TabLayout tab selection

问题:

How to select tab in TabLayout programmatically?

 TabLayout tabLayout = (TabLayout) findViewById(R.id.tabs);
 tabLayout.setupWithViewPager(viewPager);

回答1:

If you know the index of the tab you want to select, you can do it like so:

TabLayout tabLayout = (TabLayout) findViewById(R.id.tabs);
TabLayout.Tab tab = tabLayout.getTabAt(someIndex);
tab.select();

This technique works even if you're using the TabLayout by itself without a ViewPager (which is atypical, and probably bad practice, but I've seen it done).

回答2:

This is how I solved it:

void selectPage(int pageIndex){
    tabLayout.setScrollPosition(pageIndex,0f,true);
    viewPager.setCurrentItem(pageIndex);
}

回答3:

Use this:

<android.support.design.widget.TabLayout
    android:id="@+id/patienthomescreen_tabs"
    android:layout_width="match_parent"
    android:layout_height="72sp"
    app:tabGravity="fill"
    app:tabMode="fixed"
    app:tabIndicatorColor="@android:color/white"
    app:tabSelectedTextColor="@color/green"/>

After in OnClickListener:

TabLayout tabLayout = (TabLayout) findViewById(R.id.patienthomescreen_tabs);
TabLayout.Tab tab = tabLayout.getTabAt(someIndex);
tab.select();

回答4:

This is probably not the ultimate solution, and it requires that you use the TabLayout together with a ViewPager, but this is how I solved it:

void selectPage(int pageIndex)
{
    viewPager.setCurrentItem(pageIndex);
    tabLayout.setupWithViewPager(viewPager);
}

I tested how big the performance impact of using this code is by first looking at the CPU- and memory monitors in Android Studio while running the method, then comparing it to the load that was put on the CPU and memory when I navigated between the pages myself (using swipe gestures), and the difference isn't significantly big, so at least it's not a horrible solution...

Hope this helps someone!

回答5:

use tabs.getTabAt(2).select();

回答6:

If you can't use tab.select() and you don't want to use a ViewPager, you can still programmatically select a tab. If you're using a custom view through TabLayout.Tab setCustomView(android.view.View view) it is simpler. Here's how to do it both ways.

// if you've set a custom view
void updateTabSelection(int position) {
    // get the position of the currently selected tab and set selected to false
    mTabLayout.getTabAt(mTabLayout.getSelectedTabPosition()).getCustomView().setSelected(false);
    // set selected to true on the desired tab
    mTabLayout.getTabAt(position).getCustomView().setSelected(true);
    // move the selection indicator
    mTabLayout.setScrollPosition(position, 0, true);

    // ... your logic to swap out your fragments
}

If you aren't using a custom view then you can do it like this

// if you are not using a custom view
void updateTabSelection(int position) {
    // get a reference to the tabs container view
    LinearLayout ll = (LinearLayout) mTabLayout.getChildAt(0);
    // get the child view at the position of the currently selected tab and set selected to false
    ll.getChildAt(mTabLayout.getSelectedTabPosition()).setSelected(false);
    // get the child view at the new selected position and set selected to true
    ll.getChildAt(position).setSelected(true);
    // move the selection indicator
    mTabLayout.setScrollPosition(position, 0, true);

    // ... your logic to swap out your fragments
}

Use a StateListDrawable to toggle between selected and unselected drawables or something similar to do what you want with colors and/or drawables.

回答7:

Just set viewPager.setCurrentItem(index) and the associated TabLayout would select the respective tab.

回答8:

try this

    new Handler().postDelayed(
            new Runnable(){
                @Override
                public void run() {
                    if (i == 1){
                        tabLayout.getTabAt(0).select();
                    } else if (i == 2){
                        tabLayout.getTabAt(1).select();
                    }
                }
            }, 100);

回答9:

You can try solving it with this:

TabLayout tabLayout = (TabLayout) findViewById(R.id.tabs);
tabLayout.setupWithViewPager(mViewPager);

TabLayout.Tab tab = tabLayout.getTabAt(pos);
if (tab != null) {
    tab.select();
}

回答10:

add for your viewpager:

 viewPager.addOnPageChangeListener(new ViewPager.OnPageChangeListener() {

            @Override
            public void onPageSelected(int position) {
                array.clear();
                switch (position) {
                    case 1:
                        //like a example
                        setViewPagerByIndex(0);
                        break;
                }
            }

            @Override
            public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
            }

            @Override
            public void onPageScrollStateChanged(int state) {
            }
        });

//on handler to prevent crash outofmemory

private void setViewPagerByIndex(final int index){
    Application.getInstance().getHandler().post(new Runnable() {
        @Override
        public void run() {
            viewPager.setCurrentItem(index);
        }
    });
}

回答11:

I am using TabLayout to switch fragments. It works for the most part, except whenever I tried to select a tab programmatically using tab.select(), my TabLayout.OnTabSelectedListener would trigger the onTabSelected(TabLayout.Tab tab), which would cause me much grief. I was looking for a way to do programmatic selection without triggering the listener.

So I adapted @kenodoggy 's answer to my use. I was further facing a problem where some of the internal objects would return null (because they weren't created yet, because I was answering onActivityResult() from my fragment, which occurs before onCreate() in the case the activity is singleTask or singleInstance) so I wrote up a detailed if/else sequence which would report the error and fall through without the NullPointerException that would otherwise trigger. I use Timber for logging, if you're not using that substitute with Log.e().

void updateSelectedTabTo(int position) {
    if (tabLayout != null){
        int selected = tabLayout.getSelectedTabPosition();
        if (selected != -1){
            TabLayout.Tab oldTab = tabLayout.getTabAt(0);
            if (oldTab != null){
                View view = oldTab.getCustomView();
                if (view != null){
                    view.setSelected(false);
                }
                else {
                    Timber.e("oldTab customView is null");
                }
            }
            else {
                Timber.e("oldTab is null");
            }
        }
        else {
            Timber.e("selected is -1");
        }
        TabLayout.Tab newTab = tabLayout.getTabAt(position);
        if (newTab != null){
            View view = newTab.getCustomView();
            if (view != null){
                view.setSelected(false);
            }
            else {
                Timber.e("newTab customView is null");
            }
        }
        else {
            Timber.e("newTab is null");
        }
    }
    else {
        Timber.e("tablayout is null");
    }
}

Here, tabLayout is my memory variable bound to the TabLayout object in my XML. And I don't use the scrolling tab feature so I removed that as well.

回答12:

By default if you select a tab it will be highlighted. If you want to select Explicitly means use the given commented code under onTabSelected(TabLayout.Tab tab) with your specified tab index position. This code will explains about change fragment on tab selected position using viewpager.

public class GalleryFragment extends Fragment implements TabLayout.OnTabSelectedListener 
{
private ViewPager viewPager;public ViewPagerAdapter adapter;private TabLayout tabLayout;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_gallery, container, false);
viewPager = (ViewPager) rootView.findViewById(R.id.viewpager);
adapter = new ViewPagerAdapter(getChildFragmentManager());
adapter.addFragment(new PaymentCardFragment(), "PAYMENT CARDS");
adapter.addFragment(new LoyaltyCardFragment(), "LOYALTY CARDS");
viewPager.setAdapter(adapter);
tabLayout = (TabLayout) rootView.findViewById(R.id.tabs);
    tabLayout.setupWithViewPager(viewPager);
    tabLayout.setOnTabSelectedListener(this);
}

@Override
public void onTabSelected(TabLayout.Tab tab) {
    //This will be called 2nd when you select a tab or swipe using viewpager
    final int position = tab.getPosition();
    Log.i("card", "Tablayout pos: " + position);
    //TabLayout.Tab tabdata=tabLayout.getTabAt(position);
    //tabdata.select();
    tabLayout.post(new Runnable() {
        @Override
        public void run() {
            if (position == 0) {
                PaymentCardFragment paymentCardFragment = getPaymentCardFragment();
                if (paymentCardFragment != null) {
                   VerticalViewpager vp = paymentCardFragment.mypager;
                    if(vp!=null)
                    {
                      //vp.setCurrentItem(position,true);
                      vp.setCurrentItem(vp.getAdapter().getCount()-1,true);
                    }
                  }
            }
            if (position == 1) {
               LoyaltyCardFragment loyaltyCardFragment = getLoyaltyCardFragment();
                if (loyaltyCardFragment != null) {
                   VerticalViewpager vp = loyaltyCardFragment.mypager;
                    if(vp!=null)
                    {
                        vp.setCurrentItem(position);
                    }
                  }
            }
        }
    });
}

@Override
public void onTabUnselected(TabLayout.Tab tab) {
 //This will be called 1st when you select a tab or swipe using viewpager
}
@Override
public void onTabReselected(TabLayout.Tab tab) {
  //This will be called only when you select the already selected tab(Ex: selecting 3rd tab again and again)
}
 private PaymentCardFragment getLoyaltyCardFragment() {
    Fragment f = adapter.mFragmentList.get(viewPager.getCurrentItem());

   if(f instanceof PaymentCardFragment)
   {
    return (PaymentCardFragment) f;
   }
   return null;
 }
private LoyaltyCardFragment getPaymentCardFragment() {
    Fragment f = adapter.mFragmentList.get(viewPager.getCurrentItem());
    if(f instanceof LoyaltyCardFragment)
   {
    return (LoyaltyCardFragment) f;
   }
   return null;
 }
  class ViewPagerAdapter extends FragmentPagerAdapter {
   public List<Fragment> mFragmentList = new ArrayList<>();
    private final List<String> mFragmentTitleList = new ArrayList<>();
   public void addFragment(Fragment fragment, String title) {
   mFragmentList.add(fragment);
   mFragmentTitleList.add(title);
  }
 }
}

