GridLayoutManager - how to auto fit columns?

You can calculate available number of columns, given a desired column width, and load the image as calculated. Define a static funtion to calculate as:

public class Utility {
    public static int calculateNoOfColumns(Context context, float columnWidthDp) { // For example columnWidthdp=180
        DisplayMetrics displayMetrics = context.getResources().getDisplayMetrics();
        float screenWidthDp = displayMetrics.widthPixels / displayMetrics.density;
        int noOfColumns = (int) (screenWidthDp / columnWidthDp + 0.5); // +0.5 for correct rounding to int.
        return noOfColumns;
    }
}

And then when using it in the activity or fragment you can do like this :

int mNoOfColumns = Utility.calculateNoOfColumns(getApplicationContext());

............
mGridLayoutManager = new GridLayoutManager(this, mNoOfColumns);

I tried @Riten answer and worked funtastic!! But I wasn't happy with the hardcoded "180" So I modified to this:

    public class ColumnQty {
    private int width, height, remaining;
    private DisplayMetrics displayMetrics;

    public ColumnQty(Context context, int viewId) {

        View view = View.inflate(context, viewId, null);
        view.measure(View.MeasureSpec.UNSPECIFIED, View.MeasureSpec.UNSPECIFIED);
        width = view.getMeasuredWidth();
        height = view.getMeasuredHeight();
        displayMetrics = context.getResources().getDisplayMetrics();
    }
    public int calculateNoOfColumns() {

        int numberOfColumns = displayMetrics.widthPixels / width;
        remaining = displayMetrics.widthPixels - (numberOfColumns * width);
//        System.out.println("\nRemaining\t" + remaining + "\nNumber Of Columns\t" + numberOfColumns);
        if (remaining / (2 * numberOfColumns) < 15) {
            numberOfColumns--;
            remaining = displayMetrics.widthPixels - (numberOfColumns * width);
        }
        return numberOfColumns;
    }
    public int calculateSpacing() {

        int numberOfColumns = calculateNoOfColumns();
//        System.out.println("\nNumber Of Columns\t"+ numberOfColumns+"\nRemaining Space\t"+remaining+"\nSpacing\t"+remaining/(2*numberOfColumns)+"\nWidth\t"+width+"\nHeight\t"+height+"\nDisplay DPI\t"+displayMetrics.densityDpi+"\nDisplay Metrics Width\t"+displayMetrics.widthPixels);
        return remaining / (2 * numberOfColumns);
    }
}

Where "viewId" is the layout to be used as views in the RecyclerView like in R.layout.item_for_recycler

Not sure though about the impact of View.inflate as I only use it to get the Width, nothing else.

Then on the GridLayoutManager I do:

GridLayoutManager gridLayoutManager = new GridLayoutManager(this, Utility.columnQty(this, R.layout.item_for_recycler));

UPDATE: I added more lines to the code as I use it to get a minimum width spacing in the Grid. Calculate spacing:

recyclerPatternsView.addItemDecoration(new GridSpacing(columnQty.calculateSpacing()));

GridSpacing:

public class GridSpacing extends RecyclerView.ItemDecoration {
    private final int spacing;

    public GridSpacing(int spacing) {
        this.spacing = spacing;
    }

    @Override
    public void getItemOffsets(@NonNull Rect outRect, @NonNull View view, @NonNull RecyclerView parent, @NonNull RecyclerView.State state) {
        outRect.left = spacing;
        outRect.right = spacing;
        outRect.bottom = spacing;
        outRect.top = spacing;
    }
}

The GridLayoutManager's constructor has an argument spanCount that is

The number of columns in the grid

You can initialize the manager with an integer resource value and provide different values for different screens (i.e. values-w600, values-large, values-land).