我开发了一个应用程序，当用户启动它打开的应用程序并使用异步任务将数据下载到listview时。每行都有一个黑色的按钮。用户可以通过单击心形按钮来改变项目，并且它变为红色。当用户向下滚动并返回到他/她喜欢的项目时，喜欢的按钮将返回到黑色。即使用户向下/向上滚动并返回喜欢的项目，我也希望红色保持不变。
这是我的适配器
public class ListViewAdapterSup extends BaseAdapter {
// Declare Variables
Context context;
LayoutInflater inflater;
ArrayList<HashMap<String, String>> data;
HashMap<String, String> resultp = new HashMap<String, String>();
public ListViewAdapterSup(Context context,
ArrayList<HashMap<String, String>> arraylist) {
this.context = context;
data = arraylist;
}
@Override
public int getCount() {
return data.size();
}
@Override
public Object getItem(int position) {
return null;
}
@Override
public long getItemId(int position) {
return 0;
}
static class ViewHolder {
// Declare Variables
TextView artisteTV;
TextView likesCountTV;
ImageButton artisteLike;
}
ViewHolder holder;
public View getView(final int position, View itemView, ViewGroup parent) {
itemView = null;
if (itemView == null) {
inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
itemView = inflater.inflate(R.layout.sups_list_item, parent, false);
// Get the position
resultp = data.get(position);
holder = new ViewHolder();
// Locate the TextViews in listview_item.xml
holder.artisteTV = (TextView) itemView.findViewById(R.id.artiste_name);
holder.likesCountTV = (TextView) itemView.findViewById(R.id.likes_count);
holder.artisteLike= (ImageButton) itemView.findViewById(R.id.art_like);
itemView.setTag(holder);
}
else{
holder = (ViewHolder) itemView.getTag();
}
// Capture position and set results to the TextViews
holder.artisteTV.setText(resultp.get(Artiste.NAME));
holder.likesCountTV.setText(resultp.get(Sups.LIKES_COUNT));
holder.artisteLike.setTag(holder);
holder.artisteLike.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
holder = (ViewHolder)view.getTag();
resultp = data.get(position);
if(holder.artisteLike.getDrawable().getConstantState().equals(holder.artisteLike.getContext().getDrawable(R.drawable.ic_favorite_black_24dp).getConstantState())){
resultp = data.get(position);
ConnectionDetector cd = new ConnectionDetector(context);
if (!cd.isConnectingToInternet()) {
Toast.makeText(context,"No internet connection",Toast.LENGTH_SHORT).show();
}
else
{
new LikeSup().execute();
holder.artisteLike.setImageResource(R.drawable.ic_favorite_red_24dp);
}
}
else if(holder.artisteLike.getDrawable().getConstantState().equals(holder.artisteLike.getContext().getDrawable(R.drawable.ic_favorite_red_24dp).getConstantState())){
resultp = data.get(position);
ConnectionDetector cd = new ConnectionDetector(context);
if (!cd.isConnectingToInternet()) {
Toast.makeText(context,"No internet connection",Toast.LENGTH_SHORT).show();
}
else
{
new UnLikeSup().execute();
holder.artisteLike.setImageResource(R.drawable.ic_favorite_black_24dp);
}
}
}
}
});
return itemView;
}
}
答案 0 :(得分：0)
首先，如果你使用普通的ListView，那么请确保你＆＃34; pack＆＃34;对象中的列表项，当用户单击like按钮时，在这种情况下更改该对象的状态（喜欢或不喜欢）。
如果你使用的是可循环使用的ListView，那么就像评论中提到的其他人一样，无论你在每一行中获得相同的对象，你的视图都会被回收。
到这里学习ViewHolder模式，其中列表可以具有唯一元素，但同时回收它们以实现快速滚动和更好的资源管理。 https://developer.android.com/training/improving-layouts/smooth-scrolling.html
在这里，你可以学习如何实现它，它有一个正在发生的图片，所以你可以想象它。 http://www.rogcg.com/blog/2013/03/12/recycling-views-listview
答案 1 :(得分：0)
首先，在getview（）方法中，你不应该将itemView设置为null;你应该理解循环机制，＆＃34; itemView＆＃34;（称为convertView）是当前显示视图，它保持几个项目视图;
第二
用户可以通过单击心形按钮来改变项目，然后它变为红色，当用户向下滚动并返回到他/她喜欢的项目时，喜欢的按钮会变回黑色。即使用户向下/向上滚动并返回喜欢的项目，我也希望红色保持不变。
1,about ArrayList<HashMap<String, String>> data;
您应该更改arraylist包含数据库的数据结构，例如：
public class AlbumBean implements Serializable{
private static final long serialVersionUID = 1L;
private String likedCount;
private boolean isLiked;
private String picUrl;
// get() set() method
...................
