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我有这段代码可以从 URL 下载照片并将其显示在 Android 上的 ImageView 中。

如果我有一个 ArrayList 或多个 Url 的数组要下载并显示在不同的 ImageView 上，我不确定如何循环。我将不胜感激有关如何进行的任何帮助或见解！谢谢！

public class DisplayPhotoTask extends AsyncTask<String, Void, Bitmap> {
    @Override
    protected Bitmap doInBackground(String... urls) {
        Bitmap map = null;
        for (String url : urls) {
            map = downloadImage(url);
        }
        return map;     
    }

    //sets bitmap returned by doInBackground
    @Override
    protected void onPostExecute(Bitmap result) {
        ImageView imageView1 = (ImageView) findViewById(R.id.imageView);
        imageView1.setImageBitmap(result);
    }

    //creates Bitmap from InputStream and returns it
    private Bitmap downloadImage(String url) {
        Bitmap bitmap = null;
        InputStream stream = null;
        BitmapFactory.Options bmOptions = new BitmapFactory.Options();
        bmOptions.inSampleSize = 1;

        try {
            stream = getHttpConnection(url);
            bitmap = BitmapFactory.decodeStream(stream, null, bmOptions);
            stream.close();
        } catch (IOException e1) {
            e1.printStackTrace();
        }
        return bitmap;
    }

    //makes httpurlconnection and returns inputstream
    private InputStream getHttpConnection(String urlString) throws IOException {
        InputStream stream = null;
        URL url = new URL(urlString);
        URLConnection connection = url.openConnection();

        try {
            HttpURLConnection httpConnection = (HttpURLConnection) connection;
            httpConnection.setRequestMethod("GET");
            httpConnection.connect();

            if (httpConnection.getResponseCode() == HttpURLConnection.HTTP_OK) {
                stream = httpConnection.getInputStream();
            }
        } catch (Exception ex) {
            ex.printStackTrace();
        }
        return stream;
    }

}
4

1 回答 1

1

例如，您可以将 AsyncTask 的结果作为 List ant 编写类似这样的内容

protected Bitmap doInBackground(String... urls) {
    List<Bitmap> bitmaps = new ArrayList<Bitmap>;
    for (String url : urls) {
        bitmaps.add(downloadImage(url));
    }
    return bitmaps;     
}

protected void onPostExecute(List<Bitmap> result) {
    //...
}

但我真正推荐你的是使用谷歌编写的 Volley 库，它有非常简单和强大的 API（这里是关于它的谷歌 I/O 会话https://developers.google.com/live/shows/474338138和存储库https://android.googlesource.com/platform/frameworks/volley/）

于 2013-06-29T21:57:54.603 回答