我有一个包含两个片段(片段A和B)的Main片段,以及工具栏中的上面有一个搜索图标用于搜索目的。我的问题是当我只是在片段A和B之间滑动并使用搜索图标做一些搜索过滤器时,该应用程序正常工作。但问题是当我在Main片段中添加另一个新片段C时,在启动应用程序并滑动到片段C然后向后滑动到片段A或B,然后单击搜索图标,应用程序崩溃。
这是崩溃日志
2019-03-07 22:52:10.616 28866-28866 / com.example.welsenho.questfy_tw E / AndroidRuntime:FATAL EXCEPTION:main Process:com.example.welsenho.questfy_tw,PID:28866 java.lang.ClassCastException:com。 example.welsenho.questfy_tw.MainActivityFragment.MostPopularFragment无法转换为com.example的com.example.welsenho.questfy_tw.MainUserActivity.MainActivity.searchFilter(MainActivity.java:303)中的com.example.welsenho.questfy_tw.MainActivityFragment.MainActivityLatestArticleFragment。 welsenho.questfy_tw.MainUserActivity.MainActivity.access $ 200(MainActivity.java:50)位于android.support.v7.widget.SearchView的com.example.welsenho.questfy_tw.MainUserActivity.MainActivity $ 1.onQueryTextChange(MainActivity.java:158)。在android.widget.TextView上的android.widget.TextView.sendOnTextChanged(TextView.java:9364)的android.support.v7.widget.SearchView $ 10.onTextChanged(SearchView.java:1715)上的onTextChanged(SearchView.java:1181)。 setText(TextView.java:5397)在android.widget.TextView.setText(TextView.java: 5250)android.widget.EditText.setText(EditText.java:113)android.widget.TextView.setText(TextView.java:5207)android.support.v7.widget.SearchView.onActionViewExpanded(SearchView.java:1295) )在android.support.v7.widget.Toolbar $ ExpandedActionViewMenuPresenter.expandItemActionView(Toolbar.java:2397)
它说片段A不能被投射到片段B,但我不明白的是,如果我没有滑到Fragment C(在片段A和B之间),一切都会好的但是在刷到片段C并滑动之后回到片段A或B并单击搜索图标,然后应用程序将崩溃
主要活动的代码
private void searchFilter(String inputText, ArrayList<FirebaseDatabaseGetSet> decidedFilterList) {
Log.d("TAG", "searchFilter");
ArrayList<FirebaseDatabaseGetSet> filterList = new ArrayList<>();
if (!filterList.isEmpty()) {
filterList.clear();
}
MainActivityLatestArticleFragment latestArticleFragment;
MostPopularFragment mostPopularFragment;
MainSubjectChooseFragment mainSubjectChooseFragment;
//MainSubjectChooseFragment mainSubjectChooseFragment(Fragment C) = (MainSubjectChooseFragment) getSupportFragmentManager().getFragments().get(0).getChildFragmentManager() .getFragments().get(2);
latestArticleFragment(Fragment A) = (MainActivityLatestArticleFragment) getSupportFragmentManager().getFragments().get(0).getChildFragmentManager().getFragments().get(0);
mostPopularFragment(Fragment B) = (MostPopularFragment) getSupportFragmentManager().getFragments().get(0).getChildFragmentManager().getFragments().get(1);
Log.d("TAG", "Fragment");
for (FirebaseDatabaseGetSet firebaseDatabaseGetSet : decidedFilterList) {
if (firebaseDatabaseGetSet.getTitle().toLowerCase().contains(inputText.toLowerCase())) {
filterList.add(firebaseDatabaseGetSet);
if (currentFilterPage == 0) {
Log.d("TAG", "Fragment0");
if (latestArticleFragment != null) {
Log.d("TAG", "notNull");
if (!filterList.isEmpty()) {
Log.d("TAG", "filter");
latestArticleFragment.returnFilterList(filterList);
}
}
} else if (currentFilterPage == 1) {
Log.d("TAG", "Fragment1");
if (mostPopularFragment != null) {
if (!filterList.isEmpty()) {
mostPopularFragment.returnFilterList(filterList);
}
}
}
}
}
}
主片段的代码
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
View view = inflater.inflate(R.layout.fragment_main_activity_tab, container, false);
tabLayout = view.findViewById(R.id.main_activity_tabLayout);
viewPager = view.findViewById(R.id.main_activity_viewpager);
viewPager.setAdapter(new MainActivityTabAdapter(getChildFragmentManager(), Locale.getDefault().getDisplayLanguage()));
tabLayout.post(new Runnable() {
@Override
public void run() {
tabLayout.setupWithViewPager(viewPager);
}
});
viewPager.addOnPageChangeListener(new ViewPager.OnPageChangeListener() {
@Override
public void onPageScrolled(int i, float v, int i1) {
mListener.getTabCurrentPage(i);
}
@Override
public void onPageSelected(int i) {
mListener.getTabCurrentPage(i);
}
@Override
public void onPageScrollStateChanged(int i) {
}
});
return view;
适配器的代码
@Override
public Fragment getItem(int i) {
switch (i){
case 0: return new MainActivityLatestArticleFragment();
case 1: return new MostPopularFragment();
case 2: return new MainSubjectChooseFragment();
}
return null;
}
@Override
public int getCount() {
return 3;
}
@Nullable
@Override
public CharSequence getPageTitle(int position) {
if (language.equals("中文")) {
switch (position) {
case 0:
return "最新文章";
case 1:
return "熱門文章";
case 2:
return "相關科系";
}
}else {
switch (position) {
case 0:
return "Latest Article";
case 1:
return "Most Popular";
case 2:
return "Program Select";
}
}
return null;
}
片段A和B中的代码仅用于从firebase检索数据并加载到recyclerView中。它说这个问题是由这行引起的:latestArticleFragment(Fragment A)=(MainActivityLatestArticleFragment)getSupportFragmentManager()。getFragments()。get(0).getChildFragmentManager()。getFragments()。get(0);部分,但我不明白,当我不想尝试滑动片段C一切顺利,但如果我滑到片段C并刷回片段A和B然后单击搜索图标该应用程序将坠毁。我已经被这个问题困扰了3天已经尝试了一些解决方案,但它无法正常工作。任何人都可以解释为什么我有这个问题以及如何解决它?
我的预感是,如果您将屏幕页面限制设置为大于1,您将不会遇到问题。所以在你的MainFragment的onCreateView
中添加以下一行:
viewPager = view.findViewById(R.id.main_activity_viewpager);
// add below line
viewpager.setOffscreenPageLimit(2)
viewPager.setAdapter(new MainActivityTabAdapter(getChildFragmentManager(), Locale.getDefault().getDisplayLanguage()));