实现以下效果，当选择单选框1时，单选框上方显示【我选择的是radio1】，当选择单选框2时，单选框上方显示【我选择的是radio2】，要求写出布局文件代码和Activity代码

布局文件代码（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">

    <RadioGroup
        android:id="@+id/radio_group"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center_horizontal">

        <RadioButton
            android:id="@+id/radio_button_1"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Radio 1" />

        <RadioButton
            android:id="@+id/radio_button_2"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Radio 2" />

    </RadioGroup>

    <TextView
        android:id="@+id/text_view"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textAppearance="?android:textAppearanceLarge" />

</LinearLayout>

Activity 代码（MainActivity.java）：

public class MainActivity extends AppCompatActivity {

    private RadioGroup radioGroup;
    private RadioButton radioButton1;
    private RadioButton radioButton2;
    private TextView textView;

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

        radioGroup = findViewById(R.id.radio_group);
        radioButton1 = findViewById(R.id.radio_button_1);
        radioButton2 = findViewById(R.id.radio_button_2);
        textView = findViewById(R.id.text_view);

        radioGroup.setOnCheckedChangeListener(new RadioGroup.OnCheckedChangeListener() {
            @Override
            public void onCheckedChanged(RadioGroup group, int checkedId) {
                if (checkedId == R.id.radio_button_1) {
                    textView.setText("我选择的是radio1");
                } else if (checkedId == R.id.radio_button_2) {
                    textView.setText("我选择的是radio2");
                }
            }
        });
    }
}