在 android xmlPullParserException 中使用 xmlPullParser 解析本地 xml 文件时出现问题
troubles parsing local xml file with xmlPullParser in android xmlPullParserException
大家好，我遇到了 xmlPullParser 的问题。我正在尝试按照 google 开发人员教程稍作修改。我正在从原始资源文件中读取 xml 文件。该文件名为 employee.xml
它看起来像下面。
<?xml version="1.0" encoding="utf-8"?>
<employees>
<employee>
<id>1</id>
<firstName>John</firstName>
<lastName>Doe</lastName>
<title>CEO</title>
<city>San Francisco, CA</city>
<managerId>0</managerId>
<department>Corporate</department>
<officePhone>123-456-0001</officePhone>
<mobilePhone>987-654-1234</mobilePhone>
<email>John@mail.com</email>
<picture>placeholder.jpg</picture>
</employee>
<employee>
<id>2</id>
<firstName>Barack</firstName>
<lastName>Obama</lastName>
<title>President</title>
<city>Washington DC</city>
<department>Corporate</department>
<managerId>0</managerId>
<officePhone>123-456-0002</officePhone>
<mobilePhone>781-000-0002</mobilePhone>
<email>Barack@mail.com</email>
<picture>barack_obama.jpg</picture>
</employee>
<employee>
<id>3</id>
<firstName>Joe</firstName>
<lastName>Biden</lastName>
<title>VP</title>
<city>Washington DC</city>
<managerId>2</managerId>
<department>Corporate</department>
<officePhone>123-456-0003</officePhone>
<mobilePhone>987-654-1234</mobilePhone>
<email>Joe@mail.com</email>
<picture>joe_biden.jpg</picture>
</employee>
<employee>
<id>4</id>
<firstName>Hillary</firstName>
<lastName>Clinton</lastName>
<title>Secretary of State</title>
<city>Washington DC</city>
<managerId>2</managerId>
<department>Corporate</department>
<officePhone>123-456-0004</officePhone>
<mobilePhone>987-654-1234</mobilePhone>
<email>Hillary@mail.com</email>
<picture>hillary_clinton.jpg</picture>
</employee>
</employees>
但是当我尝试在我的代码中传递它时，我遇到了异常。
下面是我解析这个 xml 文件的代码，我从主 activity
调用
public List<Employee> parse(Context cont) throws XmlPullParserException, IOException
{
XmlPullParserFactory factory = XmlPullParserFactory.newInstance();
factory.setNamespaceAware(true);
parser = factory.newPullParser();
InputStream stream = cont.getResources().openRawResource(R.raw.employee);
parser.setFeature(XmlPullParser.FEATURE_PROCESS_NAMESPACES, false);
parser.setInput(stream, null);
parser.next();
return readFeed(parser);
}
private List<Employee> readFeed(XmlPullParser parser) throws XmlPullParserException, IOException
{
employeelist = new ArrayList<>();
Log.d("current tag: ", parser.getName());
Log.d("TAG", "The event type is: " + parser.getEventType());
parser.require(XmlPullParser.START_TAG, parser.getName().toString(), "employees");
Log.d("current tag : ", parser.getName());
while(parser.next() != XmlPullParser.END_TAG)
{
if (parser.getEventType() != XmlPullParser.START_TAG) {
continue;
}
String name = parser.getName();
if(name.equals("employee"))
{
employeelist.add(readEntry(parser));
}
else
{
//skip unwanted entries!!
skip(parser);
}
}
return employeelist;
}
当我在 readFeed() 方法中调用 "parser.require()" 时抛出 xmlpullparserexception。我不确定为什么，因为它似乎找到了正确的 "employees" 标签！！正如我在调用 readFeed 之前调用 parser.next() 一样！！
这是堆栈跟踪。
11-18 08:37:51.476 4660-4676/? D/current tag:: employees
11-18 08:37:51.476 4660-4676/? D/TAG: The event type is: 2
11-18 08:37:51.477 4660-4676/? W/System.err: org.xmlpull.v1.XmlPullParserException: expected: START_TAG {employees}employees (position:START_TAG <employees>@2:12 in java.io.InputStreamReader@41f7ff40)
11-18 08:37:51.477 4660-4676/? W/System.err: at org.kxml2.io.KXmlParser.require(KXmlParser.java:2056)
11-18 08:37:51.477 4660-4676/? W/System.err: at com.example.eoin_a.xmlparserexample.EmployeeXmlParser.readFeed(EmployeeXmlParser.java:57)
11-18 08:37:51.477 4660-4676/? W/System.err: at com.example.eoin_a.xmlparserexample.EmployeeXmlParser.parse(EmployeeXmlParser.java:48)
11-18 08:37:51.477 4660-4676/? W/System.err: at com.example.eoin_a.xmlparserexample.MainActivity.run(MainActivity.java:55)
11-18 08:37:51.477 4660-4676/? W/System.err: at java.lang.Thread.run(Thread.java:841)
11-18 08:37:51.479 4660-4660/? D/AndroidRuntime: Shutting down VM
11-18 08:37:51.479 4660-4660/? W/dalvikvm: threadid=1: thread exiting with uncaught exception (group=0x41670d40)
11-18 08:37:51.481 4660-4660/? E/AndroidRuntime: FATAL EXCEPTION: main
11-18 08:37:51.481 4660-4660/? E/AndroidRuntime: Process: com.example.eoin_a.xmlparserexample, PID: 4660
11-18 08:37:51.481 4660-4660/? E/AndroidRuntime: java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.eoin_a.xmlparserexample/com.example.eoin_a.xmlparserexample.MainActivity}: java.lang.NullPointerException
11-18 08:37:51.481 4660-4660/? E/AndroidRuntime: at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2198)
11-18 08:37:51.481 4660-4660/? E/AndroidRuntime: at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2257)
11-18 08:37:51.481 4660-4660/? E/AndroidRuntime: at android.app.ActivityThread.access0(ActivityThread.java:139)
11-18 08:37:51.481 4660-4660/? E/AndroidRuntime: at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1210)
11-18 08:37:51.481 4660-4660/? E/AndroidRuntime: at android.os.Handler.dispatchMessage(Handler.java:102)
11-18 08:37:51.481 4660-4660/? E/AndroidRuntime: at android.os.Looper.loop(Looper.java:136)
11-18 08:37:51.481 4660-4660/? E/AndroidRuntime: at android.app.ActivityThread.main(ActivityThread.java:5086)
11-18 08:37:51.481 4660-4660/? E/AndroidRuntime: at java.lang.reflect.Method.invokeNative(Native Method)
11-18 08:37:51.481 4660-4660/? E/AndroidRuntime: at java.lang.reflect.Method.invoke(Method.java:515)
11-18 08:37:51.481 4660-4660/? E/AndroidRuntime: at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:785)
11-18 08:37:51.481 4660-4660/? E/AndroidRuntime: at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:601)
11-18 08:37:51.481 4660-4660/? E/AndroidRuntime: at dalvik.system.NativeStart.main(Native Method)
11-18 08:37:51.481 4660-4660/? E/AndroidRuntime: Caused by: java.lang.NullPointerException
11-18 08:37:51.481 4660-4660/? E/AndroidRuntime: at com.example.eoin_a.xmlparserexample.MainActivity.onCreate(MainActivity.java:38)
我还包括了第一条调试日志消息，因为我认为它看起来很不寻常。它输出 2 个冒号而不是 1 个。我不知道为什么！如果有人能帮助我理解这个异常，那么在我不理解下面的异常或导致它的原因的那一刻会很棒。谢谢！
org.xmlpull.v1.XmlPullParserException: expected: START_TAG {employees}employees (position:START_TAG <employees>@2:12 in java.io.InputStreamReader@41f7ff40)
Here's a link to the parser.require() documentation.
