使用ViewHolder的Android listview

我有个问题。我试图在单击listview后更改它中的图标。它工作正常，尽管不仅修改了单击的图标，而且修改了未显示的图标。例如，如果我单击listview第一项中的图标，第五个图标也会更改。对于以下所有项目（listview的每五个项目）重复此行为。 这是我的getView方法：

   public class AlphabeticalAdapter extends ArrayAdapter<String>
   {
       int layoutResourceId; 
       private final Context context;
       private List<String> data;
       private ProgressDialog mProgressDialog;
       private ImageView downloadImageButton;


       public AlphabeticalAdapter(Context context, int resource, List<String> data){
           super(context, resource, data);
           this.layoutResourceId = resource;
           this.context = context;
           this.data = data;    
       }

       public View getView(int position, View convertView, ViewGroup parent) {

          // View rowView = convertView;
           final ViewHolder viewHolder;

           if (convertView == null) {

               LayoutInflater inflater = (LayoutInflater) context
                        .getSystemService(Context.LAYOUT_INFLATER_SERVICE);


               convertView  = inflater.inflate(R.layout.catalogslist_single_row, parent, false);

           viewHolder = new ViewHolder();

           viewHolder.catlogTitle=(TextView)convertView.findViewById(R.id.txtTitle);
           viewHolder.icon=(ImageView)convertView.findViewById(R.id.imageView2); 
           viewHolder.downloadImageButton=(ImageView)convertView.findViewById(R.id.downloadImageButton);

           //downloadImageButton = (ImageView)rowView.findViewById(R.id.downloadImageButton);

           viewHolder.position = position;


           viewHolder.downloadImageButton.setOnClickListener(new OnClickListener() {
               @Override  
               public void onClick(View v) {
                     System.out.println("DOWNLOAD PRESSED");

                     viewHolder.downloadImageButton = (ImageView)v.findViewById(R.id.downloadImageButton);
                     viewHolder.downloadImageButton.setImageResource(R.drawable.icon_ok);
                     viewHolder.downloadImageButton.setTag("downloaded");
                     //rowView.setTag("downloaded");


                 }
             });



           convertView.setTag(viewHolder);

           }

           else{
               viewHolder= (ViewHolder)convertView.getTag(); 
           }

           viewHolder.catlogTitle.setText(data.get(position));
           viewHolder.catlogTitle.setTypeface(regularDin);
           viewHolder.icon.setImageResource(R.drawable.cata);


           if(viewHolder.downloadImageButton.getTag() == "downloaded"){
             downloadImageButton = (ImageView)convertView.findViewById(R.id.downloadImageButton);
             downloadImageButton.setImageResource(R.drawable.icon_ok);
           }
           else{
               downloadImageButton = (ImageView)convertView.findViewById(R.id.downloadImageButton);
                 downloadImageButton.setImageResource(R.drawable.icon_download);
           }


           viewHolder.position = position;

        return convertView;

       } //close getView 

---

在下面更改您的代码。我想你错过了

public class AlphabeticalAdapter extends ArrayAdapter<String> {
    int layoutResourceId;
    private final Context context;
    private List<String> data;
    private List<String> tags;
    private ProgressDialog mProgressDialog;
    private ImageView downloadImageButton;

    public AlphabeticalAdapter(Context context, int resource, List<String> data) {
        super(context, resource, data);
        this.layoutResourceId = resource;
        this.context = context;
        this.data = data;
        tags = new ArrayList<String>();
        int size = data.size();
        for (int i = 0; i < size; i++) {
            tags.add("tag");
        }
    }

    static class ViewHolder {
        ImageView downloadImageButton;
        TextView catlogTitle;
        ImageView icon;
        int position;
    }

    public View getView(final int position, View convertView, ViewGroup parent) {

        // View rowView = convertView;
        final ViewHolder viewHolder;

        if (convertView == null) {
            LayoutInflater inflater = (LayoutInflater) context
                    .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            // convertView = inflater.inflate(R.layout.catalogslist_single_row,
            // parent, false);
            viewHolder = new ViewHolder();
            viewHolder.position = position;
            viewHolder.downloadImageButton
                    .setOnClickListener(new OnClickListener() {
                        @Override
                        public void onClick(View v) {
                            System.out.println("DOWNLOAD PRESSED");
                            viewHolder.downloadImageButton.setTag("downloaded");
                            tags.add(position, "downloaded");
                        }
                    });
            convertView.setTag(viewHolder);
        } else {
            viewHolder = (ViewHolder) convertView.getTag();
        }

        viewHolder.catlogTitle.setText(data.get(position));
        viewHolder.catlogTitle.setTypeface(regularDin);
        viewHolder.icon.setImageResource(R.drawable.cata);

        if (tags.get(position) == "downloaded") {
            downloadImageButton.setImageResource(R.drawable.icon_ok);
        } else {
            downloadImageButton.setImageResource(R.drawable.icon_download);
        }

        viewHolder.position = position;
        return convertView;
    } // close getView
}

公共类字母适配器扩展了ArrayAdapter{
国际布局资源；
私人最终语境；
私人名单数据；
私有列表标签；
private ProgressDialog mProgressDialog；
私有ImageView下载ImageButton；
公共字母适配器（上下文、int资源、列表数据）{
超级（上下文、资源、数据）；
this.layoutResourceId=资源；
this.context=上下文；
这个数据=数据；
tags=newarraylist（）；
int size=data.size（）；
对于（int i=0；i

在您的

列表视图

中，同时可见的

转换视图

行数与可见行数相同（系统将重用它）。因此，实际上您有5个

convertView

，因此，您有5个

ImageView

作为图标。问题是您使用这些ImageView的标记来存储“下载”的信息。这是5状态，这就是为什么在列表中滚动时，每五行就有一行下载

我想现在你明白了，这是行不通的。您需要存储每个项目的下载状态，因此必须将基础的

列表

更改为

列表

，其中

列表项

可以存储实际行的下载状态

---

之后，您所要做的就是更新

convertView

的

ImageView

（在

getView（）

中）以显示正确的图标。

像这样更改代码。在try块之前使用convertView添加空检查

    final MenuItem   menuItem = getItem(position);
    View view = convertView;
    final ViewHolder viewHolder;

if (convertView == null) {

    LayoutInflater inflater;

        inflater = (LayoutInflater) getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        view = inflater.inflate(R.layout.menu_item, parent, false);
        viewHolder = new ViewHolder();
//      viewHolder.half = (TextView) view.findViewById(R.id.half);
        viewHolder.name = (TextView) view.findViewById(R.id.name);
        viewHolder.description = (TextView) view.findViewById(R.id.description);
        viewHolder.price = (TextView) view.findViewById(R.id.price);
        viewHolder.add = (Button) view.findViewById(R.id.add);
        viewHolder.selectedView = view.findViewById(R.id.selectedView);
        viewHolder.remove = (Button) view.findViewById(R.id.remove);
        viewHolder.total = (TextView) view.findViewById(R.id.itemTotal);
        viewHolder.quantity = (TextView) view.findViewById(R.id.quantity);
        view.setTag(viewHolder);
}else{
    viewHolder= (ViewHolder)convertView.getTag(); 
}

public类AndroidListViewActivity扩展了ListActivity
{
私有列表视图列表视图；
私有字符串名称[]={
“高压电容器”，
“低压电容器”，
};
私有字符串描述[]={
“强大的Hypter文本标记语言5”，
“层叠样式表”，
};
专用整数imageid[]={
R.可牵引高压电容器，
R.可牵引低压电容器，
};
@凌驾
创建时的公共void（Bundle savedInstanceState）{
super.onCreate（savedInstanceState）；
//setContentView（R.layout.Capactor_layout）；
//将字符串资源存储到数组中
字符串[]product\u name=getResources（）.getStringArray（R.array.product\u name）；
//将数组绑定到ListAdapter
this.setListAdapter（新的ArrayAdapter（this，R.layout.list_项，R.id.label，product_名称））；
ListView lv=getListView（）；
//在单击时侦听单个列表项
lv.setOnItemClickListener（新的AdapterView.OnItemClickListener（）{
public void onItemClick（AdapterView父级、视图、，
内部位置，长id）{
//选定项目
字符串产品=（（TextView）视图）.getText（）.toString（）；
//在选择单个列表项时启动新活动
Intent i=newintent（getApplicationContext（），SingleListItem.class）；
//向新活动发送数据
i、 putExtra（“产品”，产品）；
星触觉（i）；
}
});
电容器列表电容器列表=新电容器列表（此、名称、描述、图像ID）；
listView=（listView）findViewById（R.id.listView）；
setAdapter（电容器列表）；
setOnItemClickListener（新的AdapterView.OnItemClickListener（）{
//在选择单个列表项时启动新活动
Intent i=新Intent（getApplicationContext（），capactorList.class）；
//向新活动发送数据
//星触觉（i）；
@凌驾
公共无效onItemClick（AdapterView AdapterView、View视图、int i、long l）{
Toast.makeText（getApplicationContext（），“您单击了”+names[i]，Toast.LENGTH\u SHORT.show（）；
}
    final MenuItem   menuItem = getItem(position);
    View view = convertView;
    final ViewHolder viewHolder;

