java.lang.runtime 예외 : 구성 요소를 시작할 수 없습니다.

Question

비디오 자습서를 통해 Java를 배우고 있지만 이상한 문제가 있습니다. Java에서 OpenedClass이라는 클래스를 만들고 두 클래스를 구현합니다.
하나는 OnClickListener이고 두 번째는 OnCheckChangeListener이지만 에뮬레이터에서 응용 프로그램을 실행하면 항상 OnClickListener이라는 오류가 발생합니다.

package com.thenewboston.thenewboston; 
import android.app.Activity; 
import android.content.Intent; 
import android.os.Bundle; 
import android.view.View; 
import android.widget.Button; 
import android.widget.RadioGroup; 
import android.widget.RadioGroup.OnCheckedChangeListener; 
import android.widget.TextView; 

public class OpenedClass extends Activity implements View.OnClickListener, 
    OnCheckedChangeListener { 

TextView question, test; 
Button returnData; 
RadioGroup selectionList; 
String gotBread; 
String setData; 
@Override 
protected void onCreate(Bundle savedInstanceState) { 
    // TODO Auto-generated method stub 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.send); 
    initialize(); 

private void initialize() { 
    // TODO Auto-generated method stub 
    question = (TextView) findViewById(R.id.tvQuestion); 
    test = (TextView) findViewById(R.id.tvTest); 
    returnData = (Button) findViewById(R.id.bResults); 
    selectionList = (RadioGroup) findViewById(R.id.rgAnswers); 
    selectionList.setOnCheckedChangeListener(this); 
    returnData.setOnClickListener(this); 
} 

@Override 
public void onClick(View v) { 
    // TODO Auto-generated method stub 
    Intent person = new Intent(); 
    Bundle backpack = new Bundle(); 
    backpack.putString("answer", setData); 
    person.putExtras(backpack); 
    setResult(RESULT_OK,person); 
    finish(); 
} 

@Override 
public void onCheckedChanged(RadioGroup group, int checkedId) { 
    // TODO Auto-generated method stub 
    switch (checkedId) { 
    case R.id.rCrazy: 
     setData = "Probably Right !"; 
     break; 
    case R.id.rSexy: 
     setData = "Definitely Right !"; 
     break; 
    case R.id.rBoth: 
     setData = "Spot On !"; 
     break; 
    } 
    test.setText(setData); 
} 

} 

이것은 로그 캣의 출력입니다 :
내 자바 클래스의 코드는

01-05 15:59:54.605: E/AndroidRuntime(313): FATAL EXCEPTION: main 
01-05 15:59:54.605: E/AndroidRuntime(313): java.lang.RuntimeException: Unable to start  activity ComponentInfo{com.thenewboston.thenewboston/com.thenewboston.thenewboston.OpenedClass}: java.lang.NullPointerException 
01-05 15:59:54.605: E/AndroidRuntime(313): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1647) 
01-05 15:59:54.605: E/AndroidRuntime(313): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1663) 
01-05 15:59:54.605: E/AndroidRuntime(313): at android.app.ActivityThread.access$1500(ActivityThread.java:117) 
01-05 15:59:54.605: E/AndroidRuntime(313): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:931) 
01-05 15:59:54.605: E/AndroidRuntime(313): at android.os.Handler.dispatchMessage(Handler.java:99) 
01-05 15:59:54.605: E/AndroidRuntime(313): at android.os.Looper.loop(Looper.java:123) 
01-05 15:59:54.605: E/AndroidRuntime(313): at android.app.ActivityThread.main(ActivityThread.java:3683) 
01-05 15:59:54.605: E/AndroidRuntime(313): at java.lang.reflect.Method.invokeNative(Native Method) 
01-05 15:59:54.605: E/AndroidRuntime(313): at java.lang.reflect.Method.invoke(Method.java:507) 
01-05 15:59:54.605: E/AndroidRuntime(313): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839) 
01-05 15:59:54.605: E/AndroidRuntime(313): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597) 
01-05 15:59:54.605: E/AndroidRuntime(313): at dalvik.system.NativeStart.main(Native Method) 
01-05 15:59:54.605: E/AndroidRuntime(313): Caused by: java.lang.NullPointerException 
01-05 15:59:54.605: E/AndroidRuntime(313): at com.thenewboston.thenewboston.OpenedClass.initialize(OpenedClass.java:44) 
01-05 15:59:54.605: E/AndroidRuntime(313): at com.thenewboston.thenewboston.OpenedClass.onCreate(OpenedClass.java:25) 
01-05 15:59:54.605: E/AndroidRuntime(313): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047) 
01-05 15:59:54.605: E/AndroidRuntime(313): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1611) 
01-05 15:59:54.605: E/AndroidRuntime(313): ... 11 more 

너희들은 오류가 있음을 알려줍니다 것을 볼 수있다 44 행, 44 행은

 returnData.setOnClickListener(this); 

나는이 줄을 주석으로 달아 주면 전혀 이해하지 못했지만 그렇지 않을 때는 레이아웃을 보여줄 것입니다. 어떤 아이디어가 이런 일이 일어나는 이유는 무엇입니까? 귀하의 의견에서

는

Answer 1

아래

returnData = (Button) findViewById(R.id.bReturn);