Custom ImageSpan not displaying properly

Question

I'm trying to create a custom class that extends ImageSpan because I need some kind of margin/padding on the spans.

What I figured I need to do is to override the getSize function to return a bigger width so the spans get graphically spaced.

The problem is that as soon as I override the getSize function my view gets completely screwed up. My educated guess is then that I'm doing something stupid inside that funcion, but I can't get what.

Custom class code:

class PaddingImageSpan(drawable: Drawable, private val offset: Float = 0f) : ImageSpan(drawable) {

    override fun getSize(
        paint: Paint,
        text: CharSequence?,
        start: Int,
        end: Int,
        fm: Paint.FontMetricsInt?
    ): Int {

        val width = paint.measureText(text, start, end)
        val fontMetricsInt = paint.fontMetricsInt

        if (fm != null){
            fm.ascent = fontMetricsInt.ascent
            fm.bottom = fontMetricsInt.bottom
            fm.descent = fontMetricsInt.descent
            fm.leading = fontMetricsInt.leading
            fm.top = fontMetricsInt.top
        }

        println(width)

        return width.roundToInt()
    }
}

score 1 · Accepted Answer · answered Aug 13 '20 at 09:57

I figured it out. I'm posting the solution so if someone looks for it he can find it!

My problem was I was using the text metrics instead of the drawable metrics.

This is the correct code:

    override fun getSize(
        paint: Paint,
        text: CharSequence?,
        start: Int,
        end: Int,
        fm: Paint.FontMetricsInt?
    ): Int {

        val rect = drawable.bounds

        if (fm != null) {
            fm.ascent = -rect.bottom
            fm.descent = 0

            fm.top = fm.ascent
            fm.bottom = 0
        }

        return rect.right// + offset

    }

That said, the cleaner way that I could come up with to space spannable is not by working on the spannable class but changing the setBounds() values.

Custom ImageSpan not displaying properly

1 Answers1