基于ViewPager滚动设置动画文本（淡出/淡入）

Question

我想实现viewpager上方的文本淡出然后当用户滚动到不同的页面时淡出。我在工具栏中有一个TextView，并根据页面设置文本。我使用的是TextView而不是工具栏标题，因为我相信实现动画会更容易。我如何设置textview的动画以使其当前文本淡出然后淡入下一页文本？如果您需要更多代码或问题有任何问题，我会更新我的答案。

布局

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:geekui="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">

    <android.support.v7.widget.Toolbar
        android:id="@+id/toolbar"
        android:layout_height="56dp"
        android:layout_width="match_parent"
        app:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar"
        android:background="@color/primary">

        <com.mobsandgeeks.ui.TypefaceTextView
            android:id="@+id/tvTitle"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textSize="20dp"
            android:textColor="@color/white"
            android:gravity="center_vertical"
            android:text="Testing"
            geekui:customTypeface="fonts/Roboto-Regular.ttf" />
    </android.support.v7.widget.Toolbar>

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

</LinearLayout>

活动

private Toolbar toolbar;

private void toolbarFunction() {
    toolbar = (Toolbar) findViewById(R.id.toolbar);
    toolbar.setNavigationIcon(getResources().getDrawable(R.drawable.ic_arrow_back_white));
    toolbar.setNavigationOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            finish();
        }
    });
    tvTitle.setText(dbTwoName);
}

private ViewPager mViewPager;

private void viewPagerConnections() {
    tvTitle = (TextView) findViewById(R.id.tvTitle);
    mViewPager = (ViewPager) findViewById(R.id.pager);
    FragmentManager fm = getSupportFragmentManager();
    mViewPager.setAdapter(new FragmentStatePagerAdapter(fm) {
        @Override
        public Fragment getItem(int position) {
            LogSecond log = logSecondAdapter.getItem(position);
            return LogThirdFragment.newInstance(log.getDB_twoName(), position, log.getDB_twoKey());
        }

        @Override
        public int getCount() {
            return logSecondAdapter.getCount();
        }
    });
    mViewPager.setCurrentItem(currentPageInt);
    mViewPager.setOnPageChangeListener(new ViewPager.OnPageChangeListener() {
        @Override
        public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {

        }

        @Override
        public void onPageSelected(int position) {
            LogSecond logSecond = logSecondAdapter.getItem(position);
            tvTitle.setText(logSecond.getDB_twoName());
        }

        @Override
        public void onPageScrollStateChanged(int state) {
        }
    });

}