How can I do something like a FlowLayout in Android?

Question

How can I do something like a FlowLayout in Android?

Answer 1

I don't have enough reputation to post a comment to Romain Guy's answer but that's where this answer should be (I created an account just to share my edit).

Anyway, I see other people have found out his pretty cool FlowLayout solution has some issues. I could find one myself and I saw, as others, that some children were clipped. Looking in details at the algorithm it seems to be a very simple mistake in the calculation of the height. When the very last child is the one being put on a new line, then the height was not properly computed. I cleaned up a bit the computation (there was a weird use of "height" vs. currentHeight).

The following change fixes the problem of "last child is clipped if on a new line":

@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec)
{
    int widthLimit = MeasureSpec.getSize(widthMeasureSpec) - getPaddingRight();
    int widthMode = MeasureSpec.getMode(widthMeasureSpec);

    boolean growHeight = widthMode != MeasureSpec.UNSPECIFIED;

    int width = 0;

    int currentWidth = getPaddingLeft();
    int currentHeight = getPaddingTop();

    int maxChildHeight = 0;

    boolean breakLine = false;
    boolean newLine = false;
    int spacing = 0;

    final int count = getChildCount();
    for (int i = 0; i < count; i++)
    {
        View child = getChildAt(i);
        measureChild(child, widthMeasureSpec, heightMeasureSpec);

        LayoutParams lp = (LayoutParams) child.getLayoutParams();
        spacing = mHorizontalSpacing;

        if (lp.horizontalSpacing >= 0)
        {
            spacing = lp.horizontalSpacing;
        }

        if (growHeight && (breakLine || ((currentWidth + child.getMeasuredWidth()) > widthLimit)))
        {               
            newLine = true;
            currentHeight += maxChildHeight + mVerticalSpacing;

            width = Math.max(width, currentWidth - spacing);

            currentWidth = getPaddingLeft();
            maxChildHeight = 0;
        }
        else
        {
            newLine = false;
        }

        maxChildHeight = Math.max(maxChildHeight, child.getMeasuredHeight());

        lp.x = currentWidth;
        lp.y = currentHeight;

        currentWidth += child.getMeasuredWidth() + spacing;

        breakLine = lp.breakLine;
    }

    if (newLine == false)
    {
        width = Math.max(width, currentWidth - spacing);
    }

    width += getPaddingRight();
    int height = currentHeight + maxChildHeight + getPaddingBottom();

    setMeasuredDimension(resolveSize(width, widthMeasureSpec),
            resolveSize(height, heightMeasureSpec));
}