如何关闭Android中的弹出窗口？

AlertDialog alertDialog = new AlertDialog.Builder(this)
        .setTitle("Title")
        .setMessage("Message")
        .setPositiveButton("OK", new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialog, int which) {
                dialog.dismiss(); // 关闭对话框
            }
        })
        .create();
alertDialog.show();

public void closeActivity(View view) {
    finish(); // 关闭当前Activity
}

WindowManager windowManager = (WindowManager) getSystemService(Context.WINDOW_SERVICE);
View popupView = LayoutInflater.from(this).inflate(R.layout.popup_layout, null);
windowManager.addView(popupView, new WindowManager.LayoutParams(
        WindowManager.LayoutParams.WRAP_CONTENT,
        WindowManager.LayoutParams.WRAP_CONTENT));

// 关闭弹出窗口
windowManager.removeView(popupView);

if (alertDialog != null && alertDialog.isShowing()) {
    alertDialog.dismiss();
}

@Override
protected void onDestroy() {
    super.onDestroy();
    if (windowManager != null) {
        windowManager.removeView(popupView);
    }
}