java.lang.IllegalStateException: 在 onSaveInstanceState 之后无法执行此操作 [英] java.lang.IllegalStateException: Can not perform this action after onSaveInstanceState
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问题描述
我正在为我的应用使用支持库.在我的 FragmentActivity 中，我使用 AsyncTask 从互联网下载数据.在 onPreExecute() 方法中，我添加了一个 Fragment，在 onPostExecute() 方法中，我再次删除了它.当方向在两者之间改变时，我得到上述异常.详情请看:
I'm using the support library for my app. In my FragmentActivity I'm using an AsyncTask for downloading data from internet. In the onPreExecute() method I add a Fragment and in the onPostExecute() method I remove it again. When the orientation is changed in between, I get the above mentioned exception. Please take a look at the details:
private class onFriendAddedAsyncTask extends AsyncTask<String, Void, String> {
DummyFragment dummyFragment;
FragmentManager fm;
FragmentTransaction ft;
@Override
protected void onPreExecute() {
Log.v("MyFragmentActivity", "onFriendAddedAsyncTask/onPreExecute");
dummyFragment = DummyFragment.newInstance();
fm = getSupportFragmentManager();
ft = fm.beginTransaction();
ft.add(dummyFragment, "dummy_fragment");
ft.commit();
}
@Override
protected void onPostExecute(String result) {
Log.v("MyFragmentActivity", "onFriendAddedAsyncTask/onPostExecute");
ft = fm.beginTransaction();
ft.remove(dummyFragment);
ft.commit();
}
@Override
protected String doInBackground(String... name) {
Log.v("MyFragmentActivity", "onFriendAddedAsyncTask/doInBackground");
...
}
我关注了 LogCut:
I get following LogCut:
01-05 23:54:19.958: V/MyFragmentActivity(12783): onFriendAddedAsyncTask/onPreExecute
01-05 23:54:19.968: V/DummyFragment(12783): onAttach
01-05 23:54:19.968: V/DummyFragment(12783): onCreate
01-05 23:54:19.968: V/MyFragmentActivity(12783): onFriendAddedAsyncTask/doInBackground
01-05 23:54:19.973: V/DummyFragment(12783): onCreateView
01-05 23:54:19.973: V/DummyFragment(12783): onActivityCreated
01-05 23:54:19.973: V/DummyFragment(12783): onStart
01-05 23:54:19.973: V/DummyFragment(12783): onResume
01-05 23:54:21.933: V/MyFragmentActivity(12783): onSaveInstanceState
01-05 23:54:21.933: V/DummyFragment(12783): onSaveInstanceState
01-05 23:54:21.933: V/MyFragmentActivity(12783): onPause
01-05 23:54:21.933: V/DummyFragment(12783): onPause
01-05 23:54:21.938: V/MyFragmentActivity(12783): onStop
01-05 23:54:21.938: V/DummyFragment(12783): onStop
01-05 23:54:21.938: V/MyFragmentActivity(12783): onDestroy
01-05 23:54:21.938: V/DummyFragment(12783): onDestroyView
01-05 23:54:21.938: V/DummyFragment(12783): onDestroy
01-05 23:54:21.938: V/DummyFragment(12783): onDetach
01-05 23:54:21.978: V/MyFragmentActivity(12783): onCreate
01-05 23:54:21.978: V/DummyFragment(12783): onAttach
01-05 23:54:21.978: V/DummyFragment(12783): onCreate
01-05 23:54:22.263: V/MyFragmentActivity(12783): onStart
01-05 23:54:22.313: V/DummyFragment(12783): onCreateView
01-05 23:54:22.313: V/DummyFragment(12783): onActivityCreated
01-05 23:54:22.313: V/DummyFragment(12783): onStart
