I'm struggling to figure out why I can't pass an int value from one activity to another. The app will ask you to press a button to generate a random number from 1-100 which will be displayed below the button. There is also another button which will open a new activity simply showing the random number that was rolled... but I just get 0.
I've looked into similar questions asked but to no avail.
Here's my code from MainActivity
public class MainActivity extends ActionBarActivity {
int n;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
public void ButtonRoll(View view) {
TextView textRoll = (TextView) findViewById(R.id.textview_roll);
Random rand = new Random();
n = rand.nextInt(100) + 1;
String roll = String.valueOf(n);
textRoll.setText("Random number is " + roll);
}
public void OpenStats(View view) {
Intent getStats = new Intent(this, Stats.class);
startActivity(getStats);
}
public int GetNumber (){ return n; }
}
Heres my 2nd class.
public class Stats extends Activity {
MainActivity statistics = new MainActivity();
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.stats);
int n = statistics.GetNumber();
TextView tvStats = (TextView) findViewById(R.id.passedNumber_textview);
String number = String.valueOf(n);
tvStats.setText(number);
}
}
Is using getters the wrong way to get data from another class when using activities? Thanks for your time.
You should pass your data as an extra attached to your intent. To do this you need to first determine a global key to be used. You could do something like this in your MainActivity
public static final String SOME_KEY = "some_key";
then modify your OpenStats method to
public void OpenStats(View view) {
Intent getStats = new Intent(this, Stats.class);
getStats.putExtra(SOME_KEY, n);
startActivity(getStats);
}
and then in Stats.class onCreate method
public void onCreate(Bundle savedInstanceState){
super.onCreate(savedInstanceState);
setContentView(R.layout.stats);
int n = getIntent().getIntExtra(MainActivity.SOME_KEY, -1);
TextView tvStats = (TextView) findViewById(R.id.passedNumber_textview);
String number = String.valueOf(n);
tvStats.setText(number);
}
You obviously should make sure that you are calling ButtonRoll at least once or that you set n so that you aren't passing a null int.
Also, as note, convention states that methods should use lower camel case formatting. That is, the first word is completely lower case and the first letter of subsequent words is upper case. That would change your methods
OpenStats() -> openStats()
ButtonRoll() -> buttonRoll()
Classes/objects are upper camel case, just to help avoid confusion.
Related
My app doesn't display anything when passing data from one class to another. I located through with the debugger that my ArrayList doesn't get the right value from the class.
I'm sending data with the following function:
public class Adaugare extends AppCompatActivity {
private ListView myListView;
private NumeAdapter numeAdapter;
String inume;
int ivarsta;
Intent intent = new Intent();
private ArrayList persoanaArrayList = new ArrayList<>();
public ArrayList getPersoanaArrayList() {
return persoanaArrayList;
}
public int getPersoanaArrayListsize() {
return persoanaArrayList.size();
}
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_adaugare);
myListView = (ListView) findViewById(R.id.persoana_list);
Button btn_fin = (Button) findViewById(R.id.btn_fin);
btn_fin.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
EditText nume_edit_text = (EditText) findViewById(R.id.ins_nume);
EditText varsta_edit_text = (EditText) findViewById(R.id.ins_var);
ivarsta = Integer.parseInt(varsta_edit_text.getText().toString());
inume = nume_edit_text.getText().toString();
persoanaArrayList.add(new Persoana(inume, ivarsta));
}
});
}
}
And recieving it with:
public class Afisare extends AppCompatActivity {
ListView myListView;
NumeAdapter numeAdapter;
Adaugare ad = new Adaugare();
int cate;
int i;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_afisare);
myListView = (ListView) findViewById(R.id.persoana_list);
ArrayList<Persoana> persoanaArrayList = new ArrayList<Persoana>(ad.getPersoanaArrayList());
numeAdapter = new NumeAdapter(this, persoanaArrayList);
myListView.setAdapter(numeAdapter);
}
The class Persoana is:
public class Persoana {
private String nume;
private int varsta;
Persoana(String inume, int ivar) {
this.nume = inume;
this.varsta = ivar;
}
public String getNume() {
return nume;
}
public int getVarsta() {
return varsta;
}
public void setNume(String nume) {
this.nume = nume;
}
public void setVarsta(int varsta) {
this.varsta = varsta;
}
}
Persoana is the main class, everything is saved in it. ad is an object of Adaugare, Adaugare being the class from which I've taken the code for getPersoanaArrayList. At debugging some values appeared at ad, namely Adaugare #4556, and persoanaArrayList remains null.
