Android TableLayout下划线宽度

用反射实现

• 直接上代码（可直接复制使用）

 /**
     * tabLayout下划线宽度
     * @param padding 左右外边距
     */
    public static void reflex(final TabLayout tabLayout, final @DimenRes int padding) {
        tabLayout.post(new Runnable() {
            @Override
            public void run() {
                try {
                    //拿到tabLayout的mTabStrip属性
                    Field mTabStripField = tabLayout.getClass().getDeclaredField("mTabStrip");
                    mTabStripField.setAccessible(true);
                    LinearLayout mTabStrip = (LinearLayout) mTabStripField.get(tabLayout);
                    int dp10 = tabLayout.getContext().getResources().getDimensionPixelOffset(padding);
                    for (int i = 0; i < mTabStrip.getChildCount(); i++) {
                        View tabView = mTabStrip.getChildAt(i);
                        //拿到tabView的mTextView属性
                        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();
                        }
                        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();
                }
            }
        });
    }

在debug包中可显示效果，release包中无效
解决方法：
在混淆文档proguard-rules.pro中去掉对widget包的混淆，即加上

-keep class android.support.design.widget.** { *; }**