01-05 23:54:22.323: V/MyFragmentActivity(12783): onResume
01-05 23:54:22.323: V/MyFragmentActivity(12783): onPostResume
01-05 23:54:22.323: V/MyFragmentActivity(12783): onResumeFragments
01-05 23:54:22.323: V/DummyFragment(12783): onResume
01-05 23:54:27.123: V/MyFragmentActivity(12783): onFriendAddedAsyncTask/onPostExecute
01-05 23:54:27.123: D/AndroidRuntime(12783): Shutting down VM
01-05 23:54:27.123: W/dalvikvm(12783): threadid=1: thread exiting with uncaught exception (group=0x4001d7d0)
01-05 23:54:27.138: E/AndroidRuntime(12783): FATAL EXCEPTION: main
01-05 23:54:27.138: E/AndroidRuntime(12783): java.lang.IllegalStateException: Can not perform this action after onSaveInstanceState
01-05 23:54:27.138: E/AndroidRuntime(12783): at android.support.v4.app.FragmentManagerImpl.checkStateLoss(FragmentManager.java:1314)
01-05 23:54:27.138: E/AndroidRuntime(12783): at android.support.v4.app.FragmentManagerImpl.enqueueAction(FragmentManager.java:1325)
01-05 23:54:27.138: E/AndroidRuntime(12783): at android.support.v4.app.BackStackRecord.commitInternal(BackStackRecord.java:548)
01-05 23:54:27.138: E/AndroidRuntime(12783): at android.support.v4.app.BackStackRecord.commit(BackStackRecord.java:532)
01-05 23:54:27.138: E/AndroidRuntime(12783): at com.xyz.dummy.MyFragmentActivity$onFriendAddedAsyncTask.onPostExecute(MyFragmentActivity.java:447)
01-05 23:54:27.138: E/AndroidRuntime(12783): at com.xyz.dummy.MyFragmentActivity$onFriendAddedAsyncTask.onPostExecute(MyFragmentActivity.java:1)
01-05 23:54:27.138: E/AndroidRuntime(12783): at android.os.AsyncTask.finish(AsyncTask.java:417)
01-05 23:54:27.138: E/AndroidRuntime(12783): at android.os.AsyncTask.access$300(AsyncTask.java:127)
01-05 23:54:27.138: E/AndroidRuntime(12783): at android.os.AsyncTask$InternalHandler.handleMessage(AsyncTask.java:429)
01-05 23:54:27.138: E/AndroidRuntime(12783): at android.os.Handler.dispatchMessage(Handler.java:99)
01-05 23:54:27.138: E/AndroidRuntime(12783): at android.os.Looper.loop(Looper.java:123)
01-05 23:54:27.138: E/AndroidRuntime(12783): at android.app.ActivityThread.main(ActivityThread.java:4627)
01-05 23:54:27.138: E/AndroidRuntime(12783): at java.lang.reflect.Method.invokeNative(Native Method)
01-05 23:54:27.138: E/AndroidRuntime(12783): at java.lang.reflect.Method.invoke(Method.java:521)
01-05 23:54:27.138: E/AndroidRuntime(12783): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:858)
01-05 23:54:27.138: E/AndroidRuntime(12783): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
01-05 23:54:27.138: E/AndroidRuntime(12783): at dalvik.system.NativeStart.main(Native Method)
在关于类似问题的其他线程中，原因似乎是在调用 onResume() 方法之前调用了 onPostExecute 方法.但是即使之前调用了 onResume() ，我也得到了异常.
In other threads about similar problems the reason seems to be that the onPostExecute method is called before the onResume() method is called. But I get the exception even though onResume() is called before.
有人知道出了什么问题吗?
Does someone knows what's wrong?
活动如下所示:
public class MyFragmentActivity extends FragmentActivity implements OnFriendSelectedListener, OnFriendAddedListener, OnFriendOptionSelectedListener, LoaderCallbacks<Cursor> {
@Override
public void onCreate(Bundle savedInstanceState) {
Log.v("MyFragmentActivity", "onCreate");
super.onCreate(savedInstanceState);
setContentView(R.layout.fragment_activity_layout);
FragmentManager fm = getSupportFragmentManager();
FragmentTransaction ft = fm.beginTransaction();
FriendListFragment friendListFragment = (FriendListFragment)fm.findFragmentById(R.id.friend_list_fragment_layout);
if (friendListFragment == null) {
friendListFragment = new FriendListFragment();
ft.add(R.id.friend_list_fragment_layout, friendListFragment);
ft.commit();
fm.executePendingTransactions();
startService(new Intent(this, MyIntentService.class));
getSupportLoaderManager().initLoader(CHECK_EMPTY_DATABASE, null, this);
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
super.onCreateOptionsMenu(menu);
getMenuInflater().inflate(R.menu.fragment_activity_options_menu, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
super.onOptionsItemSelected(item);
switch (item.getItemId()) {
case R.id.add_friend_menu_item:
AddFriendDialogFragment addFriendDialogFragment = AddFriendDialogFragment.newInstance();
addFriendDialogFragment.show(getSupportFragmentManager(), "add_friend_dialog_fragment");
return true;
default:
return false;
}
}
@Override
public void onFriendAdded(String name) {
name = name.trim();
if (name.length() > 0) {
new onFriendAddedAsyncTask().execute(name);
}
}
使用 commitAllowingStateLoss() 时出现以下异常:
When using commitAllowingStateLoss() I get the following exception:
01-06 14:54:29.548: E/AndroidRuntime(18020): FATAL EXCEPTION: main
01-06 14:54:29.548: E/AndroidRuntime(18020): java.lang.IllegalStateException: Activity has been destroyed
01-06 14:54:29.548: E/AndroidRuntime(18020): at android.support.v4.app.FragmentManagerImpl.enqueueAction(FragmentManager.java:1329)
01-06 14:54:29.548: E/AndroidRuntime(18020): at android.support.v4.app.BackStackRecord.commitInternal(BackStackRecord.java:548)
01-06 14:54:29.548: E/AndroidRuntime(18020): at android.support.v4.app.BackStackRecord.commitAllowingStateLoss(BackStackRecord.java:536)
01-06 14:54:29.548: E/AndroidRuntime(18020): at com.xyz.dummy.FadiaFragmentActivity$onFriendAddedAsyncTask.onPostExecute(FadiaFragmentActivity.java:461)
01-06 14:54:29.548: E/AndroidRuntime(18020): at com.xyz.dummy.FadiaFragmentActivity$onFriendAddedAsyncTask.onPostExecute(FadiaFragmentActivity.java:1)
01-06 14:54:29.548: E/AndroidRuntime(18020): at android.os.AsyncTask.finish(AsyncTask.java:417)
01-06 14:54:29.548: E/AndroidRuntime(18020): at android.os.AsyncTask.access$300(AsyncTask.java:127)
01-06 14:54:29.548: E/AndroidRuntime(18020): at android.os.AsyncTask$InternalHandler.handleMessage(AsyncTask.java:429)
01-06 14:54:29.548: E/AndroidRuntime(18020): at android.os.Handler.dispatchMessage(Handler.java:99)
01-06 14:54:29.548: E/AndroidRuntime(18020): at android.os.Looper.loop(Looper.java:123)
01-06 14:54:29.548: E/AndroidRuntime(18020): at android.app.ActivityThread.main(ActivityThread.java:4627)
01-06 14:54:29.548: E/AndroidRuntime(18020): at java.lang.reflect.Method.invokeNative(Native Method)
01-06 14:54:29.548: E/AndroidRuntime(18020): at java.lang.reflect.Method.invoke(Method.java:521)
01-06 14:54:29.548: E/AndroidRuntime(18020): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:858)
01-06 14:54:29.548: E/AndroidRuntime(18020): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
01-06 14:54:29.548: E/AndroidRuntime(18020): at dalvik.system.NativeStart.main(Native Method)
当我如下实现 AsynTask 时，我得到相同的 IllegalStateExeption，因为 findFragmentById() 方法返回一个空指针.
