要在折叠工具栏布局内的线性布局内设置文本视图的动画，请执行以下操作

<!-- activity_main.xml -->
<androidx.coordinatorlayout.widget.CoordinatorLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <com.google.android.material.appbar.AppBarLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content">

        <com.google.android.material.appbar.CollapsingToolbarLayout
            android:id="@+id/collapsing_toolbar"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            app:layout_scrollFlags="scroll|exitUntilCollapsed">

            <!-- 其他布局内容 -->

        </com.google.android.material.appbar.CollapsingToolbarLayout>
    </com.google.android.material.appbar.AppBarLayout>

    <LinearLayout
        android:id="@+id/linear_layout"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical"
        app:layout_behavior="@string/appbar_scrolling_view_behavior">

        <TextView
            android:id="@+id/text_view"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Hello, Animation!"
            android:layout_gravity="center_horizontal"
            android:layout_marginTop="50dp"/>
    </LinearLayout>
</androidx.coordinatorlayout.widget.CoordinatorLayout>

// MainActivity.java
import android.animation.Animator;
import android.animation.AnimatorListenerAdapter;
import android.os.Bundle;
import android.view.View;
import android.view.animation.AlphaAnimation;
import android.view.animation.Animation;
import android.widget.TextView;
import androidx.appcompat.app.AppCompatActivity;

public class MainActivity extends AppCompatActivity {

    private TextView textView;

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

        textView = findViewById(R.id.text_view);

        // 设置淡入动画
        AlphaAnimation fadeIn = new AlphaAnimation(0.0f, 1.0f);
        fadeIn.setDuration(2000); // 动画持续时间
        fadeIn.setFillAfter(true); // 动画结束后保持状态

        // 设置淡出动画
        AlphaAnimation fadeOut = new AlphaAnimation(1.0f, 0.0f);
        fadeOut.setDuration(2000);
        fadeOut.setFillAfter(true);

        // 设置动画监听器
        fadeIn.setAnimationListener(new AnimatorListenerAdapter() {
            @Override
            public void onAnimationEnd(Animator animation) {
                textView.startAnimation(fadeOut);
            }
        });

        fadeOut.setAnimationListener(new AnimatorListenerAdapter() {
            @Override
            public void onAnimationEnd(Animator animation) {
                textView.startAnimation(fadeIn);
            }
        });

        // 开始动画
        textView.startAnimation(fadeIn);
    }
}