Question

我创建了XML解析RSS阅读器，但它只读取最后3个节点（标题，链接和描述）。我想知道哪些行代码制作这个技巧（我的意思是读取最后的节点）。我想从这个rss site读取前三个节点，我应该做什么？ 我是个新人。任何人都可以将答案作为代码发布吗？

public class HandleXML {
private String title = "title";
private String link = "link";
private String description = "description";
private String title1 = "title";
private String link1 = "link";
private String description1 = "description";
private String urlString = null;
private XmlPullParserFactory xmlFactoryObject;
public volatile boolean parsingComplete = true;

public HandleXML(String url){
    this.urlString = url;
}

public String getTitle(){
    return title;
}

public String getLink(){
    return link;
}

public String getDescription(){
    return description;
}

public void parseXMLAndStoreIt(XmlPullParser myParser) {
    int event;
    String text=null;

    try {
        event = myParser.getEventType();

        while (event != XmlPullParser.END_DOCUMENT) {
            String name=myParser.getName();

            switch (event){
                case XmlPullParser.START_TAG:
                    break;

                case XmlPullParser.TEXT:
                    text = myParser.getText();
                    break;

                case XmlPullParser.END_TAG:

                    if(name.equals("title")){
                        title = text;

                    }

                    else if(name.equals("link")){
                        link = text;

                    }

                    else if(name.equals("description")){
                        description = text;

                    }

                    else{
                    }

                    break;
            }

            event = myParser.next();
        }

        parsingComplete = false;
    }

    catch (Exception e) {
        e.printStackTrace();
    }
}

public void fetchXML(){
    Thread thread = new Thread(new Runnable(){
        @Override
        public void run() {

            try {
                URL url = new URL(urlString);
                HttpURLConnection conn = (HttpURLConnection) url.openConnection();

                conn.setReadTimeout(10000 /* milliseconds */);
                conn.setConnectTimeout(15000 /* milliseconds */);
                conn.setRequestMethod("GET");
                conn.setDoInput(true);

                // Starts the query
                conn.connect();
                InputStream stream = conn.getInputStream();

                xmlFactoryObject = XmlPullParserFactory.newInstance();
                XmlPullParser myparser = xmlFactoryObject.newPullParser();

                myparser.setFeature(XmlPullParser.FEATURE_PROCESS_NAMESPACES, false);
                myparser.setInput(stream, null);

                parseXMLAndStoreIt(myparser);
                stream.close();
            }

            catch (Exception e) {
            }
        }
    });
    thread.start();
}
}

Answer 1

这部分代码负责阅读上面提到的元素。

if(name.equals("title")){
    title = text;
}
else if(name.equals("link")){
    link = text;
}
else if(name.equals("description")){
    description = text;
}
else{
 // Write similar conditions for the other tags that you want to parse.
}

Answer 2

您正在使用while循环来处理文档。在该循环中，您的代码将读取所有标题，链接和描述节点。问题是它每次都会覆盖变量，因此你得到的是最后的标题，链接和描述。

如果您只想阅读第一个标题，链接和说明，您可以执行以下操作：

初始化变量如下：

private String title;
private String link;
private String description;

比：

if(name.equals("title") && title != null){
    title = text;
}
else if(name.equals("link") && link != null){
    link = text;
}
else if(name.equals("description") && description != null){
    description = text;
}

编辑（试试这个，警告：我没有测试过它）

public class HandleXML {
    public volatile boolean parsingComplete = true;
    private String title;
    private String link;
    private String description;
    private String urlString = null;
    private XmlPullParserFactory xmlFactoryObject;

    public HandleXML(String url) {
        this.urlString = url;
    }

    public String getTitle() {
        return title;
    }

    public String getLink() {
        return link;
    }

    public String getDescription() {
        return description;
    }

    public void parseXMLAndStoreIt(XmlPullParser myParser) {
        int event;
        String text = null;

        try {
            event = myParser.getEventType();

            while (event != XmlPullParser.END_DOCUMENT) {
                String name = myParser.getName();

                switch (event) {
                    case XmlPullParser.START_TAG:
                        break;

                    case XmlPullParser.TEXT:
                        text = myParser.getText();
                        break;

                    case XmlPullParser.END_TAG:

                        if (name.equals("title") && title != null) {
                            title = text;
                        }

                        else if (name.equals("link") && link != null) {
                            link = text;
                        }

                        else if (name.equals("description") && description != null) {
                            description = text;
                        }

                        break;
                }

                event = myParser.next();
            }

            parsingComplete = false;
        }
        catch (Exception e) {
            e.printStackTrace();
        }
    }

    public void fetchXML() {
        Thread thread = new Thread(new Runnable() {
            @Override
            public void run() {

                try {
                    URL url = new URL(urlString);
                    HttpURLConnection conn = (HttpURLConnection) url.openConnection();

                    conn.setReadTimeout(10000 /* milliseconds */);
                    conn.setConnectTimeout(15000 /* milliseconds */);
                    conn.setRequestMethod("GET");
                    conn.setDoInput(true);

                    // Starts the query
                    conn.connect();
                    InputStream stream = conn.getInputStream();

                    xmlFactoryObject = XmlPullParserFactory.newInstance();
                    XmlPullParser myparser = xmlFactoryObject.newPullParser();

                    myparser.setFeature(XmlPullParser.FEATURE_PROCESS_NAMESPACES, false);
                    myparser.setInput(stream, null);

                    parseXMLAndStoreIt(myparser);
                    stream.close();
                }

                catch (Exception e) {
                    // TODO: 27/07/2017 handle exception
                }
            }
        });
        thread.start();
    }
}

哪行代码使我的RSS阅读器只读取底部标签？

2 个答案: