将Tab栏居中的方法

原始tab：

居中后的tab（边缘效果是截图的问题）：

改变方法如下：

找到Android SlidingTabLayout源代码，在Android SlidingTabLayout源代码中有一个方法：
private void populateTabStrip();

 private void populateTabStrip() {
         final PagerAdapter adapter = mViewPager.getAdapter();
         final View.OnClickListener tabClickListener = new TabClickListener();

         for (int i = 0; i < adapter.getCount(); i++) {
             View tabView = null;
             TextView tabTitleView = null;

             if (mTabViewLayoutId != 0) {
                 // If there is a custom tab view layout id set, try and inflate
                 // it
                 tabView = LayoutInflater.from(getContext()).inflate(mTabViewLayoutId, mTabStrip, false);
                 tabTitleView = (TextView) tabView.findViewById(mTabViewTextViewId);
             }

             if (tabView == null) {
                 tabView = createDefaultTabView(getContext());
             }

             if (tabTitleView == null && TextView.class.isInstance(tabView)) {
                 tabTitleView = (TextView) tabView;
             }

             tabTitleView.setText(adapter.getPageTitle(i));
             tabView.setOnClickListener(tabClickListener);

             mTabStrip.addView(tabView);
         }
     }

这是谷歌官方实现的Android SlidingTabLayout添加底部选项卡Tab的代码，如果为了实现前文所述的将Tab均分水平位置空间，则需要修改此方法，在此方法中添加如下代码：

 LinearLayout.LayoutParams layoutParams= new LinearLayout.LayoutParams(0, LayoutParams.WRAP_CONTENT, 1.0f);
             tabView.setLayoutParams(layoutParams);

这两段代码将tab view水平均分放置。

最终将private void populateTabStrip()改进成这样：

 private void populateTabStrip() {
         final PagerAdapter adapter = mViewPager.getAdapter();
         final View.OnClickListener tabClickListener = new TabClickListener();

         for (int i = 0; i < adapter.getCount(); i++) {
             View tabView = null;
             TextView tabTitleView = null;

             if (mTabViewLayoutId != 0) {
                 // If there is a custom tab view layout id set, try and inflate
                 // it
                 tabView = LayoutInflater.from(getContext()).inflate(mTabViewLayoutId, mTabStrip, false);
                 tabTitleView = (TextView) tabView.findViewById(mTabViewTextViewId);
             }

             if (tabView == null) {
                 tabView = createDefaultTabView(getContext());
             }

             if (tabTitleView == null && TextView.class.isInstance(tabView)) {
                 tabTitleView = (TextView) tabView;
             }

             tabTitleView.setText(adapter.getPageTitle(i));
             tabView.setOnClickListener(tabClickListener);

             //添加
             LinearLayout.LayoutParams layoutParams= new LinearLayout.LayoutParams(0, LayoutParams.WRAP_CONTENT, 1.0f);
             tabView.setLayoutParams(layoutParams);
             //添加

             mTabStrip.addView(tabView);
         }
     }