在没有CoordinatorLayout的情况下，以编程方式折叠/展开工具栏？

Toolbar toolbar = findViewById(R.id.toolbar);
AppBarLayout.LayoutParams params = (AppBarLayout.LayoutParams) toolbar.getLayoutParams();
params.setScrollFlags(AppBarLayout.LayoutParams.SCROLL_FLAG_SCROLL | AppBarLayout.LayoutParams.SCROLL_FLAG_ENTER_ALWAYS);
toolbar.setLayoutParams(params);

<androidx.appcompat.widget.Toolbar
    android:id="@+id/toolbar"
    android:layout_width="match_parent"
    android:layout_height="56dp"
    android:background="@color/colorPrimary"
    app:layout_scrollFlags="scroll|enterAlways">
</androidx.appcompat.widget.Toolbar>

AppBarLayout appBarLayout = findViewById(R.id.appBarLayout);
appBarLayout.addOnOffsetChangedListener(new AppBarLayout.OnOffsetChangedListener() {
    boolean isExpanded = true;
    int scrollRange = -1;

    @Override
    public void onOffsetChanged(AppBarLayout appBarLayout, int verticalOffset) {
        if (scrollRange == -1) {
            scrollRange = appBarLayout.getTotalScrollRange();
        }
        if (scrollRange + verticalOffset == 0) {
            // 完全折叠
            isExpanded = false;
        } else {
            // 非折叠状态
            isExpanded = true;
        }
    }
});