Android入门（八）：使用RadioGroup 和RadioButton组件建立单选清单

　　这一章，我们学习RadioGroup 和RadioButton组件，我们新建一个项目，编码过程与前几章的项目类似。

　　1.建立字符串资源文件strings.xml；

<resources>    <string name="app_name">健身建议</string>    <string name="promptSex">性别：</string>    <string name="promptAge">年龄：</string>    <string name="promptBtnDoSug">健身建议</string>    <string name="sugResult">结果：</string>    <string name="sugYoga">进行瑜伽运动</string>    <string name="sugRun">跑步运动</string>    <string name="sugSwim">游泳运动</string>    <string name="male">男生</string>    <string name="female">女生</string>    <string name="maleAgeRng1">小于28岁</string>    <string name="maleAgeRng2">28~33岁</string>    <string name="maleAgeRng3">大于33岁</string>    <string name="femaleAgeRng1">小于25岁</string>    <string name="femaleAgeRng2">25~30岁</string>    <string name="femaleAgeRng3">大于30岁</string></resources>

　　2.在接口布局文件中使用RadioGroup 和RadioButton标签，main.xml

<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:orientation="vertical"    android:layout_width="match_parent"    android:layout_height="match_parent"    android:gravity="center_horizontal">

    <TextView        android:layout_width="200dp"        android:layout_height="wrap_content"        android:textSize="20sp"        android:text="@string/promptSex"/>    <RadioGroup android:id="@+id/radGSex"        android:layout_width="200dp"        android:layout_height="wrap_content"        android:orientation="vertical"        android:checkedButton="@+id/radMale">        <RadioButton android:id="@+id/radMale"            android:textSize="20sp"            android:text="@string/male"/>        <RadioButton android:id="@+id/radFemale"            android:textSize="20sp"            android:text="@string/female"/>    </RadioGroup>    <TextView        android:layout_width="200dp"        android:layout_height="wrap_content"        android:textSize="20sp"        android:text="@string/promptSex"/>    <RadioGroup android:id="@+id/radGAge"        android:layout_width="200dp"        android:layout_height="wrap_content"        android:orientation="vertical"        android:checkedButton="@+id/radAgeRng1">        <RadioButton android:id="@+id/radBtnAgeRng1"            android:textSize="20sp"            android:text="@string/maleAgeRng1"/>        <RadioButton android:id="@+id/radBtnAgeRng2"            android:textSize="20sp"            android:text="@string/maleAgeRng2"/>        <RadioButton android:id="@+id/radBtnAgeRng3"            android:textSize="20sp"            android:text="@string/maleAgeRng3"/>    </RadioGroup>    <Button android:id="@+id/btnDoSug"        android:layout_width="200dp"        android:layout_height="wrap_content"        android:textSize="20sp"        android:text="@string/promptBtnDoSug"/>    <TextView android:id="@+id/txtResult"        android:layout_width="200dp"        android:layout_height="wrap_content"        android:textSize="20sp"        android:text="@string/sugResult"/></LinearLayout>

3.程序代码MainActivity

public class MainActivity extends Activity{    private Button btnDoSug;    private RadioGroup radGSex, radGAge;    private RadioButton radBtnAgeRng1, radBtnAgeRng2, radBtnAgeRng3;    private TextView txtResult;

    @Override    public void onCreate(Bundle savedInstanceState)    {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);

        setupViewComponent();    }

    private void setupViewComponent()    {        btnDoSug = (Button)findViewById(R.id.btnDoSug);        radGSex = (RadioGroup)findViewById(R.id.radGSex);        radGAge = (RadioGroup)findViewById(R.id.radGAge);        radBtnAgeRng1 = (RadioButton)findViewById(R.id.radBtnAgeRng1);        radBtnAgeRng2 = (RadioButton)findViewById(R.id.radBtnAgeRng2);        radBtnAgeRng3 = (RadioButton)findViewById(R.id.radBtnAgeRng3);        txtResult = (TextView)findViewById(R.id.txtResult);

        btnDoSug.setOnClickListener(btnDoSugOnClick);        radGSex.setOnCheckedChangeListener(radGSexOnCheChanLis);    }

    private RadioGroup.OnCheckedChangeListener radGSexOnCheChanLis = new RadioGroup.OnCheckedChangeListener()    {        public void onCheckedChanged(RadioGroup group, int checkedId)        {            if(checkedId == R.id.radMale)            {                radBtnAgeRng1.setText(getString(R.string.maleAgeRng1));                radBtnAgeRng2.setText(getString(R.string.maleAgeRng2));                radBtnAgeRng3.setText(getString(R.string.maleAgeRng3));            }            else if(checkedId == R.id.radFemale)            {                radBtnAgeRng1.setText(getString(R.string.femaleAgeRng1));                radBtnAgeRng2.setText(getString(R.string.femaleAgeRng2));                radBtnAgeRng3.setText(getString(R.string.femaleAgeRng3));            }        }    };

    private Button.OnClickListener btnDoSugOnClick = new Button.OnClickListener()    {        public void onClick(View v)        {            int iCheckedRadBtn = radGSex.getCheckedRadioButtonId();            String strSug = getString(R.string.sugResult);            switch (iCheckedRadBtn )            {                case R.id.radMale:                    switch (radGAge.getCheckedRadioButtonId())                    {                        case R.id.radBtnAgeRng1:                            strSug += getString(R.string.sugYoga);                            break;                        case R.id.radBtnAgeRng2:                            strSug += getString(R.string.sugRun);                            break;                        default:                            strSug += getString(R.string.sugSwim);                    }                    break;                case R.id.radFemale:                    switch (radGAge.getCheckedRadioButtonId())                    {                        case R.id.radBtnAgeRng1:                            strSug += getString(R.string.sugYoga);                            break;                        case R.id.radBtnAgeRng2:                            strSug += getString(R.string.sugRun);                            break;                        default:                            strSug += getString(R.string.sugSwim);                    }                    break;            }            txtResult.setText(strSug);        }    };}效果图：

我们发现，当我们选择不同的性别时，下面的年龄范围也不一样，原因是setupViewComponent()方法的最后一行把RadioGroup.OnCheckedChangeListener对象设置给性别的RadioGroup对象，因此当我们选择不同的性别时，年龄选项就会跟着改变。