}
2,in your ListViewAdapterSup ,you should define a var boolean isLiked;
3,the example as i do
@Override
public View getView(int position, View convertView, ViewGroup parent) {
ViewHolder holder = null;
if (convertView == null || !(convertView.getTag() instanceof ViewHolder)) {
convertView = LayoutInflater.from(context).inflate(R.layout.buyah_chosen_album_detail_list_item, parent, false);
holder = new ViewHolder();
holder.productImg = (ScaledRemoteImageView) convertView.findViewById(R.id.product_img);
holder.productDesc = (TextView) convertView.findViewById(R.id.product_desc);
holder.productTitle = (TextView) convertView.findViewById(R.id.product_title);
holder.favoriteCount = (TextView) convertView.findViewById(R.id.favorite_count);
holder.multiple = (TextView) convertView.findViewById(R.id.multiple_content);
holder.priceAndScoreView = (BuyahPriceAndScoreView) convertView.findViewById(R.id.price_score_view);
holder.favoriteCount.setOnClickListener(this);
convertView.setTag(holder);
} else {
holder = (ViewHolder) convertView.getTag();
}
if (holder != null) {
final ChosenAlbumDetailBean product = getItem(position);
holder.favoriteCount.setTag(R.id.price, holder);
holder.favoriteCount.setTag(R.id.favorite_count, product);
holder.productImg.setTag(R.id.product_img, product);
holder.priceAndScoreView.setPriceAndScore(product, 16);
ImageLoader.getInstance().displayImage(product.getPic(), holder.productImg);
holder.productTitle.setText(product.getTitle());
holder.favoriteCount.setText(product.getLiked());
if (product.getIs_liked()) {
isFavorited = true;
holder.favoriteCount.setCompoundDrawablesWithIntrinsicBounds(R.drawable.buyah_middle_favorite_selected, 0, 0, 0);
} else {
isFavorited = false;
holder.favoriteCount.setCompoundDrawablesWithIntrinsicBounds(R.drawable.buyah_middle_favorite_unselect, 0, 0, 0);
}
}
return convertView;
}
@Override
public void onClick(final View v) {
ChosenAlbumDetailBean product = null;
switch (v.getId()) {
case R.id.favorite_count:
ClickDurationController.controlClickDuration(v);
if (!UserInfoCommon.getInstance().isLogined()) {
if (buyahChosenAdapterNeedLoginListener != null) {
buyahChosenAdapterNeedLoginListener.onBuyahChosenAdapterClick();
}
} else {
ViewHolder holder = (ViewHolder) v.getTag(R.id.price);
product = (ChosenAlbumDetailBean) v.getTag(R.id.favorite_count);
boolean isFavorite = product.getIs_liked();
int currentFavoriteCount = Integer.valueOf(holder.favoriteCount.getText().toString());
if (isFavorite) {
isFavorite = false;
isFavorited = false;
holder.favoriteCount.setText(currentFavoriteCount - 1 + "");
holder.favoriteCount.setCompoundDrawablesWithIntrinsicBounds(R.drawable.buyah_middle_favorite_unselect, 0, 0, 0);
} else {
isFavorite = true;
isFavorited = true;
holder.favoriteCount.setCompoundDrawablesWithIntrinsicBounds(R.drawable.buyah_middle_favorite_selected, 0, 0, 0);
holder.favoriteCount.setText(currentFavoriteCount + 1 + "");
}
product.setIs_liked(isFavorite);
product.setLiked(holder.favoriteCount.getText().toString());
break;
default:
break;
}
}