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我在第 92 行遇到了从 url 获取图像的问题。请解决它。

import java.io.IOException;
import java.io.InputStream;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.ArrayList;

import android.app.Activity;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.drawable.Drawable;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.ImageView;
import android.widget.TextView;

public class EfficientAdapter extends BaseAdapter {
    private Activity activity;
    private ArrayList<Post> data;
    private ImageView iv;
    private static LayoutInflater inflater = null;
    // public ImageLoader imageLoader;
    ViewHolder holder;

    EfficientAdapter(Activity a, ArrayList<Post> d) {

        activity = a;
        data = d;
        inflater = (LayoutInflater) activity
                .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        // imageLoader = new ImageLoader(activity.getApplicationContext());

    }

    @Override
    public int getCount() {
        return data.toArray().length;

    }

    @Override
    public Object getItem(int position) {

        return position;
    }

    @Override
    public long getItemId(int position) {

        return position;
    }

    public static class ViewHolder {
        public TextView label;
        public TextView addr;
        public ImageView image;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        View vi = convertView;

        if (convertView == null) {
            vi = inflater.inflate(R.layout.row, null);
            holder = new ViewHolder();
            holder.label = (TextView) vi.findViewById(R.id.title);
            holder.addr = (TextView) vi.findViewById(R.id.details);
            holder.image = (ImageView) vi.findViewById(R.id.thumb);
            vi.setTag(holder);
        } else
            holder = (ViewHolder) vi.getTag();

        holder.label.setText(data.get(position).getTitle());
        holder.addr.setText(data.get(position).getPubDate());

        // imageLoader.DisplayImage((data.get(position).getThumbnail()),
        // activity,
        // holder.image, 72, 72);
        URL url = null;
        try {
            url = new URL((data.get(position).getThumbnail()));
        } catch (MalformedURLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

//我在这里遇到错误。你可以在 log cat 中看到错误。

InputStream content = null;
            try {
                content = (InputStream) url.getContent();
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
            Drawable d = Drawable.createFromStream(content, "src");
            Bitmap mIcon1 = null;
            try {
                mIcon1 = BitmapFactory.decodeStream(url.openConnection()
                        .getInputStream());
            } catch (IOException e) {
                e.printStackTrace();
            }
            holder.image.setImageBitmap(Bitmap.createScaledBitmap(mIcon1, 72, 72,
                    false));
                    return vi;
        }

    }

这是我的示例，我已将它的 zip 文件放在 Drop box 上。链接：https ://dl-web.dropbox.com 。请帮我。我在第 92 行的 EfficientAdapter.java 中有问题，我在空指针异常中出错。

4

1 回答 1

0

使用此功能从 URL 获取图像..

Drawable img = ImageOperations(ctx, url);
holder.image.setImageDrawable(img);

public Object fetch(String address) throws MalformedURLException, IOException {

    URL url = new URL(address);
    Object content = url.getContent();
    return content;
}  

private Drawable ImageOperations(Context ctx, String url) {

    try {
        InputStream is = (InputStream) this.fetch(url);
        Drawable d = Drawable.createFromStream(is, "src");
        return d;
    } catch (MalformedURLException e) {
        return null;
    } catch (IOException e) {
        return null;
    }
}
于 2012-04-09T08:39:18.493 回答