can we keep multiple values for same key in a bundle in android ? if so how to get those values?

Question

i was asked to design an app in android.

we have to take input of 3 numeric values and show some calculations in summary page.

i am able to do a simple application by taking the input details and passing them using bundles to summary page and doing calculations of average. (1 time entry information). but now, we want to add multiple times and summary need to give average of that. Please help me with this.

Answer 1

Storing multiple values

If you take a look at the documentation for the Intent class, you can see that you can store an arraylist of integers using the putIntegerArrayListExtra method. You can then extract the arraylist using getIntegerArrayListExtra This should make it pretty trivial to store multiple integers without doing string conversion and without really using bundles

Examples

Storing the ArrayList in the bundle

Intent intent = new Intent(this, OtherActivity.class);
ArrayList<Integer> values = new ArrayList<>();
// Add values to array list
intent.putIntegerArrayListExtra("myKey", values);

Extracting the ArrayList from the Bundle

Intent intent = getIntent();
List<Integer> values = intent.getIntegerArrayListExtra("myKey");

Communicating between two activities

Assuming you have two avtivities called InputActivity and CalculateActivity you can do something like this. For more info on using and handling startActivityForResult check out THIS question.

public class InputActivity extends Activity {
   // NOTE: Make sure this gets initialized at some point
   private ArrayList<Integer> pastValues;

    private void doSomethingWithInput(int input) {
        Intent intent = new Intent(this, CalculateActivity.class);
        this.pastValues.add(input)
        intent.putIntegerArrayListExtra("values", this.pastValues);
        startActivityForResult(intent, 1);
    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        if (requestCode == 1 && resultCode == RESULT_OK) {
            // Here is the result. Do whatever you need with it.
            int result = data.getIntExtra("result");
        }
    }

}

public class CalculateActivity extends Activity {
    private void doCalculation() {
        Intent intent = this.getIntent();
        List<Integer> values = intent.getIntegerArrayListExtra("values");

        // do something with the extracted values
        int result = ....;

        Intent returnIntent = new Intent();
        intent.putExtra("result", result);
        this.setResult(RESULT_OK, returnIntent);
        this.finish();
    }
}