使用 ViewHolder 的 Android 列表视图 [英] Android listview using ViewHolder

问题描述

我有问题.单击后，我试图更改列表视图中的图标.它可以正常工作，但不仅修改了单击的图标，还修改了未显示的图标.例如，如果我单击列表视图第一项中的图标，第五个图标也会更改.对于以下所有项目(列表视图的每五个项目)重复此行为.这是我的 getView 方法:

I have a problem. I'm attempting to change an icon in my listview after it has been clicked. It works correctly although are not modified only the clicked icons but also those who are not displayed. For example if I click the icon in the first item of the listview, also the fifth icon changes. This behaviour is repeated for all the following items (every five items of the listview). This is my getView method:

   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 

...

这是我的 ViewHolder 类:

And this is my ViewHolder class:

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

推荐答案

在下面更改您的代码.我认为你错过了这一点.

Change your code at below. I think you're missing that.

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
}

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