
users.add(e.nextElement());
}
e = null;
String sending = "matchEndData;";
for(String user: users) sending += user + "=" + UsersListToString(users_ofMatch.get(user)) + ":";
users_ofMatch = null;
conn.send(sending);
}
else if(message.startsWith("totalEnd")){
String matchId = message.split(";")[1].split("=")[1];
if(matchClients.get(matchId)!=null) {
WebSocket[] clients = matchClients.get(matchId).toArray(new WebSocket[0]);
for (WebSocket client : clients) client.close();
Enumeration<String> e = clientConnection.keys();
boolean exit = false;
while (e.hasMoreElements() && !exit) {
Log.e("totalend", "while");
for (WebSocket client : clients) {
Log.e("totalend", "for");
String tmp = e.nextElement();
if (clientConnection.get(tmp) == client) {
clientConnection.remove(tmp);
exit = true;
break;
}
}
}
e = null; clients = null;
matchClients.remove(matchId);
users_scorePerMatch.remove(matchId);
matchExtractedNumbers.remove(matchId);
}
}
}
});
thread.start();
}
#Override
public void onMessage(WebSocket conn, ByteBuffer message) {
Thread thread = new Thread(new Runnable() {
#Override
public void run() {
Log.i("WebSocket(message)", conn + ": " + message );
}
});
thread.start();
}
public static void main(String[] args){
}
#Override
public void onError(WebSocket conn, Exception ex) {
ex.printStackTrace();
}
#Override
public void onStart() {
Thread thread = new Thread(new Runnable() {
#Override
public void run() {
Log.i("WebSocket", "Server started!");
}
});
thread.start();
}
}
}
EDIT: The thing seems to be happening at the end of the match(i.e in the message.startsWith("totalEnd") or message.startsWith("endmatchdata") if cases in the onMessage method
EDIT 2: I found out that the addOnView function was badly written.
I changed it into
private static void addOnView(){
ConstraintLayout cl = binding.logsView;
Handler h = new Handler(Looper.getMainLooper());
final TextView tv = new TextView(binding.getRoot().getContext());
tv.setTextSize(16);
tv.setTextAlignment(View.TEXT_ALIGNMENT_CENTER);
tv.setPadding(40,180*(logs.size()+1),40,0);
tv.setText(logs.get(logs.size()-1));
Runnable r = new Runnable() {
#Override
public void run() {
cl.addView(tv);
}
};
h.post(r);
h = null;
r = null;
}
And it solved.

Android ChangeOverTime method freezing at runtime (but not consistently)

