使用单选按钮控件，完成性别选择，并将选择的结果以消息对话框形式进行显示，写出主要代码。

在Android开发中，你可以使用RadioGroup和RadioButton来创建性别选择单选按钮，并通过AlertDialog显示用户的选择。以下是一个简单的例子，假设你有两个RadioButton分别代表男性和女性：

首先，在`activity_main.xml`布局文件中添加RadioGroup和两个RadioButton：

<RadioButton
    android:id="@+id/radioMale"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="男" />

<RadioButton
    android:id="@+id/radioFemale"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="女" />

<LinearLayout
    android:orientation="horizontal"
    android:layout_gravity="center_horizontal">
    <Button
        android:id="@+id/btnConfirm"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="确认并显示结果"/>
</LinearLayout>

然后在`MainActivity.kt` (如果使用Kotlin) 或 `MainActivity.java` (如果使用Java) 中处理RadioGroup和确认按钮点击事件：

// Java 示例:
import android.os.Bundle
import android.util.Log
import android.view.View
import android.widget.Button
import android.widget.RadioButton
import android.widget.RadioGroup
import android.widget.Toast

class MainActivity : AppCompatActivity() {
    private lateinit var radioGroup: RadioGroup
    private lateinit var radioButtonMale: RadioButton
    private lateinit var radioButtonFemale: RadioButton

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        radioGroup = findViewById(R.id.radioGroup)
        radioButtonMale = findViewById(R.id.radioMale)
        radioButtonFemale = findViewById(R.id.radioFemale)

        btnConfirm.setOnClickListener {
            val selectedButton = findViewById<Button>(R.id.btnConfirm)
            if (radioButtonMale.isChecked) {
                Log.d("Result", "选择: 男")
                Toast.makeText(this, "选择的是男性", Toast.LENGTH_SHORT).show()
            } else if (radioButtonFemale.isChecked) {
                Log.d("Result", "选择: 女")
                Toast.makeText(this, "选择的是女性", Toast.LENGTH_SHORT).show()
            } else {
                Log.d("Result", "未选择任何选项")
                Toast.makeText(this, "请选择性别", Toast.LENGTH_SHORT).show()
            }
        }
    }
}

// Kotlin 示例:
import android.content.DialogInterface
import android.os.Bundle
import android.view.View
import android.widget.Button
import android.widget.RadioGroup
import android.widget.Toast
import androidx.appcompat.app.AlertDialog
import androidx.appcompat.app.AppCompatActivity

class MainActivity : AppCompatActivity() {
    private lateinit var radioGroup: RadioGroup
    private lateinit var radioButtonMale: RadioButton
    private lateinit var radioButtonFemale: RadioButton

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        radioGroup = findViewById(R.id.radioGroup)
        radioButtonMale = findViewById(R.id.radioMale)
        radioButtonFemale = findViewById(R.id.radioFemale)

        btnConfirm.setOnClickListener {
            val selectedButton = findViewById<Button>(R.id.btnConfirm)
            val checkedRadioButton = radioGroup.checkableButtons.firstOrNull { it.isChecked }

            when (checkedRadioButton) {
                radioButtonMale -> {
                    Toast.makeText(this, "选择的是男性", Toast.LENGTH_SHORT).show()
                    showAlertDialog("性别选择", "您选择了男性")
                }
                radioButtonFemale -> {
                    Toast.makeText(this, "选择的是女性", Toast.LENGTH_SHORT).show()
                    showAlertDialog("性别选择", "您选择了女性")
                }
                else -> {
                    Toast.makeText(this, "请选择性别", Toast.LENGTH_SHORT).show()
                }
            }
        }

    }

    private fun showAlertDialog(title: String, message: String) {
        AlertDialog.Builder(this)
            .setTitle(title)
            .setMessage(message)
            .setPositiveButton("确定") { _, _ ->
                Toast.makeText(this, "对话框关闭", Toast.LENGTH_SHORT).show()
            }
            .NegativeButton("取消", DialogInterface.OnClickListener { _, _ ->
                Toast.makeText(this, "取消操作", Toast.LENGTH_SHORT).show()
            })
            .show()
    }
}