Question

我正在尝试将this xml file加载到Android应用中。我把一切都搞定了，但出于某种原因我无法加载id。我一直在谷歌搜索，发现我应该使用parser.getattribute(null,"id"); 但由于某种原因，它不断返回null。我也尝试了parser.getattribute(0);和parser.getattribute(3);，它给了我一个越界异常但是当我通过程序调试并查看我的解析器类时，那么值3总是包含id。

这是一个简单的修复方法，但有没有人知道如何访问每个数据集的ID？获取volume，avg，max，min，stddec，median，percentile的值时，我没有遇到任何问题我还需要id。

这是我的XML文件阅读器类：

public class EveCentralRead {

    static final String KEY_SITE = "type";


    static final String KEY_volume ="volume";
    static final String KEY_avg = "avg";
    static final String KEY_max ="max";
    static final String KEY_min ="min";
    static final String KEY_stddev = "stddev";
    static final String KEY_median = "median";
    static final String KEY_precentile ="percentile";
    static final String KEY_typeID = "type";

    public static List<EveCentralHolder> getEveCentralDataFromXML(Context ctx) {

        // List of StackSites that we will return
        List<EveCentralHolder> stackSites;
        stackSites = new ArrayList<EveCentralHolder>();

        // temp holder for current StackSite while parsing
        EveCentralHolder curStackSite = null;
        // temp holder for current text value while parsing
        String curText = "";

        try {
            // Get our factory and PullParser
            XmlPullParserFactory factory = XmlPullParserFactory.newInstance();
            XmlPullParser xpp = factory.newPullParser();

            // Open up InputStream and Reader of our file.
            File file = new File(MainActivity.MainDir+"/prices.xml");


            InputStream fis = new FileInputStream(file.getPath());

            BufferedReader reader = new BufferedReader(new InputStreamReader(fis));

            // point the parser to our file.
            xpp.setInput(reader);

            // get initial eventType
            int eventType = xpp.getEventType();

            // Loop through pull events until we reach END_DOCUMENT
            boolean getdata = false;
            while (eventType != XmlPullParser.END_DOCUMENT) {
                // Get the current tag
                String tagname = xpp.getName();

                // React to different event types appropriately
                switch (eventType) {
                    case XmlPullParser.START_TAG:
//                        Log.d("hej",tagname);
                       if(tagname.equalsIgnoreCase(KEY_typeID)){
                           curStackSite = new EveCentralHolder();
                           curStackSite.setTypeID(xpp.getAttributeValue(null,"id"));

                         }
                        if(tagname.equalsIgnoreCase("sell")){
                            getdata = true;
                            curStackSite = new EveCentralHolder();
                        }

                        break;

                    case XmlPullParser.TEXT:
                        curText  = xpp.getText();
                        if(getdata) {
                            curText = xpp.getText();
                        //    Log.d("hej", "" + xpp.getText());
                        }
                        break;

                    case XmlPullParser.END_TAG:
//                        Log.d("hej",tagname);
                        if (tagname.equalsIgnoreCase("sell")) {
                            getdata = false;

                        }
                        if (tagname.equalsIgnoreCase(KEY_SITE)) {

                            stackSites.add(curStackSite);
                        }
                        if(getdata){
                            if (tagname.equalsIgnoreCase(KEY_volume)) {

                                curStackSite.setTypeID(xpp.getAttributeValue(null,"id"));
                                curStackSite.setVolume(curText);
                            } else if (tagname.equalsIgnoreCase(KEY_avg)) {

                                curStackSite.setAvg(curText);
                            } else if (tagname.equalsIgnoreCase(KEY_max)) {

                                curStackSite.setMax(curText);
                            } else if (tagname.equalsIgnoreCase(KEY_min)) {

                                curStackSite.setMin(curText);
                            }else if (tagname.equalsIgnoreCase(KEY_stddev)) {

                                curStackSite.setStddev(curText);
                            }else if (tagname.equalsIgnoreCase(KEY_precentile)) {

                                curStackSite.setPercentile(curText);
                            }
                        }


                        break;

                    default:
                        break;
                }
                //move on to next iteration
                eventType = xpp.next();
            }
        } catch (Exception e) {
            e.printStackTrace();
        }

