Android-----RadioButton单选使用（实现简单温度转换）

废话少说，直接上代码：

xml布局文件代码：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:orientation="vertical"
    tools:context="com.hs.example.exampleapplication.RadioButtonMain">

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal"
        android:gravity="center">

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="match_parent"
            android:gravity="center"
            android:text="输入温度："/>
        
        <RadioGroup
            android:id="@+id/unit"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:orientation="horizontal">

            <RadioButton
                android:id="@+id/unitF"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:textSize="22sp"
                android:text="华氏"/>

            <RadioButton
                android:id="@+id/unitC"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:textSize="22sp"
                android:text="摄氏"/>

            <RadioButton
                android:id="@+id/unitK"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:textSize="22sp"
                android:text="绝对"/>

        </RadioGroup>

    </LinearLayout>

    <EditText
        android:id="@+id/value"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:maxLength="9"
        android:singleLine="true"
        android:inputType="numberDecimal"/>

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="vertical">

        <TextView
            android:id="@+id/degF"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:gravity="center"
            android:textSize="45sp"
            android:maxLines="1"
            android:text="@string/charF"/>

        <TextView
            android:id="@+id/degC"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:gravity="center"
            android:textSize="45sp"
            android:maxLines="1"
            android:text="@string/charC"/>

        <TextView
            android:id="@+id/degK"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:gravity="center"
            android:textSize="45sp"
            android:maxLines="1"
            android:text="K"/>

    </LinearLayout>

</LinearLayout>

Java代码：

public class RadioButtonMain extends AppCompatActivity implements RadioGroup.OnCheckedChangeListener,TextWatcher{

    RadioGroup unit;
    EditText value;

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

        unit = this.findViewById(R.id.unit);
        unit.setOnCheckedChangeListener(this);

        value = this.findViewById(R.id.value);
        value.addTextChangedListener(this);

    }

    @Override
    public void beforeTextChanged(CharSequence charSequence, int i, int i1, int i2) {

    }

    @Override
    public void onTextChanged(CharSequence charSequence, int i, int i1, int i2) {

    }

    @Override
    public void afterTextChanged(Editable editable) {
        calc();
    }

    @Override
    public void onCheckedChanged(RadioGroup radioGroup, int i) {
        calc();
    }

    protected void calc(){
        TextView degF = this.findViewById(R.id.degF);
        TextView degC = this.findViewById(R.id.degC);
        TextView degK = this.findViewById(R.id.degK);

        double f,c,k;

        if(unit.getCheckedRadioButtonId() == R.id.unitF){
            f = Double.parseDouble(value.getText().toString());
            c = (f-32)*5/9;         //华氏度转摄氏度
            k = c + 273.15;         //绝对 = 摄氏度 + 273.15

        }else if(unit.getCheckedRadioButtonId() == R.id.unitC){
            c = Double.parseDouble(value.getText().toString());
            f = c*9/5+32;           //摄氏度转华氏度
            k = c + 273.15;

        }else{
            k = Double.parseDouble(value.getText().toString());
            c = k - 273.15;
            f = c*9/5+32;
        }

        degC.setText(String.format("%.1f",c)+getResources().getString(R.string.charC));
        degF.setText(String.format("%.1f",f)+getResources().getString(R.string.charF));
        degK.setText(String.format("%.2f",k)+"K");

    }

}

运行效果：

该例子还存在一些问题，这里就不指出了，运行一遍自会发现问题所在，最好能够自行解决。