如何从网络上获取图像 android

Question

我正在使用 RSS 提要处理新闻 android 项目，我的应用现在可以完美地获取新闻的标题、描述和时间，但我无法获取图像，它显示以下错误：

java.lang.NullPointerException: uriString
at android.net.Uri$StringUri.<init>(Uri.java:464)
at android.net.Uri$StringUri.<init>(Uri.java:454)
at android.net.Uri.parse(Uri.java:426)
at com.example.drmzr.myapplication.MyAdapter.onBindViewHolder(MyAdapter.java:36)
at com.example.drmzr.myapplication.MyAdapter.onBindViewHolder(MyAdapter.java:12)
at android.support.v7.widget.RecyclerView$Adapter.onBindViewHolder(RecyclerView.java:5453)                                                                                     at android.support.v7.widget.RecyclerView$Adapter.bindViewHolder(RecyclerView.java:5486)                                                                                     at android.support.v7.widget.RecyclerView$Recycler.getViewForPosition(RecyclerView.java:4723)

这是我的代码（我的Article.java）：

public class Article {

    String title,description,date,link,image;

    public String getTitle() {
        return title;
    }

    public void setTitle(String title) {
        this.title = title;
    }

    public String getImage() {
        return image;
    }

    public void setImage(String image) {
        this.image  = image;
    }


    public String getDescription() {
        return description;
    }

    public void setDescription(String description) {
        this.description = description;
    }

    public String getDate() {
        return date;
    }

    public void setDate(String date) {
        this.date = date;
    }

    public String getLink() {
        return link;
    }

    public void setLink(String link) {
        this.link = link;
    }
}

这是（我的Adapter.java）：

public class MyAdapter extends RecyclerView.Adapter<MyHolder> {

    Context c;
    ArrayList<Article> articles;

    public MyAdapter(Context c, ArrayList<Article> articles) {
        this.c = c;
        this.articles = articles;
    }

    @Override
    public MyHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View v= LayoutInflater.from(c).inflate(R.layout.model,parent,false);
        return new MyHolder(v);
    }

    @Override
    public void onBindViewHolder(MyHolder holder, int position) {

        Article article=articles.get(position);

        holder.titleTxt.setText(article.getTitle());
        holder.descTxt.setText(article.getDescription());
        holder.dateTxt.setText(article.getDate());
        holder.gimage.setImageURI(Uri.parse(article.getImage())) ;

    }

    @Override
    public int getItemCount() {
        return articles.size();
    }
}

这是包含上述错误的行 (holder.gimage.setImageURI(Uri.parse(article.getImage())) ;)

这是（我的RSSParser.java）：

public class RSSParser extends AsyncTask<Void,Void,Boolean> {

    Context c;
    InputStream is;
    RecyclerView rv;

    ProgressDialog pd;
    ArrayList<Article> articles=new ArrayList<>();

    public RSSParser(Context c, InputStream is, RecyclerView rv) {
        this.c = c;
        this.is = is;
        this.rv = rv;
    }
    @Override
    protected void onPreExecute() {
        super.onPreExecute();
        pd=new ProgressDialog(c);
        pd.setTitle("Parse data");
        pd.setMessage("Parsing data...Please wait");
        pd.show();
    }

    @Override
    protected Boolean doInBackground(Void... params) {
        return this.parseRSS();
    }

    @Override
    protected void onPostExecute(Boolean isParsed) {
        super.onPostExecute(isParsed);
        pd.dismiss();
        if(isParsed)
        {
            //Bind
            rv.setAdapter(new MyAdapter(c,articles));

        }else {
            Toast.makeText(c,"Unable To Parse", Toast.LENGTH_SHORT).show();
        }
    }

    private Boolean parseRSS()
    {
        try
        {
            XmlPullParserFactory factory=XmlPullParserFactory.newInstance();
            XmlPullParser parser=factory.newPullParser();

            parser.setInput(is, null);
            int event=parser.getEventType();

            String value=null;

            articles.clear();
            Article article=new Article();

            do {
                String name=parser.getName();

                switch (event)
                {
                    case XmlPullParser.START_TAG:
                        if(name.equals("item"))
                        {
                            article=new Article();
                        }

                        break;

                    case XmlPullParser.TEXT:
                        value=parser.getText();
                        break;

                    case XmlPullParser.END_TAG:

                        if(name.equals("title"))
                        {
                            article.setTitle(value);

                        }
                        else if(name.equals("description"))
                        {
                            article.setDescription(value);

                        }else if(name.equals("pubDate"))
                        {
                            article.setDate(value);

                        }else if(name.equals("date"))
                        {
                            article.setDate(value);

                        }else if(name.equals("image"))
                        {
                            article.setImage(value) ;

                        }

                        if(name.equals("item"))
                        {
                            articles.add(article);
                        }
                        break;
                }

                event=parser.next();

            }while (event != XmlPullParser.END_DOCUMENT);

            return true;

        } catch (XmlPullParserException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
        return false;
    }
}

Answer 1

public String getImage() {
    if (description.startsWith("<a ")) {            
        String cleanUrl = description.substring(description.indexOf("src=") + 5, description.indexOf("/>") - 2);
        return cleanUrl;
    } else {
        return image;
    }
 }

参考答案：

如何从网络上获取图像 android

How to get an image from the web android

android

rss-reader

android-studio