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Android memory leak on device, not on emulator

I'm writing a game to help teach my son some phonics: it's my first attempt at programming in Java, although I've previously used other languages. The game has four activities: a splash screen which initializes an array of variables before you dismiss it; another to choose a user; a third to choose which level of the game to play; and a fourth to actually play the game.
My problem was that if you go in and out of the game activity repeatedly, that activity would eventually crash -- logcat showed an OOM error. Watching the heap size as I did this, and looking at a heap dump with MAT, it looked as though I was leaking the whole of the fourth activity -- GC was just not being triggered.
I've tried lots of things to track down and fix the leak -- most of which are, I'm sure improvements (e.g. getting rid of all non-static inner classes from that activity) without fixing the problem. However, I've just tried running the same thing on an emulator (same target and API as my device) and there's no leak -- heap size goes up and down, GC is regularly triggered, it doesn't crash.
So I was going to post the code for the activity on here and ask for help spotting what might be causing the leak, but I'm no longer sure that's the right question. Instead I'm wondering why it works on the emulator, but not the phone... Does anyone have any ideas?
IDE: Android Studio 2.1
Target: Android 6, API 23 (Minimum SDK 8)
Emulator: Android Studio
Device: Sony Xperia Z2 (Now running 6.0.1, but I had the same issue pre recent update, i.e. on API 22)
Code for the activity:
public class GameActivity extends AppCompatActivity implements TextToSpeech.OnInitListener {
//TTS Object
private static TextToSpeech myTTS;
//TTS status check code
private int MY_DATA_CHECK_CODE = 0;
//LevelChooser request code
public static Context gameContext;
private int level;
public static String user;
private Typeface chinacat;
public static Activity gameActivity = null;
private static int[] goldstars = {R.drawable.goldstar1, R.drawable.goldstar2, R.drawable.goldstar3};
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
requestWindowFeature(Window.FEATURE_NO_TITLE);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
gameActivity = this;
gameContext = this;
level = getIntent().getIntExtra("level", 1);
user = getIntent().getStringExtra("user");
chinacat = Typeface.createFromAsset(getAssets(), "fonts/chinrg__.ttf");
Intent checkTTSIntent = new Intent();
checkTTSIntent.setAction(TextToSpeech.Engine.ACTION_CHECK_TTS_DATA);
startActivityForResult(checkTTSIntent, MY_DATA_CHECK_CODE);
}
#Override
public void onStop() {
if (myTTS != null) {
myTTS.stop();
}
super.onStop();
}
#Override
public void onDestroy() {
if (myTTS != null) {
myTTS.shutdown();
}
Button ok_button = (Button) findViewById(R.id.button);
ok_button.setOnClickListener(null);
ImageView tickImageView = (ImageView) findViewById(R.id.tickImageView);
tickImageView.setOnClickListener(null);
super.onDestroy();
}
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
if (requestCode == MY_DATA_CHECK_CODE) {
if (resultCode == TextToSpeech.Engine.CHECK_VOICE_DATA_PASS) {
myTTS = new TextToSpeech(this, this);
} else {
Intent installTTSIntent = new Intent();
installTTSIntent.setAction(TextToSpeech.Engine.ACTION_INSTALL_TTS_DATA);
startActivity(installTTSIntent);
}
}
}
public void onInit(int initStatus) {
//if tts initialized, load layout and level and assign listeners for layout elements
if (initStatus == TextToSpeech.SUCCESS) {
myTTS.setLanguage(Locale.ENGLISH);
setContentView(R.layout.activity_main);
ImageView imageView = (ImageView) findViewById(R.id.myImageView);
PhonemeGroup levelGroup = MainActivity.gamelevel[level]; //set possible words
levelGroup.setSubset(); //randomize subset of possible words for actual test
PhonicsWord[] testSet = levelGroup.getSubset(); //fill array of test words
TextView[] targetView = new TextView[3]; //textviews for beginning, middle & end of word
targetView[0] = (TextView) findViewById(R.id.targetWord0);
targetView[1] = (TextView) findViewById(R.id.targetWord1);
targetView[2] = (TextView) findViewById(R.id.targetWord2);
