致命异常:AsyncTask的#1 [英] Fatal exception : AsyncTask #1
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问题描述
我想用一个AsynTask解析XML数据。
所以在活动我:
I want to use a AsynTask to parse XML data. So in the Activity i've :
static List<String> citations = null;
static void setCitations(List<String> data) {
citations = data;
}
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
new data().execute();
和数据类我:
class data extends AsyncTask<Void, Void, List<String>> {
private XMLReader saxReader;
private SimpleContentHandler simpleContentHandler;
private List<String> citations;
@Override
protected void onPreExecute() {
Log.i("AsyncTask", "onPreExecute");
}
@Override
public void onPostExecute(List<String> citations) {
GuiguiActivity.setCitations(citations);
}
@Override
protected List<String> doInBackground(Void... params) {
citations.add("TEST 1");citations.add("TEST 2");
return citations;
}
}
相反,citations.add我我的XML解析器,但即使在这种情况下,与发生citations.add错误。
Instead of the citations.add i've my XML parser, but even in this case with citations.add errors occur.
10-24 15:28:46.647: E/AndroidRuntime(1160): FATAL EXCEPTION: AsyncTask #1
10-24 15:28:46.647: E/AndroidRuntime(1160): java.lang.RuntimeException: An error occured while executing doInBackground()
10-24 15:28:46.647: E/AndroidRuntime(1160): at android.os.AsyncTask$3.done(AsyncTask.java:278)
10-24 15:28:46.647: E/AndroidRuntime(1160): at java.util.concurrent.FutureTask$Sync.innerSetException(FutureTask.java:273)
10-24 15:28:46.647: E/AndroidRuntime(1160): at java.util.concurrent.FutureTask.setException(FutureTask.java:124)
10-24 15:28:46.647: E/AndroidRuntime(1160): at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:307)
10-24 15:28:46.647: E/AndroidRuntime(1160): at java.util.concurrent.FutureTask.run(FutureTask.java:137)
10-24 15:28:46.647: E/AndroidRuntime(1160): at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:208)
10-24 15:28:46.647: E/AndroidRuntime(1160): at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1076)
10-24 15:28:46.647: E/AndroidRuntime(1160): at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:569)
10-24 15:28:46.647: E/AndroidRuntime(1160): at java.lang.Thread.run(Thread.java:856)
10-24 15:28:46.647: E/AndroidRuntime(1160): Caused by: java.lang.NullPointerException
10-24 15:28:46.647: E/AndroidRuntime(1160): at guigui.first.project.data.doInBackground(data.java:82)
10-24 15:28:46.647: E/AndroidRuntime(1160): at guigui.first.project.data.doInBackground(data.java:1)
10-24 15:28:46.647: E/AndroidRuntime(1160): at android.os.AsyncTask$2.call(AsyncTask.java:264)
10-24 15:28:46.647: E/AndroidRuntime(1160): at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:305)
我不明白问题出在哪里。
I don't see where the problem is.
感谢:)
推荐答案
您没有初始化引用
字段。构造函数添加到您的数据
类是这样的:
You didn't initialize citations
field. Add a constructor to your data
class like this:
public data(){
citations = new ArrayList<String>();
}
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