Question

我正在尝试从网址下载图片并将其转换为位图

相应的代码是：

Bitmap pinbit=ImageDownloader.DownloadImage(URL_image+s.category+".png");
      pinbit=Bitmap.createScaledBitmap(pinbit,75,56,false);
        marker.icon(BitmapDescriptorFactory.fromBitmap(pinbit));

我用来下载图片的课程是：

package com.igloo.classes;

import java.io.IOException;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.URL;
import java.net.URLConnection;

import android.graphics.Bitmap;
import android.graphics.BitmapFactory;

public class ImageDownloader {
    public static InputStream OpenHttpConnection(String urlString)
            throws IOException
            {
                InputStream in = null;
                int response = -1;

                URL url = new URL(urlString);
                URLConnection conn = url.openConnection();

                if (!(conn instanceof HttpURLConnection))                   
                    throw new IOException("Not an HTTP connection");

                try{
                    HttpURLConnection httpConn = (HttpURLConnection) conn;
                    httpConn.setAllowUserInteraction(false);
                    httpConn.setInstanceFollowRedirects(true);
                    httpConn.setRequestMethod("GET");
                    httpConn.connect();

                    response = httpConn.getResponseCode();               
                    if (response == HttpURLConnection.HTTP_OK) {
                        in = httpConn.getInputStream();                               
                    }                   
                }
                catch (Exception ex)
                {
                    throw new IOException("Error connecting");          
                }
                return in;   
            }
           public static Bitmap DownloadImage(String URL)
            {      
                Bitmap bitmap = null;
                InputStream in = null;      
                try {
                    in = OpenHttpConnection(URL);
                    bitmap = BitmapFactory.decodeStream(in);
                    in.close();
                } catch (IOException e1) {
                    // TODO Auto-generated catch block
                    e1.printStackTrace();
                }
                return bitmap;              
            }
}

该代码适用于像Android 2.6这样的旧设备，但是当我在新的三星平板电脑上运行时，该行：

Bitmap pinbit=ImageDownloader.DownloadImage(URL_image+s.category+".png");'

显示NullPointerException。请帮忙！

Answer 1

嘿，你可以使用毕加索库并用它将它添加到你的项目中你可以在一行中从url下载图像文件。

http://square.github.io/picasso/

从android中的URL下载位图图像不起作用

1 个答案: