顯示java.lang.NullPointerException在radioGroup中

Question

這是我的代碼：

public class Survey extends Activity { 

    PopupWindow popupWindow; 
    RadioButton badChoise, mediaChoise, happyChoise; 
    RadioGroup groupRadio; 
    Button launchpopup; 
    Boolean flagBad = false; 
    Boolean flagMedia=false; 
    Boolean flagHappy=false; 
    int checkedButton; 


    @Override 
    protected void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.survey); 

     launchpopup = (Button) findViewById(R.id.popup); 

     launchpopup.setOnClickListener(new OnClickListener() { 

      @Override 
      public void onClick(View v) { 
       // TODO Auto-generated method stub 
       showPopup(); 
      } 
     }); 
    } 


public void showPopup(){ 

    LayoutInflater layoutInflater= (LayoutInflater)getBaseContext().getSystemService(LAYOUT_INFLATER_SERVICE); 
    View popupView = layoutInflater.inflate(R.layout.popup, null); 
    popupWindow = new PopupWindow(popupView,LayoutParams.WRAP_CONTENT,LayoutParams.WRAP_CONTENT); 

    badChoise =(RadioButton) findViewById(R.id.badChoise); 
    mediaChoise =(RadioButton) findViewById(R.id.mediaChoise); 
    happyChoise =(RadioButton) findViewById(R.id.happyChoise); 
    groupRadio = (RadioGroup) findViewById(R.id.group); 

    Button btnDismiss = (Button)popupView.findViewById(R.id.chiudi); 
    Button btnInvia = (Button)popupView.findViewById(R.id.invia); 

    btnDismiss.setOnClickListener(new myListener()); 
    btnInvia.setOnClickListener(new myListener()); 

    groupRadio.setOnCheckedChangeListener(new OnCheckedChangeListener() { 

     @Override 
     public void onCheckedChanged(RadioGroup group, int checkedId) { 
      // TODO Auto-generated method stub 
      // This will get the radiobutton that has changed in its check state 
      RadioButton checkedRadioButton = (RadioButton)group.findViewById(checkedId); 
      // This puts the value (true/false) into the variable 
      boolean isChecked = checkedRadioButton.isChecked(); 
      // If the radiobutton that has changed in check state is now checked... 
      if (isChecked) 
      { 
       checkedButton = checkedId; 
      } 

     } 
    }); 
    //mediaChoise.setOnClickListener(new myListener()); 
    //happyChoise.setOnClickListener(new myListener()); 

    popupWindow.showAsDropDown(launchpopup, 50, -30); 


} 

public class myListener implements OnClickListener{ 

    @Override 
    public void onClick(View v) { 
     // TODO Auto-generated method stub 

     // bottone chiudi 
     if(v.getId()== R.id.chiudi){ 

      popupWindow.dismiss(); 

     } 

     // bottone invia 
     if(v.getId()== R.id.invia){ 
     /* 
      HttpClient httpclient = new DefaultHttpClient(); 
       HttpPost httppost = new HttpPost("http://example.com/mypage.php"); 
       try { 
       List<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>(4); 

       nameValuePairs.add(new BasicNameValuePair("fname", "vinod")); 
       nameValuePairs.add(new BasicNameValuePair("fphone", "1234567890")); 
       nameValuePairs.add(new BasicNameValuePair("femail", "abc@gmail.com")); 
       nameValuePairs.add(new BasicNameValuePair("fcomment", "Help")); 
       httppost.setEntity(new UrlEncodedFormEntity(nameValuePairs)); 
       httpclient.execute(httppost); 

      } catch (ClientProtocolException e) { 
       // TODO Auto-generated catch block 
      } catch (IOException e) { 
       // TODO Auto-generated catch block 
      }*/ 
      popupWindow.dismiss(); 
     }   
    } 
} 

@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); 
} 
} 

我有一個顯示java.lang.NullPointerException在這條線：

groupRadio.setOnCheckedChangeListener(new OnCheckedChangeListener() { 

這是錯誤日誌：

10-29 14:11:51.859: E/AndroidRuntime(21090): FATAL EXCEPTION: main 
10-29 14:11:51.859: E/AndroidRuntime(21090): java.lang.NullPointerException 
10-29 14:11:51.859: E/AndroidRuntime(21090): at com.example.survey.Survey.showPopup(Survey.java:96) 
10-29 14:11:51.859: E/AndroidRuntime(21090): at com.example.survey.Survey$1.onClick(Survey.java:65) 
10-29 14:11:51.859: E/AndroidRuntime(21090): at android.view.View.performClick(View.java:4377) 
10-29 14:11:51.859: E/AndroidRuntime(21090): at android.view.View$PerformClick.run(View.java:18044) 
10-29 14:11:51.859: E/AndroidRuntime(21090): at android.os.Handler.handleCallback(Handler.java:725) 
10-29 14:11:51.859: E/AndroidRuntime(21090): at android.os.Handler.dispatchMessage(Handler.java:92) 
10-29 14:11:51.859: E/AndroidRuntime(21090): at android.os.Looper.loop(Looper.java:137) 
10-29 14:11:51.859: E/AndroidRuntime(21090): at android.app.ActivityThread.main(ActivityThread.java:5306) 
10-29 14:11:51.859: E/AndroidRuntime(21090): at java.lang.reflect.Method.invokeNative(Native Method) 
10-29 14:11:51.859: E/AndroidRuntime(21090): at java.lang.reflect.Method.invoke(Method.java:511) 
10-29 14:11:51.859: E/AndroidRuntime(21090): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1102) 
10-29 14:11:51.859: E/AndroidRuntime(21090): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:869) 
10-29 14:11:51.859: E/AndroidRuntime(21090): at dalvik.system.NativeStart.main(Native Method) 

我試圖管理radiogroup偵聽器在我的數據庫中發送「戳」。 http後的代碼只是一個例子。我必須改變它。 有人可以幫我嗎？ 謝謝

Answer 1

你需要從新膨脹的母視圖，即popupView找到你想要的視圖。

因此，更改以下（以及類似）：

badChoise = (RadioButton) findViewById(R.id.badChoise); 

要這樣：

badChoise = (RadioButton) popupView.findViewById(R.id.badChoise); 

Answer 2

你得到，因爲這條線

groupRadio = (RadioGroup) findViewById(R.id.group); 

groupRadio的NullPointerException異常是空對象所以做它的例子：

groupRadio.setOnCheckedChangeListener(new OnCheckedChangeListener() { 

會拋出異常。看看你的調查佈局，並檢查你是否正確定義了電臺組ID（電話號碼）