Android的碎片和线程 [英] Android Fragment and thread
问题描述
我用 FragmentActivity
来交换两个标签。这就是标签A和B.选项卡以制表B I正在使用的ListView
与Loadmore按钮,假设loadmore按钮点击时我刚打电话化背景主题。
私有类loadMoreListView扩展的AsyncTask<太虚,太虚,太虚> {
@覆盖
在preExecute保护无效(){
//发送HTTP请求之前,显示进度对话框
pDialog =新ProgressDialog(
getActivity());
pDialog.setMessage(请稍候...);
pDialog.setIndeterminate(真);
pDialog.setCancelable(假);
pDialog.show();
} 保护无效doInBackground(虚空......未使用){
尝试{
//服务URL fectch数据..
// xml解析
}赶上(例外五){
响应=失败;
的System.out.println(SEC XML帕兴错误时抛出=+ e)条;
} INT currentPosition = listViewattlist.getFirstVisiblePosition(); //追加新数据的ArrayList菜单项
适配器=新CustomAdapter(getActivity(),R.layout.att_list,R.id.title,数据);
listViewattlist.setAdapter(适配器); //设置新的滚动位置
listViewattlist.setSelectionFromTop(currentPosition + 1,0);
回报(NULL);
} 保护无效onPostExecute(虚空未使用){
//关闭进度对话框
pDialog.dismiss();
}
}
当我换,并点击该按钮,我能看到进度条,但它显示如下错误:
11月7日至十三日:42:29.386:E / AndroidRuntime(894):致命异常:AsyncTask的#2
11月7日至13日:42:29.386:E / AndroidRuntime(894):了java.lang.RuntimeException:执行doInBackground发生错误()
11月7日至13日:42:29.386:E / AndroidRuntime(894):在android.os.AsyncTask $ 3.done(AsyncTask.java:299)
11月7日至13日:42:29.386:E / AndroidRuntime(894):在java.util.concurrent.FutureTask中$ Sync.innerSetException(FutureTask.java:273)
11月7日至13日:42:29.386:E / AndroidRuntime(894):在java.util.concurrent.FutureTask.setException(FutureTask.java:124)
11月7日至13日:42:29.386:E / AndroidRuntime(894):在java.util.concurrent.FutureTask中$ Sync.innerRun(FutureTask.java:307)
11月7日至13日:42:29.386:E / AndroidRuntime(894):在java.util.concurrent.FutureTask.run(FutureTask.java:137)
11月7日至13日:42:29.386:E / AndroidRuntime(894):在android.os.AsyncTask $ SerialExecutor $ 1.run(AsyncTask.java:230)
11月7日至13日:42:29.386:E / AndroidRuntime(894):在java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1076)
11月7日至13日:42:29.386:E / AndroidRuntime(894):在java.util.concurrent.ThreadPoolExecutor中的$ Worker.run(ThreadPoolExecutor.java:569)
11月7日至13日:42:29.386:E / AndroidRuntime(894):在java.lang.Thread.run(Thread.java:856)
11月7日至13日:42:29.386:E / AndroidRuntime(894):$ android.view.ViewRootImpl CalledFromWrongThreadException:只有创建视图层次可以触摸其观点原来的线程所致。
11月7日至13日:42:29.386:E / AndroidRuntime(894):在android.view.ViewRootImpl.checkThread(ViewRootImpl.java:4607)
11月7日至13日:42:29.386:E / AndroidRuntime(894):在android.view.ViewRootImpl.invalidateChildInParent(ViewRootImpl.java:867)
11月7日至13日:42:29.386:E / AndroidRuntime(894):在android.view.ViewGroup.invalidateChild(ViewGroup.java:4066)
11月7日至13日:42:29.386:E / AndroidRuntime(894):在android.view.View.invalidate(View.java:10250)
11月7日至13日:42:29.386:E / AndroidRuntime(894):在android.view.View.invalidate(View.java:10205)
11月7日至13日:42:29.386:E / AndroidRuntime(894):在android.widget.ImageView.invalidateDrawable(ImageView.java:190)
11月7日至13日:42:29.386:E / AndroidRuntime(894):在android.graphics.drawable.Drawable.invalidateSelf(Drawable.java:350)
11月7日至13日:42:29.386:E / AndroidRuntime(894):在android.graphics.drawable.Drawable.setVisible(Drawable.java:546)
11月7日至13日:42:29.386:E / AndroidRuntime(894):在android.widget.ImageView.onDetachedFromWindow(ImageView.java:1173)
11月7日至13日:42:29.386:E / AndroidRuntime(894):在android.view.View.dispatchDetachedFromWindow(View.java:11789)
11月7日至13日:42:29.386:E / AndroidRuntime(894):在android.view.ViewGroup.dispatchDetachedFromWindow(ViewGroup.java:2532)
11月7日至13日:42:29.386:E / AndroidRuntime(894):在android.view.ViewGroup.removeAllViewsInLayout(ViewGroup.java:3819)
11月7日至13日:42:29.386:E / AndroidRuntime(894):在android.widget.AbsListView.resetList(AbsListView.java:1936)
