Q:

multiplying 2 spinner values together

String.xml
  <string-array name="fruits">
       <item>Apple</item>
       <item>Banana</item>
       <item>Orange</item>
       <item>Pear</item>
       <item>Watermelon</item>
       <item>Mango</item>
       <item>Pineapple</item>
       <item>Strawberry</item>
</string-array>

<string-array name="total">
    <item>1</item>
    <item>2</item>
    <item>3</item>
    <item>4</item>
    <item>5</item>
    <item>6</item>
    <item>7</item>
    <item>8</item>
</string-array>

<string-array name="calorie">
    <item>80</item>
    <item>101</item>
    <item>71</item>
    <item>100</item>
    <item>45</item>
    <item>135</item>
    <item>80</item>
    <item>53</item>
</string-array>    

Java file:
    public class Fruit extends Activity implements OnClickListener, OnItemSelectedListener {
private TextView tvFruit, tvNo;
Context context=this;   
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.fruit);

    tvFruit = (TextView) findViewById(R.id.tvfruit);
    tvNo = (TextView) findViewById(R.id.tvno);

    final Spinner fruits = (Spinner)findViewById(R.id.spin_fruit);
    ArrayAdapter<CharSequence> adapter = ArrayAdapter.createFromResource(
            this,R.array.fruits,android.R.layout.simple_spinner_item);
    adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
    fruits.setAdapter(adapter);
    fruits.setOnItemSelectedListener(this);

    fruits.setOnItemSelectedListener(new OnItemSelectedListener(){
    public void onItemSelected(AdapterView<?> arg0, View arg1, int arg2,
    long arg3) {
            // TODO Auto-generated method stub
            String selectedItem = fruits.getSelectedItem().toString();
            tvFruit.setText(selectedItem);
        }

    public void onNothingSelected(AdapterView<?> arg0) {
        // TODO Auto-generated method stub

    }

    });

    final Spinner num = (Spinner)findViewById(R.id.spin_no);
    ArrayAdapter<CharSequence> adapter1 = ArrayAdapter.createFromResource(
            this,R.array.total,android.R.layout.simple_spinner_item);
    adapter1.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
    num.setAdapter(adapter1);
    num.setOnItemSelectedListener(this);

    num.setOnItemSelectedListener(new OnItemSelectedListener(){
        public void onItemSelected(AdapterView<?> arg0, View arg1, int arg2,
        long arg3) {
                // TODO Auto-generated method stub
                String selectedItem = num.getSelectedItem().toString();
                tvNo.setText(selectedItem);
            }

        public void onNothingSelected(AdapterView<?> arg0) {
            // TODO Auto-generated method stub

        }

        });

    Button save = (Button) findViewById(R.id.bsave);
    save.setTextColor(Color.BLUE);
    save.setOnClickListener(new View.OnClickListener() {

            public void onClick(View arg0) {
                // TODO Auto-generated method stub
                // Get the subject details and show it in an alertdialog
                AlertDialog.Builder builder = new AlertDialog.Builder(context);
                builder.setMessage("Success");
                builder.setPositiveButton("OK", null);
                builder.setNegativeButton("View Log", new DialogInterface.OnClickListener(){

                    public void onClick(DialogInterface dialog, int which) { // this part is done for the negative button 
                                                                             // if we want it to link to new intent
                        launchIntent();
                    }

                });
                builder.create().show();
            }

            //making the "View Log" button in dialog box to go to new intent FruitLog.class
            private void launchIntent(){
                Intent i = new Intent(Fruit.this, FruitLog.class);
                i.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
                startActivity(i);
            }

        });

    }

so when user click 3 bananas in spinner, i want to know how to do the code for multiplication of calories. once done with the calculation, it should show 303 calories in the "total calorie" textview
can someone guide me on how to do the coding for the calculation. example, help me with 2 Apple calories and the rest i will try to figure out.thank you so much. this community have being very helpful.

A:

Using your existing code, I would try something along the line of this:
First, change your calorie array to an integer-array. Next, add:
public int calculateCalories() {
    int[] calorie = getResources().getIntArray(R.array.calorie);
    return Integer.parseInt((String) num.getSelectedItem()) * calorie[fruits.getSelectedItemPosition()];
}

This function should return the number of the chosen fruit times its caloric value. To be explicit you set this directly into a TextView like so:
totalTextView.setText(String.valueOf(calculateCalories()));

You will have to make num and fruits visible to the entire class, by declaring them the same way tvFruit is declared.

