效果圖:

MainActivity.java檔案

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        final TabLayout id_tabl_one_s = (TabLayout)
 
 findViewById(R.id.id_tab_one_fill_fixed);
        id_tabl_one_s.addTab(id_tabl_one_s.newTab().setText("新聞"));
        id_tabl_one_s.addTab(id_tabl_one_s.newTab().setText("熱門"));
        id_tabl_one_s.addTab(id_tabl_one_s.newTab().setText("日報"));

        final TabLayout id_tabl_one_s1 = (TabLayout)
 
 findViewById(R.id.id_tab_one_fill_fixed1);
        id_tabl_one_s1.addTab(id_tabl_one_s1.newTab().setText("新聞"));
        id_tabl_one_s1.addTab(id_tabl_one_s1.newTab().setText("熱門"));
        id_tabl_one_s1.addTab(id_tabl_one_s1.newTab().setText("日報"));

        final TabLayout id_tabl_one_s2 = (TabLayout)
 
 findViewById(R.id.id_tab_one_fill_fixed2);
        id_tabl_one_s2.addTab(id_tabl_one_s2.newTab().setText("新聞"));
        id_tabl_one_s2.addTab(id_tabl_one_s2.newTab().setText("熱門"));
        id_tabl_one_s2.addTab(id_tabl_one_s2.newTab().setText("日報"));


        setIndicator(id_tabl_one_s1, 25, 25);
        setIndicator(id_tabl_one_s2, 35, 35);


        TabLayout id_tabl_four_s = (TabLayout) findViewById(R.id.id_tab_four_center_scrollable);
        id_tabl_four_s.addTab(id_tabl_four_s.newTab().setText("新聞"));
        id_tabl_four_s.addTab(id_tabl_four_s.newTab().setText("熱門"));
        id_tabl_four_s.addTab(id_tabl_four_s.newTab().setText("日報"));


        TabLayout id_tabl_four_s1 = (TabLayout) findViewById(R.id.id_tab_four_center_scrollable1);
        id_tabl_four_s1.addTab(id_tabl_four_s1.newTab().setText("新聞"));
        id_tabl_four_s1.addTab(id_tabl_four_s1.newTab().setText("熱門"));
        id_tabl_four_s1.addTab(id_tabl_four_s1.newTab().setText("日報"));

        TabLayout id_tabl_four_s2 = (TabLayout) findViewById(R.id.id_tab_four_center_scrollable2);
        id_tabl_four_s2.addTab(id_tabl_four_s2.newTab().setText("新聞"));
        id_tabl_four_s2.addTab(id_tabl_four_s2.newTab().setText("熱門"));
        id_tabl_four_s2.addTab(id_tabl_four_s2.newTab().setText("日報"));


        setTabLayoutWidth(id_tabl_four_s1, 10, 10);
        setTabLayoutWidth(id_tabl_four_s2, 15, 15);

    }


    /**
     * 反射指示器變短
     */
    public void setIndicator(TabLayout tabs, int leftDip, int rightDip) {
        tabs.post(() -> {
            Class<?> tabLayout = tabs.getClass();
            Field tabStrip = null;
            try {
                tabStrip = tabLayout.getDeclaredField("mTabStrip");
            } catch (NoSuchFieldException e) {
                e.printStackTrace();
            }

            tabStrip.setAccessible(true);
            LinearLayout llTab = null;
            try {
                llTab = (LinearLayout) tabStrip.get(tabs);
            } catch (IllegalAccessException e) {
                e.printStackTrace();
            }

            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());


            //直接獲取子view改變寬度
            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;
                child.setLayoutParams(params);
                child.invalidate();
            }
        });
    }

    /**
     * 反射拿到文字的屬性對指示器進行操作
     */
    public void setTabLayoutWidth(TabLayout tabLayout, int leftDip, int rightDip) {
        tabLayout.post(() -> {
            try {
                //拿到tabLayout的mTabStrip屬性
                LinearLayout mTabStrip = (LinearLayout) tabLayout.getChildAt(0);
                for (int i = 0; i < mTabStrip.getChildCount(); i++) {
                    View tabView = mTabStrip.getChildAt(i);

