Android api28 tablayout改变

设置tablayout下划线的宽度 （TabLayout和28之前有差异，mTabStrip已经是slidingTabIndicator了，API 28下TabLayout的差异）

两种实现方式

 /**
     * 设置tablayout下划线的宽度
     */
    public  static void reflex(final TabLayout tabLayout){
        //了解源码得知 线的宽度是根据 tabView的宽度来设置的
        tabLayout.post(new Runnable() {
            @Override
            public void run() {
                try {
                    //拿到tabLayout的mTabStrip属性
                    LinearLayout mTabStrip = (LinearLayout) tabLayout.getChildAt(0);

                    int dp10 = dp2px(50);

                    for (int i = 0; i < mTabStrip.getChildCount(); i++) {
                        View tabView = mTabStrip.getChildAt(i);

                        //拿到tabView的mTextView属性  tab的字数不固定一定用反射取mTextView
                        Field mTextViewField = tabView.getClass().getDeclaredField("mTextView");
                        mTextViewField.setAccessible(true);

                        TextView mTextView = (TextView) mTextViewField.get(tabView);

                        tabView.setPadding(0, 0, 0, 0);

                        //因为我想要的效果是   字多宽线就多宽，所以测量mTextView的宽度
                        int width = 0;
                        width = mTextView.getWidth();
                        if (width == 0) {
                            mTextView.measure(0, 0);
                            width = mTextView.getMeasuredWidth();
                        }

                        //设置tab左右间距为10dp  注意这里不能使用Padding 因为源码中线的宽度是根据 tabView的宽度来设置的
                        LinearLayout.LayoutParams params = (LinearLayout.LayoutParams) tabView.getLayoutParams();
                        params.width = width ;
                        params.leftMargin = dp10;
                        params.rightMargin = dp10;
                        tabView.setLayoutParams(params);

                        tabView.invalidate();
                    }

                } catch (NoSuchFieldException e) {
                    e.printStackTrace();
                } catch (IllegalAccessException e) {
                    e.printStackTrace();
                }
            }
        });
    }

---

   public static void setIndicatorWidth(@NonNull final TabLayout tabLayout, final int margin) {
       tabLayout.post(new Runnable() {
           @Override public void run() {
               try {
                   // 拿到tabLayout的slidingTabIndicator属性
                   Field slidingTabIndicatorField = tabLayout.getClass().getDeclaredField("slidingTabIndicator");
                   slidingTabIndicatorField.setAccessible(true);
                   LinearLayout mTabStrip = (LinearLayout) slidingTabIndicatorField.get(tabLayout);
                   for (int i = 0; i < mTabStrip.getChildCount(); i++) { View tabView = mTabStrip.getChildAt(i);
                       //拿到tabView的mTextView属性
                       Field textViewField = tabView.getClass().getDeclaredField("textView");
                       textViewField.setAccessible(true);
                       TextView mTextView = (TextView) textViewField.get(tabView);
                       tabView.setPadding(0, 0, 0, 0);
                       // 因为想要的效果是字多宽线就多宽，所以测量mTextView的宽度
                       int width = mTextView.getWidth();
                       if (width == 0) { mTextView.measure(0, 0);
                           width = mTextView.getMeasuredWidth();
                       }
                       // 设置tab左右间距,注意这里不能使用Padding,因为源码中线的宽度是根据tabView的宽度来设置的
                       LinearLayout.LayoutParams params = (LinearLayout.LayoutParams) tabView.getLayoutParams();
                       params.width = width; params.leftMargin = margin; params.rightMargin = margin;
                       tabView.setLayoutParams(params); tabView.invalidate();
                   }
               } catch (NoSuchFieldException e) {
                   e.printStackTrace();
               } catch (IllegalAccessException e) {
                   e.printStackTrace();
               }
           }
       });

   }

原简书博文，现迁至这