adding a double to an ArrayList

I wrote an android app that solves quadratic equations and then is supposed to graph them. The library I am using requires the data sets to be in ArrayList form. However the loop I have to create the array involves adding a double to them which you cannot do with array lists. Here is the code:

List<double[]> x = new ArrayList<double[]>();
List<double[]> values = new ArrayList<double[]>();
QuadraticActivity c = new QuadraticActivity();


x=(c.xValueArr);
values=(c.yValueArr);

for (; c.xCurrent <= c.xEnd; c.xCurrent += c.xStep) {
    double yCurrent = (c.a)*Math.pow(c.xCurrent, 2) + (c.b)*c.xCurrent + (c.c);
    c. xValueArr .add ((c.xCurrent));
    c. yValueArr .add ((yCurrent));

Judging from your code, c.xValueArr and c.yValueArr are of type, double[]. If so, then just change the first 7 lines of code to this:

QuadraticActivity c = new QuadraticActivity ();
ArrayList<Double> x = Arrays.asList (c.xValueArr);
ArrayList<Double> values = Arrays.asList (c.yValueArr);

Note: You're instantiating two new ArrayLists in lines 1 and 2 but are replacing them in lines 6 and 7. Also, you'll have to add the new values inside the loop manually, as x and values don't point to the same arrays as c's arrays. A better fix would be to declare and initialize x and values after the iteration, but since you didn't include a closing }, I'm assuming you need them in the iteration.

ArrayList should work fine with Integer or Double because they are as good as other object. Note that they must have the first letter capitalized.

You should also consider Double.valueOf(double d) which returns an object of Double for your use case

Is it possible to use a subclass of Number? It wraps a value in an object. http://download.oracle.com/javase/1.4.2/docs/api/java/lang/Number.html

Try Double with a capital 'D'.

http://download.oracle.com/javase/1.4.2/docs/api/java/lang/Double.html

Use the Double object instead of the double native type.

List<Double> x = new ArrayList<Double>();
List<Double> values = new ArrayList<Double>();