TabLayout+ViewPager

依赖：

implementation 'com.android.support:design:27.1.1'

xml布局

 <android.support.design.widget.TabLayout
        android:id="@+id/order_tab"
        android:layout_width="match_parent"
        android:layout_height="@dimen/dp_28"
        android:layout_below="@id/text1"
        app:tabIndicatorColor="@color/colorRed"
        app:tabMode="fixed"
        app:tabSelectedTextColor="@color/colorRed"
        app:tabTextColor="@color/colorBlack">

    </android.support.design.widget.TabLayout>


    <android.support.v4.view.ViewPager
        android:id="@+id/order_vpger"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_below="@id/text">

    </android.support.v4.view.ViewPager>

添加数据：

  private void initData() {
        tab_sell = new ArrayList<>();
        tab_sell.add("全部");
        tab_sell.add("代付款");
        tab_sell.add("代发货");
        tab_sell.add("代收货");
        tab_sell.add("代评价");

        fragment_sell = new ArrayList<>();
        fragment_sell.add(new OrderAllFragment());
        fragment_sell.add(new OrderDfkFragment());
        fragment_sell.add(new OrderDfhFragment());
        fragment_sell.add(new OrderDshFragment());
        fragment_sell.add(new OrderDpjFragment());

    }

初始化，绑定适配器

 private void initViewPager() {
//        viewpager适配器
        mOrderVpger.setAdapter(new MyOrderPagerAdapter(getSupportFragmentManager(), fragment_sell, tab_sell));
//        绑定TabLayout
        mOrderTab.setupWithViewPager(mOrderVpger);

    }

viewpager适配器

public class MyOrderPagerAdapter extends FragmentPagerAdapter {
    private List<Fragment> fragment_sell;
    private List<String> tab_sell;


    public MyOrderPagerAdapter(FragmentManager fm, List<Fragment> fragment_sell, List<String> tab_sell) {
        super(fm);
        this.fragment_sell = fragment_sell;
        this.tab_sell=tab_sell;
    }

    @Nullable
    @Override
    public CharSequence getPageTitle(int position) {
        return tab_sell.get(position);
    }

    @Override
    public Fragment getItem(int position) {
        return fragment_sell.get(position);
    }

    @Override
    public int getCount() {
        return fragment_sell.size();
    }
}

//    自定义设置下划线长度
    @Override
    public void onStart() {
        super.onStart();
        mSyTab.post(new Runnable() {
            @Override
            public void run() {
                setIndicator(mSyTab, 25, 25);
            }
        });
    }

//    初始化下划线长度
    public void setIndicator(TabLayout tabs, int leftDip, int rightDip) {
        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());

        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();
        }


    }

设置tablayout下划线长度的方法

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

    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();
    }


}

需要用的时候，，只要在有tablayout的地方就可以用了

使用的方法如下面的代码所示

这里面直接post了这个，并开了Runnable，然后设置当前的tablayout的对象，并设置长度就可以了

@Override
public void onStart() {
    super.onStart();
    tabLayout.post(new Runnable() {
        @Override
        public void run() {
            setIndicator(tabLayout, 50, 50);
        }
    });
}

ScrollView嵌套ViewPager＋Fragment时冲突问题解决办法

1.ViewPager 中的Fragment 不显示
给xml中ScrollView设置android:fillViewport=”true” 属性。通过这个就可以让ViewPager中的内容显示。
顾名思义，这个属性允许 NestedScrollView中的组件去充满它。

<android.support.v4.widget.NestedScrollView
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:fillViewport="true">

            <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
                android:layout_width="match_parent"
                android:layout_height="match_parent"
                android:background="@color/com_bg_gray_eeeeee"

                android:descendantFocusability="blocksDescendants"
                android:orientation="vertical">

                <com.bigkoo.convenientbanner.ConvenientBanner
                    android:id="@+id/acty_main_cbanner"
                    android:layout_width="match_parent"
                    android:layout_height="@dimen/comm_dim_150" />

                <android.support.design.widget.TabLayout
                    android:id="@+id/acty_main_tab"
                    android:layout_width="match_parent"
                    android:layout_height="@dimen/comm_dim_40"
                    android:layout_alignParentBottom="true"
                    app:tabBackground="@drawable/selector_tab_bg"
                    app:tabIndicatorHeight="0dp"
                    app:tabSelectedTextColor="@color/com_tv_white_ffffff"
                    app:tabTextAppearance="@style/tab_txtSize"
                    app:tabTextColor="@color/com_tv_black_333333" />

                <android.support.v4.view.ViewPager
                    android:id="@+id/acty_main_vp"
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content" />

            </LinearLayout>


        </android.support.v4.widget.NestedScrollView>

2.上下拖动ViewPager 不能垂直方向滚动

最开始使用的默认的ViewPager，发现不能上下滑动，然后通过查找别人的解决办法,NestedScrollView嵌套ViewPager后，如果viewPager中的fragment高度太长，会发现滑动不了，需要自定义ViewPager,测量ViewPager的高度.

public class WrapContentHeightViewPager extends ViewPager {
    public WrapContentHeightViewPager(Context context) {
        super(context);  
    }  

    public WrapContentHeightViewPager(Context context, AttributeSet attrs) {
        super(context, attrs);  
    }  

    @Override  
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {  
        super.onMeasure(widthMeasureSpec, heightMeasureSpec);  

        int height = 0;  
        for (int i = 0; i < getChildCount(); i++) {  
            View child = getChildAt(i);
            child.measure(widthMeasureSpec, MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED));  
            int h = child.getMeasuredHeight();  
            if (h > height) height = h;  
        }  
        heightMeasureSpec = MeasureSpec.makeMeasureSpec(height, MeasureSpec.EXACTLY);  
        super.onMeasure(widthMeasureSpec, heightMeasureSpec);  
    }  
}  

然后将xml布局的ViewPager替换为我们自定义的ViewPager

<android.support.v4.widget.NestedScrollView
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:fillViewport="true">

            <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
                android:layout_width="match_parent"
                android:layout_height="match_parent"
                android:background="@color/com_bg_gray_eeeeee"

                android:descendantFocusability="blocksDescendants"
                android:orientation="vertical">

                <com.bigkoo.convenientbanner.ConvenientBanner
                    android:id="@+id/acty_main_cbanner"
                    android:layout_width="match_parent"
                    android:layout_height="@dimen/comm_dim_150" />

                <android.support.design.widget.TabLayout
                    android:id="@+id/acty_main_tab"
                    android:layout_width="match_parent"
                    android:layout_height="@dimen/comm_dim_40"
                    android:layout_alignParentBottom="true"
                    app:tabBackground="@drawable/selector_tab_bg"
                    app:tabIndicatorHeight="0dp"
                    app:tabSelectedTextColor="@color/com_tv_white_ffffff"
                    app:tabTextAppearance="@style/tab_txtSize"
                    app:tabTextColor="@color/com_tv_black_333333" />

                <com.aoben.qproj.widget.WrapContentHeightViewPager
                    android:id="@+id/acty_main_vp"
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content" />

            </LinearLayout>


        </android.support.v4.widget.NestedScrollView>