TextView[] answersView = new TextView[3]; //textviews for possible user answer choices
answersView[0] = (TextView) findViewById(R.id.letter0);
answersView[1] = (TextView) findViewById(R.id.letter1);
answersView[2] = (TextView) findViewById(R.id.letter2);
//set first target word, image for word, and possible answers
testSet[0].setWord(levelGroup, targetView, answersView, imageView);
testSet[0].speakWord(myTTS);
//subset index is equal to array index for testSet, but visible to & settable by methods
levelGroup.setSubsetIndex(0);
for(int i=0; i<3; i++) {
answersView[i].setTypeface(chinacat);
}
TextView letter0 = (TextView) findViewById(R.id.letter0);
letter0.setOnClickListener(new LetterOnClickListener(testSet, levelGroup, targetView, answersView, 0) );
TextView letter1 = (TextView) findViewById(R.id.letter1);
letter1.setOnClickListener(new LetterOnClickListener(testSet, levelGroup, targetView, answersView, 1) );
TextView letter2 = (TextView) findViewById(R.id.letter2);
letter2.setOnClickListener(new LetterOnClickListener(testSet, levelGroup, targetView, answersView, 2) );
Button ok_button = (Button) findViewById(R.id.button);
ok_button.setOnClickListener(new OKButtonOnClickListener(testSet, levelGroup, targetView, level) );
ImageView tickImageView = (ImageView) findViewById(R.id.tickImageView);
tickImageView.setOnClickListener(new TickClick(myTTS, testSet, levelGroup, targetView, answersView, imageView) );
imageView.setOnClickListener(new WordImageClick(testSet, levelGroup) );
}
/*else if TODO*/
}
private static class WordImageClick implements View.OnClickListener {
//speaks the test word when the test image is clicked
PhonicsWord[] testSet;
PhonemeGroup levelGroup;
public WordImageClick(PhonicsWord[] testSet, PhonemeGroup levelGroup) {
this.testSet = testSet;
this.levelGroup = levelGroup;
}
#Override
public void onClick(View view) {
testSet[levelGroup.getSubsetIndex()].speakWord(myTTS);
}
}
private static class LetterOnClickListener implements View.OnClickListener {
PhonemeGroup levelGroup;
PhonicsWord currentWord;
PhonicsWord[] testSet;
TextView[] targetView;
TextView[] answersView;
int item;
int phonemeclicked;
public LetterOnClickListener(PhonicsWord[] testSet, PhonemeGroup levelGroup, TextView[] targetView, TextView[] answersView, int phonemeclicked) {
this.testSet = testSet;
this.levelGroup = levelGroup;
this.targetView = targetView;
this.answersView = answersView;
this.phonemeclicked = phonemeclicked;
}
#Override
public void onClick(View view) {
this.item = this.levelGroup.getSubsetIndex();
this.currentWord = this.testSet[item];
int i = currentWord.getOmit_index();
targetView[i].setText(answersView[phonemeclicked].getText());
}
}
private void crossClick(View view) {
view.setVisibility(View.INVISIBLE);
if(view.getTag()==4){
finish();
}
}
The static variable gameActivity is used so that when you've finished a level an external class can call GameActivity.gameActivity.finish() after it's displayed how many stars you've got for the level (it's also used to call GameActivity.gameActivity.findViewById in another external class).
public class ShowStarsWithDelay extends Handler {
public void handleMessage(Message msg) {
ImageView starView = (ImageView) ((LevelEndScreens) msg.obj).starView;
ImageView highscoreView = (ImageView) ((LevelEndScreens) msg.obj).highscoreView;
int num_currentstars = (int) ((LevelEndScreens) msg.obj).num_currentstars;
int num_finalstars = (int) ((LevelEndScreens) msg.obj).num_finalstars;
Boolean highscore = (Boolean) ((LevelEndScreens) msg.obj).highscore;
int[] goldstars = (int[])((LevelEndScreens) msg.obj).goldstars;
if(num_currentstars == num_finalstars) {
if(!highscore) {
starView.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
GameActivity.gameActivity.finish();
}
});
}
else {
highscoreView.setImageResource(R.drawable.highscore);
highscoreView.setVisibility(View.VISIBLE);
highscoreView.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
GameActivity.gameActivity.finish();
}
});
}
}
else {
starView.setImageResource(goldstars[num_currentstars++]);
Message message = new Message();
LevelEndScreens endScreens = new LevelEndScreens(starView, highscoreView, num_currentstars, num_finalstars, highscore, goldstars);
message.obj = endScreens;
this.sendMessageDelayed(message, 1000);
}
}
}

In general, you want to avoid having any static reference to a Context anywhere in your application (this includes Activity classes, of course). The only reference to a Context which MAY be acceptable is referencing the application context (as there is only one and it is always in memory while your app is alive anyway).
If you need a reference to the calling activity in one of your children, you'll need to pass the context as a parameter, or else use one of the child views methods to retrieve the context (such as getContext() for views and fragments).
More information that should help understand memory leaks and why this is important is here:
http://android-developers.blogspot.com/2009/01/avoiding-memory-leaks.html
As an example, in your code for calling finish(), you could safely change it to this:
highscoreView.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
if (v.getContext() instanceof Activity) {
((Activity)v.getContext()).finish();
}
}
});
To sum up, in order to fix your memory leaks, you'll need to remove the static keyword for all of your Context fields.

How to modify a global variable in a method

I have an animation for android with 10 buttons, and I need to trigger this buttons with an order, so I have a variable named order, if order=1 button1 can get activated, if order=2 button 2 can get activated and so on. When I open the program, an animation starts, then a second animation repeats itself after the first one ends and in between I need to change the variable order to 1. I have the next code:
public class Juego extends Activity
{
private AnimationDrawable animacion, loop;
private MediaPlayer miPlayer;
private int order = 0;
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_juego);
ImageView video = (ImageView) findViewById(R.id.secuencia);
video.setBackgroundResource(R.drawable.animation_drawable_start);
animacion = (AnimationDrawable) video.getBackground();
animacion.start();
checkIfAnimationDone0(animacion);
}
public void checkIfAnimationDone0(AnimationDrawable anim)
{
final AnimationDrawable a = anim;
int timeBetweenChecks = 20;
android.os.Handler h = new android.os.Handler();
h.postDelayed(new Runnable()
{
public void run()
{
if (a.getCurrent() != a.getFrame(a.getNumberOfFrames() - 1))
{
checkIfAnimationDone1(a);
}
else
{
ImageView video = (ImageView) findViewById(R.id.secuencia);
video.setBackgroundResource(R.drawable.animation_drawable_loop_inicio);
loop = (AnimationDrawable) video.getBackground();
loop.start();
order=1;
}
}
}, timeBetweenChecks);
};
public void onClickButton2(View any)
{
if (order == 1)
{
ImageView video = (ImageView) findViewById(R.id.secuencia);
video.setBackgroundResource(R.drawable.animation_drawable_boton_1);
animacion = (AnimationDrawable) video.getBackground();
miPlayer = MediaPlayer.create(Juego.this, R.raw.sonido_boton_1);
animacion.start();
miPlayer.start();
checkIfAnimationDone1(animacion);
order=2;
}
}
etc..
The problem is that the value of the global variable order does not get changed in the line order=1, and the method onClickButton() cannot start. How do I solve this?

In checkIfAnimationDone0(), when
a.getCurrent() != a.getFrame(a.getNumberOfFrames() - 1)
you go to checkIfAnimationDone1(), so order is never set as 1.
Change checkIfAnimationDone1() in checkIfAnimationDone0() to checkIfAnimationDone0().

How do I randomize images in android studio? The code I wrote isn't working

I want to randomize the the back images that will be brought from a database(code still not added), but the code I wrote isn't working. I have originally just added the flip function. I searched up how to randomize images and tried to follow the code given. Sadly its not working for me.
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// get references to the imageView objects
imgUpperLeft = (ImageView) findViewById(R.id.imgUpperLeft);
imgUpperRight = (ImageView) findViewById(R.id.imageView2);
imgLowerLeft = (ImageView) findViewById(R.id.imageView3);
imgLowerRight = (ImageView) findViewById(R.id.imageView4);
// Setting the initial image (First face of cards)
imgUpperLeft.setImageResource(R.drawable.img_waterfall);
imgUpperRight.setImageResource(R.drawable.img_waterfall);
imgLowerLeft.setImageResource(R.drawable.img_waterfall);
imgLowerRight.setImageResource(R.drawable.img_waterfall);
imgUpperLeft.setVisibility(View.VISIBLE);
imgUpperRight.setVisibility(View.VISIBLE);
imgLowerLeft.setVisibility(View.VISIBLE);
imgLowerRight.setVisibility(View.VISIBLE);
}
ImageView imgView = new ImageView(this);
Random rand = new Random();
int rndInt = rand.nextInt(4) + 1; // n = the number of images, that start at idx 1
String imgName = "img" + rndInt;
int id = getResources().getIdentifier(imgName, "drawable", getPackageName());
// Shows the second face of the cards
public void showUpperLeftImage(View v){
imgView.setImageResource(id);
}
public void showUpperRightImage(View v){
imgView.setImageResource(id);
}
public void showLowerLeftImage(View v){
imgView.setImageResource(id);
}
public void showLowerRightImage(View v){
imgView.setImageResource(id);
}

Two things in your code stand out to me:
ImageView imgView = new ImageView(this);
This ImageView is not part of the view hierarchy, meaning it is not on screen. Was it ever meant to be on screen? If not, then I don't think you need this.
public void showUpperLeftImage(View v){
imgView.setImageResource(id);
}
You have four methods like this one that change the image of the view that is not on screen. Judging by their method names, I think you want to change the image of the four ImageViews you found earlier with findViewById().
I think you want to do this:
public void showUpperLeftImage(int id) {
imgUpperLeft.setImageResource(id);
}
public void showUpperRightImage(int id) {
imgUpperRight.setImageResource(id);
}
public void showLowerLeftImage(int id) {
imgLowerLeft.setImageResource(id);
}
public void showLowerRightImage(int id) {
imgLowerRight.setImageResource(id);
}

Android button loop

I have this code :
private ImageView d1;
private ArrayList<Integer> listaImagenes = new ArrayList<Integer>();
private ArrayList<String> listaFrases = new ArrayList<String>();
private Button button;
private Integer contador = 0;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
this.rellenarImagenes();
setContentView(R.layout.imagentonas);
d1 = (ImageView) findViewById(R.id.imagenes01);
while (contador < listaImagenes.size()) {
d1.setImageResource(listaImagenes.get(contador));
button = (Button) findViewById(R.id.botoncillo);
button.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
contador++;
}
});
}
}
private void rellenarImagenes() {
listaImagenes.add(R.drawable.a01);
listaImagenes.add(R.drawable.a02);
listaImagenes.add(R.drawable.a03)
}
I am trying do a loop that when I press the button , increment contador and d1 change image.
but it is not working, application background remains black and not working.

remove while loop and setimage in onclick method.

You are expecting that modifying the value of the variable contador would result in the array item to change.
Keep in mind that in the code line d1.setImageResource(listaImagenes.get(contador));, the get function receives an int. So at the time where it's called it receives a value, not a reference to an Integer. When you change the value of contador, the value that was used to obtain the index in the array is not changed.
And even if the value did change, d1 would still be using the same resource.
What you need to do in the onClickListener is add the code to set the image. Something along the lines of
public void onClick(View v) {
++contador;
if (contador >= listaImagenes.size())
{
contador=0;
}
//you'll probably need to modify the next line to be able to access the button variable.
//one way to do it is to use a final variable in the onCreate method that creates this OnClickListener
button.setImageResource(listaImagenes.get(contador));
}
The while loop is not needed. What your code is doing is setting the image to the 3 items of the array, one after the other, and adding a new click listener 3 times.

