Changing number of columns in RecyclerView gridlayout

Question

I am trying to change the number of columns that appear in the recycler view (grid layout) based on the display size. However I couldn\'t figure out a proper way of achievin

Answer 1

public class VarColumnGridLayoutManager extends GridLayoutManager {

private int minItemWidth;

public VarColumnGridLayoutManager(Context context, int minItemWidth) {
    super(context, 1);
    this.minItemWidth = minItemWidth;
}

@Override
public void onLayoutChildren(RecyclerView.Recycler recycler,
        RecyclerView.State state) {
    updateSpanCount();
    super.onLayoutChildren(recycler, state);
}

private void updateSpanCount() {
    int spanCount = getWidth() / minItemWidth;
    if (spanCount < 1) {
        spanCount = 1;
    }
    this.setSpanCount(spanCount);
}}

Answer 2

You could create a screen dependent resource file and load it. A booleans.xml in values-w820p folder for example. Or possibly just create a layout for large screens and be done with it.

Answer 3

If you provide a fixed column width, you can extend RecyclerView and set the span count in onMeasure accordingly:

public AutofitRecyclerView(Context context, AttributeSet attrs) {
  super(context, attrs);

  if (attrs != null) {
    // Read android:columnWidth from xml
    int[] attrsArray = {
        android.R.attr.columnWidth
    };
    TypedArray array = context.obtainStyledAttributes(attrs, attrsArray);
    columnWidth = array.getDimensionPixelSize(0, -1);
    array.recycle();
  }

  manager = new GridLayoutManager(getContext(), 1);
  setLayoutManager(manager);
}

protected void onMeasure(int widthSpec, int heightSpec) {
  super.onMeasure(widthSpec, heightSpec);
  if (columnWidth > 0) {
    int spanCount = Math.max(1, getMeasuredWidth() / columnWidth);
    manager.setSpanCount(spanCount);
  }
}

See my blog post for more info: http://blog.sqisland.com/2014/12/recyclerview-autofit-grid.html

Answer 4

Here's my solution.

public class ResponsiveGridLayoutManager extends GridLayoutManager {
    boolean hasSetupColumns;
    int columnWidthPx;

    public ResponsiveGridLayoutManager(Context context, int orientation,
        boolean reverseLayout, int columnWidthUnit, float columnWidth) {

        super(context, 1, orientation, reverseLayout);

        Resources r;
        if (context == null) {
            r = Resources.getSystem();
        } else {
            r = context.getResources();
        }

        float colWidthPx = TypedValue.applyDimension(columnWidthUnit,
            columnWidth, r.getDisplayMetrics());

        this.columnWidthPx = Math.round(colWidthPx);
    }

    public ResponsiveGridLayoutManager(Context context, AttributeSet attrs,
        int defStyleAttr, int defStyleRes) {

        super(context, attrs, defStyleAttr, defStyleRes);
        int[] requestedValues = {
            android.R.attr.columnWidth,
        };

        TypedArray a = context.obtainStyledAttributes(attrs, requestedValues);
        this.columnWidthPx = a.getDimensionPixelSize(0, -1);
        a.recycle();
    }

    @Override
    public int getWidth() {
        int width = super.getWidth();
        if (!hasSetupColumns && width > 0) {
            this.setSpanCount((int)Math.floor(width / this.columnWidthPx));
        }

        return width;
    }
}

You can use it with either XML:

<android.support.v7.widget.RecyclerView
    android:id="@+id/recycler"
    android:scrollbars="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent"

    app:layoutManager="com.caff.localflix.ResponsiveGridLayoutManager"
    android:columnWidth="148dp" />

Or Java:

ResponsiveGridLayoutManager layoutManager = new ResponsiveGridLayoutManager(
    this,
    GridLayoutManager.VERTICAL,
    false,
    TypedValue.COMPLEX_UNIT_DIP,
    148f
);