第十七篇-使用RadioGroup实现单项选择

上效果图

首先进行控件布局，一个textview，6个radiobutton，

main_activity.xml

<?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=".MainActivity">

    <TextView
        android:id="@+id/textView"
        android:layout_width="233dp"
        android:layout_height="74dp"
        android:textSize="35sp"
        tools:ignore="MissingConstraints"
        tools:layout_editor_absoluteX="0dp"
        tools:layout_editor_absoluteY="25dp" />

    <RadioGroup
        android:id="@+id/RG"
        android:layout_width="264dp"
        android:layout_height="202dp"
        android:layout_marginTop="16dp"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/textView"
        tools:ignore="MissingConstraints">

        <RadioButton
            android:id="@+id/RB1"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="@string/radiobutton1"
            tools:ignore="MissingConstraints"
            tools:layout_editor_absoluteX="62dp"
            tools:layout_editor_absoluteY="87dp" />

        <RadioButton
            android:id="@+id/RB2"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="@string/radiobutton2"
            tools:ignore="MissingConstraints"
            tools:layout_editor_absoluteX="62dp"
            tools:layout_editor_absoluteY="143dp" />

        <RadioButton
            android:id="@+id/RB3"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="@string/radiobutton3"
            tools:ignore="MissingConstraints"
            tools:layout_editor_absoluteX="62dp"
            tools:layout_editor_absoluteY="214dp" />

        <RadioButton
            android:id="@+id/RB4"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="@string/radiobutton4"
            tools:ignore="MissingConstraints"
            tools:layout_editor_absoluteX="62dp"
            tools:layout_editor_absoluteY="278dp" />

        <RadioButton
            android:id="@+id/RB5"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="@string/radiobutton5"
            tools:ignore="MissingConstraints"
            tools:layout_editor_absoluteX="62dp"
            tools:layout_editor_absoluteY="356dp" />

        <RadioButton
            android:id="@+id/RB6"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="@string/radiobutton6"
            tools:ignore="MissingConstraints"
            tools:layout_editor_absoluteX="61dp"
            tools:layout_editor_absoluteY="429dp" />
    </RadioGroup>


</android.support.constraint.ConstraintLayout>

 MainActivity.java

package com.example.aimee.radiogrouptest;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.MotionEvent;
import android.widget.RadioButton;
import android.widget.RadioGroup;
import android.widget.TextView;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {
    TextView textview;
    RadioGroup RG;
    RadioButton RB1;
    RadioButton RB2;
    RadioButton RB3;
    RadioButton RB4;
    RadioButton RB5;
    RadioButton RB6;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        textview=findViewById(R.id.textView);
        RG=findViewById(R.id.RG);
        RB1=findViewById(R.id.RB1);
        RB2=findViewById(R.id.RB2);
        RB3=findViewById(R.id.RB3);
        RB4=findViewById(R.id.RB4);
        RB5=findViewById(R.id.RB5);
        RB6=findViewById(R.id.RB6);

        RG.setOnCheckedChangeListener(ChangeRadioGroup);
    }
    private RadioGroup.OnCheckedChangeListener ChangeRadioGroup=new RadioGroup.OnCheckedChangeListener() {
        @Override
        public void onCheckedChanged(RadioGroup group, int checkedId) {
            if(checkedId==RB1.getId()&&RB1.isChecked()){
                textview.setText(RB1.getText());
                Toast.makeText(MainActivity.this,RB1.getText()+"被选择",Toast.LENGTH_SHORT).show();
            }
            else if(checkedId==RB2.getId()&&RB2.isChecked()){
                textview.setText(RB2.getText());
                Toast.makeText(MainActivity.this,RB2.getText()+"被选择",Toast.LENGTH_SHORT).show();

            }
            else if(checkedId==RB3.getId()&&RB3.isChecked()){
                textview.setText(RB3.getText());
                Toast.makeText(MainActivity.this,RB3.getText()+"被选择",Toast.LENGTH_SHORT).show();

            }
            else if(checkedId==RB4.getId()&&RB4.isChecked()){
                textview.setText(RB4.getText());
                Toast.makeText(MainActivity.this,RB4.getText()+"被选择",Toast.LENGTH_SHORT).show();

            }
            else if(checkedId==RB5.getId()&&RB5.isChecked()){
                textview.setText(RB5.getText());
                Toast.makeText(MainActivity.this,RB5.getText()+"被选择",Toast.LENGTH_SHORT).show();

            }
            else if(checkedId==RB6.getId()&&RB6.isChecked()){
                textview.setText(RB6.getText());
                Toast.makeText(MainActivity.this,RB6.getText()+"被选择",Toast.LENGTH_SHORT).show();

            }
        }
    };
}

 /res/values/string.xml

<resources>
    <string name="app_name">RadioGroupTest</string>
    <string name="radiobutton1">Android</string>
    <string name="radiobutton2">Sysbian</string>
    <string name="radiobutton3">WinCE</string>
    <string name="radiobutton4">PalmOS</string>
    <string name="radiobutton5">Linux</string>
    <string name="radiobutton6">iphoneOS</string>
</resources>