        // return the populated list.
        return stackSites;
    }
}

这是我的XML文件：

<evec_api version="2.0" method="marketstat_xml">
<marketstat>
<type id="34">
<buy>
<volume>46278278835</volume>
<avg>6.02</avg>
<max>6.44</max>
<min>2.96</min>
<stddev>0.62</stddev>
<median>6.22</median>
<percentile>6.43</percentile>
</buy>
<sell>
<volume>12569824799</volume>
<avg>6.64</avg>
<max>8.85</max>
<min>6.47</min>
<stddev>0.46</stddev>
<median>6.53</median>
<percentile>6.49</percentile>
</sell>
<all>
<volume>58848103634</volume>
<avg>6.15</avg>
<max>8.85</max>
<min>2.96</min>
<stddev>0.75</stddev>
<median>6.34</median>
<percentile>4.60</percentile>
</all>
</type>
<type id="35">
<buy>
<volume>3893959033</volume>
<avg>11.40</avg>
<max>11.90</max>
<min>7.05</min>
<stddev>1.01</stddev>
<median>11.71</median>
<percentile>11.89</percentile>
</buy>
<sell>
<volume>9116786204</volume>
<avg>13.45</avg>
<max>17.41</max>
<min>11.98</min>
<stddev>0.96</stddev>
<median>12.30</median>
<percentile>12.01</percentile>
</sell>
<all>
<volume>13010745237</volume>
<avg>12.83</avg>
<max>17.41</max>
<min>7.05</min>
<stddev>1.10</stddev>
<median>12.09</median>
<percentile>10.42</percentile>
</all>
</type>
<type id="36">
<buy>
<volume>1287271345</volume>
<avg>44.36</avg>
<max>47.85</max>
<min>23.10</min>
<stddev>5.34</stddev>
<median>47.06</median>
<percentile>47.80</percentile>
</buy>
<sell>
<volume>3753914760</volume>
<avg>56.10</avg>
<max>66.51</max>
<min>48.87</min>
<stddev>4.97</stddev>
<median>54.00</median>
<percentile>49.09</percentile>
</sell>
<all>
<volume>5041186105</volume>
<avg>53.10</avg>
<max>66.51</max>
<min>23.10</min>
<stddev>5.86</stddev>
<median>50.74</median>
<percentile>37.13</percentile>
</all>
</type>
<type id="37">
<buy>
<volume>260386951</volume>
<avg>122.15</avg>
<max>130.02</max>
<min>73.50</min>
<stddev>14.82</stddev>
<median>128.77</median>
<percentile>130.01</percentile>
</buy>
<sell>
<volume>721404372</volume>
<avg>149.07</avg>
<max>215.00</max>
<min>132.00</min>
<stddev>16.06</stddev>
<median>141.37</median>
<percentile>132.75</percentile>
</sell>
<all>
<volume>981791323</volume>
<avg>141.93</avg>
<max>215.00</max>
<min>73.50</min>
<stddev>17.79</stddev>
<median>140.00</median>
<percentile>98.15</percentile>
</all>
</type>
<type id="38">
<buy>
<volume>67805138</volume>
<avg>701.02</avg>
<max>726.00</max>
<min>436.11</min>
<stddev>92.94</stddev>
<median>715.30</median>
<percentile>722.45</percentile>
</buy>
<sell>
<volume>254352194</volume>
<avg>792.02</avg>
<max>1227.41</max>
<min>728.95</min>
<stddev>78.64</stddev>
<median>757.27</median>
<percentile>729.99</percentile>
</sell>
<all>
<volume>322157332</volume>
<avg>772.86</avg>
<max>1227.41</max>
<min>436.11</min>
<stddev>86.94</stddev>
<median>740.90</median>
<percentile>644.00</percentile>
</all>
</type>
<type id="39">
<buy>
<volume>27385528</volume>
<avg>594.54</avg>
<max>654.94</max>
<min>401.00</min>
<stddev>77.95</stddev>
<median>580.03</median>
<percentile>654.91</percentile>
</buy>
<sell>
<volume>308516889</volume>
<avg>973.62</avg>
<max>1599.92</max>
<min>681.96</min>
<stddev>181.14</stddev>
<median>779.83</median>
<percentile>682.79</percentile>
</sell>
<all>
<volume>338902417</volume>
<avg>934.45</avg>
<max>1599.92</max>
<min>7.30</min>
<stddev>218.01</stddev>
<median>760.00</median>
<percentile>456.32</percentile>
</all>
</type>
<type id="40">
<buy>
<volume>14578614</volume>
<avg>1090.66</avg>
<max>1481.00</max>
<min>500.00</min>
<stddev>340.57</stddev>
<median>1387.51</median>
<percentile>1480.15</percentile>
</buy>
<sell>
<volume>170054750</volume>
<avg>2496.43</avg>
<max>3899.91</max>
<min>1498.99</min>
<stddev>689.33</stddev>
<median>2222.44</median>
<percentile>1514.55</percentile>
</sell>
<all>
<volume>194933364</volume>
<avg>2259.76</avg>
<max>3899.91</max>
<min>5.00</min>
<stddev>733.71</stddev>
<median>1950.92</median>
<percentile>6.94</percentile>
</all>
</type>
</marketstat>
</evec_api>

Answer 1

这是你的问题，我认为这只是一个复制粘贴错误：

    ...
    if (tagname.equalsIgnoreCase(KEY_volume)) {
         curStackSite.setTypeID(xpp.getAttributeValue(null,"id")); <-- REMOVE THIS
         curStackSite.setVolume(curText);
    } else if (tagname.equalsIgnoreCase(KEY_avg)) {
    ...

您在END_TAG上调用了getAttributeValue（），并且该属性不存在。因此，对于curStackSite ID，您的最终结果将为NULL。

Android XML pull解析器无法获取属性

1 个答案: