Trying to create array of Points

Question

Hello there, I'm trying to create array of points, but for some reason I get this error message.

Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.graphics.Point.set(int, int)' on a null object reference at absoft.test.MainActivity.onCreate(MainActivity.java:31)

This is an example of what I'm trying to do.

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        RelativeLayout layout = (RelativeLayout) findViewById(R.id.layout);
        LinearLayout linearLayout = (LinearLayout) findViewById(R.id.linearLayout);

        Point[] point = new Point[5];

                TextView view = new TextView(this);
                 point[0].set(1, 5);
                 point[1].set(2,4);
                 point[2].set(5,3);
                 point[3].set(3,2);
                 point[4].set(1,3);

                linearLayout.addView(view);

            }

First of all I'm curious, is it possible to create array of Point? I'm trying to create graph using some calculations that are already done in the program. I'm not sure whether I'm going on the right track or not. I tried graphView API, but it looks like it doesn't support loops. So do you recommend any solution?

Thanks, Sayed

Answer 1 · 2015-12-03T17:31:15Z

December 3, 2015 5:31pm

Yep, you can create an array of pretty much anything. You're issue is that the default values for an array of Objects (i.e. non-primitives) is null. So you're array is: [null, null, null, null, null]. And when you call set() on null, you get a Null Pointer Exception.

Try this:

point[0] = new Point();
point[0].set(1, 5);

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Sayed Ahmad Behbehani

Sayed Ahmad Behbehani

Trying to create array of Points

1 Answer

Ben Deitch

Ben Deitch