Android中如何实现可扩展面板

Android中如何实现可扩展面板？

    android:layout_width="match_parent"
    android:layout_height="match_parent">
            android:id="@+id/btnToggle"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Toggle Panel"
        android:layout_centerInParent="true" />
            android:id="@+id/panelLayout"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="vertical"
        android:visibility="gone">
        
    

java
public class MainActivity extends AppCompatActivity {
    private Button btnToggle;
    private LinearLayout panelLayout;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        btnToggle = findViewById(R.id.btnToggle);
        panelLayout = findViewById(R.id.panelLayout);
        btnToggle.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if (panelLayout.getVisibility() == View.VISIBLE) {
                    panelLayout.setVisibility(View.GONE);
                } else {
                    panelLayout.setVisibility(View.VISIBLE);
                }
            }
        });
    }
}

java
public class MainActivity extends AppCompatActivity {
    private Button btnToggle;
    private LinearLayout panelLayout;
    private int panelHeight;
    private boolean isPanelVisible = false;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        btnToggle = findViewById(R.id.btnToggle);
        panelLayout = findViewById(R.id.panelLayout);
        // 获取面板的高度
        panelLayout.post(new Runnable() {
            @Override
            public void run() {
                panelHeight = panelLayout.getHeight();
                panelLayout.setVisibility(View.GONE);
            }
        });
        btnToggle.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if (isPanelVisible) {
                    hidePanel();
                } else {
                    showPanel();
                }
            }
        });
    }
    private void showPanel() {
        panelLayout.setVisibility(View.VISIBLE);
        ValueAnimator animator = ValueAnimator.ofInt(0, panelHeight);
        animator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
            @Override
            public void onAnimationUpdate(ValueAnimator animation) {
                int value = (int) animation.getAnimatedValue();
                ViewGroup.LayoutParams layoutParams = panelLayout.getLayoutParams();
                layoutParams.height = value;
                panelLayout.setLayoutParams(layoutParams);
            }
        });
        animator.setDuration(300);
        animator.start();
        isPanelVisible = true;
    }
    private void hidePanel() {
        ValueAnimator animator = ValueAnimator.ofInt(panelHeight, 0);
        animator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
            @Override
            public void onAnimationUpdate(ValueAnimator animation) {
                int value = (int) animation.getAnimatedValue();
                ViewGroup.LayoutParams layoutParams = panelLayout.getLayoutParams();
                layoutParams.height = value;
                panelLayout.setLayoutParams(layoutParams);
            }
        });
        animator.setDuration(300);
        animator.addListener(new AnimatorListenerAdapter() {
            @Override
            public void onAnimationEnd(Animator animation) {
                panelLayout.setVisibility(View.GONE);
            }
        });
        animator.start();
        isPanelVisible = false;
    }
}