11月7日至13日:42:29.386:E / AndroidRuntime(894):在android.widget.ListView.resetList(ListView.java:502)
11月7日至13日:42:29.386:E / AndroidRuntime(894):在android.widget.ListView.setAdapter(ListView.java:442)11月7日至13日:42:29.386:E / AndroidRuntime(894):在com.owentech.testswipeab.TabTwo $ loadMoreListView.doInBackground(TabTwo.java:372)
11月7日至13日:42:29.386:E / AndroidRuntime(894):在com.owentech.testswipeab.TabTwo $ loadMoreListView.doInBackground(TabTwo.java:1)
11月7日至13日:42:29.386:E / AndroidRuntime(894):在android.os.AsyncTask $ 2.call(AsyncTask.java:287)
11月7日至13日:42:29.386:E / AndroidRuntime(894):在java.util.concurrent.FutureTask中$ Sync.innerRun(FutureTask.java:305)
11月7日至13日:42:29.386:E / AndroidRuntime(894):... 5个-------------------------------------------------- ----------------------
doInBackground()
执行其他线程。在 doInBackground()
您尝试更新 listViewattlist
,这是在UI线程创建的。这是一个错误,你应该更新 listViewattlist
在 onPostExecute()
方法。
I'm using FragmentActivity
to swap two tabs. That is tab A and tab B. In Tab B I'm using ListView
with Loadmore button, when suppose the loadmore button clicked I just called backgroud thread.
private class loadMoreListView extends AsyncTask<Void, Void, Void> {
@Override
protected void onPreExecute() {
// Showing progress dialog before sending http request
pDialog = new ProgressDialog (
getActivity());
pDialog.setMessage("Please wait..");
pDialog.setIndeterminate(true);
pDialog.setCancelable(false);
pDialog.show();
}
protected Void doInBackground(Void... unused) {
try {
//service url to fectch data..
//xml parsing
} catch (Exception e) {
response = "failure";
System.out.println(" sec XML Pasing Excpetion = " + e);
}
int currentPosition = listViewattlist.getFirstVisiblePosition();
// Appending new data to menuItems ArrayList
adapter = new CustomAdapter(getActivity(), R.layout.att_list, R.id.title, data);
listViewattlist.setAdapter(adapter);
// Setting new scroll position
listViewattlist.setSelectionFromTop(currentPosition + 1, 0);
return (null);
}
protected void onPostExecute(Void unused) {
// closing progress dialog
pDialog.dismiss();
}
}
When I swap and clicked that button I am able to see the progressbar but it shows the error as below:
07-13 11:42:29.386: E/AndroidRuntime(894): FATAL EXCEPTION: AsyncTask #2
07-13 11:42:29.386: E/AndroidRuntime(894): java.lang.RuntimeException: An error occured while executing doInBackground()
07-13 11:42:29.386: E/AndroidRuntime(894): at android.os.AsyncTask$3.done(AsyncTask.java:299)
07-13 11:42:29.386: E/AndroidRuntime(894): at java.util.concurrent.FutureTask$Sync.innerSetException(FutureTask.java:273)
07-13 11:42:29.386: E/AndroidRuntime(894): at java.util.concurrent.FutureTask.setException(FutureTask.java:124)
07-13 11:42:29.386: E/AndroidRuntime(894): at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:307)
07-13 11:42:29.386: E/AndroidRuntime(894): at java.util.concurrent.FutureTask.run(FutureTask.java:137)
07-13 11:42:29.386: E/AndroidRuntime(894): at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:230)
07-13 11:42:29.386: E/AndroidRuntime(894): at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1076)
07-13 11:42:29.386: E/AndroidRuntime(894): at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:569)
07-13 11:42:29.386: E/AndroidRuntime(894): at java.lang.Thread.run(Thread.java:856)
07-13 11:42:29.386: E/AndroidRuntime(894): Caused by: android.view.ViewRootImpl$CalledFromWrongThreadException: Only the original thread that created a view hierarchy can touch its views.
