Convert Drawable resource to Bitmap

Question

I tried to convert a drawable resource to a bitmap but every code snippet and every own try returned null or an empty string.

I tried it with basic approaches like Bitmapfactory.decodeResource (Here i tried it with activity context, application context etc. and with every kind of drawable resource (png, vector, xml) and i tried different code snippets from convertion and it always returns null or "". I tried to change the drawable folders also instead of drawable-24 i tried the basic drawable folder.

 BitmapFactory.decodeResource(applicationContext.resources,
            R.drawable.test) 

 BitmapFactory.decodeResource(this.resources,
            R.drawable.test) 

 BitmapFactory.decodeResource(resources,
            R.mipmap.ic_launcher) 


 fun drawableToBitmap(drawable: Drawable): Bitmap {
    var bitmap: Bitmap? = null

    if (drawable is BitmapDrawable) {
        if (drawable.bitmap != null) {
            return drawable.bitmap
        }
    }

    if (drawable.intrinsicWidth <= 0 || drawable.intrinsicHeight <= 
 0) {
        bitmap =
            Bitmap.createBitmap(1, 1, Bitmap.Config.ARGB_8888) // Single color bitmap will be created of 1x1 pixel
    } else {
        bitmap = Bitmap.createBitmap(drawable.intrinsicWidth, drawable.intrinsicHeight, Bitmap.Config.ARGB_8888)
    }

    val canvas = Canvas(bitmap!!)
    drawable.setBounds(0, 0, canvas.width, canvas.height)
    drawable.draw(canvas)
    return bitmap
}

///////////

fun drawableToBitmap(drawable: Drawable): Bitmap {
    var bitmap: Bitmap? = null

    if (drawable is BitmapDrawable) {
        val bitmapDrawable = drawable as BitmapDrawable
        if (bitmapDrawable.bitmap != null) {
            return bitmapDrawable.bitmap
        }
    }

    bitmap = if (drawable.intrinsicWidth <= 0 || 
 drawable.intrinsicHeight <= 0) {
        Bitmap.createBitmap(1, 1, Bitmap.Config.ARGB_8888)
    } else {
        Bitmap.createBitmap(
            drawable.intrinsicWidth,
            drawable.intrinsicHeight,
            Bitmap.Config.ARGB_8888
        )
    }

    val canvas = Canvas(bitmap!!)
    drawable.setBounds(0, 0, canvas.width, canvas.height)
    drawable.draw(canvas)
    return bitmap
}

Answer 1

试试这个（上下文是您的活动上下文或其他）

Bitmap myLogo = BitmapFactory.decodeResource(context.getResources(), R.drawable.my_drawable);