Android Studio单选按钮在选择时未被选为

Question

我正在使用if语句来检查电台组中的哪个单选按钮被选中，但应用程序总是认为第二个单选按钮被选中。我无法弄清楚为什么。

@TargetApi(24) 
public class MainActivity extends AppCompatActivity { 

    @Override 
    protected void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.activity_main); 
     getSupportActionBar().setDisplayShowHomeEnabled(true); 
     getSupportActionBar().setLogo(R.drawable.ic_launcher_carwash); 
     getSupportActionBar().setDisplayUseLogoEnabled(true); 

     final EditText washNumInput = (EditText)findViewById(R.id.txtWashNum); 
     final RadioButton extOnly = (RadioButton)findViewById(R.id.radBtnExtOnly); 
     final RadioButton extAndInt = (RadioButton)findViewById(R.id.radBtnExtAndInt); 
     final Button btnCalc = (Button)findViewById(R.id.btnCalc); 
     final TextView output = (TextView)findViewById(R.id.txtOutput); 

     btnCalc.setOnClickListener(new View.OnClickListener() { 
      @Override 
      public void onClick(View v) { 
       int washes = Integer.parseInt(washNumInput.getText().toString()); 
       double cost = 0.0; 
       DecimalFormat currency = new DecimalFormat("$###,###.##"); 
       if (washes < 12){ 
        Toast.makeText(MainActivity.this,"No discount for less than 12 washes", 
          Toast.LENGTH_LONG).show(); 
        if (extOnly.isSelected()){ 
         cost += washes * 10.99; 
         output.setText(currency.format(cost) + " for " + washes + " washes"); 
        } 
        else{ 
         cost += washes * 15.99; 
         output.setText(currency.format(cost) + " for " + washes + " washes"); 
        } 
       } 
       else{ 
        if (extOnly.isSelected()){ 
         cost += washes * 8.99; 
         output.setText(currency.format(cost) + " for " + washes + " washes"); 
        } 
        else{ 
         cost += washes * 12.99; 
         output.setText(currency.format(cost) + " for " + washes + " washes"); 
        } 
       } 
      } 
     }); 
    } 
} 

这里是万一XML文件，可以帮助：

<?xml version="1.0" encoding="utf-8"?> 
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android" 
    xmlns:app="http://schemas.android.com/apk/res-auto" 
    xmlns:tools="http://schemas.android.com/tools" 
    android:layout_width="match_parent" 
    android:layout_height="match_parent" 
    tools:context="com.example.travis.carwashapp.MainActivity"> 

    <TextView 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     android:text="@string/car_wash_packages" 
     android:textColor="@android:color/holo_orange_dark" 
     android:textSize="36sp" 
     app:layout_constraintBottom_toBottomOf="parent" 
     app:layout_constraintLeft_toLeftOf="parent" 
     app:layout_constraintRight_toRightOf="parent" 
     app:layout_constraintTop_toTopOf="parent" 
     app:layout_constraintVertical_bias="0.032" 
     android:id="@+id/textView2" 
     app:layout_constraintHorizontal_bias="0.515" /> 

    <TextView 
     android:id="@+id/textView" 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     android:layout_marginBottom="8dp" 
     android:layout_marginTop="8dp" 
     android:text="@string/discount_params" 
     android:textColor="@android:color/darker_gray" 
     android:textSize="18sp" 
     app:layout_constraintBottom_toBottomOf="parent" 
     app:layout_constraintHorizontal_bias="0.502" 
     app:layout_constraintLeft_toLeftOf="parent" 
     app:layout_constraintRight_toRightOf="parent" 
     app:layout_constraintTop_toTopOf="parent" 
     app:layout_constraintVertical_bias="0.104" /> 

    <EditText 
     android:id="@+id/txtWashNum" 
     android:layout_width="358dp" 
     android:layout_height="43dp" 
     android:layout_marginBottom="8dp" 
     android:layout_marginTop="8dp" 
     android:ems="10" 
     android:hint="@string/washnumber" 
     android:inputType="textPersonName" 
     android:textAlignment="center" 
     app:layout_constraintBottom_toBottomOf="parent" 
     app:layout_constraintHorizontal_bias="0.502" 
     app:layout_constraintLeft_toLeftOf="parent" 
     app:layout_constraintRight_toRightOf="parent" 
     app:layout_constraintTop_toTopOf="parent" 
     app:layout_constraintVertical_bias="0.196" /> 