public abstract void require (int type, String namespace, String name)
这里中间的一个是我认为导致你的问题的原因。 parser.require 正在寻找正确的标签类型、正确的命名空间和正确的标签名称；如果其中之一不匹配，它将抛出异常。
在您的例子中，对于中间参数，您使用 getName 获取当前标签的名称 ("employees") 并要求 parser.require() 检查是否匹配 命名空间。 Namespace 与标签名称不同，因此会抛出异常。
使用parser.require()时不需要自己使用getName，只需要传入你期望的名称即可。
根据文档 "null will match any namespace and any name"。如果你正在做的是检查你有 <employees> 开始标签，那么你可以通过使用 null 作为命名空间参数来忽略命名空间部分：
parser.require(XmlPullParser.START_TAG, null, "employees");
这将检查它是一个开始标签，并且标签名称是 "employees"。
大家好，我遇到了 xmlPullParser 的问题。我正在尝试按照 google 开发人员教程稍作修改。我正在从原始资源文件中读取 xml 文件。该文件名为 employee.xml
它看起来像下面。
<?xml version="1.0" encoding="utf-8"?>
<employees>
<employee>
<id>1</id>
<firstName>John</firstName>
<lastName>Doe</lastName>
<title>CEO</title>
<city>San Francisco, CA</city>
<managerId>0</managerId>
<department>Corporate</department>
<officePhone>123-456-0001</officePhone>
<mobilePhone>987-654-1234</mobilePhone>
<email>John@mail.com</email>
<picture>placeholder.jpg</picture>
</employee>
<employee>
<id>2</id>
<firstName>Barack</firstName>
<lastName>Obama</lastName>
<title>President</title>
<city>Washington DC</city>
<department>Corporate</department>
<managerId>0</managerId>
<officePhone>123-456-0002</officePhone>
<mobilePhone>781-000-0002</mobilePhone>
<email>Barack@mail.com</email>
<picture>barack_obama.jpg</picture>
</employee>
<employee>
<id>3</id>
<firstName>Joe</firstName>
<lastName>Biden</lastName>
<title>VP</title>
<city>Washington DC</city>
<managerId>2</managerId>
<department>Corporate</department>
<officePhone>123-456-0003</officePhone>
<mobilePhone>987-654-1234</mobilePhone>
<email>Joe@mail.com</email>
<picture>joe_biden.jpg</picture>
</employee>
<employee>
<id>4</id>
<firstName>Hillary</firstName>
<lastName>Clinton</lastName>
<title>Secretary of State</title>
<city>Washington DC</city>
<managerId>2</managerId>
<department>Corporate</department>
<officePhone>123-456-0004</officePhone>
<mobilePhone>987-654-1234</mobilePhone>
<email>Hillary@mail.com</email>
<picture>hillary_clinton.jpg</picture>
</employee>
</employees>
但是当我尝试在我的代码中传递它时，我遇到了异常。 下面是我解析这个 xml 文件的代码，我从主 activity
调用 public List<Employee> parse(Context cont) throws XmlPullParserException, IOException
{
XmlPullParserFactory factory = XmlPullParserFactory.newInstance();
factory.setNamespaceAware(true);
parser = factory.newPullParser();
InputStream stream = cont.getResources().openRawResource(R.raw.employee);
parser.setFeature(XmlPullParser.FEATURE_PROCESS_NAMESPACES, false);
parser.setInput(stream, null);
parser.next();
return readFeed(parser);
}
private List<Employee> readFeed(XmlPullParser parser) throws XmlPullParserException, IOException
{
employeelist = new ArrayList<>();
Log.d("current tag: ", parser.getName());
Log.d("TAG", "The event type is: " + parser.getEventType());
parser.require(XmlPullParser.START_TAG, parser.getName().toString(), "employees");
Log.d("current tag : ", parser.getName());
while(parser.next() != XmlPullParser.END_TAG)
{
if (parser.getEventType() != XmlPullParser.START_TAG) {
continue;
}
String name = parser.getName();
if(name.equals("employee"))
{
employeelist.add(readEntry(parser));
}
else
{
//skip unwanted entries!!
