Change CardBackgroundColor on RecyclerView

Question

I have the following code on my RecyclerView:

class TaskViewHolder(v: View) : RecyclerView.ViewHolder(v), View.OnClickListener
    {
        var mId: TextView = v.task_id
        var mDescription: TextView = v.task_description
        var mCard: CardView = v.task_card
        var mView: View = v
    }

override fun onBindViewHolder(holder: TaskViewHolder, position: Int)
{
    // Initialize ViewHolder content
    holder.mId.text = items[position].getID().toString()
    holder.mDescription.text = items[position].getDescription()
    holder.mTask = items[position]

    for (elem in priorities)
    {
        if (elem.getID() == items[position].getPriority())
        {
            holder.mCard.setCardBackgroundColor(Color.parseColor("#c2c2c2"))
            break
        }
    }
}

I don't know why, but CardView backgroundColor isn't changing.

If I use the following code, it works correctly:

holder.mCard.setCardBackgroundColor(ContextCompat.getColor(holder.mView.context, R.color.priority3))

What I should do to set CardBackgroundColor progrmatically?

Try replacing `"#c2c2c2"` with `"#ffc2c2c2"` to make sure you provide a [correct alpha](https://stackoverflow.com/a/52258918/3891038) for the background colour. — Julio E. Rodríguez Cabañas, Apr 29 '19 at 12:14
The color string that requires an alpha component. Like Julio E. said you should add "FF" to the color string. — cincy_anddeveloper, Apr 29 '19 at 12:24
I have extended my comment and added it as an actual answer, please take a look. — Julio E. Rodríguez Cabañas, Apr 29 '19 at 12:31

score 1 · Answer 1 · answered Apr 29 '19 at 12:38

1

First of all, You need to provide else part as transparent or another color to avoid color duplicate render issue. second, you have to pass context from your activity or fragment to adapter and that context will be used to get color like below.

if (elem.getID() == items[position].getPriority())
    {
        holder.mCard.setCardBackgroundColor(ContextCompat.getColor(mContext, [first color]))  
    } else {
        holder.mCard.setCardBackgroundColor(ContextCompat.getColor(mContext,[second color]))
    }

answered Apr 29 '19 at 12:38

Dipakk Sharma

976
1
8
11

You are right in that some default colour should be provided for the recycling to work properly. However, it is not necessary to pass the context as a parameter because it can be accessed via `holder.mView.context`. – Julio E. Rodríguez Cabañas Apr 29 '19 at 12:41
Yeah, you can use that too for context. then is it working for you? – Dipakk Sharma Apr 29 '19 at 12:44
I am not the one asking haha. – Julio E. Rodríguez Cabañas Apr 29 '19 at 12:45

score 0 · Answer 2 · answered Apr 29 '19 at 12:31

0

Try replacing "#c2c2c2" with "#ffc2c2c2" to make sure you provide a correct alpha for the background colour. On android, this extra byte added at the beginning represents the alpha of the colour:

`#ffc2c2c2`

ff: alpha
c2: red
c2: green
c2: blue

answered Apr 29 '19 at 12:31

Julio E. Rodríguez Cabañas

2,042
15
18

Change CardBackgroundColor on RecyclerView

2 Answers2

#ffc2c2c2

`#ffc2c2c2`