Android java.lang.IllegalStateException:Can';不改变碎片的标签
嗨,我在使用pageViwer和适配器滑过3个片段时遇到了这个错误 这是我的页面适配器Android java.lang.IllegalStateException:Can';不改变碎片的标签,android,android-fragments,Android,Android Fragments,嗨,我在使用pageViwer和适配器滑过3个片段时遇到了这个错误 这是我的页面适配器 public class FreedomPageAdapter extends FragmentPagerAdapter { private List<Fragment> listFragment; public FreedomPageAdapter(FragmentManager fm, List<Fragment> listFragment) {
public class FreedomPageAdapter extends FragmentPagerAdapter {
private List<Fragment> listFragment;
public FreedomPageAdapter(FragmentManager fm, List<Fragment> listFragment) {
super(fm);
this.listFragment = listFragment;
}
/*
* (non-Javadoc)
*
* @see android.support.v4.app.FragmentPagerAdapter#getItem(int)
*/
@Override
public Fragment getItem(int position) {
// TODO Auto-generated method stub
return listFragment.get(position);
}
/*
* (non-Javadoc)
*
* @see android.support.v4.view.PagerAdapter#getCount()
*/
@Override
public int getCount() {
// TODO Auto-generated method stub
return listFragment.size();
}
页面视图侦听器
/*
* (non-Javadoc)
*
* @see android.support.v4.view.ViewPager.OnPageChangeListener#
* onPageScrollStateChanged(int)
*/
@Override
public void onPageScrollStateChanged(int arg0) {
}
/*
* (non-Javadoc)
*
* @see
* android.support.v4.view.ViewPager.OnPageChangeListener#onPageScrolled
* (int, float, int)
*/
@Override
public void onPageScrolled(int arg0, float arg1, int arg2) {
}
/*
* (non-Javadoc)
*
* @see
* android.support.v4.view.ViewPager.OnPageChangeListener#onPageSelected
* (int)
*/
@Override
public void onPageSelected(int position) {
actionBar.setSelectedNavigationItem(position);
}
自定义片段对象
public class SubscribedFragment extends Fragment{
/* (non-Javadoc)
* @see android.app.Fragment#onCreate(android.os.Bundle)
*/
@Override
public void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
}
/* (non-Javadoc)
* @see android.app.Fragment#onCreateView(android.view.LayoutInflater, android.view.ViewGroup, android.os.Bundle)
*/
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// TODO Auto-generated method stub
return inflater.inflate(R.layout.discussion_list_layout, container);
}
}
错误的完整堆栈跟踪:
05-02 19:15:44.599: E/AndroidRuntime(19839): FATAL EXCEPTION: main
05-02 19:15:44.599: E/AndroidRuntime(19839): java.lang.IllegalStateException: Can't change tag of fragment SubscribedFragment{41157420 id=0x7f070005 android:switcher:2131165189:0}: was android:switcher:2131165189:0 now android:switcher:2131165189:1
05-02 19:15:44.599: E/AndroidRuntime(19839): at android.support.v4.app.BackStackRecord.doAddOp(BackStackRecord.java:398)
05-02 19:15:44.599: E/AndroidRuntime(19839): at android.support.v4.app.BackStackRecord.add(BackStackRecord.java:389)
05-02 19:15:44.599: E/AndroidRuntime(19839): at android.support.v4.app.FragmentPagerAdapter.instantiateItem(FragmentPagerAdapter.java:99)
05-02 19:15:44.599: E/AndroidRuntime(19839): at android.support.v4.view.ViewPager.addNewItem(ViewPager.java:800)
05-02 19:15:44.599: E/AndroidRuntime(19839): at android.support.v4.view.ViewPager.populate(ViewPager.java:991)
05-02 19:15:44.599: E/AndroidRuntime(19839): at android.support.v4.view.ViewPager.populate(ViewPager.java:880)
05-02 19:15:44.599: E/AndroidRuntime(19839): at android.support.v4.view.ViewPager.onMeasure(ViewPager.java:1374)
05-02 19:15:44.599: E/AndroidRuntime(19839): at android.view.View.measure(View.java:15518)
05-02 19:15:44.599: E/AndroidRuntime(19839): at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:4825)
05-02 19:15:44.599: E/AndroidRuntime(19839): at android.widget.FrameLayout.onMeasure(FrameLayout.java:310)
05-02 19:15:44.599: E/AndroidRuntime(19839): at android.view.View.measure(View.java:15518)
05-02 19:15:44.599: E/AndroidRuntime(19839): at android.widget.LinearLayout.measureVertical(LinearLayout.java:847)
05-02 19:15:44.599: E/AndroidRuntime(19839): at android.widget.LinearLayout.onMeasure(LinearLayout.java:588)
