1、寫個工具類 封裝：

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呼叫

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