将web图像加载到Android时出现黑屏

当从网络上加载图像时，我会看到一个黑屏

我从网络上获取页面，将其放入画布，然后将其设置为ImageView

现在，当我加载它时，我会在图像中看到一个黑屏

活动代码：

public class ImageActivity extends Activity {

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        ImageView i = (ImageView) findViewById(R.id.imageView1);

        try {
            String url = "http://www.rotoworld.com/images/headshots/NBA/1372.jpg";
            Drawable image = ImageOperations(this, url);
            i.setImageDrawable(image);
        } catch (Exception ex) {
            ex.printStackTrace();
        }
        i.setMinimumWidth(22);
        i.setMinimumHeight(22);

        i.setMaxWidth(22);
        i.setMaxHeight(22);

    }

    private Drawable ImageOperations(Context ctx, String url) {
        try {
            InputStream is = (InputStream) this.fetch(url);
            Drawable d = Drawable.createFromStream(is, "src");
            return d;
        } catch (MalformedURLException e) {
            return null;
        } catch (IOException e) {
            return null;
        }
    }

    public Object fetch(String address) throws MalformedURLException, IOException {

        URL url = new URL(address);
        Object content = url.getContent();
        return content;
    }

}

XML:

试试这个

try 
            {
                URL feedImage = new URL(imageUrl);
                HttpURLConnection conn= (HttpURLConnection)feedImage.openConnection();
                InputStream is = conn.getInputStream();
                Bitmap img = BitmapFactory.decodeStream(is);
                i.setImageBitmap(img);



            } 
            catch (MalformedURLException e) 
            {
                e.printStackTrace();
            } 
            catch (IOException e) 
            {
                e.printStackTrace();
            }

---

在android中打开活动时出现黑屏的常见原因是创建活动需要很长时间

---

我认为您应该将图像的获取放在异步任务或类似任务中。

试试这个。它可能会对您有所帮助

 public void onCreate(Bundle savedInstanceState) 
        {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.main);
ImageView imageView= (ImageView)findViewById(R.id.imageView1);
            new loadImageTask().execute("http://www.rotoworld.com/images/headshots/NBA/1372.jpg");
        }  

      public static Drawable LoadImageFromWeb(String url)
            {
                try 
                {
                    InputStream is = (InputStream) new URL(url).getContent();
                    Drawable d = Drawable.createFromStream(is, "");
                    return d;

                } 
                catch (Exception e) 
                {
                    return null;
                }


            }

            public class loadImageTask extends AsyncTask<String, Void, Void>
            {

                Drawable imgLoad;

                @Override
                protected void onPreExecute() 
                {
                    super.onPreExecute();
                }

                @Override
                protected Void doInBackground(String... params) 
                {
                    imgLoad = LoadImageFromWeb(params[0]);

                    return null;
                }

                @Override
                protected void onPostExecute(Void result) 
                {
                    super.onPostExecute(result);
                                imageView.setVisibility(View.VISIBLE);

                }

            }

public void onCreate（Bundle savedInstanceState）
{
super.onCreate（savedInstanceState）；
setContentView（R.layout.main）；
ImageView ImageView=（ImageView）findViewById（R.id.imageView1）；
新建loadImageTask（）。执行（“http://www.rotoworld.com/images/headshots/NBA/1372.jpg");
}  
公共静态可绘制LoadImageFromWeb（字符串url）
{
尝试
{
InputStream为=（InputStream）新URL（URL）.getContent（）；
Drawable d=Drawable.createFromStream（为“”）；
返回d；
} 
捕获（例外e）
{
返回null；
}
}
公共类loadImageTask扩展了AsyncTask
{
可抽出式imgLoad；
@凌驾
受保护的void onPreExecute（）
{
super.onPreExecute（）；
}
@凌驾
受保护的Void doInBackground（字符串…参数）
{
imgLoad=LoadImageFromWeb（参数[0]）；
返回null；
}
@凌驾
受保护的void onPostExecute（void结果）
{
super.onPostExecute（结果）；
设置可见性（View.VISIBLE）；
}
}

下面是它最后是如何做到的

需要使用Asynctask时，我还将html发送到web页面，以便从web检索实际的jpg

String namesTr1 = pb;
    System.out.println(">>>>NAMEBEFORE"+pb);
    String nameminus1 = namesTr1.replace(' ','-' );
    System.out.println(">>>>NAMEAFTERREPLACe"+nameminus1);
    PGCalc pgcalc = new PGCalc();
    String playerhtml="http://www.rotoworld.com/player/nba/1860/"+nameminus1+"/1";
    System.out.println(">>>>Before JSOUP"+playerhtml);

    //Getting html image from Jspoup
    try {
        imagehtml = pgcalc.getimage(playerhtml);
        System.out.println(">>>>>>jsoupimagehtml"+imagehtml);
    } catch (IOException e1) {
        // TODO Auto-generated catch block
        e1.printStackTrace();
    }
    //Setting image in Imageview
    try 
    {
        URL feedImage = new URL(imagehtml);
        HttpURLConnection conn= (HttpURLConnection)feedImage.openConnection();
        InputStream is = conn.getInputStream();
        Bitmap img;
        return img = BitmapFactory.decodeStream(is);
        //imageview1.setImageBitmap(img);

    } 
    catch (MalformedURLException e) 
    {
        e.printStackTrace();
    } 
    catch (IOException e) 
    {
        e.printStackTrace();
    }
    return null;
}

---

谢谢你的快速回复！！未工作我正在获取默认设置的图标。我在我的问题中添加了XML，谢谢您的时间！！谢谢从未听说过异步任务。有好的例子吗？@user1163234文档通常都很好。的文档包括一个如何使用它的示例。谢谢KKC！尝试运行并获得“E/AndroidRuntime（855）：java.lang.RuntimeException:无法实例化活动组件信息{com.image/com.image.ImageActivity}:java.lang.NullPointerException”

String namesTr1 = pb;
    System.out.println(">>>>NAMEBEFORE"+pb);
    String nameminus1 = namesTr1.replace(' ','-' );
    System.out.println(">>>>NAMEAFTERREPLACe"+nameminus1);
    PGCalc pgcalc = new PGCalc();
    String playerhtml="http://www.rotoworld.com/player/nba/1860/"+nameminus1+"/1";
    System.out.println(">>>>Before JSOUP"+playerhtml);

    //Getting html image from Jspoup
    try {
        imagehtml = pgcalc.getimage(playerhtml);
        System.out.println(">>>>>>jsoupimagehtml"+imagehtml);
    } catch (IOException e1) {
        // TODO Auto-generated catch block
        e1.printStackTrace();
    }
    //Setting image in Imageview
    try 
    {
        URL feedImage = new URL(imagehtml);
        HttpURLConnection conn= (HttpURLConnection)feedImage.openConnection();
        InputStream is = conn.getInputStream();
        Bitmap img;
        return img = BitmapFactory.decodeStream(is);
        //imageview1.setImageBitmap(img);

    } 
    catch (MalformedURLException e) 
    {
        e.printStackTrace();
    } 
    catch (IOException e) 
    {
        e.printStackTrace();
    }
    return null;
}