// Adding menuItems to ListView


   mylist=(ListView)findViewById(R.id.lstshowcatalogue);
        ListAdapter adapter=new LazyAdapter(this, menuItems,getApplicationContext());

             mylist.setAdapter(adapter);
             mylist.setOnItemClickListener(new OnItemClickListener(){

                @Override
                public void onItemClick(AdapterView<?> Parent, View view, int position,
                        long id) {
                    // TODO Auto-generated method stub
                    if(position>=0)
                    {
                        TextView c = (TextView) view.findViewById(R.id.txtlargeimage);
                       largeimage  = c.getText().toString();
                        ImageView thumb_image=(ImageView)view.findViewById(R.id.ivcatalouge); // thumb image
                        thumb_image.setOnClickListener(new OnClickListener(){

                            @Override
                            public void onClick(View v) {
                                // TODO Auto-generated method stub
                                if(largeimage.length()>0)
                                {
                                Intent i=new Intent();
                                i.setClass(getApplicationContext(), FrmShowSingleImage.class);
                                i.putExtra("largeimage", largeimage);
                                startActivity(i);
                                //Toast.makeText(getApplicationContext(), largeimage, Toast.LENGTH_SHORT).show();
                                largeimage="";
                                }
                            }}); 


                      //Toast.makeText(getApplicationContext(), largeimage, Toast.LENGTH_SHORT).show();


                    }
                }});

我想在缩略图onclick上打开一个新活动.当首次选择项目时,它工作正常.如果我单击缩略图而不选择项目,则它会变旧

Here is my updated listview adapter
 public View getView(int position, View convertView, ViewGroup parent) {
        View vi=convertView;
        if(convertView==null)
            vi = inflater.inflate(R.layout.list_item, null);

        TextView name = (TextView)vi.findViewById(R.id.name); // name
        TextView desc = (TextView)vi.findViewById(R.id.desciption); // collection
        TextView cost = (TextView)vi.findViewById(R.id.cost); // cost
        TextView category = (TextView)vi.findViewById(R.id.txtcategory); // cost
        TextView spec = (TextView)vi.findViewById(R.id.txtspec); // cost
        TextView largeimg = (TextView)vi.findViewById(R.id.txtlargeimage); // cost

        ImageView thumb_image=(ImageView)vi.findViewById(R.id.ivcatalouge); // thumb image

       thumb_image.setOnClickListener(new OnClickListener(){

        @Override
        public void onClick(View v) {
            // TODO Auto-generated method stub

            TextView c = (TextView) v.findViewById(R.id.txtlargeimage);

             Intent i=new Intent();
                i.setClass(mCtx, FrmShowSingleImage.class);
                i.putExtra("largeimage", c.getText());
                mCtx.startActivity(i);

        }});

        HashMap<String, String> song = new HashMap<String, String>();
        song = data.get(position);

        // Setting all values in listview
        name.setText(song.get(FrmShowCatlogue.KEY_MODEL));
        desc.setText(song.get(FrmShowCatlogue.KEY_COLLECTION));
        cost.setText(song.get( FrmShowCatlogue.KEY_MRP));
        category.setText(song.get( FrmShowCatlogue.KEY_CATEGORY));
        spec.setText(song.get( FrmShowCatlogue.KEY_SPEC));
        largeimg.setText(song.get( FrmShowCatlogue.KEY_LARGE));
        largeimg.setVisibility(View.GONE);
                try 
        {
            String filename=song.get(FrmShowCatlogue.KEY_IMAGES.toString());
            filename="thumbs/" + filename;
            // get input stream
            InputStream ims = mCtx.getAssets().open(filename);
            // load image as Drawable
            Drawable d = Drawable.createFromStream(ims, null);
            // set image to ImageView
            thumb_image.setImageDrawable(d);
        }
        catch(IOException ex) 
        {

            //thumb_image.setVisibility(View.GONE);
        }

        return vi;
    }

现在,我在单击拇指时得到了空指针异常.
我已经从listview的SetOnItemClickListener中删除了thumb_image onclick

解决方法:

如果您的列表项单击没有被识别,那是因为您的自定义列表项中包含许多可单击项(图像按钮,按钮…).将android：focusable = false用于这些项目,您的列表视图点击将没问题.

然后就像JaredLua所说的那样,您应该在适配器中添加onClickLisener(),因为它仅用于thumb_image而不是整个listitem