回答13:

If it so happens that your default tab is the first one(0) and you happen to switch to a fragment, then you must manually replace the fragment for the first time. This is because the tab is selected before the listener gets registered.

private TabLayout mTabLayout;

...

@Override
public View onCreateView(@NonNull LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
    View view = inflater.inflate(R.layout.fragment_tablayout, container, false);
    mTabLayout = view.findViewById(R.id.sliding_tabs);
    mTabLayout.addOnTabSelectedListener(mOnTabSelectedListener);

    getActivity().getSupportFragmentManager().beginTransaction()
        .replace(R.id.tabContent, MyFirstFragment.newInstance()).commit();
    return view;
}

Alternatively, you can consider calling getTabAt(0).select() and overriding onTabReselected like so:

@Override
public void onTabReselected(TabLayout.Tab tab) {
    // Replace the corresponding tab fragment.
}

This would work because you are essentially replacing the fragment on every tab reselect.

回答14:

This can help too

viewPager.addOnPageChangeListener(new ViewPager.OnPageChangeListener() {
    @Override
    public void onPageScrolled(int i, float v, int i1) {
    }

    @Override
    public void onPageSelected(int i) {
        tablayout.getTabAt(i).select();
    }

    @Override
    public void onPageScrollStateChanged(int i) {
    }
});

回答15:

You can set TabLayout position using following functions

public void setTab(){
 tabLayout.setScrollPosition(YOUR_SCROLL_INDEX,0,true);
 tabLayout.setSelected(true);
}

回答16:

If you have trouble understanding, this code can help you

private void MyTabLayout(){
    TabLayout.Tab myTab = myTabLayout.newTab(); // create a new tab
    myTabLayout.addTab(myTab); // add my new tab to myTabLayout
    myTab.setText("new tab"); 
    myTab.select(); // select the new tab
}

You can also add this to your code:

myTabLayout.setTabTextColors(getColor(R.color.colorNormalTab),getColor(R.color.colorSelectedTab));

回答17:

Try this way.

tabLayout.setTabTextColors(getResources().getColor(R.color.colorHintTextLight),
                           getResources().getColor(R.color.colorPrimaryTextLight));

回答18:

if u are using TabLayout without viewPager this helps

 mTitles = getResources().getStringArray(R.array.tabItems);
    mIcons = getResources().obtainTypedArray(R.array.tabIcons);
    for (int i = 0; i < mTitles.length; i++) {

        tabs.addTab(tabs.newTab().setText(mTitles[i]).setIcon(mIcons.getDrawable(i)));
        if (i == 0) {
            /*For setting selected position 0 at start*/
            Objects.requireNonNull(Objects.requireNonNull(tabs.getTabAt(i)).getIcon()).setColorFilter(ContextCompat.getColor(getApplicationContext(), R.color.colorPrimary), PorterDuff.Mode.SRC_IN);
        }
    }

    tabs.addOnTabSelectedListener(new TabLayout.OnTabSelectedListener() {
        @Override
        public void onTabSelected(TabLayout.Tab tab) {
            Objects.requireNonNull(tab.getIcon()).setColorFilter(ContextCompat.getColor(getApplicationContext(), R.color.colorPrimary), PorterDuff.Mode.SRC_IN);
        }

        @Override
        public void onTabUnselected(TabLayout.Tab tab) {
            Objects.requireNonNull(tab.getIcon()).setColorFilter(ContextCompat.getColor(getApplicationContext(), R.color.white), PorterDuff.Mode.SRC_IN);
        }

        @Override
        public void onTabReselected(TabLayout.Tab tab) {

        }
    });

回答19:

A bit late but might be a useful solution. I am using my TabLayout directly in my Fragment and trying to select a tab quite early in the Fragment's Lifecycle. What worked for me was to wait until the TabLayout finished drawing its child views by using android.view.View#post method. i.e:

int myPosition = 0;
myFilterTabLayout.post(() -> { filterTabLayout.getTabAt(myPosition).select(); });

回答20:

A combined solution from different answers is:

new Handler().postDelayed(() -> {

  myViewPager.setCurrentItem(position, true);

  myTabLayout.setScrollPosition(position, 0f, true);
},
100);