java AsyncTask执行doInBackground()时出错
protected String doInBackground(String... params) {
int progress = 0;
publishProgress(progress += 10);
String[] link_list = new String[100];
Bitmap bmp ;
Document xmlDoc = Jsoup.parse(url, 3000);
Elements title = xmlDoc.select("div[class=meta]");
title_lenth = title.size();
for (int i = 0; i < title_lenth; i++) {
link_list[count] = title.get(i).text();
try{
JSONObject JObj_link ;
JObj_link = new JSONObject(link_list[count]);
link_list[count] = JObj_link.getString("ou");
Log.e("ou Content", link_list[count]);
}catch (Exception e){
Log.e("ou Content", e.toString());
}
System.out.print(titlelist[count]);
count ++ ;
}
setBmp(link_list);
publishProgress(progress += 15);
} catch (MalformedURLException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
publishProgress(progress = 100);
return title_word;
}
我删除了一些不重要的代码
我想做什么
->;setBmp(链接列表)
链接列表是一个字符串数组内容URL(http://xxx.xx.jpg)
setbmp可以下载图片并设置图像视图
现在出现了错误消息
日志:
03-10 09:32:23.461 16218-16493/com.takepickpicturedemo E/AndroidRuntime﹕ FATAL EXCEPTION: AsyncTask #1
Process: com.takepickpicturedemo, PID: 16218
java.lang.RuntimeException: An error occurred while executing doInBackground()
at 安卓.os.AsyncTask$3.done(AsyncTask.java:309)
at java.util.concurrent.FutureTask.finishCompletion(FutureTask.java:354)
at java.util.concurrent.FutureTask.setException(FutureTask.java:223)
at java.util.concurrent.FutureTask.run(FutureTask.java:242)
at 安卓.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:234)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1113)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:588)
at java.lang.Thread.run(Thread.java:818)
Caused by: 安卓.view.ViewRootImpl$CalledFromWrongThreadException: Only the original thread that created a view hierarchy can touch its views.
at 安卓.view.ViewRootImpl.checkThread(ViewRootImpl.java:6556)
at 安卓.view.ViewRootImpl.invalidateChildInParent(ViewRootImpl.java:942)
at 安卓.view.ViewGroup.invalidateChild(ViewGroup.java:5081)
at 安卓.view.View.invalidateInternal(View.java:12713)
at 安卓.view.View.invalidate(View.java:12677)
at 安卓.view.View.invalidate(View.java:12661)
at 安卓.widget.AbsListView.resetList(AbsListView.java:1996)
at 安卓.widget.GridView.setAdapter(GridView.java:194)
at com.takepickpicturedemo.MainActivity.setBmp(MainActivity.java:741)
at com.takepickpicturedemo.MainActivity$GetPredict.doInBackground(MainActivity.java:582)
at com.takepickpicturedemo.MainActivity$GetPredict.doInBackground(MainActivity.java:497)
at 安卓.os.AsyncTask$2.call(AsyncTask.java:295)
at java.util.concurrent.FutureTask.run(FutureTask.java:237)
at 安卓.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:234)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1113)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:588)
at java.lang.Thread.run(Thread.java:818)
编辑
所以
- 主线程不能在网络上运行
- doInBackground无法设置UI
如何下载&;更改用户界面
# 1 楼答案
发生错误的原因是
setBmp()
以某种方式影响视图,这在UI线程以外的其他线程上是不允许的。用runOnUiThread()
包装它会有所帮助。更换线路作者:
要使其工作,您还应该在创建时将
link_list
设置为final:# 2 楼答案
这里是你setBmp(链接列表)方法。可能是这种方法试图显示图像
**doInBackground**
方法不创建视图谢谢
# 3 楼答案
如我所见,
setBmp()
方法调用UI更新。UI线程中应该发生UI更新。你应该知道doInBackground
出现在后台线程中,而不是UI线程不要在
doInBackground
方法中调用它,而是尝试从AsyncTask
的onPostExecute
方法调用setBmp()
注意:
onPostExecute
方法在UI线程中执行