布局

代码

mViewPager = (ViewPager) view.findViewById(R.id.view_pager);         mTabLayout = (TabLayout) view.findViewById(R.id.tab_layout);         initTabList();         mAdapter = new TabLayoutFragmentAdapter(getChildFragmentManager(), mTabList, getActivity(), mFragments, mTabImgs);         mViewPager.setAdapter(mAdapter);         mViewPager.setCurrentItem(0);         mTabLayout.setupWithViewPager(mViewPager);         mTabLayout.setTabMode(TabLayout.MODE_FIXED);//设置TabLayout的模式         for (int i = 0; i < mTabLayout.getTabCount(); i++) {             mTabLayout.getTabAt(i).setCustomView(mAdapter.getTabView(i));         }         mTabLayout.addOnTabSelectedListener(this);//设置TabLayout的选中监听

这里需要注意的就是TabLayout的使用。TabLayou配合ViewPager使用。要用  mTabLayout.setupWithViewPager(mViewPager);使二者联系起来。另外这里面使用的是customView，当然TabLayout自带方法也可实现icon+text的效果。也就是效果：TabLayout  + ViewPager 2

根据Tab选中状态显示Tab键效果

@Override    public void onTabSelected(TabLayout.Tab tab) {        setTabSelectedState(tab);    }     @Override    public void onTabUnselected(TabLayout.Tab tab) {        setTabUnSelectedState(tab);    }      @Override    public void onTabReselected(TabLayout.Tab tab) {     }     private void setTabSelectedState(TabLayout.Tab tab) {        View customView = tab.getCustomView();        TextView tabText = (TextView) customView.findViewById(R.id.tv_tab_text);        ImageView tabIcon = (ImageView) customView.findViewById(R.id.iv_tab_icon);        tabText.setTextColor(ContextCompat.getColor(getActivity(), R.color.colorPrimary));        String s = tabText.getText().toString();        if (getString(R.string.item_home).equals(s)) {            tabIcon.setImageResource(R.drawable.home_fill);        } else if (getString(R.string.item_location).equals(s)) {            tabIcon.setImageResource(R.drawable.location_fill);        } else if (getString(R.string.item_like).equals(s)) {            tabIcon.setImageResource(R.drawable.like_fill);        } else if (getString(R.string.item_person).equals(s)) {            tabIcon.setImageResource(R.drawable.person_fill);        }    }     private void setTabUnSelectedState(TabLayout.Tab tab) {        View customView = tab.getCustomView();        TextView tabText = (TextView) customView.findViewById(R.id.tv_tab_text);        ImageView tabIcon = (ImageView) customView.findViewById(R.id.iv_tab_icon);        tabText.setTextColor(ContextCompat.getColor(getActivity(), R.color.black_1));        String s = tabText.getText().toString();        if (getString(R.string.item_home).equals(s)) {            tabIcon.setImageResource(R.drawable.home);        } else if (getString(R.string.item_location).equals(s)) {            tabIcon.setImageResource(R.drawable.location);        } else if (getString(R.string.item_like).equals(s)) {            tabIcon.setImageResource(R.drawable.like);        } else if (getString(R.string.item_person).equals(s)) {            tabIcon.setImageResource(R.drawable.person);        }    }

这里面不用设置defaultFragment，TabLayout会默认显示***个;

另外，这里也贴出使用TabLayout自带方法来实现效果代码

值得说的是，自带方法不能自定义icon和text的间距。用起来很方便，但是可能不是你要求的那个尺寸大小。我没有去深究这里面的源码。如果有人知道这个自带方法怎么改变的，也请告知一下。

 mViewPager = (ViewPager) view.findViewById(R.id.view_pager);         mTabLayout = (TabLayout) view.findViewById(R.id.tab_layout);         initTabList();         mAdapter = new TabLayoutFragment2Adapter(getChildFragmentManager(), mTabList, getActivity(), mFragments, mTabImgs);         mViewPager.setAdapter(mAdapter);         mViewPager.setCurrentItem(0);         mTabLayout.setupWithViewPager(mViewPager);         mTabLayout.setTabMode(TabLayout.MODE_FIXED); //        for (int i = 0; i < mTabLayout.getTabCount(); i++) { //            mTabLayout.getTabAt(i).setCustomView(mAdapter.getTabView(i)); //        }         mTabLayout.addOnTabSelectedListener(this); //        mViewPager.setCurrentItem(0);         mTabLayout.getTabAt(0).setIcon(R.drawable.home_fill);//自有方法添加icon         mTabLayout.getTabAt(1).setIcon(R.drawable.location);         mTabLayout.getTabAt(2).setIcon(R.drawable.like);         mTabLayout.getTabAt(3).setIcon(R.drawable.person);

Tab切换

@Override     public void onTabSelected(TabLayout.Tab tab) { //        setTabSelectedState(tab);//这个也无需使用         resetTabIcon();         int position = tab.getPosition();         Log.e("Kevin", "position--->" + position);         switch (position) {             case 0:                 tab.setIcon(R.drawable.home_fill);                 break;             case 1:                 tab.setIcon(R.drawable.location_fill);                 break;             case 2:                 tab.setIcon(R.drawable.like_fill);                 break;             case 3:                 tab.setIcon(R.drawable.person_fill);                 break;          }     }   private void resetTabIcon() {         mTabLayout.getTabAt(0).setIcon(R.drawable.home);         mTabLayout.getTabAt(1).setIcon(R.drawable.location);         mTabLayout.getTabAt(2).setIcon(R.drawable.like);         mTabLayout.getTabAt(3).setIcon(R.drawable.person);     }