您已经为每个单选按钮分配了一个id。使用case block，你可以手动检测选中的单选按钮，或者使用OnCheckedChangeListener，你也可以得到它。

xml:

    <RadioGroup
        android:id="@+id/rd_group_pick_reason"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintTop_toBottomOf="@id/ti_titel"
        android:orientation="horizontal"
        android:paddingHorizontal="16dp"
        >
        <com.google.android.material.radiobutton.MaterialRadioButton
            android:id="@+id/rd_not_deliverable"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_weight="0.5"
            android:text="@string/txt_not_deliverable"
            android:checked="true"
            />

        <com.google.android.material.radiobutton.MaterialRadioButton
            android:id="@+id/rd_after_pack"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_weight="0.5"
            android:text="@string/txt_after_pack"
            />
    </RadioGroup>

java:

final RadioGroup radioGroup = dialogView.findViewById(R.id.rd_group_pick_reason);    
switch (radioGroup.getCheckedRadioButtonId()) {
    case R.id.rd_not_deliverable:
        // TODO
    break;
    case R.id.rd_after_pack:
        // TODO
    break;
}

or

radioGroup.setOnCheckedChangeListener((group, checkedId) -> {
    switch (group.getCheckedRadioButtonId()) {
        case R.id.rd_not_deliverable:
            System.out.println("not deliverable");
            break;
        case R.id.rd_after_pack:
            System.out.println("after pack");
            break;
    }

你可以使用OnCheckedChangeListener或者使用getCheckedRadioButtonId()

你所需要做的就是先给你的RadioButton设置值，例如:

RadioButton radioButton = (RadioButton)findViewById(R.id.radioButton);      
radioButton.setId(1);        //some int value

然后无论何时这个特殊的radioButton将被选中，你可以通过你给它的Id拉出它的值

RadioGroup radioGroup = (RadioGroup)findViewById(R.id.radioGroup);                     
int whichIndex = radioGroup.getCheckedRadioButtonId(); //of course the radioButton
                                                       //should be inside the "radioGroup"
                                                       //in the XML

干杯!

您可以有一个对单选组的引用，并使用getCheckedRadioButtonId()来获得选中的单选按钮id。看这里

RadioGroup radioGroup = (RadioGroup)findViewById(R.id.radio_group);

然后当你需要得到选定的无线电选项。

int checkedRadioButtonId = radioGroup.getCheckedRadioButtonId();
if (checkedRadioButtonId == -1) {
    // No item selected
}
else{
    if (checkedRadioButtonId == R.id.radio_button1) {
        // Do something with the button
    }
}

你应该可以这样做:

int radioButtonID = radioButtonGroup.getCheckedRadioButtonId();
View radioButton = radioButtonGroup.findViewById(radioButtonID);
int idx = radioButtonGroup.indexOfChild(radioButton);

如果RadioGroup包含其他视图(如TextView)，则indexOfChild()方法将返回错误的索引。

要在RadioGroup上获得选定的RadioButton文本:

 RadioButton r = (RadioButton) radioButtonGroup.getChildAt(idx);
 String selectedtext = r.getText().toString();

radioSexGroup = (RadioGroup) findViewById(R.id.radioSex);
btnDisplay = (Button) findViewById(R.id.btnDisplay);
btnDisplay.setOnClickListener(new OnClickListener() {
        @Override
        public void onClick(View v) {
            // get selected radio button from radioGroup
            int selectedId = radioSexGroup.getCheckedRadioButtonId();
            // find the radiobutton by returned id
            radioSexButton = (RadioButton) findViewById(selectedId);
Toast.makeText(MainActivity.this,radioSexButton.getText(),Toast.LENGTH_SHORT).show();
        }
    });