Question

I can’t see to get a double boolean array to pass through to the another activity. I use putExtra and when I retrieve it and cast it to boolean[][], it states that it can not cast and crashes. Boolean[] works however.

How would I go about passing a boolean[][] between activities?

Answer 1

If you absolutely need a boolean[][] (and can’t do this with just a flat boolean[] array passed to Parcel.writeBooleanArray()), then the formal way to do this is to wrap it in a Parcelable class and do the marshalling/unmarshalling there.

I’ll sketch out the code, though this is not tested so there are certainly to be some issues.

public class BooleanArrayArray implements Parcelable {
    private final boolean[][] mArray;

    public BooleanArrayArray(boolean[][] array) {
        mArray = array;
    }

    private BooleanArrayArray(Parcelable in) {
        boolean[][] array;
        final int N = in.readInt();
        array = new boolean[][N];
        for (int i=0; i<N; i++) {
            array[i] = in.createBooleanArray();
        }
        mArray = array;
    }

    @Override
    public int describeContents() {
        return 0;
    }

    @Override
    public void writeToParcel(Parcel out, int flags) {
        final int N = mArray.length;
        out.writeInt(N);
        for (int i=0; i<N; i++) {
            out.writeBooleanArray(mArray[i]);
        }
    }

    public static final Parcelable.Creator<BooleanArrayArray> CREATOR
            = new Parcelable.Creator<BooleanArrayArray>() {
        public BooleanArrayArraycreateFromParcel(Parcel in) {
            return new BooleanArrayArray(in);
        }

        public BooleanArrayArray[] newArray(int size) {
            return new BooleanArrayArray[size];
        }
    };
}