如何将int值从一个类传递到另一个类？

Question

I can't believe I have so much trouble with this. I have this variable in my game activity:

public static int numberOfPointsA;

and in another activity

public static int numberOfPointsB;

Now I need these values to pass to another activity, where I should total these values and set result to textView. Since these are public static variables I tried:

public static int totalScore = ClassA.numberOfPointsA + ClassB.numberOfPointsB;

textView.setText("" + totalScore);

But that's not working. So I tried with intent:

In game classA:

Intent intent = new Intent(this, Menu.class);
                intent.putExtra("foobar", numberOfPointsA);
                startActivity(intent);

and in menu class:

Intent intent = getIntent();
    int numberOfPointsA = intent.getIntExtra("foobar", 0);

But that's not working either. If I place in the scope of activity, as soon as activity starts it crashes. If I place it in onCreate method, I can's use my int variable anymore, I don't need it in onCreate method, I need it elsewhere.

So how to set my variable in game class, pass to menu class, save it there and then make it wait until I finish my game class B and do the same with that variable, and then total those two variables and set it successfuly to the textView?

Menu activity:

public class Izbor extends Activity implements OnClickListener{

private int asocijacijeUkupno = 0;
private int thUkupno = 0;

int ukupanBrojPoena = asocijacijeUkupno + thUkupno;

Button toploHladno, asocijacije, cigle, spojnice, nazad, poeniTH, poeniAso, poeniCigle, poeniSpojnice, poeniUkupno;
TextView naslov;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    asocijacijeUkupno = getIntent().getIntExtra("RUNNING_TOTAL", 0);
    thUkupno = getIntent().getIntExtra("RUNNING_TOTAL2", 0);

    setContentView(R.layout.izbor);

    addListenerOnButton();

}


private void addListenerOnButton() {

    naslov = (TextView) findViewById(R.id.tvIzborNaslov);
    toploHladno = (Button) findViewById(R.id.bIzbor1);
    asocijacije = (Button) findViewById(R.id.bIzbor2);
    cigle = (Button) findViewById(R.id.bIzbor3);
    spojnice = (Button) findViewById(R.id.bIzbor4);
    nazad = (Button) findViewById(R.id.bIzborNazad);
    poeniTH = (Button) findViewById(R.id.bPoeniTH);
    poeniAso = (Button) findViewById(R.id.bPoeniAso);
    poeniCigle = (Button) findViewById(R.id.bPoeniCigle);
    poeniSpojnice = (Button) findViewById(R.id.bPoeniSpojnice);
    poeniUkupno = (Button) findViewById(R.id.bPoeniUkupno);


    toploHladno.setOnClickListener(this);
    asocijacije.setOnClickListener(this);
    cigle.setOnClickListener(this);
    spojnice.setOnClickListener(this);
    nazad.setOnClickListener(this);

}


@Override
protected void onStart() {
    super.onStart();

    if(asocijacijeUkupno != 0){
    poeniAso.setText("" + asocijacijeUkupno);
    }else{
        poeniAso.setText("");
    }
    if(thUkupno != 0){
    poeniTH.setText("" + thUkupno);
    }else{
        poeniTH.setText("");
    }
    if(ukupanBrojPoena != 0){
    poeniUkupno.setText("" + ukupanBrojPoena);
    }else{
        poeniUkupno.setText("");
    }
}

public void onClick(View v) {
    switch(v.getId()){
    case R.id.bIzbor1:
        if(music == true){
            buttonClicks.start();
                }
        startActivity(new Intent("rs.androidaplikacije.toplo_hladno.TOPLOHLADNO"));
        break;
    case R.id.bIzbor2:
        if(music == true){
            buttonClicks.start();
                }
        startActivity(new Intent("rs.androidaplikacije.toplo_hladno.ASOCIJACIJE"));
        break;
    case R.id.bIzbor3:
        if(music == true){
            buttonClicks.start();
                }

        break;
    case R.id.bIzbor4:
        if(music == true){
            buttonClicks.start();
                }

        break;
    case R.id.bIzborNazad:
        if(music == true){
            buttonBack.start();
                }
        finish();
        break;
    }

}

}

Answer 1

The following is a very basic example, using two activities to pass an int around.

First Activity, which you start from:

public class FirstActivity extends Activity {
    private int mTotal = 0;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
        //.... onCreate code, layout stuff etc....    
    }

    // this is tied to a View onClick call
    public void moveToSecondAct(View view) {
        Intent intent = new Intent();
        intent.putExtra("RUNNING_TOTAL",mTotal);
        intent.setClass(this, SecondActivity.class);
        //... any other options like ...
        intent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
        // start the second Activity
        startActivity(intent);
    }
}

And the second Activity example is something like:

public class SecondActivity extends Activity {
    private int mTotal = 0;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
        mTotal = getIntent().getIntExtra("RUNNING_TOTAL", 0);
        //.... onCreate code, layout stuff etc....

        Log.i("Running total is:"+ mTotal);
        // update the total on the TextView
        TextView tv = (TextView) findViewById(R.id.poeniUkupno);
        tv.setText("Total: "+ mTotal);
    }
}

Edit: Some changes to try help make things clearer

Answer 2

I didn't completely get what you have been trying to say but what I got was you want to create a variable in FirstActivity send its value to SecondActivity and then pass their sum to ResultActivity if its so then here you go

//First Activity
public class FirstActivity extends Activity{
    int firstValue;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        firstValue = 10;
    }
    public sendValueToSecondActivity(View view){
        Intent intent = new Intent(this, SecondActivity.class);
        intent.putExtra("firstValue", firstValue);
        startActivity(intent);
    }
}

//Second Activity
public class SecondActivity extends Activity{
    int sumOfFirstAndSecond;
    int secondValue;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        secondValue = 20;

    }
    public sendValueToSecondActivity(View view){
        sumOfFirstAndSecond = getIntent().getIntExtra("firstValue") + secondValue;
        Intent intent = new Intent(this, ResultActivity.class);
        intent.putExtra("sumOfFirstAndSecond", sumOfFirstAndSecond);
        startActivity(intent);
    }
}

//Result Activity
public class ResultActivity extends Activity{
    TextView textView;
    int result;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        secondValue = 20;
        textView = (TextView) findViewById(R.id.textView);
    }
    public setResultToTextView(View view){
        result = getIntent().getIntExtra("sumOfFirstAndSecond");
        textView.setText(""+result);
    }
}