I get the same IllegalStateExeption when I implement the AsynTask as follows, because the findFragmentById() method returns a null pointer.
private class onFriendAddedAsyncTask extends AsyncTask<String, Void, String> {
protected void onPreExecute() {
Log.v("MyFragmentActivity", "onFriendAddedAsyncTask/onPreExecute");
FragmentManager fm = getSupportFragmentManager();
FragmentTransaction ft = fm.beginTransaction();
DummyFragment dummyFragment = DummyFragment.newInstance();
ft.add(R.id.dummy_fragment_layout, dummyFragment);
ft.commit();
}
protected void onPostExecute(String result) {
Log.v("MyFragmentActivity", "onFriendAddedAsyncTask/onPostExecute");
FragmentManager fm = getSupportFragmentManager();
FragmentTransaction ft = fm.beginTransaction();
DummyFragment dummyFragment = (DummyFragment) fm.findFragmentById(R.id.dummy_fragment_layout);
ft.remove(dummyFragment);
ft.commitAllowingStateLoss();
}
在下一步中，我使用处理程序来添加和删除 DummyFragment.此外，我还添加了更多调试输出.
In the next step I use a handler for the adding and removing the DummyFragment. Additionally I've added some more debug output.
private class onFriendAddedAsyncTask extends AsyncTask<String, Void, String> {
@Override
protected void onPreExecute() {
Log.v("MyFragmentActivity", "onFriendAddedAsyncTask/onPreExecute " + getSupportFragmentManager());
Log.v("MyFragmentActivity", "onFriendAddedAsyncTask/onPreExecute " + getSupportFragmentManager().findFragmentById(R.id.dummy_fragment_layout));
Log.v("MyFragmentActivity", "onFriendAddedAsyncTask/onPreExecute " + getSupportFragmentManager().findFragmentById(R.id.friend_list_fragment_layout));
new Handler().post(new Runnable() {
public void run() {
Log.v("MyFragmentActivity", "onFriendAddedAsyncTask/onPreExecute " + getSupportFragmentManager());
Log.v("MyFragmentActivity", "onFriendAddedAsyncTask/onPreExecute " + getSupportFragmentManager().findFragmentById(R.id.dummy_fragment_layout));
Log.v("MyFragmentActivity", "onFriendAddedAsyncTask/onPreExecute " + getSupportFragmentManager().findFragmentById(R.id.friend_list_fragment_layout));
FragmentManager fm = getSupportFragmentManager();
FragmentTransaction ft = fm.beginTransaction();
DummyFragment dummyFragment = DummyFragment.newInstance();
ft.add(R.id.dummy_fragment_layout, dummyFragment);
ft.commit();
}
});
@Override
protected void onPostExecute(String result) {
Log.v("MyFragmentActivity", "onFriendAddedAsyncTask/onPostExecute " + getSupportFragmentManager());
Log.v("MyFragmentActivity", "onFriendAddedAsyncTask/onPostExecute " + getSupportFragmentManager().findFragmentById(R.id.dummy_fragment_layout));
Log.v("MyFragmentActivity", "onFriendAddedAsyncTask/onPostExecute " + getSupportFragmentManager().findFragmentById(R.id.friend_list_fragment_layout));
new Handler().post(new Runnable() {
public void run() {
Log.v("MyFragmentActivity", "onFriendAddedAsyncTask/onPostExecute " + getSupportFragmentManager());
Log.v("MyFragmentActivity", "onFriendAddedAsyncTask/onPostExecute " + getSupportFragmentManager().findFragmentById(R.id.dummy_fragment_layout));
Log.v("MyFragmentActivity", "onFriendAddedAsyncTask/onPostExecute " + getSupportFragmentManager().findFragmentById(R.id.friend_list_fragment_layout));
FragmentManager fm = getSupportFragmentManager();
FragmentTransaction ft = fm.beginTransaction();
DummyFragment dummyFragment = (DummyFragment) fm.findFragmentById(R.id.dummy_fragment_layout);
ft.remove(dummyFragment);
ft.commitAllowingStateLoss();
}
});
我关注了 LogCut:
I get following LogCut:
01-07 19:00:17.273: V/MyFragmentActivity(4124): onFriendAddedAsyncTask/onPreExecute FragmentManager{45e384a8 in MyFragmentActivity{45e38358}}
01-07 19:00:17.273: V/MyFragmentActivity(4124): onFriendAddedAsyncTask/onPreExecute null
01-07 19:00:17.273: V/MyFragmentActivity(4124): onFriendAddedAsyncTask/onPreExecute FriendListFragment{45e38ab0 #0 id=0x7f0a0002}
01-07 19:00:17.283: V/MyFragmentActivity(4124): onFriendAddedAsyncTask/onPreExecute FragmentManager{45e384a8 in MyFragmentActivity{45e38358}}
01-07 19:00:17.288: V/MyFragmentActivity(4124): onFriendAddedAsyncTask/doInBackground
01-07 19:00:17.288: V/MyFragmentActivity(4124): onFriendAddedAsyncTask/onPreExecute null
01-07 19:00:17.288: V/MyFragmentActivity(4124): onFriendAddedAsyncTask/onPreExecute FriendListFragment{45e38ab0 #0 id=0x7f0a0002}
01-07 19:00:17.308: V/DummyFragment(4124): onAttach DummyFragment{45dd7498 #2 id=0x7f0a0004}
01-07 19:00:17.308: V/DummyFragment(4124): onCreate DummyFragment{45dd7498 #2 id=0x7f0a0004}
01-07 19:00:17.308: V/DummyFragment(4124): onCreateView DummyFragment{45dd7498 #2 id=0x7f0a0004}
01-07 19:00:17.308: V/DummyFragment(4124): onActivityCreated DummyFragment{45dd7498 #2 id=0x7f0a0004}
01-07 19:00:17.308: V/DummyFragment(4124): onStart DummyFragment{45dd7498 #2 id=0x7f0a0004}
01-07 19:00:17.313: V/DummyFragment(4124): onResume DummyFragment{45dd7498 #2 id=0x7f0a0004}
01-07 19:00:18.098: V/MyFragmentActivity(4124): onSaveInstanceState DummyFragment{45dd7498 #2 id=0x7f0a0004}
01-07 19:00:18.098: V/DummyFragment(4124): onSaveInstanceState DummyFragment{45dd7498 #2 id=0x7f0a0004}
01-07 19:00:18.098: V/MyFragmentActivity(4124): onPause DummyFragment{45dd7498 #2 id=0x7f0a0004}
01-07 19:00:18.098: V/DummyFragment(4124): onPause DummyFragment{45dd7498 #2 id=0x7f0a0004}
01-07 19:00:18.103: V/MyFragmentActivity(4124): onStop DummyFragment{45dd7498 #2 id=0x7f0a0004}
01-07 19:00:18.103: V/DummyFragment(4124): onStop DummyFragment{45dd7498 #2 id=0x7f0a0004}
01-07 19:00:18.103: V/MyFragmentActivity(4124): onDestroy DummyFragment{45dd7498 #2 id=0x7f0a0004}
01-07 19:00:18.103: V/DummyFragment(4124): onDestroyView DummyFragment{45dd7498 #2 id=0x7f0a0004}
01-07 19:00:18.108: V/DummyFragment(4124): onDestroy DummyFragment{45dd7498 #2 id=0x7f0a0004}
01-07 19:00:18.113: V/DummyFragment(4124): onDetach DummyFragment{45dd7498 #2 id=0x7f0a0004}
01-07 19:00:18.138: V/MyFragmentActivity(4124): onCreate
01-07 19:00:18.138: V/FriendListFragment(4124): FriendListFragment
01-07 19:00:18.138: V/FriendListFragment(4124): onAttach FriendListFragment{45e4a7f8 #0 id=0x7f0a0002}
01-07 19:00:18.138: V/FriendListFragment(4124): onCreate FriendListFragment{45e4a7f8 #0 id=0x7f0a0002}
01-07 19:00:18.148: V/DummyFragment(4124): onAttach DummyFragment{45d7d1a0 #2 id=0x7f0a0004}
01-07 19:00:18.153: V/DummyFragment(4124): onCreate DummyFragment{45d7d1a0 #2 id=0x7f0a0004}
01-07 19:00:18.523: V/MyFragmentActivity(4124): onStart DummyFragment{45d7d1a0 #2 id=0x7f0a0004}
01-07 19:00:18.543: V/FriendListFragment(4124): onActivityCreated FriendListFragment{45e4a7f8 #0 id=0x7f0a0002}
01-07 19:00:18.548: V/DummyFragment(4124): onCreateView DummyFragment{45d7d1a0 #2 id=0x7f0a0004}
01-07 19:00:18.548: V/DummyFragment(4124): onActivityCreated DummyFragment{45d7d1a0 #2 id=0x7f0a0004}
01-07 19:00:18.548: V/FriendListFragment(4124): onLoadFinished FragmentManager{45d8e478 in MyFragmentActivity{45e4a6d8}}
01-07 19:00:18.548: V/FriendListFragment(4124): onLoadFinished FriendListFragment{45e4a7f8 #0 id=0x7f0a0002}
01-07 19:00:18.553: V/DummyFragment(4124): onStart DummyFragment{45d7d1a0 #2 id=0x7f0a0004}
01-07 19:00:18.553: V/FriendListFragment(4124): onLoadFinished FragmentManager{45d8e478 in MyFragmentActivity{45e4a6d8}}
01-07 19:00:18.553: V/FriendListFragment(4124): onLoadFinished FriendListFragment{45e4a7f8 #0 id=0x7f0a0002}
01-07 19:00:18.558: V/MyFragmentActivity(4124): onResume DummyFragment{45d7d1a0 #2 id=0x7f0a0004}
01-07 19:00:18.558: V/MyFragmentActivity(4124): onPostResume DummyFragment{45d7d1a0 #2 id=0x7f0a0004}
01-07 19:00:18.558: V/MyFragmentActivity(4124): onResumeFragments DummyFragment{45d7d1a0 #2 id=0x7f0a0004}
01-07 19:00:18.558: V/FriendListFragment(4124): onResume FriendListFragment{45e4a7f8 #0 id=0x7f0a0002}
01-07 19:00:18.563: V/FriendListFragment(4124): onCreateLoader FriendListFragment{45e4a7f8 #0 id=0x7f0a0002}
01-07 19:00:18.563: V/DummyFragment(4124): onResume DummyFragment{45d7d1a0 #2 id=0x7f0a0004}
01-07 19:00:18.723: V/FriendListFragment(4124): onLoadFinished FragmentManager{45d8e478 in MyFragmentActivity{45e4a6d8}}
01-07 19:00:18.723: V/FriendListFragment(4124): onLoadFinished FriendListFragment{45e4a7f8 #0 id=0x7f0a0002}
01-07 19:00:18.893: V/MyFragmentActivity(4124): onFriendAddedAsyncTask/onPostExecute FragmentManager{45e384a8 in null}}
01-07 19:00:18.893: V/MyFragmentActivity(4124): onFriendAddedAsyncTask/onPostExecute null
01-07 19:00:18.893: V/MyFragmentActivity(4124): onFriendAddedAsyncTask/onPostExecute null
01-07 19:00:18.923: V/MyFragmentActivity(4124): onFriendAddedAsyncTask/onPostExecute FragmentManager{45e384a8 in null}}
01-07 19:00:18.923: V/MyFragmentActivity(4124): onFriendAddedAsyncTask/onPostExecute null
01-07 19:00:18.923: V/MyFragmentActivity(4124): onFriendAddedAsyncTask/onPostExecute null
