Android ListView's item's Image background color does not change

Question

I have some Android app, which is mixture of Java and Kotlin and inside this app I have Listview , which contains available WiFi networks. When I select element of this ListView , Dialog pops up asking for user intervention, which is all ok so far. Now, when I press Submit button , this Dialog hides and the selected ListView 's item's ImageView should get Steelblue color, but it does not:

    dialog.buttonNewGroup.setOnClickListener { _: View? ->
        val newGroupDialog: MaterialDialog = MaterialDialog.Builder(this@AddDevicesActivity)
                .title(R.string.new_group_dialog_title)
                .content(R.string.new_group_dialog_content)
                .inputType(InputType.TYPE_CLASS_TEXT
                        + InputType.TYPE_TEXT_VARIATION_NORMAL
                        + InputType.TYPE_TEXT_FLAG_AUTO_CORRECT + InputType.TYPE_TEXT_FLAG_AUTO_COMPLETE + InputType.TYPE_TEXT_FLAG_CAP_SENTENCES)
                .inputRange(1, 32)
                .input(R.string.group_name, 0, false, { _, _ -> })
                .negativeText(R.string.cancel)
                .positiveText(R.string.submit)
                .onPositive { dialog, _ ->
                    // Add new group to database
                    mDb.addGroup(VentGroup(dialog.inputEditText?.text.toString()))
                    // Get refreshed list of the groups
                    mGroups.clear()
                    mDb.getGroups().toCollection(mGroups)
                    mGroupsAdapter.notifyDataSetChanged()
                    this@AddDevicesActivity.imageView.setBackgroundColor(Color.parseColor("0xff4682b4"))    // IMAGE BACKGROUND DOES NOT CHANGE TO "Steelblue" color
                }
                .build()
        newGroupDialog.show()
    }

I've added breakpoint in this part of code and it DOES GETS executed, however, the background of ImageView does not change. Why?

PS: I am new to Kotlin and rather new in Android/Java and I ask for a little understanding before downvoting, since I am aware there must be some dumb mistake behind it.

Answer 1

您好KernelPanic试试，

(dialog.actiivty as AddDevicesActivity).imageView.setBackgroundColor(Color.parseColor("0xff4682br"))