So I am running into a problem with a function I made to slowly change the value of a monitored variable over time that is causing all the java logic to lock up. It doesn't seem to be producing an error or make the application crash so it must be getting stuck in the while loop or something but the logging isn't firing while it is locked so I am just very confused. If anyone can help me figure out how to diagnose what is causing the freezing that would be very much appreciated
EDIT: Turns out the problem was updating the UI from another thread, I manged to get it to crash and got the error and used a CountDownTimer instead of the background thread and now it is working fine. For those curious checkout my GitHub for this project.
Function in question:
public static void changeOverTime(final MonitoredVariable<Integer> tVar, final int tTo, final long tTime, final long tUpdateFreq) {
if (tTime < tUpdateFreq) { Log.e(TAG, "Time must be greater then update freq."); }
if (tVar == null) { Log.e(TAG, "Container cannot be null."); }
else {
final Thread tBackgroundThread = new Thread(new Runnable() {
#Override
public void run() {
float tSteps = tTime / tUpdateFreq; // 2000/100 = 20
float tInterval = (tTo - tVar.get()) / tSteps; // 67-175 = -108/20 = -5.4
float tVal = tVar.get(); //175
while (Math.round(tVal) != tTo) { //67(After 20 Times) != 67 -> FALSE
Debug.Log(TAG, "EQ: " + Math.round(tVal) + "?=" + tTo);
tVal += tInterval; // -5.4 * 20(Times) = -108+175 = 67
tryToSleep(tUpdateFreq); // 100ms * 20(Times) = 2000ms total
tVar.set(Math.round(tVal));
}
}
});
tBackgroundThread.start();
}
}
Supporting Function:
private static void tryToSleep(long tTime) {
try { sleep(tTime); }
catch (InterruptedException e) { e.printStackTrace(); }
}
Monitored Variable Class:
public class MonitoredVariable<Prototype> {
protected Prototype mData;
protected ChangeListener mListener;
public MonitoredVariable(Prototype tData) {
this(tData, null);
}
public MonitoredVariable(Prototype tData, ChangeListener tListener) {
if (tListener != null) setListener(tListener);
mData = tData;
}
public Prototype get() {
return mData;
}
public void set(Prototype tData) {
if (mData != tData) {
mData = tData;
notifyChange();
}
}
public void setListener(ChangeListener tListener) {
mListener = tListener;
}
public ChangeListener getListener() {
return mListener;
}
public void notifyChange() {
if (mListener != null) mListener.onChange();
}
public interface ChangeListener {
void onChange();
}
}
Usage:
public static void init() {
MonitoredVariable.ChangeListener tUpdateBackground = new MonitoredVariable.ChangeListener() {
#Override
public void onChange() { updateBackgroud();
}
};
mTop = new MonitoredVariable[]{
new MonitoredVariable<>(0, tUpdateBackground),
new MonitoredVariable<>(0, tUpdateBackground),
new MonitoredVariable<>(0, tUpdateBackground)
};
mBottom = new MonitoredVariable[]{
new MonitoredVariable<>(0, tUpdateBackground),
new MonitoredVariable<>(0, tUpdateBackground),
new MonitoredVariable<>(0, tUpdateBackground)
};
mAnimationLoop = new Handler();
mAnimation = new Runnable() {
#Override
public void run() {
Debug.Log(TAG, "RUNNING ANIMATION");
final Random RNG = new Random();
for (MonitoredVariable<Integer>[] tBackground: new MonitoredVariable[][] {mTop, mBottom}) {
for (MonitoredVariable<Integer> tColor : tBackground) {
int tRandomColor = RNG.nextInt(255);
//tColor.set(tRandomColor);
Shift.changeOverTime(tColor, tRandomColor, 2000, 100);
}
}
if(mAnimate.get()) {
mAnimationLoop.postDelayed(mAnimation, 10000);
}
}
};
mAnimate = new MonitoredVariable<>(false, new MonitoredVariable.ChangeListener() {
#Override
public void onChange() {
