Question

我的Android应用中有一个图片视图，我必须从网址设置一个简单的图像。我尝试了以下代码，但它没有从url设置图像。

try {
        URL url = new URL("https://drive.google.com/...");
        HttpURLConnection connection = (HttpURLConnection)url.openConnection();
        connection.setDoInput(true);
        connection.connect();
        InputStream stream = connection.getInputStream();
        Bitmap teamBmpImage = BitmapFactory.decodeStream(stream);
        teamImgView.setImageBitmap(teamBmpImage);
    }
    catch (Exception e) {

    }

有人可以指导我做到这一点吗？

更新的代码：哪个给出Nullpointer异常

public class AboutActivity extends ActionBarActivity {
    ImageView teamImgView;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_about);

        teamImgView = (ImageView) this.findViewById(R.id.teamImageView);
        new DownloadImageTask(teamImgView).execute("http://docs.oracle.com/javase/tutorial/2d/images/examples/strawberry.jpg");
    }

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

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

        @Override
        protected void onPreExecute() {
            // TODO Auto-generated method stub
            super.onPreExecute();
            //pd.show();
        }

        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;
        }

        @Override
        protected void onPostExecute(Bitmap result) {
            super.onPostExecute(result);
            //pd.dismiss();
            bmImage.setImageBitmap(result);
        }
    }
}

Answer 1

我猜你正在MainThread上执行代码，导致android中的NetworkOnMainThreadException。尝试执行代码异步，如下例所示

new AsyncTask<String, Integer, Bitmap>() {

@Override
protected Bitmap doInBackground(String... params) {
    try {
        URL url = new URL(params[0]);
        return BitmapFactory.decodeStream(url.openConnection().getInputStream());
    } catch (MalformedURLException e) {
        e.printStackTrace();
    } catch (IOException e) {
        e.printStackTrace();
    }
    return null;
}

@Override
protected void onPostExecute(Bitmap bm) {
    ImageView teamImgView = (ImageView) findViewById(R.id.teamImageView);
    teamImgView.setImageBitmap(bm);
}
}.execute("https://drive.google.com/uc?....");

Answer 2

您可以使用Picasso library，here是有关如何执行此操作的详细教程。

这是非常简单的示例用法

Picasso.with(activityContext)
    .load("https://drive.google.com/uc?....")
    .placeholder(R.drawable.image_name)
    .into(imageView);

Answer 3

正如bojan所说，你可以使用Picasso库来处理Android上许多常见的图像加载陷阱。

Picasso.with(context).load("http://myurl/myImage.png").into(imageView);

Picasso

无论如何，也要查看这个威胁：）

How to load an ImageView by URL in Android?

Answer 4

请尝试以下链接： http://www.tutorialsbuzz.com/2014/11/android-volley-url-imageview.html

这将帮助您使用Volley库加载您的图像，它将在网络线程上执行所有网络工作并在主UI线程上设置您的图像。它还有LRUCache部分，如果你愿意，你可以跳过它。

从url设置图像

4 个答案: