Question

我试图从网址加载图片，但它无法正常工作。发生了两个不同的错误。当我放置一个以www开头的URL时，应用程序没有关闭，但既没有加载图像，只显示一个空白区域。但是，当URL以http：//开头时，应用程序将关闭。

我用来加载图片的代码是下一个：

public class ThreadAdapter extends BaseAdapter {
    ArrayList<Threadx> data;
    LayoutInflater inflater;
    public ThreadAdapter(Context context, ArrayList<Threadx> data) {
        super();
        inflater = LayoutInflater.from(context);
        this.data = data;
    }

    @Override
    public int getCount() {
        return data.size();
    }

    @Override
    public Object getItem(int position) {
        return data.get(position);
    }

    @Override
    public long getItemId(int position) {
        return position;
    }
    private static class ViewHolder {
        TextView tvSubject;
        TextView tvContent;
        ImageView imagen;
    }
    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        ViewHolder viewHolder = null;
        if (convertView == null) {
            convertView = inflater.inflate(R.layout.list_row_thread, null);
            viewHolder = new ViewHolder();
            viewHolder.tvSubject = (TextView) convertView
                    .findViewById(R.id.tvSubject);
            viewHolder.tvContent = (TextView) convertView
                    .findViewById(R.id.tvContent);
            viewHolder.imagen = (ImageView) convertView
                    .findViewById(R.id.image);
            convertView.setTag(viewHolder);
        } else {
            viewHolder = (ViewHolder) convertView.getTag();
        }
        String subject = data.get(position).getSubject();
        String content = data.get(position).getContent();
        String imagen = data.get(position).getImagen();
        viewHolder.tvSubject.setText(subject);
        viewHolder.tvContent.setText(content);
        Bitmap bitmap = null;
        HttpURLConnection urlConnection = null;
        try {
            URL url = new URL("www.matrallune.com/images/imagen_corporativa.jpg");
            //bitmap = BitmapFactory.decodeStream((InputStream)new URL("www.matrallune.com/images/imagen_corporativa.jpg").getContent());
            //bitmap = BitmapFactory.decodeStream(url.openConnection().getInputStream());
            urlConnection = (HttpURLConnection) url.openConnection();
            InputStream is = urlConnection.getInputStream();
            bitmap = BitmapFactory.decodeStream(is);
        } catch (IOException e) {
            e.printStackTrace();
        }
        viewHolder.imagen.setImageBitmap(bitmap);
        return convertView;
    }
}

我尝试了不同的方法，你可以在代码中看到，但所有方法都有相同的问题。我的目的是从变量“imagen”中捕获URL。

Answer 1

使用此问题＆gt;＆gt; Loading Bitmap to ImageView from URL in android

public class DownloadImageTask extends AsyncTask<String, Void, Bitmap> {
    private ImageView imageView;
    private Bitmap image;

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

    protected Bitmap doInBackground(String... urls) {
        String urldisplay = urls[0];
        try {
            InputStream in = new java.net.URL(urldisplay).openStream();
            image = BitmapFactory.decodeStream(in);
        } catch (Exception e) {
            image = null;
        }
        return image;
    }

    @SuppressLint("NewApi")
    protected void onPostExecute(Bitmap result) {
        if (result != null) {
            imageView.setImageBitmap(result);
        }
    }
}

现在请致电您的代码：

public View getView(int position, View convertView, ViewGroup parent) {
    ViewHolder viewHolder = null;
    if (convertView == null) {
        conv`enter code here`ertView = inflater.inflate(R.layout.list_row_thread, null);
        viewHolder = new ViewHolder();
        viewHolder.tvSubject = (TextView) convertView
                .findViewById(R.id.tvSubject);
        viewHolder.tvContent = (TextView) convertView
                .findViewById(R.id.tvContent);
        viewHolder.imagen = (ImageView) convertView
                .findViewById(R.id.image);
        convertView.setTag(viewHolder);
    } else {
        viewHolder = (ViewHolder) convertView.getTag();
    }
    String subject = data.get(position).getSubject();
    String content = data.get(position).getContent();
    String imagen = data.get(position).getImagen();
    viewHolder.tvSubject.setText(subject);
    viewHolder.tvContent.setText(content);
    new DownloadImageTask(viewHolder.imagen).execute("www.matrallune.com/images/imagen_corporativa.jpg");
    return convertView;
}

Answer 2

我猜你错过了urlConnection.connect();
将您的代码更改为：

    try {
            URL url = new URL("www.matrallune.com/images/imagen_corporativa.jpg");
            urlConnection = (HttpURLConnection) url.openConnection();
            urlConnection.connect();
            InputStream is = urlConnection.getInputStream();
            bitmap = BitmapFactory.decodeStream(is);
        } catch (IOException e) {
            e.printStackTrace();
        }

不确定。

并且如评论中所建议的那样，使用像Picasso这样的库是明智的。这很容易。只需将代码集成并更改为：

Picasso.with(context).load(url).into(imgView);

更新：尝试包括 connection.setDoInput(true); setUseCaches(false)。

Answer 3

通过Picasso加载图像就像说123，你已经完成了

Picasso
.with(context) //Context 
.load("http://i.imgur.com/DvpvklR.png") //Can be Url,File..
.into(imageView)//The ImageView;

这只是正常加载，您可以在Documentation

中找到更多选项

根据您的代码

Picasso
    .with(context) //Context 
    .load("http://matrallune.com/images/imagen_corporativa.jpg") //Can be Url,File..
    .into(viewHolder.imagen)//The ImageView;

您只想用上面的代码替换图像加载代码。

您的最终适配器

public class ThreadAdapter extends BaseAdapter {
    ArrayList<Threadx> data;
    LayoutInflater inflater;
    private Context mContext;

    public ThreadAdapter(Context mContext, ArrayList<Threadx> data) {
        super();
        inflater = LayoutInflater.from(context);
        this.data = data;
        this.mContext = mContext;
    }

    @Override
    public int getCount() {
        return data.size();
    }

    @Override
    public Object getItem(int position) {
        return data.get(position);
    }

    @Override
    public long getItemId(int position) {
        return position;
    }

    private static class ViewHolder {
        TextView tvSubject;
        TextView tvContent;
        ImageView imagen;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        ViewHolder viewHolder = null;
        if (convertView == null) {
            convertView = inflater.inflate(R.layout.list_row_thread, null);
            viewHolder = new ViewHolder();
            viewHolder.tvSubject = (TextView) convertView
                    .findViewById(R.id.tvSubject);
            viewHolder.tvContent = (TextView) convertView
                    .findViewById(R.id.tvContent);
            viewHolder.imagen = (ImageView) convertView
                    .findViewById(R.id.image);
            convertView.setTag(viewHolder);
        } else {
            viewHolder = (ViewHolder) convertView.getTag();
        }
        String subject = data.get(position).getSubject();
        String content = data.get(position).getContent();
        String imagen = data.get(position).getImagen();
        viewHolder.tvSubject.setText(subject);
        viewHolder.tvContent.setText(content);

        //Loading image
        Picasso
        .with(mContext) //Context 
        .load("http://matrallune.com/images/imagen_corporativa.jpg") //Can be Url,File..
        .into(viewHolder.imagen)//The ImageView;


        return convertView;
    }
}

如果要从Fragment初始化适配器，则应将上下文作为getActivity（）传递，或者也可以在片段的onAttach()中初始化它。

如果要从活动初始化适配器。你只想通过this。

<强>初始化

来自活动

ThreadAdapter tAdapter = new ThreadAdapter(this,data);

来自Fragement的

ThreadAdapter tAdapter = new ThreadAdapter(getActivity(),data);

Answer 4

使用Picaso Lib http://square.github.io/picasso/致电Picasso.with(context).load("http://imageUrl/image.png").into(imageView);

无法从网址

4 个答案: