How can I write a onPrepareOptionsMenu for a PopupMenu with Kotlin in Android Studio?

Question

The function showActionMenu() shows a popup menu, it works well.

I hope to change the title of a menu item when the menu is popup.

I try to add onPrepareOptionsMenu(menu: Menu) in the code, but it doesn't work, how can I fix it?

Code A

   private fun showActionMenu() {
        val view = mActivity.findViewById<View>(R.id.menuMoreAction) ?: return

        PopupMenu(mContext, view).run {
            menuInflater.inflate(R.menu.menu_option_action, menu)

            /*
            onPrepareOptionsMenu(menu: Menu)  {
                for (item in menu){
                    if (item.itemId == R.id.menuMoreActionSelectAll){
                        item.title = "My new title"   
                    }
                } 
            }
           */                  

            setOnMenuItemClickListener {
                when (it.itemId) {    
                    R.id.menuMoreActionSelectAll -> {
                        mHomeViewModel.setSelectStatus(ESelect.SelectAll)
                    }
                    ...    
                }
                true
            }
            show()
        }
    }

Answer 1

You call show() immediately, so the menu is being shown immediately. Therefore you don't need any onPrepareOptionsMenu() call - just run that code immediately after your call to inflate() :

PopupMenu(mContext, view).run {
    menuInflater.inflate(R.menu.menu_option_action, menu)

    for (item in menu){
        if (item.itemId == R.id.menuMoreActionSelectAll){
            item.title = "My new title"   
        }
    }                 

    setOnMenuItemClickListener {
        when (it.itemId) {    
            R.id.menuMoreActionSelectAll -> {
                mHomeViewModel.setSelectStatus(ESelect.SelectAll)
            }
            ...    
        }
        true
    }
    show()
}

Of course, if you're always setting the title of R.id.menuMoreActionSelectAll , you should just set that title in your R.menu.menu_option_action and skip your 'prepare' work entirely.