我有一个 TabLayout，里面有 ViewPager.我需要在标签布局(材料设计)中动态添加和删除标签.我可以动态添加选项卡，但是在删除选项卡时，选项卡正在正确删除.但是viewpager最后一项被删除了.所以选项卡没有显示特定的片段.仅供参考，我使用了 FragmentPagerAdapter.
I have a TabLayout and inside that I have ViewPager. I need to dynamically add and remove tab in tablayout(material design). I can able to add the tabs dynamically but while removing the tab, tab is removing correctly. But viewpager last item is deleted. So tab is not showing specific fragment. FYI i have used FragmentPagerAdapter.
我已经按照这个教程来实现这个
I have followed this tutorial to implement this
https://androidbelieve.com/navigation-drawer-with-swipe-tabs-using-design-support-library
public class TabFragment extends Fragment {
public static TabLayout tabLayout;
public static ViewPager viewPager;
public static int int_items = 2;
private MyNewsFragment mMyNewsFragment;
private ArrayList<TabFragmentModelClass> mFragmentArrayList;
private TabLayoutAdapter mTabLayoutAdapter;
@Nullable
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
mMyNewsFragment = new MyNewsFragment();
/**
*Inflate tab_layout and setup Views.i;;a
*/
View x = inflater.inflate(R.layout.tab_layout, null);
tabLayout = (TabLayout) x.findViewById(R.id.tabs);
tabLayout.setTabMode(TabLayout.MODE_SCROLLABLE); // scorllable tab
tabLayout.setTabGravity(TabLayout.GRAVITY_FILL); // tab name fill parent
viewPager = (ViewPager) x.findViewById(R.id.viewpager);
mFragmentArrayList = new ArrayList<>();
mFragmentArrayList.add(new TabFragmentModelClass(new MyNewsSelectionFragment(), "", ""));
mFragmentArrayList.add(new TabFragmentModelClass(mMyNewsFragment, "", getResources().getString(R.string.mynews)));
mFragmentArrayList.add(new TabFragmentModelClass(new BreakingNewsFragment(), "", getResources().getString(R.string.breakingnews)));
// Selected news from shared preference
ArrayList<MyNewsSharedPreferenceModelClass> tempSharedPreferenceModelClass = new MyNewsSharedPreferenceClass().loadFavorites(getActivity());
for (int i = 0; i < tempSharedPreferenceModelClass.size(); i++) {
mFragmentArrayList.add(new TabFragmentModelClass(new CategoreyNewsFragment(tempSharedPreferenceModelClass.get(i).getmCatID()), tempSharedPreferenceModelClass.get(i).getmCatID(),
tempSharedPreferenceModelClass.get(i).getmCatName()));
}
}
/**
*Set an Apater for the View Pager
*/
mTabLayoutAdapter = new TabLayoutAdapter(getChildFragmentManager(), mFragmentArrayList);
viewPager.setAdapter(mTabLayoutAdapter);
viewPager.setOffscreenPageLimit(mFragmentArrayList.size());
tabLayout.setupWithViewPager(viewPager);
viewPager.addOnPageChangeListener(new ViewPager.OnPageChangeListener() {
@Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
}
@Override
public void onPageSelected(int position) {
tabLayout.getTabAt(position);
}
@Override
public void onPageScrollStateChanged(int state) {
if (state == 1) {
updateMyNewsFragment();
}
}
});
/**
* Now , this is a workaround ,
* The setupWithViewPager dose't works without the runnable .
* Maybe a Support Library Bug .
*/
tabLayout.post(new Runnable() {
@Override
public void run() {
tabLayout.getTabAt(0).setIcon(R.mipmap.mynewselection);
tabLayout.setOnTabSelectedListener(new TabLayout.OnTabSelectedListener() {
@Override
public void onTabSelected(TabLayout.Tab tab) {
viewPager.setCurrentItem(tab.getPosition());
switch (tab.getPosition()) {
case 1:
System.out.println("000000000000000000000 ");
updateMyNewsFragment();
break;
}
}
@Override
public void onTabUnselected(TabLayout.Tab tab) {
}
@Override
public void onTabReselected(TabLayout.Tab tab) {
}
});
}
});
return x;
}
/**
* update the mynews selection
* this method trigger from the MainNewsActivity
*/
public void updateMyNewsFragment() {
if (ApplicationController.getInstance().getBoolPref(CommonVariableInterFace.isNewsSelected)) {
mMyNewsFragment.sendMyNewsRequest();
ApplicationController.getInstance().setBoolPref(CommonVariableInterFace.isNewsSelected, false);
}
}
/**
* update the tab values
* this method trigger from the MainNewsActivity
* if value is zero need to add in tab
* if value is one need to remove in tab
*/
public void updateTabvalue(String catId, String catName, int value) {
if (value == 0) { // add the value in tab
mFragmentArrayList.add(new TabFragmentModelClass(new CategoreyNewsFragment(catId), catId,
catName));
} else { // Removing the tab
for (int i = 0; i < mFragmentArrayList.size(); i++) {
if (mFragmentArrayList.get(i).getmCatID().equalsIgnoreCase(catId)) {
Log.i("-----same id ", catId);
mFragmentArrayList.remove(i);
mTabLayoutAdapter = new TabLayoutAdapter(getChildFragmentManager(), mFragmentArrayList);
viewPager.setAdapter(mTabLayoutAdapter);
}
}
}
mTabLayoutAdapter.notifyDataSetChanged();
viewPager.setOffscreenPageLimit(mFragmentArrayList.size());
tabLayout.getTabAt(0).setIcon(R.mipmap.mynewselection);
tabLayout.setupWithViewPager(viewPager);
tabLayout.post(new Runnable() {
@Override
public void run() {
tabLayout.getTabAt(0).setIcon(R.mipmap.mynewselection);
tabLayout.setOnTabSelectedListener(new TabLayout.OnTabSelectedListener() {
@Override
public void onTabSelected(TabLayout.Tab tab) {
viewPager.setCurrentItem(tab.getPosition());
switch (tab.getPosition()) {
case 1:
updateMyNewsFragment();
break;
}
}
@Override
public void onTabUnselected(TabLayout.Tab tab) {
}
@Override
public void onTabReselected(TabLayout.Tab tab) {
}
});
}
});
}
public void openSpecificTab() {
// tabLayout.settab
// tabLayout.se
}
}
适配器代码:
public class TabLayoutAdapter extends FragmentPagerAdapter {
private long baseId = 0;
ArrayList<TabFragmentModelClass> fragmentAdapterArrayList;
public TabLayoutAdapter(FragmentManager fm, ArrayList<TabFragmentModelClass> fragmentArrayList) {
super(fm);
fragmentAdapterArrayList = fragmentArrayList;
}
@Override
public Fragment getItem(int position) {
if (position == 0)
return fragmentAdapterArrayList.get(position).getmFragment();
if (position == 1)
return fragmentAdapterArrayList.get(position).getmFragment();
if (position == 2)
return fragmentAdapterArrayList.get(position).getmFragment();
return new CategoreyNewsFragment().newInstance(fragmentAdapterArrayList.get(position).getmCatID());
}
@Override
public int getCount() {
return fragmentAdapterArrayList.size();
}
//this is called when notifyDataSetChanged() is called
@Override
public int getItemPosition(Object object) {
// refresh all fragments when data set changed
return TabLayoutAdapter.POSITION_NONE;
}
@Override
public long getItemId(int position) {
// give an ID different from position when position has been changed
return baseId + position;
}
/**
* Notify that the position of a fragment has been changed.
* Create a new ID for each position to force recreation of the fragment
*
* @param n number of items which have been changed
*/
public void notifyChangeInPosition(int n) {
// shift the ID returned by getItemId outside the range of all previous fragments
baseId += getCount() + n;
}
/**
* // * This method returns the title of the tab according to the position.
* //
*/
@Override
public CharSequence getPageTitle(int position) {
return fragmentAdapterArrayList.get(position).getmCatName();
}
}
Remove tab from TabLayout
Remove tab from TabLayout
...
public void removeTab(int position) {
if (mTabLayout.getTabCount() >= 1 && position<mTabLayout.getTabCount()) {
mTabLayout.removeTabAt(position);
mPagerAdapter.removeTabPage(position);
}
}
...
将 removeTabPage 方法添加到您的 PagerAdapter
Add a removeTabPage method to your PagerAdapter
...
public void removeTabPage(int position) {
if (!tabItems.isEmpty() && position<tabItems.size()) {
tabItems.remove(position);
notifyDataSetChanged();
}
}
...
添加一个标签
...
private void addTab(String title) {
mTabLayout.addTab(mTabLayout.newTab().setText(title));
mPagerAdapter.addTabPage(title);
}
...
将 addTabPage 方法添加到您的 PagerAdapter
Add a addTabPage method to your PagerAdapter
...
public void addTabPage(String title) {
tabItems.add(title);
notifyDataSetChanged();
}
...
查看此示例代码以获取完整示例:...samples/SupportDesignDemos/src/com/example/android/support/design/widget/TabLayoutUsage.java
Check out this sample code for a full example: ...samples/SupportDesignDemos/src/com/example/android/support/design/widget/TabLayoutUsage.java
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