Question

everything else in my app works, but when I add

public void onClickRandomColor(View v) {
        Random rRed = null;
        Random rGreen = null;
        Random rBlue = null;
        int min = 0, max = 255;
        int randomRed = rRed.nextInt(max - min + 1) + min;
        int randomGreen = rGreen.nextInt(max - min + 1) + min;
        int randomBlue = rBlue.nextInt(max - min + 1) + min;
        Rset = randomRed;
        Gset = randomGreen;
        Bset = randomBlue;
    }

to MainActivity.java and the ONCLICK line to activity_main.xml

<Button
        android:id="@+id/btnRandom"
        android:layout_below="@+id/btnChoose"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:onClick="onClickRandomColor"
        android:text="@string/random"/>

She force closes on me. There are plenty of other controls, the sliders use the Rset, Gset, and Bset just fine. It has to be something with my method of obtaining random integers.

Answer 1

1. You need to create the Random objects with new Random() instead of assigning null. You can’t call anything on null, you have to create the object.
2. There is no point in having three different Random objects, you can get an infinite number of random numbers from a single object

Your corrected code would look like this:

public void onClickRandomColor(View v) {
    Random rnd = new Random();
    int min = 0, max = 255;
    int randomRed = rnd.nextInt(max - min + 1) + min;
    int randomGreen = rnd.nextInt(max - min + 1) + min;
    int randomBlue = rnd.nextInt(max - min + 1) + min;
    Rset = randomRed;
    Gset = randomGreen;
    Bset = randomBlue;
}