05-02 19:15:44.599: E/AndroidRuntime(19839): at android.view.View.measure(View.java:15518)
05-02 19:15:44.599: E/AndroidRuntime(19839): at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:4825)
05-02 19:15:44.599: E/AndroidRuntime(19839): at android.widget.FrameLayout.onMeasure(FrameLayout.java:310)
05-02 19:15:44.599: E/AndroidRuntime(19839): at com.android.internal.policy.impl.PhoneWindow$DecorView.onMeasure(PhoneWindow.java:2434)
05-02 19:15:44.599: E/AndroidRuntime(19839): at android.view.View.measure(View.java:15518)
05-02 19:15:44.599: E/AndroidRuntime(19839): at android.view.ViewRootImpl.performMeasure(ViewRootImpl.java:1874)
05-02 19:15:44.599: E/AndroidRuntime(19839): at android.view.ViewRootImpl.measureHierarchy(ViewRootImpl.java:1089)
05-02 19:15:44.599: E/AndroidRuntime(19839): at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1265)
05-02 19:15:44.599: E/AndroidRuntime(19839): at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:989)
05-02 19:15:44.599: E/AndroidRuntime(19839): at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:4351)
05-02 19:15:44.599: E/AndroidRuntime(19839): at android.view.Choreographer$CallbackRecord.run(Choreographer.java:749)
05-02 19:15:44.599: E/AndroidRuntime(19839): at android.view.Choreographer.doCallbacks(Choreographer.java:562)
05-02 19:15:44.599: E/AndroidRuntime(19839): at android.view.Choreographer.doFrame(Choreographer.java:532)
05-02 19:15:44.599: E/AndroidRuntime(19839): at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:735)
05-02 19:15:44.599: E/AndroidRuntime(19839): at android.os.Handler.handleCallback(Handler.java:725)
05-02 19:15:44.599: E/AndroidRuntime(19839): at android.os.Handler.dispatchMessage(Handler.java:92)
05-02 19:15:44.599: E/AndroidRuntime(19839): at android.os.Looper.loop(Looper.java:137)
05-02 19:15:44.599: E/AndroidRuntime(19839): at android.app.ActivityThread.main(ActivityThread.java:5226)
05-02 19:15:44.599: E/AndroidRuntime(19839): at java.lang.reflect.Method.invokeNative(Native Method)
05-02 19:15:44.599: E/AndroidRuntime(19839): at java.lang.reflect.Method.invoke(Method.java:511)
05-02 19:15:44.599: E/AndroidRuntime(19839): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:795)
05-02 19:15:44.599: E/AndroidRuntime(19839): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:562)
05-02 19:15:44.599: E/AndroidRuntime(19839): at dalvik.system.NativeStart.main(Native Method)
这可能是因为您在列表中添加了三次相同的片段实例。您应该为每个页面创建一个新实例
此外,如果您还没有进入开发阶段,我建议您研究一下FragmentStatePagerAdapter。如果您想刷新主活动中片段的内容,那么这可能是一个更好的选择。您已经创建了SubscribedFragment()类的实例 然后将此对象的列表传递到ViewPager Adpeter:
FreedomPageAdapter(FragmentManager fm, List<Fragment> listFragment)
以下方法应为每个选项卡返回一个片段:
@Override
public Fragment getItem(int position) {
//Add some code
//to verify that it will not return null
return listFragment.get(position);
}
代码很好,但是请确保listFragment包含三个不同的片段,并且片段不为null。在我的例子中,我没有返回特定位置的片段实例。 我认为FragmentPagerAdapter接收到的是null,而不是标记。 这就是为什么它会显示“无法更改片段的标记”
如果我错了,请纠正我。在我的例子中,这是由于返回了一些null片段,而getItem(position)函数没有处理这些片段。希望它能帮助别人。很可能是这样,您发送的片段实例为空。永远不要将片段实例发送为空。
public static MyFragment getInstance() {
MyFragment myFragment = new MyFragment();
return myFragment;
}
在寻呼机适配器中,始终使用@覆盖
公共片段getItem(int位置){
返回碎片[位置];
}
或
根据你的碎片清单。也请选择链接
注意:-永远不要将上下文内存用作静态内存请参阅我的相关问题:@CorneliuDascalu那么使用
FragmentStatePagerAdapter
可以解决问题吗?还有什么必要的吗,比如如何处理savedInstanceState
?多么模糊的错误。。。StackOverflow&再次拯救令人敬畏的用户!你能帮我解决这个问题吗?这与这个问题非常相似。但我确实需要添加具有相同类的实例。
fragmentList.add((Fragment)savedListFragment);
viewPager.setAdapter(new FreedomPageAdapter(fragmentManager(), fragmentList));
@Override
public Fragment getItem(int position) {
//Add some code
//to verify that it will not return null
return listFragment.get(position);
}
public static MyFragment getInstance() {
MyFragment myFragment = new MyFragment();
return myFragment;
}
@Override
public Fragment getItem(int position) {
return fragments.get(position);
}