skip(parser);
}
}
return employeelist;
}
当我在 readFeed() 方法中调用 "parser.require()" 时抛出 xmlpullparserexception。我不确定为什么，因为它似乎找到了正确的 "employees" 标签！！正如我在调用 readFeed 之前调用 parser.next() 一样！！ 这是堆栈跟踪。
11-18 08:37:51.476 4660-4676/? D/current tag:: employees
11-18 08:37:51.476 4660-4676/? D/TAG: The event type is: 2
11-18 08:37:51.477 4660-4676/? W/System.err: org.xmlpull.v1.XmlPullParserException: expected: START_TAG {employees}employees (position:START_TAG <employees>@2:12 in java.io.InputStreamReader@41f7ff40)
11-18 08:37:51.477 4660-4676/? W/System.err: at org.kxml2.io.KXmlParser.require(KXmlParser.java:2056)
11-18 08:37:51.477 4660-4676/? W/System.err: at com.example.eoin_a.xmlparserexample.EmployeeXmlParser.readFeed(EmployeeXmlParser.java:57)
11-18 08:37:51.477 4660-4676/? W/System.err: at com.example.eoin_a.xmlparserexample.EmployeeXmlParser.parse(EmployeeXmlParser.java:48)
11-18 08:37:51.477 4660-4676/? W/System.err: at com.example.eoin_a.xmlparserexample.MainActivity.run(MainActivity.java:55)
11-18 08:37:51.477 4660-4676/? W/System.err: at java.lang.Thread.run(Thread.java:841)
11-18 08:37:51.479 4660-4660/? D/AndroidRuntime: Shutting down VM
11-18 08:37:51.479 4660-4660/? W/dalvikvm: threadid=1: thread exiting with uncaught exception (group=0x41670d40)
11-18 08:37:51.481 4660-4660/? E/AndroidRuntime: FATAL EXCEPTION: main
11-18 08:37:51.481 4660-4660/? E/AndroidRuntime: Process: com.example.eoin_a.xmlparserexample, PID: 4660
11-18 08:37:51.481 4660-4660/? E/AndroidRuntime: java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.eoin_a.xmlparserexample/com.example.eoin_a.xmlparserexample.MainActivity}: java.lang.NullPointerException
11-18 08:37:51.481 4660-4660/? E/AndroidRuntime: at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2198)
11-18 08:37:51.481 4660-4660/? E/AndroidRuntime: at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2257)
11-18 08:37:51.481 4660-4660/? E/AndroidRuntime: at android.app.ActivityThread.access0(ActivityThread.java:139)
11-18 08:37:51.481 4660-4660/? E/AndroidRuntime: at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1210)
11-18 08:37:51.481 4660-4660/? E/AndroidRuntime: at android.os.Handler.dispatchMessage(Handler.java:102)
11-18 08:37:51.481 4660-4660/? E/AndroidRuntime: at android.os.Looper.loop(Looper.java:136)
11-18 08:37:51.481 4660-4660/? E/AndroidRuntime: at android.app.ActivityThread.main(ActivityThread.java:5086)
11-18 08:37:51.481 4660-4660/? E/AndroidRuntime: at java.lang.reflect.Method.invokeNative(Native Method)
11-18 08:37:51.481 4660-4660/? E/AndroidRuntime: at java.lang.reflect.Method.invoke(Method.java:515)
11-18 08:37:51.481 4660-4660/? E/AndroidRuntime: at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:785)
11-18 08:37:51.481 4660-4660/? E/AndroidRuntime: at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:601)
11-18 08:37:51.481 4660-4660/? E/AndroidRuntime: at dalvik.system.NativeStart.main(Native Method)
11-18 08:37:51.481 4660-4660/? E/AndroidRuntime: Caused by: java.lang.NullPointerException
11-18 08:37:51.481 4660-4660/? E/AndroidRuntime: at com.example.eoin_a.xmlparserexample.MainActivity.onCreate(MainActivity.java:38)
我还包括了第一条调试日志消息，因为我认为它看起来很不寻常。它输出 2 个冒号而不是 1 个。我不知道为什么！如果有人能帮助我理解这个异常，那么在我不理解下面的异常或导致它的原因的那一刻会很棒。谢谢！
org.xmlpull.v1.XmlPullParserException: expected: START_TAG {employees}employees (position:START_TAG <employees>@2:12 in java.io.InputStreamReader@41f7ff40)
Here's a link to the parser.require() documentation.
public abstract void require (int type, String namespace, String name)
这里中间的一个是我认为导致你的问题的原因。 parser.require 正在寻找正确的标签类型、正确的命名空间和正确的标签名称；如果其中之一不匹配，它将抛出异常。
在您的例子中，对于中间参数，您使用 getName 获取当前标签的名称 ("employees") 并要求 parser.require() 检查是否匹配 命名空间。 Namespace 与标签名称不同，因此会抛出异常。
使用parser.require()时不需要自己使用getName，只需要传入你期望的名称即可。
根据文档 "null will match any namespace and any name"。如果你正在做的是检查你有 <employees> 开始标签，那么你可以通过使用 null 作为命名空间参数来忽略命名空间部分：
parser.require(XmlPullParser.START_TAG, null, "employees");
这将检查它是一个开始标签，并且标签名称是 "employees"。