I will try to answer and point some of the flaws you have in the code.
wat if there were 100 drawable like R01 ,R02...? Instead you can use getting drawable using string.
why are you using while loop ? since you have the counter you can directly use that.
Let me try to write the code
int contador=1;
#Override
public void onCreate (Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.imagentonas);
context=this;
d1=(ImageView)findViewById(R.id.imagenes01);
button=(Button)findViewById(R.id.botoncillo);
button=(Button)findViewById(R.id.botoncillo);
button.setOnClickListener( new View . OnClickListener () {
public void onClick ( View v ) {
int id = context.getResources().getIdentifier("a"+contador,
"drawable", context.getPackageName());
d1.setImageResource(id);
contador++;
}
});
}
Notice : int id = context.getResources().getIdentifier("a"+contador,"drawable", context.getPackageName()); Here using the string you can access the drawable this solves the issue for any number of consecutive drawables.
Hope you get the concept...
Thanks

Get the Integer behind ImageView Array

I have this thing into my application.
That I want to do is this, when someone presses the die with the number 5 I want to add 5 points into his ArrayList. I was thinking for an Listener but how would I know which ImageView has been pressed?
Currently I am using this method to get the right placeholders in the board
public ImageView[] initiateDice() {
ImageView pDice1 = (ImageView) findViewById(R.id.die_one);
ImageView pDice2 = (ImageView) findViewById(R.id.die_two);
ImageView pDice3 = (ImageView) findViewById(R.id.die_three);
ImageView pDice4 = (ImageView) findViewById(R.id.die_four);
ImageView pDice5 = (ImageView) findViewById(R.id.die_five);
ImageView pDice6 = (ImageView) findViewById(R.id.die_six);
ImageView pDice7 = (ImageView) findViewById(R.id.die_seven);
ImageView pDice8 = (ImageView) findViewById(R.id.die_eight);
ImageView[] placeHolders = new ImageView[] {pDice1, pDice2, pDice3, pDice4, pDice5, pDice6, pDice7, pDice8};
return placeHolders;
}
and I am "printing" the dice on the screen using that method
public void printDice(int[] array1, ImageView[] array2) {
for (int i = 0; i < array1.length; i++) {
array2[i].setImageResource(diceImages[array1[i] - 1]);
array2[i].setVisibility(View.VISIBLE);
}
}
where the first array is 8 random generated numbers for the dice and the second array is the PlaceHolders.
The diceImages is for the images of the dice, the six states of them.
private final int[] diceImages = new int[] {R.drawable.dice_one, R.drawable.dice_two, R.drawable.dice_three,
R.drawable.dice_four, R.drawable.dice_five, R.drawable.dice_pico };
Any thoughts or suggestions are welcome.

Other answers are providing some of the solution, but you're actually asking about how to get the number displayed in the image view, in which case, you can save it to the tag:
public void printDice(int[] array1, ImageView[] array2) {
for (int i = 0; i < array1.length; i++) {
array2[i].setImageResource(diceImages[array1[i] - 1]);
array2[i].setVisibility(View.VISIBLE);
array2[i].setTag(array1[i]);
}
}
And modifying Matt's answer:
OnClickListener listener = new OnClickListener() {
#Override
public void onClick(View v) {
Integer dieValue = v.getTag();
// do something
}
};
pDice1.setOnClickListnener(listener);
pDice2.setOnClickListnener(listener);
pDice3.setOnClickListnener(listener);
pDice4.setOnClickListnener(listener);
pDice5.setOnClickListnener(listener);
pDice6.setOnClickListnener(listener);
pDice6.setOnClickListnener(listener);
pDice8.setOnClickListnener(listener);

One way to do it is to set an OnClickListener like this:
OnClickListener listener = new OnClickListener() {
#Override
public void onClick(View v) {
if (v == pDice1) {
// do something
} else if (v == pDice2) {
...
}
}
};
pDice1.setOnClickListnener(listener);
pDice2.setOnClickListnener(listener);
pDice3.setOnClickListnener(listener);
pDice4.setOnClickListnener(listener);
pDice5.setOnClickListnener(listener);
pDice6.setOnClickListnener(listener);
pDice6.setOnClickListnener(listener);
pDice8.setOnClickListnener(listener);

You would set an OnClickListener() to all ImageViews. The OnClickListener() gets passed the View that has clicked. View has a getId() that returns an int with the id of the View. Then it is only a matter of adding either a switch or if(){...} else if(...)() to perform a specific action based on the id of the View that was clicked.