07-13 11:42:29.386: E/AndroidRuntime(894): at android.view.ViewRootImpl.checkThread(ViewRootImpl.java:4607)
07-13 11:42:29.386: E/AndroidRuntime(894): at android.view.ViewRootImpl.invalidateChildInParent(ViewRootImpl.java:867)
07-13 11:42:29.386: E/AndroidRuntime(894): at android.view.ViewGroup.invalidateChild(ViewGroup.java:4066)
07-13 11:42:29.386: E/AndroidRuntime(894): at android.view.View.invalidate(View.java:10250)
07-13 11:42:29.386: E/AndroidRuntime(894): at android.view.View.invalidate(View.java:10205)
07-13 11:42:29.386: E/AndroidRuntime(894): at android.widget.ImageView.invalidateDrawable(ImageView.java:190)
07-13 11:42:29.386: E/AndroidRuntime(894): at android.graphics.drawable.Drawable.invalidateSelf(Drawable.java:350)
07-13 11:42:29.386: E/AndroidRuntime(894): at android.graphics.drawable.Drawable.setVisible(Drawable.java:546)
07-13 11:42:29.386: E/AndroidRuntime(894): at android.widget.ImageView.onDetachedFromWindow(ImageView.java:1173)
07-13 11:42:29.386: E/AndroidRuntime(894): at android.view.View.dispatchDetachedFromWindow(View.java:11789)
07-13 11:42:29.386: E/AndroidRuntime(894): at android.view.ViewGroup.dispatchDetachedFromWindow(ViewGroup.java:2532)
07-13 11:42:29.386: E/AndroidRuntime(894): at android.view.ViewGroup.removeAllViewsInLayout(ViewGroup.java:3819)
07-13 11:42:29.386: E/AndroidRuntime(894): at android.widget.AbsListView.resetList(AbsListView.java:1936)
07-13 11:42:29.386: E/AndroidRuntime(894): at android.widget.ListView.resetList(ListView.java:502)
07-13 11:42:29.386: E/AndroidRuntime(894): at android.widget.ListView.setAdapter(ListView.java:442)
07-13 11:42:29.386: E/AndroidRuntime(894): at com.owentech.testswipeab.TabTwo$loadMoreListView.doInBackground(TabTwo.java:372)
07-13 11:42:29.386: E/AndroidRuntime(894): at com.owentech.testswipeab.TabTwo$loadMoreListView.doInBackground(TabTwo.java:1)
07-13 11:42:29.386: E/AndroidRuntime(894): at android.os.AsyncTask$2.call(AsyncTask.java:287)
07-13 11:42:29.386: E/AndroidRuntime(894): at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:305)
07-13 11:42:29.386: E/AndroidRuntime(894): ... 5 more
------------------------------------------------------------------------
doInBackground()
executes in other thread. In doInBackground()
you try to update listViewattlist
, which was created in the UI-thread. This is a mistake, and you should update listViewattlist
in your onPostExecute()
method.
这篇关于Android的碎片和线程的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持IT屋!