                    //拿到tabView的mTextView屬性  tab的字數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);

                    //因為我想要的效果是字多寬線就多寬，所以測量mTextView的寬度
                    int width = 0;
                    width = mTextView.getWidth();
                    if (width == 0) {
                        mTextView.measure(0, 0);
                        width = mTextView.getMeasuredWidth();
                    }

                    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());

                    //設定tab左右間距 注意這裡不能使用Padding 因為原始碼中線的寬度是根據 tabView的寬度來設定的
                    LinearLayout.LayoutParams params = (LinearLayout.LayoutParams) tabView.getLayoutParams();
                    params.width = width + left + right;   //如果只是width就是指示器和文字長度一樣長
                    params.leftMargin = left;
                    params.rightMargin = right;
                    tabView.setLayoutParams(params);
                    tabView.invalidate();
                }

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

    }
}

activity_main.xml佈局檔案

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    tools:context=".MainActivity">
    <!--所有  TabLayout  layout_width設定為match_parent的情況下-->


    <Button
        android:id="@+id/btn_tab"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:visibility="gone"
        android:text="tab" />


    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="10dp"
        android:text="B.標題想數目數量少的時候" />


    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="10dp"
        android:text="1.tabGravity:fill,tabMode:fixed" />


    <android.support.design.widget.TabLayout
        android:id="@+id/id_tab_one_fill_fixed"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        app:tabGravity="fill"
        app:tabIndicatorColor="@color/colorAccent"
        app:tabMode="fixed"
        app:tabSelectedTextColor="@color/colorAccent"
        app:tabTextColor="@color/c_9b9b9b" />


    <android.support.design.widget.TabLayout
        android:id="@+id/id_tab_one_fill_fixed1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        app:tabGravity="fill"
        app:tabIndicatorColor="@color/colorAccent"
        app:tabMode="fixed"
        app:tabSelectedTextColor="@color/colorAccent"
        app:tabTextColor="@color/c_9b9b9b" />

    <android.support.design.widget.TabLayout
        android:id="@+id/id_tab_one_fill_fixed2"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        app:tabGravity="fill"
        app:tabIndicatorColor="@color/colorAccent"
        app:tabMode="fixed"
        app:tabSelectedTextColor="@color/colorAccent"
        app:tabTextColor="@color/c_9b9b9b" />



    <!--&#45;&#45;&#45;&#45;&#45;&#45;&#45;&#45;&#45;&#45;&#45;&#45;&#45;&#45;&#45;&#45;&#45;&#45;&#45;&#45;&#45;&#45;&#45;&#45;&#45;&#45;&#45;&#45;&#45;&#45;&#45;&#45;&#45;&#45;&#45;&#45;&#45;&#45;&#45;&#45;&#45;&#45;&#45;&#45;&#45;&#45;&#45;&#45;&#45;&#45;&#45;&#45;-->

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="10dp"
        android:text="4.tabGravity:center,tabMode:scrollable常用"
        android:textColor="@color/colorAccent" />


    <android.support.design.widget.TabLayout
        android:id="@+id/id_tab_four_center_scrollable"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        app:tabGravity="center"
        app:tabIndicatorColor="@color/colorAccent"
        app:tabMode="scrollable"
        app:tabSelectedTextColor="@color/colorAccent"
        app:tabTextColor="@color/c_9b9b9b" />


    <android.support.design.widget.TabLayout
        android:id="@+id/id_tab_four_center_scrollable1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        app:tabGravity="center"
        app:tabIndicatorColor="@color/colorAccent"
        app:tabMode="scrollable"
        app:tabSelectedTextColor="@color/colorAccent"
        app:tabTextColor="@color/c_9b9b9b" />

    <android.support.design.widget.TabLayout
        android:id="@+id/id_tab_four_center_scrollable2"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        app:tabGravity="center"
        app:tabIndicatorColor="@color/colorAccent"
        app:tabMode="scrollable"
        app:tabSelectedTextColor="@color/colorAccent"
        app:tabTextColor="@color/c_9b9b9b" />


</LinearLayout>