if (mAnimate.get()) mAnimationLoop.postDelayed(mAnimation, 0);
else mAnimationLoop.removeCallbacks(mAnimation);
}
});
}
public static void setBackground(final Activity tActivity){
final View tActivityBackground = tActivity.findViewById(R.id.background);
mListener = new ChangeListener() {
#Override
public void onChange() { tActivityBackground.setBackground(mBackground); }
};
notifyChange();
}
private static void updateBackgroud() {
int tTop = Color.argb(255, mTop[0].get(), mTop[1].get(), mTop[2].get());
int tBottom = Color.argb(255, mBottom[0].get(), mBottom[1].get(), mBottom[2].get());
int[] colors = {tTop, tBottom};
mBackground = new GradientDrawable(GradientDrawable.Orientation.TOP_BOTTOM, colors);
mBackground.setCornerRadius(0f);
notifyChange();
}
public static void animateBackground(boolean tAnimate) {
mAnimate.set(tAnimate);
}
public static void notifyChange() {
if (mListener != null) mListener.onChange();
}
public interface ChangeListener {
void onChange();
}

Speeding the Random process

I am practising on a simple Android Game where a round button is randomly placed on the screen when the user taps on it..
it works fine but i want to speedify the process of placing the button so that the game gets harder for user...
here is the Code I'm using -
public class GameWindow extends Activity implements View.OnClickListener {
static int score;
private Timer t;
private int TimeCounter = 29;
private boolean canMove = true;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setVolumeControlStream(AudioManager.STREAM_MUSIC);
////Remove title screen for activty.
requestWindowFeature(Window.FEATURE_NO_TITLE);
setContentView(R.layout.activity_game_window);
moveButton();
endonTimeOver();
}
public void endonTimeOver(){
////Activity timer for 60 seconds.
final TextView timer = (TextView) findViewById(R.id.seconds);
t = new Timer();
t.scheduleAtFixedRate(new TimerTask() {
////Set string to timer.
#Override
public void run() {
// TODO Auto-generated method stub
runOnUiThread(new Runnable() {
public void run() {
timer.setText(String.valueOf(TimeCounter)); // you can set it to a textView to show it to the user to see the time passing while he is writing.
TimeCounter = TimeCounter - 1;
}
});
}
}, 1000, 1000); // 1000 means start from 1 sec, and the second 1000 is do the loop each 1 sec.
new Timer().schedule(new TimerTask(){
public void run() {
GameWindow.this.runOnUiThread(new Runnable() {
public void run() {
startActivity(new Intent(GameWindow.this, Finished.class));
}
});
}
}, 30000);
}
////Move button.
private void moveButton()
{
if(!canMove){ return; }
runOnUiThread(
new Runnable()
{
#Override
public void run()
{
Display display = getWindowManager().getDefaultDisplay();
Point size = new Point();
display.getSize(size);
int width = size.x;
int height = size.y;
Button button = (Button)findViewById(R.id.button);
Random r = new Random();
int startX = width/2;
int startY = height/2;
if(score==0){
button.setX(startX);
button.setY(startY);
}
else {
int x = r.nextInt(width - 210);
int y = r.nextInt(height - 200);
button.setX(x);
button.setY(y);
}
}
}
);
}
////Display score
public void displayScore(int score) {
TextView scoreView = (TextView) findViewById(R.id.score);
scoreView.setText(String.valueOf(score));
}
#Override
public void onClick(View v) {
MediaPlayer mp = MediaPlayer.create(this, R.raw.buttonsound);
mp.setOnCompletionListener(new OnCompletionListener() {
#Override
public void onCompletion(MediaPlayer mp) {
// TODO Auto-generated method stub
mp.release();
}
});
mp.start();
score = score + 1;
displayScore(score);
switch (v.getId()) {
case (R.id.button): {
moveButton();
}
}
}
public static int getScore(){
return score;
}}

