如何在微调器下拉单击时打开新活动

<!-- res/layout/activity_main.xml -->
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:padding="16dp">

    <Spinner
        android:id="@+id/my_spinner"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" />
</LinearLayout>

// MainActivity.java
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.Spinner;
import androidx.appcompat.app.AppCompatActivity;

public class MainActivity extends AppCompatActivity {

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

        Spinner spinner = findViewById(R.id.my_spinner);

        // 创建一个字符串数组作为Spinner的数据源
        String[] items = new String[]{"Item 1", "Item 2", "Item 3"};

        // 创建适配器并设置给Spinner
        ArrayAdapter<String> adapter = new ArrayAdapter<>(this,
                android.R.layout.simple_spinner_item, items);
        adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
        spinner.setAdapter(adapter);

        // 设置ItemSelectedListener
        spinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
            @Override
            public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
                // 当下拉列表被点击时，启动新的Activity
                Intent intent = new Intent(MainActivity.this, SecondActivity.class);
                startActivity(intent);
            }

            @Override
            public void onNothingSelected(AdapterView<?> parent) {
                // 当没有选择任何项目时调用
            }
        });
    }
}

<!-- AndroidManifest.xml -->
<activity android:name=".SecondActivity"></activity>

// 在onCreate中手动触发一次onItemSelected
spinner.setSelection(0, false);