6th-单选按钮小程序：简单的测试题

  这个小程序主要是对按钮（单选）的一个应用，加上了toast的功能。

修改的文档有所增加：

java：

package com.example.hello2;

import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.view.Gravity;
import android.view.Menu;
import android.view.MenuItem;

import android.widget.TextView;
import android.widget.RadioButton;
import android.widget.RadioGroup;
import android.widget.Toast;
import android.widget.RadioGroup.OnCheckedChangeListener;

public class MainActivity extends ActionBarActivity {
    TextView mTextView;
    RadioGroup radioGroup;
    RadioButton answer1;
    RadioButton answer2;
    RadioButton answer3;
    RadioButton answer4;
    
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        
        mTextView=(TextView)findViewById(R.id.myTextView);
        mTextView.setText("请问1+1等于多少？");
        
        radioGroup=(RadioGroup)this.findViewById(R.id.radioGroup);
        
        answer1=(RadioButton)this.findViewById(R.id.answer1);
        answer2=(RadioButton)this.findViewById(R.id.answer2);
        answer3=(RadioButton)this.findViewById(R.id.answer3);
        answer4=(RadioButton)this.findViewById(R.id.answer4);
        
        radioGroup.setOnCheckedChangeListener(new OnCheckedChangeListener(){
            @Override
            public void onCheckedChanged(RadioGroup group, int checkID){
                if(answer2.getId()==checkID){
                    DisplayToast("你知道的太多了，嘻嘻");
                }else{
                    DisplayToast("你答错啦！");
                }
            }
        });        
    }
    public void DisplayToast(String str){
        Toast toast=Toast.makeText(this, str, Toast.LENGTH_LONG);
        toast.setGravity(Gravity.TOP, 0, 220);
        
        toast.show();
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();
        if (id == R.id.action_settings) {
            return true;
        }
        return super.onOptionsItemSelected(item);
    }
}

9-13行为增加的头文件

main.xml

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.example.hello2.MainActivity" >

    <TextView
        android:id="@+id/myTextView"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"/>

    <RadioGroup
        android:id="@+id/radioGroup"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignLeft="@+id/myTextView"
        android:layout_below="@+id/myTextView"
        android:layout_marginTop="14dp" >

        <RadioButton
            android:id="@+id/answer1"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="@string/answer1" />

        <RadioButton
            android:id="@+id/answer2"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="@string/answer2" />

        <RadioButton
            android:id="@+id/answer3"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="@string/answer3" />

        <RadioButton
            android:id="@+id/answer4"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="@string/answer4" />
    </RadioGroup>

</RelativeLayout>

设置radiogroup和radiobutton

string.xml

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <string name="app_name">自我测评</string>
    <string name="hello">Welcome!</string>
    <string name="action_settings">Settings</string>
    <string name="answer1">等于1</string>
    <string name="answer2">等于2</string>
    <string name="answer3">等于3</string>
    <string name="answer4">等于4</string>
</resources>

结果：

学习感悟：

设置完radiogroup的参数后，不要忘了设置其监听器，这里选用OnCheckedChangeListener，监听单选按钮状态改变事件，单击单选按钮时，CheckedChangeListener的onCheckedChanged方法被触发，该方法包含了两个参数：

RadioGroup group 是RadioGroup的对象

int checkedID:当前发生状态改变的单选按钮的id