01-07 19:00:18.928: D/AndroidRuntime(4124): Shutting down VM
01-07 19:00:18.928: W/dalvikvm(4124): threadid=1: thread exiting with uncaught exception (group=0x4001d7d0)
01-07 19:00:18.938: E/AndroidRuntime(4124): FATAL EXCEPTION: main
01-07 19:00:18.938: E/AndroidRuntime(4124): java.lang.IllegalStateException: Activity has been destroyed
01-07 19:00:18.938: E/AndroidRuntime(4124): at android.support.v4.app.FragmentManagerImpl.enqueueAction(FragmentManager.java:1329)
01-07 19:00:18.938: E/AndroidRuntime(4124): at android.support.v4.app.BackStackRecord.commitInternal(BackStackRecord.java:548)
01-07 19:00:18.938: E/AndroidRuntime(4124): at android.support.v4.app.BackStackRecord.commitAllowingStateLoss(BackStackRecord.java:536)
01-07 19:00:18.938: E/AndroidRuntime(4124): at com.xyz.dummy.MyFragmentActivity$onFriendAddedAsyncTask$2.run(MyFragmentActivity.java:476)
01-07 19:00:18.938: E/AndroidRuntime(4124): at android.os.Handler.handleCallback(Handler.java:587)
01-07 19:00:18.938: E/AndroidRuntime(4124): at android.os.Handler.dispatchMessage(Handler.java:92)
01-07 19:00:18.938: E/AndroidRuntime(4124): at android.os.Looper.loop(Looper.java:123)
01-07 19:00:18.938: E/AndroidRuntime(4124): at android.app.ActivityThread.main(ActivityThread.java:4627)
01-07 19:00:18.938: E/AndroidRuntime(4124): at java.lang.reflect.Method.invokeNative(Native Method)
01-07 19:00:18.938: E/AndroidRuntime(4124): at java.lang.reflect.Method.invoke(Method.java:521)
01-07 19:00:18.938: E/AndroidRuntime(4124): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:858)
01-07 19:00:18.938: E/AndroidRuntime(4124): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
01-07 19:00:18.938: E/AndroidRuntime(4124): at dalvik.system.NativeStart.main(Native Method)
在 onPreExecute() 中，FriendListFragment 的 id=0x7f0a0002.在处理程序中，使用 id=0x7f0a0004 创建了 DummyFragment.在 onPostExecute() 中，两个 ID 都为空.在 onPreExecute() 中，MyFragmentActivity 的地址是 45e38358.但在 onPostExecute() 中它是空的.但是在这两种方法中，FragmentManager 地址都是 45e384a8.我猜 onPostExecute 使用了无效的 FragmentManager.但为什么?
In onPreExecute() the FriendListFragment has the id=0x7f0a0002. Inside the handler the DummyFragment is created with id=0x7f0a0004. In onPostExecute() both IDs are null. In onPreExecute() the address of MyFragmentActivity is 45e38358. but in onPostExecute() it's null. But in both methods the FragmentManager address is 45e384a8. I guess onPostExecute uses an invalid FragmentManager. But why?
推荐答案
你应该在 Handler 中做如下事务:
You should do the transaction in a Handler as follows:
@Override
protected void onPostExecute(String result) {
Log.v("MyFragmentActivity", "onFriendAddedAsyncTask/onPostExecute");
new Handler().post(new Runnable() {
public void run() {
fm = getSupportFragmentManager();
ft = fm.beginTransaction();
ft.remove(dummyFragment);
ft.commit();
}
});
}
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