I need the persoanaArrayList so that i can initialize my Adapter and listView. Everything else in the code seems fine from step by step testing with debugger.
Your problem is with the following line in the Afisare class:
Adaugare ad = new Adaugare();
You can't simply new one activity from another activity and expect to access a shared list between them. To share instance data between java objects you need a reference to the other object. Creating a new instance will create a new empty list. That's why you are "losing" data. A quick fix would be to make the list static so it can be accessed from any instance.
But since you're dealing with Android, the right way to share data between activities is by using intent extras. The first activity starts the second activity via an intent. The first activity places the desired data in the intent as extras. The second activity uses getIntent() and the various methods on Intent to access the extras.
One last tip, in Android, you never use the new operator with Activities. Activities are created by the system to service an intent. If you find yourself using the new operator, that's a sign that you're doing something wrong.
This question already has an answer here:
How to receive an int through an Intent
(1 answer)
Closed 4 years ago.
I'm trying to pass an Integer (from an edittext) to another activity through an intent.
When the user clicks a button, the text in the edittext will transform into a string and then into an int, then the int will be sent through an intent to another activity, but i have to use the int after that.
Here the activity sending the intent:
public class HomeActivityPro extends ActionBarActivity {
private InterstitialAd interstitial;
EditText conttext = (EditText) findViewById ( R.id.texthome );
Button buttone = (Button) findViewById(R.id.buttone);
String maxom = conttext.getText().toString();
int maxam = Integer.parseInt(maxom);
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.layout_home);
View.OnClickListener maxim = new View.OnClickListener() {
#Override
public void onClick (View view) {
Intent wall = new Intent(HomeActivityPro.this, GuessOne.class);
wall.putExtra("maxPressed", maxam);
startActivity(wall);
}
};
buttone.setOnClickListener(maxim);
Here the activity receiving it:
public class GuessOne extends ActionBarActivity {
int randone;
int contone;
int wall = 0;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.layout_guess_one);
wall = getIntent().getIntExtra("maxPressed", -1);
randone = (int) (Math.random()*10+1);
contone = 0;
}
Here i'm using it:
public void guessone (View view){
contone++;
textcontone.setText(getString(R.string.attempts) + "" + contone);
if (contone >= wall ){
resultaone.setText("You Failed" + " " + wall);
Toast.makeText(this, "You Failed", Toast.LENGTH_LONG).show();
}
When i use the app, the value of the int is always -1. Where i am wrong.
You can't use findViewById without setting the xml to the activity. That means you need to use findViewById method only after you have called setContentView.
Also you need to read the EditText text value once you click on the button otherwise it always will be null/empty.
Do this
public class HomeActivityPro extends ActionBarActivity {
private InterstitialAd interstitial;
EditText conttext;
Button buttone;
String maxom;
int maxam = -1;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.layout_home);
conttext = (EditText) findViewById ( R.id.texthome );
buttone = (Button) findViewById(R.id.buttone);
View.OnClickListener maxim = new View.OnClickListener() {
#Override
public void onClick (View view) {
maxom = conttext.getText().toString();
maxam = Integer.parseInt(maxom);
Intent wall = new Intent(HomeActivityPro.this, GuessOne.class);
wall.putExtra("maxPressed", maxam);
startActivity(wall);
}
};
buttone.setOnClickListener(maxim);
Problem 1
Put this in the on click listener instead:
String maxom = conttext.getText().toString();
int maxam = Integer.parseInt(maxom);
You want the values to be read at the time you click the button not when you open the activity, correct?
Problem 2
The following needs to be after setContentView in onCreate:
conttext = (EditText) findViewById ( R.id.texthome );
buttone = (Button) findViewById(R.id.buttone);
Keep the declarations where they are. Just the declarations:
EditText conttext;
Button buttone;
Note
Follow the same pattern in all your activities. Declare views as field variables, assign them in onCreate after setContentLayout. Get the values at the time they're needed.
public int getIntExtra (String name, int defaultValue)
Added in API level 1 Retrieve extended data from the intent.
