我应该如何选择一个标签在TabLayout编程?
TabLayout tabLayout = (TabLayout) findViewById(R.id.tabs);
tabLayout.setupWithViewPager(viewPager);
我应该如何选择一个标签在TabLayout编程?
TabLayout tabLayout = (TabLayout) findViewById(R.id.tabs);
tabLayout.setupWithViewPager(viewPager);
当前回答
如果你正在使用TabLayout和viewPager,那么这有助于你。你可以在addOnpagelistener中使用ViewPager设置TabLayout。
如果你想直接设置TabLayout的位置(不是点击Tab个人)试试下面的代码TabLayout . gettabat (position_you_want_to_set).select()
/* will be invoked whenever the page changes or is incrementally scrolled*/
viewPager.addOnPageChangeListener(new ViewPager.OnPageChangeListener() {
@Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
}
@Override
public void onPageSelected(int position) {
tabLayout.getTabAt(position).select();
}
@Override
public void onPageScrollStateChanged(int state) {
}
});
其他回答
我是这样解决的:
void selectPage(int pageIndex){
tabLayout.setScrollPosition(pageIndex,0f,true);
viewPager.setCurrentItem(pageIndex);
}
默认情况下,如果你选择一个选项卡,它将高亮显示。如果你想选择显式意味着使用给定的注释代码在onTabSelected(TabLayout。标签标签)与您指定的标签索引位置。这段代码将解释使用viewpager在选项卡选择位置上更改片段。
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);
}
}
}
你应该使用viewPager来使用viewpage . setcurrentitem ()
viewPager.setCurrentItem(n);
tabLayout.setOnTabSelectedListener(new TabLayout.OnTabSelectedListener() {
@Override
public void onTabSelected(TabLayout.Tab tab) {
viewPager.setCurrentItem(tab.getPosition());
}
@Override
public void onTabUnselected(TabLayout.Tab tab) {
}
@Override
public void onTabReselected(TabLayout.Tab tab) {
}
});
我使用TabLayout切换片段。它在大多数情况下都是有效的,除了当我试图以编程方式使用tab.select(),我的TabLayout选择一个选项卡时。OnTabSelectedListener将触发onTabSelected(TabLayout。Tab Tab),这会让我很伤心。我正在寻找一种不触发侦听器的方法来做程序化选择。
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");
}
}
这里,tabLayout是绑定到XML中的tabLayout对象的内存变量。我不使用滚动标签功能,所以我把它也删除了。
这可能不是最终的解决方案,它需要你使用TabLayout和一个ViewPager,但这是我解决它的方法:
void selectPage(int pageIndex)
{
viewPager.setCurrentItem(pageIndex);
tabLayout.setupWithViewPager(viewPager);
}
我测试了使用这段代码对性能的影响有多大,首先在Android Studio中运行该方法时查看CPU和内存监视器,然后将其与我自己在页面之间导航时(使用滑动手势)对CPU和内存的负载进行比较,结果发现差异并不大,所以至少这不是一个可怕的解决方案……
希望这能帮助到一些人!