TabLayout 设置指示器宽度问题Alone的博客-

 public static void setTabLayoutWidth(int left, int right, TabLayout tabLayout, Activity Activity) {     try {         Field slidingTabIndicatorField;         Field textViewField;         // 拿到tabLayout的slidingTabIndicator属性         if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.P) {             slidingTabIndicatorField = tabLayout.getClass().getDeclaredField("slidingTabIndicator");          } else {             slidingTabIndicatorField = tabLayout.getClass().getDeclaredField("mTabStrip");         }          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             if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.P) {                 textViewField = tabView.getClass().getDeclaredField("textView");             } else {                 textViewField = tabLayout.getClass().getDeclaredField("mTextView");             }             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 = left;             params.rightMargin = right;             tabView.setLayoutParams(params);             tabView.invalidate();         }     } catch (NoSuchFieldException e) {         e.printStackTrace();     } catch (IllegalAccessException e) {         e.printStackTrace();     }  }

 app:tabIndicatorFullWidth="false"设置为false 就是指示线跟tabitem的文字一样宽 

要设置为true 才能设置上边的才有效

有同学肯定好奇为啥上边还有版本判断

因为sdk大于等于28 是 slidingTabIndicator这个 小于的就是  mTabStrip  因为sdk版本都有差异 找不到的话 就会 Exception

然后就尴尬了

这是根据我日常遇到的问题出来 希望能解决各位同学的问题 不许勿喷！白白