Parameters name The name of the desired item. defaultValue the value
to be returned if no value of the desired type is stored with the
given name. Returns the value of an item that previously added with
putExtra() or the default value if none was found. See Also
putExtra(String, int)
This means that no int was found when you called getIntExtra(valueName, defaultValue); so the default value was chosen.
You should check to see what your maxam value is before you call the new activity.
In the activity you receive it:
wall = getIntent().getIntExtra("maxPressed");
SOLVED: by getInt and String.valueOf
private static final String IMGID = "ImgID";
if (getIntent().getExtras().containsKey(IMGID)) {
//Picasso.with(this).load(getIntent().getExtras().getString(IMG)).into(mImg);
Picasso.with(this).load(getIntent().getExtras().getInt(String.valueOf(IMGID))).into(mImg);
}
How do i set the text of a TextView to a value of an integer from another class.
the main activity where i want the text set below
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_my);
TextView counterText = (TextView) findViewById(R.id.counter);
counterText.setText();
}
the class below
public class Ship implements Serializable {
private static int counter = 0;
public int getCounter()
{
return counter;
}
}
For a starter this should help
Ship s=new Ship();
int i=s.getCounter();
String value=String.valueOf(i);
counterText.setText(value);
Use String.valueOf to show Integer in TextView,as:
counterText.setText(String.valueOf(new Ship().getCounter()));
As far as i know you cannot access the UI component of 2nd activity while being in first activity. So the best way is to pass the value through putExtra method of intents and then set it to textview in the onCreate of 2nd activity by getting it. Here is link which shows this method: http://mobileorchard.com/android-app-development-using-intents-to-pass-data-and-return-results-between-activities/
I know this is a simpleton question, but I am not going to school for java, just learning it online.
how to a have a textview with an initial value of 0. and then everytime you press a button it ads 25 points to the score board.
At first I wanted the button press to add a random number between 42-57 to the score board.
And then how to do convert that int or long to a string to make it fit into a textview and keep the current score, and then add a new score.
EDIT: ok so someone said I should post the code so here it is.. where do i put this..
TextView txv182 = (TextView) findViewById(R.id.welcome);
txv182.setText(toString(finalScore));
Because when I do it, I get an error: The method toString() in the type Object is not applicable for the arguments (int)
public class MainActivity extends Activity {
// Create the Chartboost object
private Chartboost cb;
MediaPlayer mp = new MediaPlayer();
SoundPool sp;
int counter;
int db1 = 0;
Button bdub1;
TextView txv182;
int finalScore;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
txv182 = (TextView) findViewById(R.id.welcome);
finalScore = 100;
sp = new SoundPool(10, AudioManager.STREAM_MUSIC, 0);
db1 = sp.load(this, R.raw.snd1, 1);
bdub1 = (Button) findViewById(R.id.b4DUB1);
bdub1.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
// TODO Auto-generated method stub
if (db1 != 0)
sp.play(db1, 1, 1, 0, 0, 1);
txv182.setText(finalScore);
}
});
First you need to store your score to certain integer variable say score and set it to any initial value you want and use.
TextView tv = (TextView) findViewById(R.id.myTextView);
tv.setText(toString(score));
you do not need to initialize the textview with value just in onclick() of button do score+=25and add text to your textview as above.
hope this helps
It's actually like this..
pernts+=25;
txv182.setText(String.valueOf(pernts));
in android, after the
public class MainActivity extends Activity {
but before..
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
i wrote..
int pernts;
String strI;
so then after the above #Override majigy, i wrote..
strI = "" + pernts;
pernts = 0;
because when i wrote it like.. int pernts = 0; it never worked, forcing me to add final and what not..
any way.. How to convert an integer value to string? anSwered the question..
and so the end was like this
pernts+=25;
txv182.setText(String.valueOf(pernts));
i figured out you have to add a value to the int variable not the string.. i kept wanting to add 25 and i was getting 25252525252525.., instead of 25 50 75 100.. kinda cool actually.. separating the logic of how to "add" 25 .. anyway thanks.. SOF!
30 minutes later... found this.. How can I generate random number in specific range in Android?
..
import android.app.Activity;
public class InsMenu extends Activity {
static TextView txv182;
static int pernts;
Button bdub1;
public static void addPernts() {
int min = 37;
int max = 77;
Random r = new Random();
int i1 = r.nextInt(max - min + 1) + min;
pernts+=i1;
txv182.setText(String.valueOf(pernts));
}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.BLAHBLAH);
bdub1 = (Button) findViewById(R.id.b4DUB1);
txv182 = (TextView) findViewById(R.id.welcome);
bdub1.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
// TODO Auto-generated method stub
addPernts();
}
--- i created my first objekt thanks to this too.. http://www.tutorialspoint.com/java/java_methods.htm ..