if (convertView == null) {

    LayoutInflater inflater;

        inflater = (LayoutInflater) getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        view = inflater.inflate(R.layout.menu_item, parent, false);
        viewHolder = new ViewHolder();
//      viewHolder.half = (TextView) view.findViewById(R.id.half);
        viewHolder.name = (TextView) view.findViewById(R.id.name);
        viewHolder.description = (TextView) view.findViewById(R.id.description);
        viewHolder.price = (TextView) view.findViewById(R.id.price);
        viewHolder.add = (Button) view.findViewById(R.id.add);
        viewHolder.selectedView = view.findViewById(R.id.selectedView);
        viewHolder.remove = (Button) view.findViewById(R.id.remove);
        viewHolder.total = (TextView) view.findViewById(R.id.itemTotal);
        viewHolder.quantity = (TextView) view.findViewById(R.id.quantity);
        view.setTag(viewHolder);
}else{
    viewHolder= (ViewHolder)convertView.getTag(); 
}

public class AndroidListViewActivity extends ListActivity 
{
   private ListView listView;
   private String names[] = {
        "HV CAPACITOR",
        "LV CAPACITORCSS",

         };

private String desc[] = {
        "The Powerful Hypter Text Markup Language 5",
        "Cascading Style Sheets",

};


private Integer imageid[] = {
        R.drawable.hv_capacitor,
        R.drawable.lv_capacitor,

};

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
   // setContentView(R.layout.capacitor_layout);
    // storing string resources into Array
    String[] product_name = getResources().getStringArray(R.array.product_name);
    // Binding Array to ListAdapter
    this.setListAdapter(new ArrayAdapter<String>(this, R.layout.list_item, R.id.label, product_name));

    ListView lv = getListView();

    // listening to single list item on click

    lv.setOnItemClickListener(new AdapterView.OnItemClickListener() {
        public void onItemClick(AdapterView<?> parent, View view,
                                int position, long id) {

            // selected item
            String product = ((TextView) view).getText().toString();

            // Launching new Activity on selecting single List Item
            Intent i = new Intent(getApplicationContext(), SingleListItem.class);
            // sending data to new activity
            i.putExtra("product", product);
            startActivity(i);

        }
    });


    CapacitorList capacitorList = new CapacitorList(this, names, desc, imageid);
    listView = (ListView) findViewById(R.id.listView);
    listView.setAdapter(capacitorList);

    listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {

        // Launching new Activity on selecting single List Item
        Intent i = new Intent(getApplicationContext(), CapacitorList.class);
        // sending data to new activity

       // startActivity(i);

        @Override
        public void onItemClick(AdapterView<?> adapterView, View view, int i, long l) {
            Toast.makeText(getApplicationContext(), "You Clicked " + names[i], Toast.LENGTH_SHORT).show();
        }
    });

}

    @Override
    public boolean onCreateOptionsMenu (Menu menu){
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.menu_main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected (MenuItem item){
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();

        //noinspection SimplifiableIfStatement
        if (id == R.id.action_settings) {
            return true;
        }

        return super.onOptionsItemSelected(item);


    }
}

public class CustomArrayAdapter extends ArrayAdapter {

// declare your custom list with type;
private List<YourModelClass> allData = new ArrayList<YourModelClass>();

public CustomArrayAdapter(@NonNull Context context, List<YourModelClass> allData) {
    super(context, R.layout.your_layout, allData); // add your_layout.xml
    this.allData = allData;
}

class ViewHolder {
    TextView name, phone; // declare your your_layout.xml view type
}

@NonNull
@Override
public View getView(int position, @Nullable View convertView, @NonNull ViewGroup parent) {
    LayoutInflater inflater = (LayoutInflater) getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
    ViewHolder holder = new ViewHolder();
    if (convertView == null) {

        convertView = inflater.inflate(R.layout.your_layout, parent, false); // inflate your_layout.xml

        //initialize your your_layout.xml view
        holder.name = convertView.findViewById(R.id.tv_item_name);
        holder.phone = convertView.findViewById(R.id.tv_item_phone);

        convertView.setTag(holder);
    } else {
        holder = (ViewHolder) convertView.getTag();
    }

    //set value into your_layout.xml
    holder.name.setText(allData.get(position).getName());
    holder.phone.setText(allData.get(position).getNumber());

    return convertView;
}