Use global variables for values that don't change:
findViewById is slow
Creating new Random every time is not necessary
getting the window parameter every time is not necessary either

You seem to be starting a new thread and telling it to runonui , this might be slowing you down , try this :
private void moveButton()
{
if(!canMove){ return; }
Display display = getWindowManager().getDefaultDisplay();
Point size = new Point();
display.getSize(size);
int width = size.x;
int height = size.y;
Button button = (Button)findViewById(R.id.button);
Random r = new Random();
int startX = width/2;
int startY = height/2;
if(score==0){
button.setX(startX);
button.setY(startY);
}
else {
int x = r.nextInt(width - 210);
int y = r.nextInt(height - 200);
button.setX(x);
button.setY(y);
}
}
the computation itself doesn't seem to heavy so no need for another thread , you can do it on the main thread , if you're calling from oncreate that means you're already on main thread , this might give you the answer if i understood the question , try it

Latitude and longitude per pixel Google static maps

I have a static map, i know center coordinates in latitude and longitude, zoom level and image dimensions.
I don't understood if google static maps are already flattened and latitude and longitude per pixel are the same anywhere. If it's not like that i whant to know how can i calculate latidude and longitude per pixel and then meters per pixel , and how does that values vary with latitude .
P.S. I'm developing an android application that download an static map and computes distance between 2 points , but i've done that asuming the lat and long per pixel are the same ...and doesn't depend on latitude(position on globe)
Here is my mainactivity
package com.mnav.nav;
import android.app.*;
import android.os.*;
import android.view.*;
import android.widget.*;
import android.view.View.*;
import java.net.*;
import org.apache.http.*;
import android.graphics.*;
import java.io.*;
import android.graphics.drawable.*;
public class MainActivity extends Activity
{ Button start, dist;
TextView txt;
EditText lat, longit, zoom;
ImageView img;
Handler mhandler ;
Bitmap bit, original;
Boolean run = false, firstpoint = false, secondpoint = false;
String z, latitude, longitude;
int level;
int[] pointa = new int[2];
int[] pointb = new int[2];
double unit;
int maxx, maxy, minx, miny, distx, disty, distance1;
double distance;
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
start=(Button)findViewById(R.id.button);
lat = (EditText)findViewById(R.id.latitude);
longit = (EditText)findViewById(R.id.longitude);
img = (ImageView)findViewById(R.id.img);
zoom =(EditText)findViewById(R.id.zoom);
dist = (Button)findViewById(R.id.dist);
txt = (TextView)findViewById(R.id.txt);
mhandler = new Handler();
start.setOnClickListener(new OnClickListener()
{
#Override
public void onClick(View v)
{ z = zoom.getText().toString();
latitude = lat.getText().toString();
longitude = longit.getText().toString();
Thread thr = new Thread(new GetImage());
thr.start();
}
});
img.setOnTouchListener(new OnTouchListener()
{
#Override
public boolean onTouch(View v, MotionEvent event)
{ int i, j;
int x = (int)event.getX();
int vertical = (int)event.getY();
if(secondpoint==true)
{ bit = original.copy(Bitmap.Config.ARGB_4444, true);
img.setImageBitmap(bit);
secondpoint = false;
}
txt.setText(Integer.toString(x)+ " "+Integer.toString(vertical));
for (i = x-2; i < x+3; i++)
{
for(j=vertical-2; j<vertical+3; j++)
{
bit.setPixel(i,j, Color.WHITE);
}
}
bit.setPixel(x,vertical,Color.GREEN);
img.setImageBitmap(bit);
if(firstpoint)
{
pointb[0] = x; pointb[1]=vertical;
secondpoint = true;
firstpoint = false;
}
else
{
pointa[0]=x; pointa[1]=vertical;
firstpoint=true;
}
return false;
}
});
dist.setOnClickListener(new OnClickListener()
{
#Override
public void onClick(View p1)
{
unit = 0.1412/800;
unit = unit*500;
level = Integer.parseInt(z);
if(level == 20)
{
unit = unit;
}
else
if(level == 19)
{
unit = unit*2;
}
else
if(level==18)
{
unit = unit*4;
}
else
if(level == 17)
{
unit =unit*8;
}
else
if(level==16)
{
unit = unit*16;
}
else
if(level==15)
{
unit = unit*32;
}
else
if(level==14)
{
unit = unit*64;
}
else
if(level==13)
{
unit = unit*128;
}
else
if(level == 12)
{
unit = unit*256;
}
else
if(level==11)
{
unit = unit*512;
}
else
if(level==10)
{
unit = unit*1024;
}
distx = Math.abs(pointa[0]-pointb[0]);
disty= Math.abs(pointa[1]-pointb[1]);
distance1 = distx*distx+disty*disty;
distance = Math.sqrt(distance1);
distance = unit*distance;
txt.setText(Double.toString(distance)+" meters");
}
});
}
public class GetImage implements Runnable
{
String Url = "http://maps.google.com/staticmap?center=" + latitude+","+longitude+"&format=png&zoom="+ z +"&size=500x500&scale=1&maptype=hybrid&key=ABQIAAAA-O3c-Om9OcvXMOJXreXHAxRexG7zW5nSjltmIc1ZE-b8yotBWhQYQEU3J87QIBc4nfuySpoW_K6woA";
Bitmap bmp;
#Override
public void run()
{
try
{ mhandler.post(new Runnable()
{
#Override
public void run()
{
txt.setText("Wait...file is downloading...");
}
});
bmp = BitmapFactory.decodeStream((InputStream)new URL(Url).getContent());
}
catch (IOException e)
{ mhandler.post(new Runnable()
{
#Override
public void run()
{
// TODO: Implement this method
Toast.makeText(getApplicationContext(), "Something wrong just happend", Toast.LENGTH_LONG).show();
}
});
e.printStackTrace();
}
mhandler.post(new Runnable()
{
#Override
public void run()
{
if (bmp!=null)
{ txt.setText("Map downloaded..");
img.setImageBitmap(bmp);
bit = ((BitmapDrawable)img.getDrawable()).getBitmap();
bit = bit.copy(Bitmap.Config.ARGB_4444, true);
original = bit.copy(Bitmap.Config.ARGB_4444, true);
}
else
{
mhandler.post(new Runnable()
{
#Override
public void run()
{
Toast.makeText(getApplicationContext(), "null bitmap, sorry", Toast.LENGTH_LONG).show();
}
});
}
}
});
}
}
}

