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java - 在列表适配器中单击时尝试更改图像视图的可绘制对象

问题描述

实际上，问题是当我单击单个项目的图像视图时，它的可绘制对象正在发生变化，但许多其他随机项目的图像视图也会随着单击而发生变化。下面是我的列表适配器代码。我已经从一些来源看到了这个问题的解决方案，我发现设置标签然后设置点击侦听器是可行的，但它对我不起作用。作为参考，addMealItem 是单击时要更改的视图的 id。我什至添加了 toast 来测试出了什么问题，但是在这种情况下，toast 并不是很有帮助。


class FoodsAdapter(application: Application, val context: Context, val clickListener: MealItemclickListener) : ListAdapter<MealItemModel, FoodsAdapter.ViewHolder>(MealItemDiffCallBack()) {
    val database = MealItemDatabase.getInstance(application)

    class ViewHolder private constructor(val binding: MealitemBinding) : RecyclerView.ViewHolder(binding.root) {
        fun bind(item: MealItemModel, clickListener: MealItemclickListener, context: Context, database: MealItemDatabase) {
            binding.food = item
            GlobalScope.launch {
                withContext(Dispatchers.IO) {
                    if(database.mealItemDao.getBreakfastItem(item.itemTitle)!=null) {
                        if (database.mealItemDao.getBreakfastItem(item.itemTitle).likedOrNot) {
                            binding.addmealItem.setTag("unliked")
                            withContext(Dispatchers.Main){
                                Toast.makeText(context,"Unliked",Toast.LENGTH_LONG).show()
                            }
                            binding.addmealItem.setImageResource(R.drawable.ic_add_button)
                        } else {
                            withContext(Dispatchers.Main){
                                Toast.makeText(context,"Liked",Toast.LENGTH_LONG).show()
                            }
                            binding.addmealItem.setTag("liked")
                            binding.addmealItem.setImageResource(R.drawable.ic_add_button_filled)
                        }
                    }
                }
            }
            binding.addmealItem.setOnClickListener {
                clickListener.onClick(item)
                GlobalScope.launch {
                    withContext(Dispatchers.IO) {
                        if(database.mealItemDao.getBreakfastItem(item.itemTitle)!=null) {
                            if (database.mealItemDao.getBreakfastItem(item.itemTitle).likedOrNot) {
                                binding.addmealItem.setTag("unliked")
                                withContext(Dispatchers.Main){
                                    Toast.makeText(context,"Unliked",Toast.LENGTH_LONG).show()
                                }
                                binding.addmealItem.setImageResource(R.drawable.ic_add_button)
                                database.mealItemDao.getBreakfastItem(item.itemTitle).likedOrNot = false
                            } else {
                                binding.addmealItem.setTag("liked")
                                withContext(Dispatchers.Main){
                                    Toast.makeText(context,"Liked",Toast.LENGTH_LONG).show()
                                }
                                binding.addmealItem.setImageResource(R.drawable.ic_add_button_filled)
                                database.mealItemDao.getBreakfastItem(item.itemTitle).likedOrNot = true
                            }
                        }
                    }
                }
            }

//            binding.addmealItem.setOnClickListener {
//                clickListener.onClick(item)
//                if (binding.addmealItem.drawable.constantState!!.equals(ResourcesCompat.getDrawable(context.resources, R.drawable.ic_add_button, null)!!.constantState)) {
//                    binding.addmealItem.setImageResource(R.drawable.ic_add_button_filled)
//                } else {
//                    binding.addmealItem.setImageResource(R.drawable.ic_add_button)
//                }
//            }
            binding.executePendingBindings()
        }

        companion object {
            fun from(parent: ViewGroup): ViewHolder {
                val layoutInflater = LayoutInflater.from(parent.context)
                val binding = MealitemBinding.inflate(layoutInflater, parent, false)
                return ViewHolder(binding)
            }
        }
    }

    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ViewHolder {
        return ViewHolder.from(parent)
    }

    override fun onBindViewHolder(holder: ViewHolder, position: Int) {
        val item = getItem(position)
        holder.bind(item, clickListener, context, database)
    }
}

class MealItemDiffCallBack : DiffUtil.ItemCallback<MealItemModel>() {
    override fun areItemsTheSame(oldItem: MealItemModel, newItem: MealItemModel): Boolean {
        return oldItem == newItem
    }

    override fun areContentsTheSame(oldItem: MealItemModel, newItem: MealItemModel): Boolean {
        return oldItem.itemTitle == newItem.itemTitle
    }
}

class MealItemclickListener(val clickListener: (foodTitle: String) -> Unit) {
//    var flag = false
    fun onClick(mealItem: MealItemModel) {
//        flag = !flag
        return clickListener(mealItem.itemTitle)
    }
}

标签： javaandroidandroid-studiokotlinadapter

解决方案

如果您要实现的是类似/不同的功能。您应该尝试创建自定义可绘制对象。

<selector xmlns:android="http://schemas.android.com/apk/res/android">
<item android:android:state_enabled="true"
      android:drawable="@android:color/liked"/>
<item android:drawable="@android:color/unliked"/>
</selector>

使用它作为 xml 中图像的可绘制对象，您将能够通过访问视图来访问和切换图像的两种状态

addMealItem.isEnabled=true //(or false) this should be able to do the switching easily.

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