當(dāng)我單擊心形圖標(biāo)時(shí)，它會(huì)將項(xiàng)目發(fā)送到收藏夾并更改顏色，但是當(dāng)加載活動(dòng)時(shí)，圖標(biāo)會(huì)恢復(fù)正常顏色，但該項(xiàng)目仍在收藏夾中。我如何檢查收藏夾中的項(xiàng)目是否基于數(shù)據(jù)庫(kù)房間的監(jiān)聽(tīng)器之類的東西更改圖標(biāo)顏色？這是適配器：- public class BSAdapter extends RecyclerView.Adapter<BSAdapter.BestSellerHolder> { private Context context; private List<ProductsBestSeller> bestSellerList; public BSAdapter(Context context, List<ProductsBestSeller> bestSellerList) { this.context = context; this.bestSellerList = bestSellerList; } @Override public BestSellerHolder onCreateViewHolder(ViewGroup parent, int viewType) { View bestSellerView = LayoutInflater.from(parent.getContext()).inflate(R.layout.default_product_items_horizontal, parent, false); return new BestSellerHolder(bestSellerView); } @Override public void onBindViewHolder(BestSellerHolder holder, int position) { ProductsBestSeller bestSeller = bestSellerList.get(position); holder.onBindData(bestSeller); } @Override public int getItemCount() { if (bestSellerList != null) { return bestSellerList.size(); } else { return 0; } } public class BestSellerHolder extends RecyclerView.ViewHolder { TextView productName, productPrice; ImageView productIcon; CheckBox favouriteIcon; public BestSellerHolder(View itemView) { super(itemView); productIcon = itemView.findViewById(R.id.product_icon_horizontal); productName = itemView.findViewById(R.id.product_name_horizontal); productPrice = itemView.findViewById(R.id.product_price_horizontal); favouriteIcon = itemView.findViewById(R.id.favourite_icon_horizontal); }
1 回答
森欄
TA貢獻(xiàn)1810條經(jīng)驗(yàn) 獲得超5個(gè)贊
我可以在上面的代碼中看到 2 個(gè)問(wèn)題，
當(dāng)我們添加和刪除時(shí)您正在更新數(shù)據(jù)庫(kù)，這很好，但是您處理本地視圖引用的方式是錯(cuò)誤的。
原因：因?yàn)樵谀愕那闆r下，不僅當(dāng)你轉(zhuǎn)到另一個(gè)屏幕時(shí)它不會(huì)工作，如果你滾動(dòng)更多如果你有更多的項(xiàng)目然后回來(lái)它也不會(huì)工作，因?yàn)榛厥找晥D重用你更新的視圖在檢查監(jiān)聽(tīng)器中，這導(dǎo)致了第二個(gè)問(wèn)題
在 onBindData 中，你總是應(yīng)該使用非收藏圖標(biāo)，所以每當(dāng)你滾動(dòng)和查看重用它時(shí)，它只會(huì)顯示非收藏圖標(biāo)，你應(yīng)該檢查該項(xiàng)目是否是收藏，你應(yīng)該更新視圖
例如，你應(yīng)該像下面那樣
override fun onBindViewHolder(holder: VM, position: Int) {
val item = items.get(position)
if (item.favourite == 0) {
holder.name.text = item.name
} else {
holder.name.text = item.name + " Liked "
}
holder.favouriteIcon.setOnCheckedChangeListener { compoundButton, isChecked ->
// Should not update local view reference here
if(isChecked) {
// Update the local reference object, Just not to update from DB
item.favourite = 1
// Do the logic to update the DB to add the item in Fav
} else {
// Update the local reference object, Just not to update from DB
item.favourite = 0
// Do the logic to update to remove the item from Fav list
}
notifyItemChanged(position) // Helps to update the particular item
}
}
請(qǐng)根據(jù)您的項(xiàng)目修改代碼。
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