This is kind of hard to explain. Basically it's kind of like a simple game. I want the people to input their names (currently the submit button is not working correctly) hit submit for each name and when all names are in they hit play. It then opens up the next class. It needs to get the string array from the prior class as well as the number of players. It then needs to select each persons name in order and give them a task to do (which it randomly generates). Then it allows the other people to click a button scoring how they did. (I am not sure how to set up the score system. Not sure if there is a way to assign a score number to a particular array string) I would then like it after 5 rounds to display the winner. If you have any input or could help me out I would be extremely grateful. Thanks for taking the time... here are the two classes i have.
Class 1
public class Class1 extends Activity
{
int players=0;
String names[];
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.class1);
final EditText input = (EditText) findViewById(R.id.nameinput);
Button submitButton = (Button) findViewById(R.id.submit_btn);
submitButton.setOnClickListener(new View.OnClickListener()
{
public void onClick(View submit1)
{
players++;
for(int i=0; i < players; i++)
{
names[i] = input.getText().toString();
input.setText("");
}
}
});
Button doneButton = (Button) findViewById(R.id.done_btn);
doneButton.setOnClickListener(new View.OnClickListener()
{
public void onClick(View done1)
{
Intent done = new Intent(Class1.this, Class2.class);
done.putExtra("players", players);
done.putExtra("names", names[players]);
startActivity(done);
}
});
}
Class 2
public class Class2 extends Activity
{
int players, counter, score, ptasks,rindex;
String[] names, tasks;
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.class2);
Intent game = getIntent();
players = game.getIntExtra("players", 1);
names = game.getStringArrayExtra("names");
Random generator = new Random();
tasks[0]= "task1";
tasks[1]= "task2";
tasks[2]= "task3";
tasks[3]= "task4";
tasks[4]= "task5";
tasks[5]= "task6";
tasks[6]= "task7";
tasks[7]= "task8";
tasks[8]= "task9";
tasks[9]= "task10";
while (counter <5)
{
for (int i = 0; i < players; i++)
{
TextView name1 = (TextView) findViewById(R.id.pname);
name1.setText( names[i]+":");
ptasks = 10;
rindex = generator.nextInt(ptasks);
TextView task = (TextView) findViewById(R.id.task);
task.setText( tasks[rindex]);
}
Button failButton = (Button) findViewById(R.id.fail_btn);
failButton.setOnClickListener(new View.OnClickListener()
{
public void onClick(View failed)
{
//not sure what to put here to get the scores set up
}
});
Button notButton = (Button) findViewById(R.id.notbad_btn);
notButton.setOnClickListener(new View.OnClickListener()
{
public void onClick(View notbad)
{
//not sure what to put here to get the scores set up
}
});
Button champButton = (Button) findViewById(R.id.champ_btn);
champButton.setOnClickListener(new View.OnClickListener()
{
public void onClick(View champp)
{
//not sure what to put here
}
});
counter++;
}
}
I'm sure this thing is riddled with errors. And I'm sorry if it is I'm not that well experienced a programmer. Thanks again
You can pass a string array from one activity to another using a Bundle.
Bundle bundle = new Bundle();
bundle.putStringArray("arrayKey", stringArray);
You can then access this stringArray from the next activity as follows:
Bundle bundle = this.getIntent().getExtras();
String[] stringArray = bundle.getStringArray("arrayKey");
I'm not sure if this is the only thing you intend to do. I hope it helps. Also, to assign a score to a particular string array, assuming your scores are int's you could use a HashMap as follows,
HashMap<String[],int> imageData = new HashMap<String[],int>();
But I'm not sure how you would pass this Map to another activity if you intend to do so.
http://developer.android.com/reference/android/content/Intent.html#putExtra(java.lang.String,%20java.lang.String[])
Use this cheat:
In Class2, convert you array string (tasks) to string (strSavedTask)by adding "|" separator. After that, pass your strSavedTask into Bundle and start to Class1.
When return to Class1, read strSavedTask from Bundle, split it by "|".
That's my cheat to pass array between 2 activity ^^
Hope this way can help you!