致命错误：主要错误

我是android的新手，正在尝试编写Diet Planner android应用程序。在第一部分中，我尝试计算BMI，理想体重以及每日卡路里，但是当我要运行项目时，会出现致命错误，而且我不知道该如何解决。谁能帮我？错误：

08-02 08:05:24.693: E/AndroidRuntime(1046): FATAL EXCEPTION: main
08-02 08:05:24.693: E/AndroidRuntime(1046): java.lang.RuntimeException: Unable to start     activity ComponentInfo{com.dietandroidproject/com.dietandroidproject.MainActivity}:    java.lang.ClassCastException: android.widget.RelativeLayout cannot be cast to  android.widget.RadioGroup
08-02 08:05:24.693: E/AndroidRuntime(1046):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2059)
08-02 08:05:24.693: E/AndroidRuntime(1046):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2084)
08-02 08:05:24.693: E/AndroidRuntime(1046):     at android.app.ActivityThread.access$600(ActivityThread.java:130)
08-02 08:05:24.693: E/AndroidRuntime(1046):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1195)
08-02 08:05:24.693: E/AndroidRuntime(1046):     at android.os.Handler.dispatchMessage(Handler.java:99)
08-02 08:05:24.693: E/AndroidRuntime(1046):     at android.os.Looper.loop(Looper.java:137)
08-02 08:05:24.693: E/AndroidRuntime(1046):     at android.app.ActivityThread.main(ActivityThread.java:4745)
08-02 08:05:24.693: E/AndroidRuntime(1046):     at java.lang.reflect.Method.invokeNative(Native Method)
08-02 08:05:24.693: E/AndroidRuntime(1046):     at java.lang.reflect.Method.invoke(Method.java:511)
08-02 08:05:24.693: E/AndroidRuntime(1046):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)
08-02 08:05:24.693: E/AndroidRuntime(1046):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
08-02 08:05:24.693: E/AndroidRuntime(1046):     at dalvik.system.NativeStart.main(Native Method)
08-02 08:05:24.693: E/AndroidRuntime(1046): Caused by: java.lang.ClassCastException: android.widget.RelativeLayout cannot be cast to android.widget.RadioGroup
08-02 08:05:24.693: E/AndroidRuntime(1046):     at com.dietandroidproject.MainActivity$1.<init>(MainActivity.java:30)
08-02 08:05:24.693: E/AndroidRuntime(1046):     at com.dietandroidproject.MainActivity.onCreate(MainActivity.java:24)
08-02 08:05:24.693: E/AndroidRuntime(1046):     at android.app.Activity.performCreate(Activity.java:5008)
08-02 08:05:24.693: E/AndroidRuntime(1046):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1079)
08-02 08:05:24.693: E/AndroidRuntime(1046):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2023)
08-02 08:05:24.693: E/AndroidRuntime(1046):     ... 11 more

我的主要活动代码

package com.dietandroidproject;

import Databasedata.Person;
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.RadioGroup;
import android.widget.Spinner;
import android.widget.TextView;
import android.widget.Toast;
public class MainActivity extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);


    Button saveinformation = (Button) findViewById(R.id.saveinformation);
    saveinformation.setOnClickListener(new View.OnClickListener() {

        EditText weighttext = (EditText) findViewById(R.id.weighttext);
        EditText heighttext = (EditText) findViewById(R.id.heighttext);
        EditText usernametext = (EditText) findViewById(R.id.usernametext);
        EditText agetext = (EditText) findViewById(R.id.agetext);
        RadioGroup genderselected = (RadioGroup) findViewById(R.id.choosegender);
        Spinner activitytext = (Spinner) findViewById(R.id.chooseactivity);
        Button saveinformation = (Button) findViewById(R.id.saveinformation);
        TextView genderchoosed = (TextView) findViewById(genderselected
                .getCheckedRadioButtonId());
        String gender = genderchoosed.getText().toString();
        String pa = activitytext.getSelectedItem().toString();

        @Override
        public void onClick(View v) {
         int weight = (int) Float.parseFloat(weighttext.getText()
                    .toString());
         int height = (int) Float.parseFloat(heighttext.getText()
                    .toString());
         String username = usernametext.getText().toString();
         int age = (int) Float.parseFloat(agetext.getText().toString());
         TextView genderchoosed = (TextView) findViewById(genderselected
                    .getCheckedRadioButtonId());
         String gender = genderchoosed.getText().toString();
         String pa = activitytext.getSelectedItem().toString();
         //=========================================================
         int Bmivalue = calculateBMI(weight, height);
         String bmiInterpretation = interpretBMI(Bmivalue);
         float idealweight = idealweight(weight, height, gender, pa, age);
         double dailycalories=dailycalories(weight,height,gender,pa,age);

         // insert in to============================================

          Person person = new Person();
            person.setUsername(username);
            person.setHeight(height);
            person.setWeight(weight);
            person.setAge(age);
            person.setGender(gender);
            person.setPa(pa);
            person.setBmivalue(Bmivalue);
            person.setBmiInterpretation(bmiInterpretation);
            person.setIdealweight(idealweight);
            person.setDailycalories(dailycalories);
            // ?????????????????????????????????????????/
            Databasedata.DatabaseAdapter dbAdapter = new Databasedata.DatabaseAdapter(
                    MainActivity.this);
            dbAdapter.insertPerson(person);

            Toast.makeText(getApplicationContext(),
                    Bmivalue + "and you are" + bmiInterpretation,
                    Toast.LENGTH_LONG).show();

          }
        });

       }
       // BMI function==================================================
        private int calculateBMI(int weight, int height) {

    return (int) (weight / (height * height));
};

private String interpretBMI(int Bmivalue) {

    if (Bmivalue < 18.5) {
        return "Underweight";
    } else if (Bmivalue < 25) {
        return "Normal";
    } else if (Bmivalue < 30) {
        return "Overweight";
    } else {
        return "Obese";
    }

