Question

I am trying to do something extremely basic! And it wont work :(. I feel like I’m going in circles.

Here’s the rundown: I would like the user to input a series of numbers into an EditText box (separated by comma’s). After the add button is selected a split method will separate each number into its own slot in a String[]. EVENTUALLY, if I can get this part to work, the numbers will be pulled out of the array and converted to doubles.Then they will be used in a calculation or two. I have tried several different ways of getting this done and it seems like the problem is coming from the split method or for-loop. The code listed below returns an empty string.

Also, through my trial and error I ended up with a return method calculate(). How much stuff can a cram in an onClick method? Was this a bad idea? Please be as a brutal as needed!!! I’m new to android. Thanks in advance.

---

package com.simplydesign.android.standarddev;

import android.app.Activity;
import android.os.Bundle;
import android.widget.*;
import android.view.*;

public class Main extends Activity {
/** Called when the activity is first created. */

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);

    final Button addBtn = (Button) findViewById(R.id.addBtn);
    final EditText userData = (EditText) findViewById(R.id.editText1);
    final TextView dataCollection = (TextView) findViewById(R.id.textView1);

    addBtn.setOnClickListener(new View.OnClickListener() {

        @Override
        public void onClick(View v) {

            String[] rawData;
            rawData = userData.getText().toString().split(",");
            dataCollection.setText(calculate(rawData));
        }

    });

}

public String calculate(String[] a) {

    String output = "";

    for (int i = 0; i < a.length - 1; i++) {
        output += " " + a[i];
        } return output;
}
}

Answer 1

In your for-loop you should iterate from 0 to a.length - 1. This means the loop must look like:

for (int i = 0; i < a.length; i++) { /* ... */ }

But you’d better use something like that:

public String calculate(String[] a) {

    StringBuilder output = new StringBuilder();

    for (String s : a) {
        output.append(' ').append(s);
    }
    return output.toString();
}

Unfortunately, I don’t think it will completly solve your problem but it definitely fixes one error.