选中时，Android Studio单选按钮未读取为选中状态

Question

我使用if语句来检查无线电组中的两个单选按钮中的哪一个被选中但应用程序总是认为无论如何都选择了第二个单选按钮。我无法弄清楚原因。

@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");
                    }
                }
            }
        });
    }
}

如果有帮助，这是XML文件：

<?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()。我们的代码总是假设第二个RadioButton被检查的原因是因为isSelected()返回false，不断陷入条件语句的else情况;你在哪里处理第二个按钮！

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