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

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。

其他回答

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!

TabLayout jobTabs = v.findViewById(R.id.jobTabs);
ViewPager jobFrame = v.findViewById(R.id.jobPager);
jobFrame.addOnPageChangeListener(new TabLayout.TabLayoutOnPageChangeListener(jobTabs));

这将选择标签作为视图分页器滑动页面

为你的viewpager添加:

 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处理程序,以防止crash outofmemory

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

科特林修复

viewPager.currentItem = 0

tabs.setupWithViewPager(viewPager)

如果碰巧你的默认选项卡是第一个(0),而你碰巧切换到一个片段,那么你必须手动替换第一次的片段。这是因为在注册侦听器之前选择了选项卡。

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;
}

或者,你可以考虑调用getTabAt(0).select()并像这样重写onTabReselected:

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

这是可行的,因为你实际上是在每个选项卡重新选择上替换片段。