android - 如何在GridView中设置文字下方的图像？

我按以下方式尝试，但是在iv.setImageBitmap（bm）上出现了空指针异常。
我尝试使用网格视图和Layout Inflater设置带有文本的图像。我也进行了调试过程，但仍然无法解决问题。请检查以下代码。

public class CategoryAdapter extends BaseAdapter {
private Context mContext;
public static final int ACTIVITY_CREATE = 10;
int id=-1;
public CategoryAdapter(Context c) {
        mContext = c;
 }
public int getCount() {
    return CategorylogoActivity.logoarray.length;
}

public Object getItem(int position) {
    return position;
}

public long getItemId(int position) {
    return position;
}

public View getView(int position, View convertView, ViewGroup parent) {
       Bitmap bm=null;
       ImageView iv = null ;
       TextView tv=null;
       View v;
                    if(convertView==null){

                        @SuppressWarnings("static-access")
                        LayoutInflater li = (LayoutInflater)mContext.getSystemService(mContext.LAYOUT_INFLATER_SERVICE);

                        v = li.inflate(R.layout.category_icon, null);
                        tv= (TextView)v.findViewById(R.id.icon_text);

                        iv = (ImageView)v.findViewById(R.id.icon_image);


                    }
                    else
                    {
                        v = convertView;
                    }
                        try {
                            URL aURL = new URL(CategorylogoActivity.logoarray[position]);
                            URLConnection conn = aURL.openConnection();
                            conn.connect();
                            InputStream is = conn.getInputStream();
                            // Buffered is always good for a performance plus.
                            BufferedInputStream bis = new BufferedInputStream(is);
                            // Decode url-data to a bitmap.
                            bm = BitmapFactory.decodeStream(bis);

                            bis.close();
                            is.close();
                        } catch (MalformedURLException e) {

                            e.printStackTrace();
                        } catch (IOException e) {

                            e.printStackTrace();
                        }
                     iv.setImageBitmap(bm);
                    tv.setText(CategorylogoActivity.namearray[0]);

                    return v;

最佳答案

static class viewHolder {
       ImageView iv = null ;
       TextView tv=null;
}


public View getView(int position, View convertView, ViewGroup parent) {
       Bitmap bm=null;
       viewHolder vh;
       View v;
                    if(convertView==null){
                        vh = new viewHolder();
                        @SuppressWarnings("static-access")
                        LayoutInflater li = (LayoutInflater)mContext.getSystemService(mContext.LAYOUT_INFLATER_SERVICE);


                        v = li.inflate(R.layout.category_icon, null);
                        vh.tv= (TextView)v.findViewById(R.id.icon_text);

                        vh.iv = (ImageView)v.findViewById(R.id.icon_image);

                        v.setTag(vh);
                    }
                    else
                    {
                        vh = (viewHolder)convertView.getTag();
                        v = convertView;
                    }
                        try {
                            URL aURL = new URL(CategorylogoActivity.logoarray[position]);
                            URLConnection conn = aURL.openConnection();
                            conn.connect();
                            InputStream is = conn.getInputStream();
                            // Buffered is always good for a performance plus.
                            BufferedInputStream bis = new BufferedInputStream(is);
                            // Decode url-data to a bitmap.
                            bm = BitmapFactory.decodeStream(bis);

                            bis.close();
                            is.close();
                        } catch (MalformedURLException e) {

                            e.printStackTrace();
                        } catch (IOException e) {

                            e.printStackTrace();
                        }
                     vh.iv.setImageBitmap(bm);
                    vh.tv.setText(CategorylogoActivity.namearray[0]);

                    return v;

您必须使用viewHolder类型的对象，当convertView不为null时，您的iv imageView为null。因此您在空对象上使用setImageBitmap（）。试试我的代码。

HTH。

关于android - 如何在GridView中设置文字下方的图像？，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/7849962/