修改TabLayout下划线的宽度和文字和线的距离

1、写个工具类 封装：

import android.content.res.Resources;
import android.support.design.widget.TabLayout;
import android.util.TypedValue;
import android.view.View;
import android.widget.LinearLayout;

import java.lang.reflect.Field;

/**
 * Copyright © 2016年 AXD. All rights reserved.
 */

public class TabUtils {
    /**
    *  @param tabs TabLayout
     * @param leftDip marginLeft
     * @param rightDip marginRight
    */
   

public static void setIndicator(TabLayout tabs, int leftDip, int rightDip, int bottomDip) {

Class tabLayout = tabs.getClass() ;
 Field tabStrip = null;
try {
tabStrip = tabLayout.getDeclaredField( "mTabStrip") ;
 } catch (NoSuchFieldException e) {
 e.printStackTrace() ;
 return;
 }
tabStrip.setAccessible( true) ;
LinearLayout llTab = null;
 try {
llTab = (LinearLayout) tabStrip.get(tabs) ;
 } catch (IllegalAccessException e) {
 e.printStackTrace() ;

                  return；
        }

        int left = (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, leftDip, Resources.getSystem().getDisplayMetrics());
        int right = (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, rightDip, Resources.getSystem().getDisplayMetrics());

       int bottom = (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, bottomDip, Resources.getSystem().getDisplayMetrics());

for ( int i = 0 ; i < llTab.getChildCount() ; i++) {

 View child = llTab.getChildAt(i) ;
 child.setPadding( 0 , 0 , 0 , 0) ;
LinearLayout.LayoutParams params = new LinearLayout.LayoutParams( 0 , LinearLayout.LayoutParams. MATCH_PARENT , 1) ;
params. leftMargin = left ;
params. rightMargin = right ;

           params.bottomMargin = bottom;

  child.setLayoutParams(params) ;
 child.invalidate() ;
 }
 }
}

2、在Activity调用

tab_view.post(new Runnable() {
    @Override
    public void run() {
        TabUtils.setIndicator(tab_view,10,10);
    }
});

3、此方法是通过反射获取tablayout私有属性进修改属性值，如果app启动混淆 会报NoSuchFieldException；

解决方案：在proguard-rules.pro混淆文件中添加-keep class Android.support.design.widget.TabLayout{*;}