如何在ImageView中使用URL引用的图像?


当前回答

要做到这一点,一个简单而干净的方法是使用开源库Prime。

其他回答

public class LoadWebImg extends Activity {

String image_URL=
 "http://java.sogeti.nl/JavaBlog/wp-content/uploads/2009/04/android_icon_256.png";

   /** Called when the activity is first created. */
   @Override
   public void onCreate(Bundle savedInstanceState) {
       super.onCreate(savedInstanceState);
       setContentView(R.layout.main);

       ImageView bmImage = (ImageView)findViewById(R.id.image);
    BitmapFactory.Options bmOptions;
    bmOptions = new BitmapFactory.Options();
    bmOptions.inSampleSize = 1;
    Bitmap bm = LoadImage(image_URL, bmOptions);
    bmImage.setImageBitmap(bm);
   }

   private Bitmap LoadImage(String URL, BitmapFactory.Options options)
   {       
    Bitmap bitmap = null;
    InputStream in = null;       
       try {
           in = OpenHttpConnection(URL);
           bitmap = BitmapFactory.decodeStream(in, null, options);
           in.close();
       } catch (IOException e1) {
       }
       return bitmap;               
   }

private InputStream OpenHttpConnection(String strURL) throws IOException{
 InputStream inputStream = null;
 URL url = new URL(strURL);
 URLConnection conn = url.openConnection();

 try{
  HttpURLConnection httpConn = (HttpURLConnection)conn;
  httpConn.setRequestMethod("GET");
  httpConn.connect();

  if (httpConn.getResponseCode() == HttpURLConnection.HTTP_OK) {
   inputStream = httpConn.getInputStream();
  }
 }
 catch (Exception ex)
 {
 }
 return inputStream;
}
}
    String img_url= //url of the image
    URL url=new URL(img_url);
    Bitmap bmp; 
    bmp=BitmapFactory.decodeStream(url.openConnection().getInputStream());
    ImageView iv=(ImageView)findviewById(R.id.imageview);
    iv.setImageBitmap(bmp);

你必须先下载图像

public static Bitmap loadBitmap(String url) {
    Bitmap bitmap = null;
    InputStream in = null;
    BufferedOutputStream out = null;

    try {
        in = new BufferedInputStream(new URL(url).openStream(), IO_BUFFER_SIZE);

        final ByteArrayOutputStream dataStream = new ByteArrayOutputStream();
        out = new BufferedOutputStream(dataStream, IO_BUFFER_SIZE);
        copy(in, out);
        out.flush();

        final byte[] data = dataStream.toByteArray();
        BitmapFactory.Options options = new BitmapFactory.Options();
        //options.inSampleSize = 1;

        bitmap = BitmapFactory.decodeByteArray(data, 0, data.length,options);
    } catch (IOException e) {
        Log.e(TAG, "Could not load Bitmap from: " + url);
    } finally {
        closeStream(in);
        closeStream(out);
    }

    return bitmap;
}

然后使用Imageview。setImageBitmap将位图设置为ImageView

我最近在这里找到了一个线程,因为我必须为带有图像的列表视图做类似的事情,但原理很简单,正如您可以在那里显示的第一个示例类中读到的那样(由jleedev)。 你得到图像的输入流(从网络)

private InputStream fetch(String urlString) throws MalformedURLException, IOException {
    DefaultHttpClient httpClient = new DefaultHttpClient();
    HttpGet request = new HttpGet(urlString);
    HttpResponse response = httpClient.execute(request);
    return response.getEntity().getContent();
}

然后你将图像存储为可绘制的,你可以将它传递给ImageView(通过setImageDrawable)。同样从上面的代码片段来看一下整个线程。

InputStream is = fetch(urlString);
Drawable drawable = Drawable.createFromStream(is, "src");

来自Android开发者:

// show The Image in a ImageView
new DownloadImageTask((ImageView) findViewById(R.id.imageView1))
            .execute("http://java.sogeti.nl/JavaBlog/wp-content/uploads/2009/04/android_icon_256.png");

public void onClick(View v) {
    startActivity(new Intent(this, IndexActivity.class));
    finish();

}

private class DownloadImageTask extends AsyncTask<String, Void, Bitmap> {
    ImageView bmImage;

    public DownloadImageTask(ImageView bmImage) {
        this.bmImage = bmImage;
    }

    protected Bitmap doInBackground(String... urls) {
        String urldisplay = urls[0];
        Bitmap mIcon11 = null;
        try {
            InputStream in = new java.net.URL(urldisplay).openStream();
            mIcon11 = BitmapFactory.decodeStream(in);
        } catch (Exception e) {
            Log.e("Error", e.getMessage());
            e.printStackTrace();
        }
        return mIcon11;
    }

    protected void onPostExecute(Bitmap result) {
        bmImage.setImageBitmap(result);
    }
}

确保你在AndroidManifest.xml中设置了以下权限来访问互联网。

<uses-permission android:name="android.permission.INTERNET" />