android控件之radiobutton checkbox

这里有一个问题，现在还不清楚，为什么这里的toast不能显示呢？

main.xml

<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:layout_width="fill_parent"    android:layout_height="fill_parent"    android:orientation="vertical" ><TextView android:id="@+id/text1"    android:layout_width="wrap_content"    android:layout_height="wrap_content"    android:text="你最喜欢的动物是："/>    <ImageView android:id="@+id/image"        android:layout_width="fill_parent"        android:layout_height="wrap_content"        android:layout_marginTop="30dp"/><RadioGroup android:id="@+id/radioGroup"    android:orientation="horizontal"    android:layout_width="fill_parent"    android:layout_height="wrap_content"    android:gravity="left">        <RadioButton        android:id="@+id/radioButton1"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:text="猫" />    <RadioButton        android:id="@+id/radioButton2"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:text="狗" />    </RadioGroup><TextView android:id="@+id/text2"    android:layout_width="wrap_content"    android:layout_height="wrap_content"    android:text="你喜欢的运动是："/>    <CheckBox        android:id="@+id/checkBox1"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:text="跑步" />    <CheckBox        android:id="@+id/checkBox2"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:text="游泳" />    </LinearLayout>

CheckboxAndRadiobutton.java

package com.android.forlinx;import android.app.Activity;import android.os.Bundle;import android.widget.CheckBox;import android.widget.CompoundButton.OnCheckedChangeListener;import android.widget.CompoundButton;import android.widget.ImageSwitcher;import android.widget.ImageView;import android.widget.RadioButton;import android.widget.RadioGroup;import android.widget.TextView;import android.widget.Toast;public class CheckboxAndRadiobutton extends Activity {private ImageView image = null;private RadioGroup mradio = null;private RadioButton rButton1,rButton2;private CheckBox mcheck = null;private CheckBox mcheck2;private TextView mresult = null;    /** Called when the activity is first created. */    @Override    public void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.main);                image = (ImageView)findViewById(R.id.image);        mradio = (RadioGroup)findViewById(R.id.radioGroup);        rButton1 = (RadioButton)findViewById(R.id.radioButton1);        rButton2 = (RadioButton)findViewById(R.id.radioButton2);        mcheck = (CheckBox)findViewById(R.id.checkBox1);        mcheck2 = (CheckBox)findViewById(R.id.checkBox2);                mradio.setOnCheckedChangeListener(new RadioGroup.OnCheckedChangeListener() {@Overridepublic void onCheckedChanged(RadioGroup group, int checkedId) {// TODO Auto-generated method stubif (checkedId == rButton1.getId()){Toast.makeText(CheckboxAndRadiobutton.this, "您最喜欢的动物是"+rButton1.getText(), Toast.LENGTH_LONG);image.setImageResource(R.drawable.p1);}else if(checkedId == rButton2.getId()){Toast.makeText(CheckboxAndRadiobutton.this, "您最喜欢的动物是"+rButton2.getText(), Toast.LENGTH_LONG);image.setImageResource(R.drawable.p2);}}});        mcheck.setOnCheckedChangeListener(listener);        mcheck2.setOnCheckedChangeListener(listener);      //  mradio.set    }    OnCheckedChangeListener listener = new OnCheckedChangeListener() {@Overridepublic void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {// TODO Auto-generated method stubif (mcheck.isChecked()){Toast.makeText(CheckboxAndRadiobutton.this, "您喜欢的运动是"+mcheck.getText(), Toast.LENGTH_LONG);//为什么这里的toast不能显示呢？因为在listener中吗？System.out.println("您喜欢的运动是"+mcheck.getText());}else if(mcheck2.isChecked()){System.out.println("您喜欢的运动是"+mcheck2.getText());}}};}

效果图：