Question

我需要从服务器获取图像并将其加载到图像按钮。当应用程序片段启动时，动态加载的图像超过50个。最好的方法是什么。目前我使用下面的代码，当我运行它时，应用程序卡住了，我也跟着Android Loading Image from URL (HTTP)教程，但是当有多个时，它没有显示图像图像。

这是我正在使用的代码，但应用程序正在冻结

private void setListParentItemInfo(View convertView,final IPTVChannel iptvChannel){
 ImageButton logoBtn = ((ImageButton) convertView.findViewById(R.id.channelLogo));

        String image_url="http://Channel.com.au/ChannelLogos/"+Channel.getLogoName();
  logoBtn.setImageBitmap(downloadBitmap(image_url));
}


private Bitmap downloadBitmap(String url) {
    // initilize the default HTTP client object
    final DefaultHttpClient client = new DefaultHttpClient();

    //forming a HttoGet request
    final HttpGet getRequest = new HttpGet(url);
    try {

        HttpResponse response = client.execute(getRequest);

        //check 200 OK for success
        final int statusCode = response.getStatusLine().getStatusCode();

        if (statusCode != HttpStatus.SC_OK) {
            Log.w("ImageDownloader", "Error " + statusCode +
                    " while retrieving bitmap from " + url);
            return null;

        }

        final HttpEntity entity = response.getEntity();
        if (entity != null) {
            InputStream inputStream = null;
            try {
                // getting contents from the stream
                inputStream = entity.getContent();

                // decoding stream data back into image Bitmap that android understands
                final Bitmap bitmap = BitmapFactory.decodeStream(inputStream);

                return bitmap;
            } finally {
                if (inputStream != null) {
                    inputStream.close();
                }
                entity.consumeContent();
            }
        }
    } catch (Exception e) {
        // You Could provide a more explicit error message for IOException
        getRequest.abort();
        Log.e("ImageDownloader", "Something went wrong while" +
                " retrieving bitmap from " + url + e.toString());
    }

    return null;
}

如何解决此问题或其他原因？

Answer 1

使用Picasso Library

private void setListParentItemInfo(View convertView,final IPTVChannel iptvChannel){
 ImageButton logoBtn = ((ImageButton) convertView.findViewById(R.id.channelLogo));

 String image_url="http://Channel.com.au/ChannelLogos/"+Channel.getLogoName();
 Picasso.with(context).load(image_url).placeholder(yourDrawableImage).into(logoBtn);
}

Answer 2

使用picaso库，它易于使用且快速并节省现金以供进一步使用。

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

Answer 3

是的，它正在冻结，因为它在与UI（主线程）相同的线程中运行。始终使用不同的线程（例如AsyncTask）从网络加载某些东西，较新的API级别根本不允许您这样做。但在这种情况下，绝对应该使用Picasso库。

Answer 4

如果您使用小图片，则可以使用如下的异步任务加载图像。如果您有大图片，则需要关注http://developer.android.com/intl/es/training/displaying-bitmaps/load-bitmap.html

class ImageLoader extends AsyncTask<String, Void, Bitmap> {

    @Override
    protected Bitmap doInBackground(String... params) {
        return getBitmapFromURL(params[0]);
    }

    @Override
    protected void onPostExecute(Bitmap result) {
        super.onPostExecute(result);
        imageButton.setImageBitmap(result);
    }

}

public Bitmap getBitmapFromURL(String imageURL) {
    try {
        URL url = new URL(imageURL);
        HttpURLConnection connection = (HttpURLConnection) url
                .openConnection();
        connection.setDoInput(true);
        connection.connect();
        InputStream input = connection.getInputStream();
        Bitmap myBitmap = BitmapFactory.decodeStream(input);
        return myBitmap;
    } catch (IOException e) {
        // Log exception
        return null;
    }
}

Answer 5

我想你应该为How to use separate thread to perform http requests

中显示的每个图像使用多个线程

Answer 6

使用Facebook等壁画库。 http://frescolib.org/

使用此功能，您无需从外部下载图像。只需设置通过uri的图像。它会自动下载并将其设置为视图。

如何从url

6 个答案: