如果DiffUtil不正确通知您的所有更改,可能是由于您未正确设置Payload。请确保在使用DiffUtil.Callback时覆盖getChangePayload()方法,并正确返回数据更改的有效负载。以下是一个示例:
class MyDiffUtilCallback : DiffUtil.ItemCallback() {
override fun areItemsTheSame(oldItem: MyItem, newItem: MyItem): Boolean {
return oldItem.id == newItem.id
}
override fun areContentsTheSame(oldItem: MyItem, newItem: MyItem): Boolean {
return oldItem == newItem
}
override fun getChangePayload(oldItem: MyItem, newItem: MyItem): Any? {
// Return payload object if they have different image URLs
if (oldItem.imageUrl != newItem.imageUrl) {
return Bundle().apply {
putString("imageUrl", newItem.imageUrl)
}
}
return null
}
}
在RecyclerView.Adapter中,当调用notifyItemChanged()
时,您需要在第三个参数中添加有效负载(payload),如下所示:
class MyAdapter(private val items: MutableList) : RecyclerView.Adapter() {
//...
fun updateItems(newItems: List) {
val diffResult = DiffUtil.calculateDiff(MyDiffUtilCallback(), true)
items.clear()
items.addAll(newItems)
diffResult.dispatchUpdatesTo(this)
}
override fun onBindViewHolder(holder: MyViewHolder, position: Int, payloads: MutableList) {
if (payloads.isNotEmpty()) {
val bundle = payloads[0] as Bundle
if (bundle.containsKey("imageUrl")) {
// Update just the ImageView
holder.imageView.load(bundle.getString("imageUrl"))
}
} else {
super.onBindViewHolder(holder, position, payloads)
}
}
}
重写onBindViewHolder()
时,如果您收到一个非空的有效负载(payload),则只更新ImageView(或其他需要更新的视图)。否则,调用super.onBindViewHolder()
将按正常方式更新ViewHolder。