    <RadioGroup 
     android:id="@+id/radGroup" 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     android:layout_marginBottom="8dp" 
     android:layout_marginLeft="8dp" 
     android:layout_marginRight="8dp" 
     android:layout_marginTop="8dp" 
     android:checkedButton="@+id/radBtnExtOnly" 
     app:layout_constraintBottom_toBottomOf="parent" 
     app:layout_constraintHorizontal_bias="0.4" 
     app:layout_constraintLeft_toLeftOf="parent" 
     app:layout_constraintRight_toRightOf="parent" 
     app:layout_constraintTop_toTopOf="parent" 
     app:layout_constraintVertical_bias="0.33"> 

     <RadioButton 
      android:id="@+id/radBtnExtOnly" 
      android:layout_width="wrap_content" 
      android:layout_height="wrap_content" 
      android:layout_marginBottom="8dp" 
      android:layout_marginTop="8dp" 
      android:layout_weight="1" 
      android:text="@string/exterior_only" 
      app:layout_constraintBottom_toBottomOf="parent" 
      app:layout_constraintHorizontal_bias="0.257" 
      app:layout_constraintLeft_toLeftOf="parent" 
      app:layout_constraintRight_toRightOf="parent" 
      app:layout_constraintTop_toTopOf="parent" 
      app:layout_constraintVertical_bias="0.306" /> 

     <RadioButton 
      android:id="@+id/radBtnExtAndInt" 
      android:layout_width="wrap_content" 
      android:layout_height="wrap_content" 
      android:layout_marginBottom="8dp" 
      android:layout_marginTop="8dp" 
      android:layout_weight="1" 
      android:text="@string/exterior_with_interior_vacuum" 
      app:layout_constraintBottom_toBottomOf="parent" 
      app:layout_constraintHorizontal_bias="1.0" 
      app:layout_constraintLeft_toLeftOf="parent" 
      app:layout_constraintRight_toRightOf="parent" 
      app:layout_constraintTop_toTopOf="parent" 
      app:layout_constraintVertical_bias="1.0" /> 
    </RadioGroup> 

    <Button 
     android:id="@+id/btnCalc" 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     android:layout_marginBottom="8dp" 
     android:layout_marginTop="8dp" 
     android:text="@string/calculate_package" 
     app:layout_constraintBottom_toBottomOf="parent" 
     app:layout_constraintHorizontal_bias="0.502" 
     app:layout_constraintLeft_toLeftOf="parent" 
     app:layout_constraintRight_toRightOf="parent" 
     app:layout_constraintTop_toTopOf="parent" 
     app:layout_constraintVertical_bias="0.498" /> 

    <ImageView 
     android:id="@+id/imageView" 
     android:layout_width="320dp" 
     android:layout_height="167dp" 
     android:layout_marginBottom="16dp" 
     android:layout_marginTop="8dp" 
     android:contentDescription="@string/app_name" 
     app:layout_constraintBottom_toBottomOf="parent" 
     app:layout_constraintHorizontal_bias="0.516" 
     app:layout_constraintLeft_toLeftOf="parent" 
     app:layout_constraintRight_toRightOf="parent" 
     app:layout_constraintTop_toTopOf="parent" 
     app:layout_constraintVertical_bias="1.0" 
     app:srcCompat="@drawable/carwash" 
     tools:layout_editor_absoluteY="328dp" /> 

    <TextView 
     android:id="@+id/txtOutput" 
     android:layout_width="377dp" 
     android:layout_height="35dp" 
     android:layout_marginBottom="8dp" 
     android:layout_marginTop="8dp" 
     android:textAlignment="center" 
     android:textColor="@android:color/holo_green_light" 
     android:textSize="18sp" 
     android:textStyle="bold" 
     app:layout_constraintBottom_toBottomOf="parent" 
     app:layout_constraintHorizontal_bias="0.571" 
     app:layout_constraintLeft_toLeftOf="parent" 
     app:layout_constraintRight_toRightOf="parent" 
     app:layout_constraintTop_toTopOf="parent" 
     app:layout_constraintVertical_bias="0.604" /> 

</android.support.constraint.ConstraintLayout> 

Answer 1

尝试使用isChecked()和不isSelected()。您的代码总是假设第二个RadioButton的原因被检查是因为​​返回false，不断落入您的条件语句的else的情况;你在哪里处理第二个按钮！

如果您单独使用多个if条件而不是if/else检查每个按钮的状态，此行为会更加明显;因为RadioGroup总是保证只能选择一个选项。