TabLayout与ViewPager结合时不显示Tab标题

当我们将TabLayout与ViewPager结合时,会出现Tab标题不显示的问题. mTabLayout.setupWithViewPager(viewPager);从源码里找答案.先看下方法调用流程大致流程如图,这里只给出populateFromPagerAdapter()方法源码.void populateFromPagerAdapter() { removeAllTabs(); if (mPagerAdapter != null) { //返回ViewPager设置的PagerAdapter.getCount() final int adapterCount = mPagerAdapter.getCount(); for (int i = 0; i < adapterCount; i++) { //重新添加,并通过PagerAdapter.getPageTitle()为tab设置标题 addTab(newTab().setText(mPagerAdapter.getPageTitle(i)), false); } // Make sure we reflect the currently set ViewPager item if (mViewPager != null && adapterCount > 0) { final int curItem = mViewPager.getCurrentItem(); if (curItem != getSelectedTabPosition() && curItem < getTabCount()) { selectTab(getTabAt(curItem)); } } } }这个方法的第一步 removeAllTabs();./** * Remove all tabs from the action bar and deselect the current tab. */ public void removeAllTabs() { // Remove all the views for (int i = mTabStrip.getChildCount() - 1; i >= 0; i–) { removeTabViewAt(i); } for (final Iterator<Tab> i = mTabs.iterator(); i.hasNext();) { final Tab tab = i.next(); i.remove(); tab.reset(); sTabPool.release(tab); } mSelectedTab = null; }移除了TabLayout添加的tab.下一步final int adapterCount = mPagerAdapter.getCount();则是返回你设置给ViewPager的PagerAdapter的getCount()返回值.然后在for循环中 addTab(newTab().setText(mPagerAdapter.getPageTitle(i)), 添加新的tab,并将PagerAdapter.getPageTitle()返回值设置为tab的标题.因此,当ViewPager与TabLayout结合使用时,不必给TabLayout添加tab,也就是不用调用TabLayout.addTab().