Setting one element in array changes others

I checked other similar tags with almost same title. Those answers were not relevant
When setting element at one position of array, both the elements have the same value.
public class LogActivity extends Activity
{
#Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_list);
startStopButton = (Button) findViewById(R.id.btnStart);
loggingStatusText = (TextView) findViewById(R.id.logStatusText);
mSensorManager = (SensorManager) getSystemService(SENSOR_SERVICE);
sensorList = mSensorManager.getSensorList(Sensor.TYPE_ALL);
sensorValues=new ArrayList<float[]>(sensorList.size());
sensorValsArray=new float[sensorList.size()][];
sensorNameList = new ArrayList<String>();
selectedSensorNames = new ArrayList<String>();
for (Sensor itemSensor : sensorList)
{
if (itemSensor != null)
{
sensorNameList.add(itemSensor.getName());
}
}
showSensorList();
}
private void showSensorList()
{
AlertDialog.Builder builder = new AlertDialog.Builder(this);
builder.setIcon(R.drawable.ic_launcher);
builder.setMultiChoiceItems((CharSequence[]) sensorNameList
.toArray(new CharSequence[sensorNameList.size()]),
new boolean[sensorNameList.size()],
new DialogInterface.OnMultiChoiceClickListener()
{
public void onClick(DialogInterface dialog,
int whichButton, boolean isChecked)
{
if (isChecked)
{
if (!selectedSensorNames.contains(sensorNameList
.get(whichButton)))
selectedSensorNames.add(sensorNameList
.get(whichButton));
} else
{
if (selectedSensorNames.contains(sensorNameList
.get(whichButton)))
{
selectedSensorNames.remove(sensorNameList
.get(whichButton));
}
}
}
});
builder.setPositiveButton("Ok", new DialogInterface.OnClickListener()
{
public void onClick(DialogInterface dialog, int whichButton)
{
listeners=new SensorEventListener[selectedSensorNames.size()];
float[] tempVals = new float[] { 0, 0, 0 };
for (int i = 0; i < selectedSensorNames.size(); i++)
{
sensorValsArray[i]=tempVals;
}
showRateList();
}
});
builder.setCancelable(false);
builder.create().show();
}
void registerSensors()
{
for (Sensor sensor : sensorList)
{
if (selectedSensorNames.contains(sensor.getName()))
{
mSensorManager.registerListener(listeners[selectedSensorNames.indexOf(sensor.getName())], sensor, selectedDelay);
}
}
}
class SchedulerTask extends TimerTask
{
/*
* The task to run should be specified in the implementation of the
* run() method
*/
public void run()
{
logSensorData();
}
}
private void createLog(String fileName)
{
File root = getExternalFilesDir(null);// Get the Android external
// storage directory
Date cDate = new Date();
String bstLogFileName = fileName;
bstLogFile = new File(root, bstLogFileName);// Construct a new file for
// using the specified
// directory and name
FileWriter bstLogWriter;
logScheduler = new Timer();// Create a new timer for updating values
// from content provider
logScheduler.schedule(new SchedulerTask(),
LOG_TASK_DELAY_IN_MILLISECONDS,
getLogPeriodInMilliSeconds(selectedDelay));
}
public void logSensorData()
{
Date stampDate = new Date();
String LogPack ="\r\n";
for (int count=0;count<selectedSensorNames.size();count++)
{
LogPack += sensorValsArray[count][0] + "," + sensorValsArray[count][1] + "," + sensorValsArray[count][2] + ",";
}
LogPack += "\r\n";
try
{
F_StreamWriter.write(LogPack);
F_StreamWriter.flush();
}
catch (IOException e)
{
}
catch (NullPointerException e)
{
}
}
public void startStopLog(View v)
{
if (startStopButton.getText().equals("Start"))
{
createSensorListeners();
registerSensors();
showFilenameDialog();
} else if (startStopButton.getText().equals("Stop"))
{
stopLog();
}
}
public void startLog(String fileName)
{
createLog(fileName);
}
public void stopLog()
{
logScheduler.cancel();
logScheduler.purge();
for(int i=0;i<listeners.length;i++)
mSensorManager.unregisterListener(listeners[i]);
}
private void showFilenameDialog()
{
final Dialog dialog = new Dialog(this);
dialog.setContentView(R.layout.custom_text_input_dialog);
dialog.setCancelable(true);
final EditText fileNameInput = (EditText) dialog
.findViewById(R.id.fileNameText);
Button button = (Button) dialog.findViewById(R.id.okButton);
button.setOnClickListener(new OnClickListener()
{
#Override
public void onClick(View v)
{
startLog(nameInput);
dialog.dismiss();
}
});
dialog.show();
}
private void createSensorListeners()
{
listeners=new SensorEventListener[selectedSensorNames.size()];
for (int i = 0; i < selectedSensorNames.size(); i++)
{
listeners[i]=new SensorEventListener()
{
#Override
public void onSensorChanged(SensorEvent event)
{
sensorValsArray[selectedSensorNames.indexOf(event.sensor.getName())]=event.values;
}
#Override
public void onAccuracyChanged(Sensor sensor, int accuracy)
{
}
};
}
}
}
When index is 0, when set command is executed, it also changes the the value at index position '1'.
Can anyone help me with this?
Thanks in Advance,
Dheepak

When index is 0, when set command is executed, it also changes the the value at index position '1'. Can anyone help me with this?
You are definitely mistaken as to what it is causing this. Setting the value at one position of an ArrayList WILL NOT mysteriously cause the value at another position to change. It simply does not work like that.
The effect you are observing will be due to something else:
maybe the value of index is not what you expect
maybe the value of event.values is not what you expect. (Maybe you've made a mistake in the way that you create the Event objects, and they are all sharing one float[] object.)
maybe the value at position 1 was already that value
maybe you've got multiple threads updating the sensorValues list.