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);
        }
    }