  }
  //==========================IDEAL WEIGHT function======================
    private float idealweight(int weight, int height, String gender, String pa,
        int age) {
    float x = (float) 0.0;
    int bmi;

    bmi = idealbmi(age);
    x = bmi * (height * height);
    return x;

  }

  public int idealbmi(int age) {
    int bmi = 0;
    if (age > 17 && age <= 19) {
        bmi = 21;
    }
    if (age > 19 && age <= 24) {
        bmi = 22;
    }
    if (age > 24 && age <= 34) {
        bmi = 23;
    }
    if (age > 34 && age <= 44) {
        bmi = 24;
    }
    if (age > 44 && age <= 54) {
        bmi = 25;
    }
    if (age > 54 && age <= 64) {
        bmi = 26;
    }
    if (age > 64) {
        bmi = 27;
    }

    return bmi;
   }
   //======================DAILY CALORIES function ==============
   public double suitablepa(String pa) {
    double suitablepa = 0;
    if (pa.equals("Highly active")) {
        suitablepa =  1.48;
    }
    if (pa.equals("Active")) {
        suitablepa =  1.25;
    }
    if (pa.equals("Low activity")) {
        suitablepa =  1.11;
    }
    if (pa.equals("Sedentary")) {
        suitablepa =  1;
    }
    return suitablepa;

}
private double dailycalories(int weight, int height, String gender,
        String pa, int age) {
    double dailycalori = 0;
    double i;
    double j;
    double h;
    double k;
    if(gender.equals("femaleselected")){

        i=9.36*weight;
        j=726*height;
        h=suitablepa(pa)*(i+j);
        k=6.91*age;
        dailycalori=354-k+h;

    }else if(gender.equals("maleselected")){

        i=15.91*weight;
        j=539.6*height;
        h=suitablepa(pa)*(i+j);
        k=9.53*age;
        dailycalori=662-k+h;
    }
    return dailycalori;
   }
  }

XML编码

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="@drawable/backgroundmain"
android:orientation="vertical" >

<RelativeLayout
    android:id="@+id/personinformation"
    android:layout_width="match_parent"
    android:layout_height="0dp"
    android:layout_weight="1.98" >

    <EditText
        android:id="@+id/heighttext"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignLeft="@+id/usernametext"
        android:layout_below="@+id/usernametext"
        android:ems="10"
        android:hint="Enter Your Height" >
    </EditText>

    <EditText
        android:id="@+id/usernametext"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentTop="true"
        android:layout_centerHorizontal="true"
        android:layout_marginTop="20dp"
        android:ems="10"
        android:hint="Enter Username" />

    <EditText
        android:id="@+id/weighttext"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignLeft="@+id/heighttext"
        android:layout_below="@+id/heighttext"
        android:ems="10"
        android:hint="Enter Your Weight" />

    <EditText
        android:id="@+id/agetext"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignLeft="@+id/weighttext"
        android:layout_below="@+id/weighttext"
        android:ems="10"
        android:hint="Enter Your Age" >

        <requestFocus />
    </EditText>

</RelativeLayout>

<View
    android:layout_width="250dp"
    android:layout_height="1dip"
    android:layout_gravity="center"
    android:layout_marginTop="20dp"
    android:background="#aaa" />

<RelativeLayout
    android:id="@+id/choosegender"
    android:layout_width="match_parent"
    android:layout_height="0dp"
    android:layout_weight="0.78" >

    <TextView
        android:id="@+id/choosefemaleormale"
        android:layout_width="match_parent"
        android:layout_height="30dip"
        android:layout_alignParentLeft="true"
        android:layout_alignParentTop="true"
        android:layout_marginTop="10dip"
        android:gravity="center"
        android:text="Gender : "
        android:textAlignment="center"
        android:textColor="#555"
        android:textSize="19sp" />

    <RadioGroup
        android:layout_width="220dip"
        android:layout_height="wrap_content"
        android:layout_below="@+id/choosefemaleormale"
        android:layout_centerHorizontal="true"
        android:orientation="horizontal" >

        <RadioButton
            android:id="@+id/femaleselected"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_gravity="left"
            android:layout_weight="1"
            android:checked="true"
            android:text="female"
            android:onClick="onRadioButtonClicked"
             />

        <RadioButton
            android:id="@+id/maleselected"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_gravity="right"
            android:layout_weight="1"
            android:text="male"
            android:onClick="onRadioButtonClicked" />
    </RadioGroup>
</RelativeLayout>
    <View
    android:layout_width="250dp"
    android:layout_height="1dip"
    android:layout_gravity="center"
    android:layout_marginTop="20dp"
    android:background="#aaa" />
<RelativeLayout
    android:id="@+id/choosepa"
    android:layout_width="250dip"
    android:layout_height="0dp"
    android:layout_weight="1"
    android:layout_gravity="center" >

    <Spinner
        android:id="@+id/chooseactivity"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:layout_alignParentTop="true"
        android:entries="@array/activityitems"
        android:gravity="center"
        android:prompt="@string/level_of_activity" />

</RelativeLayout>

<Button
    android:layout_width="90dp"
    android:layout_height="0dp"
    android:layout_gravity="right"
    android:layout_marginBottom="10dip"
    android:layout_marginRight="20dp"
    android:layout_weight="0.46"
    android:background="@drawable/recent_foods_depressed"
    android:hint="save"
    android:text="save"
    android:textColor="#fff"
    android:textSize="20sp"
    android:textStyle="bold" 
    android:onClick="saveinformation"
    android:id="@+id/saveinformation"/>

  </LinearLayout>