我有一个应用程序,其中包含在选项卡模式下使用ActionBarSherlock的应用程序。我有5个选项卡,每个选项卡的内容都是使用片段处理的。但是对于tab2,我有一个片段,该片段的xml文件包含一个ViewPager元素,而该元素又具有一些片段页面。最初启动应用程序时,我可以在选项卡之间进行切换,但是第二次按tab2时,出现上述错误。主要活动如下:
public class MainActivity extends SherlockFragmentActivity
{
@Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
ActionBar actionBar = getSupportActionBar();
ActionBar.Tab tab1 = actionBar.newTab().setText("Tab1");
ActionBar.Tab tab3 = actionBar.newTab().setText("Tab3");
ActionBar.Tab tab2 = actionBar.newTab().setText("Tab2");
ActionBar.Tab tab4 = actionBar.newTab().setText("Tab4");
ActionBar.Tab tab5 = actionBar.newTab().setText("Tab5");
Fragment fragment1 = new Tab1();
Fragment fragment3 = new Tab3();
Fragment fragment2 = new Tab2();
Fragment fragment5 = new Tab5();
Fragment fragment4 = new Tab4();
tab1.setTabListener(new MyTabListener(fragment1));
tab3.setTabListener(new MyTabListener(fragment3));
tab2.setTabListener(new MyTabListener(fragment2));
tab5.setTabListener(new MyTabListener(fragment5));
tab4.setTabListener(new MyTabListener(fragment4));
actionBar.addTab(tab1);
actionBar.addTab(tab2);
actionBar.addTab(tab3);
actionBar.addTab(tab4);
actionBar.addTab(tab5);
actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
}
class MyTabListener implements ActionBar.TabListener
{
Fragment fragment;
public MyTabListener(Fragment fragment)
{
this.fragment = fragment;
}
@Override
public void onTabSelected(com.actionbarsherlock.app.ActionBar.Tab tab,FragmentTransaction ft)
{
ft.replace(R.id.fragment_container,fragment);
}
@Override
public void onTabUnselected(com.actionbarsherlock.app.ActionBar.Tab tab,FragmentTransaction ft)
{
}
@Override
public void onTabReselected(com.actionbarsherlock.app.ActionBar.Tab tab,FragmentTransaction ft)
{
}
}
}
没有ViewPager的片段类如下:
public class Tab1 extends Fragment
{
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,Bundle savedInstanceState)
{
return inflater.inflate(R.layout.activity_tab1, container, false);
}
}
使用ViewPager的片段类如下:
public class Tab2 extends Fragment
{
ViewPager mViewPager;
private MyFragmentPagerAdapter mMyFragmentPagerAdapter;
private static int NUMBER_OF_PAGES = 5;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,Bundle savedInstanceState)
{
View view = inflater.inflate(R.layout.activity_tab2, container, false);
return view;
}
@Override
public void onViewCreated(View view,Bundle savedInstanceState)
{
super.onViewCreated(view, savedInstanceState);
mViewPager = (ViewPager) view.findViewById(R.id.viewpager);
mMyFragmentPagerAdapter = new MyFragmentPagerAdapter(getChildFragmentManager());
mViewPager.setAdapter(mMyFragmentPagerAdapter);
}
private static class MyFragmentPagerAdapter extends FragmentPagerAdapter
{
public MyFragmentPagerAdapter(FragmentManager fm)
{
super(fm);
}
@Override
public Fragment getItem(int index)
{
return PageFragment.newInstance("My Message " + index);
}
@Override
public int getCount()
{
return NUMBER_OF_PAGES;
}
}
}
从我在不同地方阅读的内容(如果我错了,请纠正我),这是因为第二遍的片段管理器试图重用活动中不再存在的片段,从而产生错误。但是我不确定为什么在这里发生这种情况,因为我没有使用片段活动。根据logcat,该错误是在Tab2类中,在显示mViewPager.setAdapter(mMyFragmentPagerAdapter)的行上的onViewCreated方法中。任何帮助都将不胜感激...谢谢。
03-04 12:01:05.468: E/AndroidRuntime(2474): FATAL EXCEPTION: main
03-04 12:01:05.468: E/AndroidRuntime(2474): java.lang.IllegalStateException: Activity has been destroyed
03-04 12:01:05.468: E/AndroidRuntime(2474): at android.support.v4.app.FragmentManagerImpl.enqueueAction(FragmentManager.java:1342)
03-04 12:01:05.468: E/AndroidRuntime(2474): at android.support.v4.app.BackStackRecord.commitInternal(BackStackRecord.java:595)
03-04 12:01:05.468: E/AndroidRuntime(2474): at android.support.v4.app.BackStackRecord.commitAllowingStateLoss(BackStackRecord.java:578)
03-04 12:01:05.468: E/AndroidRuntime(2474): at android.support.v4.app.FragmentPagerAdapter.finishUpdate(FragmentPagerAdapter.java:139)
03-04 12:01:05.468: E/AndroidRuntime(2474): at android.support.v4.view.ViewPager.populate(ViewPager.java:1011)
03-04 12:01:05.468: E/AndroidRuntime(2474): at android.support.v4.view.ViewPager.populate(ViewPager.java:880)
03-04 12:01:05.468: E/AndroidRuntime(2474): at android.support.v4.view.ViewPager.setAdapter(ViewPager.java:433)
03-04 12:01:05.468: E/AndroidRuntime(2474): at com.example.tabs.Tab2.onViewCreated(Tab2.java:31)
03-04 12:01:05.468: E/AndroidRuntime(2474): at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:925)
03-04 12:01:05.468: E/AndroidRuntime(2474): at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1088)
03-04 12:01:05.468: E/AndroidRuntime(2474): at android.support.v4.app.BackStackRecord.run(BackStackRecord.java:682)
03-04 12:01:05.468: E/AndroidRuntime(2474): at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1444)
03-04 12:01:05.468: E/AndroidRuntime(2474): at android.support.v4.app.FragmentManagerImpl$1.run(FragmentManager.java:429)
03-04 12:01:05.468: E/AndroidRuntime(2474): at android.os.Handler.handleCallback(Handler.java:587)
03-04 12:01:05.468: E/AndroidRuntime(2474): at android.os.Handler.dispatchMessage(Handler.java:92)
03-04 12:01:05.468: E/AndroidRuntime(2474): at android.os.Looper.loop(Looper.java:123)
03-04 12:01:05.468: E/AndroidRuntime(2474): at android.app.ActivityThread.main(ActivityThread.java:3687)
03-04 12:01:05.468: E/AndroidRuntime(2474): at java.lang.reflect.Method.invokeNative(Native Method)
03-04 12:01:05.468: E/AndroidRuntime(2474): at java.lang.reflect.Method.invoke(Method.java:507)
03-04 12:01:05.468: E/AndroidRuntime(2474): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:842)
03-04 12:01:05.468: E/AndroidRuntime(2474): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:600)
03-04 12:01:05.468: E/AndroidRuntime(2474): at dalvik.system.NativeStart.main(Native Method)