我正在开发一个带有 viewpager 选项卡的应用程序。我正在使用 fragmentstatepageradapter 来处理 viewpager 选项卡。我正在使用 childFragmentmanager 将第一个片段替换为嵌套片段,并将当前片段添加到后台堆栈。控制流程如下。
第一个选项卡片段 A -> 替换为片段 B -> 替换为片段 C -> 替换为片段 D。
现在,当我单击片段 D 中的特定按钮时,我需要返回片段 B,从后台堆栈中清除片段 C、D。
我试过了
getSupportFragmentManager().popBackStack(
getSupportFragmentManager().getBackStackEntryAt(0).getId(), FragmentManager.POP_BACK_STACK_INCLUSIVE);
但不成功。有人能告诉我清除后台堆栈并从片段 D 导航到片段 B 的正确方法吗?这是我的片段状态页面适配器
public class HomeViewPagerAdapter extends FragmentStatePagerAdapter {
CharSequence Titles[]; // This will Store the Titles of the Tabs which are
Context mcontext; // Going to be passed when ViewPagerAdapter is
int[] images; // created
int NumbOfTabs;
private Fragment mFragmentAtPos0;
SparseArray<Fragment> registeredFragments = new SparseArray<Fragment>();
Fragment homefragment;
Context context;
FragmentManager fragmentmanager;
public HomeViewPagerAdapter(Context context, FragmentManager fm,
CharSequence mTitles[], int mNumbOfTabsumb) {
super(fm);
this.Titles = mTitles;
this.NumbOfTabs = mNumbOfTabsumb;
this.context = context;
this.fragmentmanager = fm;
}
@Override
public Fragment getItem(int position) {
// TODO Auto-generated method stub
if (position == 0)
{
SharedPreferences LoginPref = this.context.getSharedPreferences("login_credentials", Context.MODE_PRIVATE);
if (LoginPref.contains("login_pref") && LoginPref.getString("login_pref", "").equals("loggedin")) {
homefragment = new SearchHomeFragment();
} else {
homefragment = new HomeScreenFragment();
}
return homefragment;
} else if (position == 1)
{
HomeCategoriesFragment homecategoriesfragment = new HomeCategoriesFragment();
return homecategoriesfragment;
} else if (position == 2)
{
HomePriceComparisonFragment homepricecomparefragment = new HomePriceComparisonFragment();
return homepricecomparefragment;
} else if (position == 3)
{
HomeEnterFeedFragment homeenterfeedfragment = new HomeEnterFeedFragment();
return homeenterfeedfragment;
} else {
HomeMoreFragment homemorefragment = new HomeMoreFragment();
return homemorefragment;
}
}
@Override
public int getItemPosition(Object object) {
Log.e("getItemPosition", "getItemPosition");
if (object instanceof HomeScreenFragment)
return POSITION_NONE;
else
return POSITION_UNCHANGED;
}
@Override
public Object instantiateItem(ViewGroup container, int position) {
Fragment fragment = (Fragment) super.instantiateItem(container, position);
registeredFragments.put(position, fragment);
return fragment;
}
@Override
public void destroyItem(ViewGroup container, int position, Object object) {
registeredFragments.remove(position);
if(MyTabFragment.shouldDestroy) {
super.destroyItem(container, position, object);
MyTabFragment.shouldDestroy=false;
}
}
public void resetScreendata() {
if (homefragment != null) {
homefragment.getChildFragmentManager().popBackStack(null, FragmentManager.POP_BACK_STACK_INCLUSIVE);
}
}
public void resettoSearch() {
if (homefragment != null) {
homefragment.getChildFragmentManager().popBackStack("search", FragmentManager.POP_BACK_STACK_INCLUSIVE);
}
}
public Fragment getRegisteredFragment(int position) {
return registeredFragments.get(position);
}
@Override
public CharSequence getPageTitle(int position) {
// TODO Auto-generated method stub
return Titles[position];
}
@Override
public int getCount() {
// TODO Auto-generated method stub
return NumbOfTabs;
}
}
这就是我替换片段的方式。
final SearchHomeFragment newFragment = new SearchHomeFragment();
FragmentTransaction transaction =getChildFragmentManager().beginTransaction();
transaction.setCustomAnimations(R.anim.slide_in_right,R.anim.slide_out_left,R.anim.slide_in_left,R.anim.slide_out_right);
transaction.replace(R.id.fragment_mainLayout, newFragment);
transaction.addToBackStack("search");
transaction.commit();