setContentView가 Null 포인터 예외를 발생시킵니다.

Question

가져온 패키지에서 메소드를 호출하려고하는 주요 활동이 있습니다. 아래에 전화와 방법을 게시했습니다. 내가 얻는 오류 메시지는 그 줄입니다.

setContentView (twitterSite);

널 포인트 예외가 발생했습니다. 방법

public void loginNewUser(View v, Context context) { 
    mPrefs = context.getSharedPreferences("twitterPrefs", MODE_PRIVATE); 
    Log.i(TAG, "Got Preferences"); 

    // Load the twitter4j helper 
    mTwitter = new TwitterFactory().getInstance(); 
    Log.i(TAG, "Got Twitter4j"); 

    // Tell twitter4j that we want to use it with our app 
    mTwitter.setOAuthConsumer(CONSUMER_KEY, CONSUMER_SECRET); 

    try { 
     Log.i(TAG, "Request App Authentication"); 
     mReqToken = mTwitter.getOAuthRequestToken(CALLBACK_URL); 

     Log.i(TAG, "Starting Webview to login to twitter"); 
     WebView twitterSite = new WebView(context); 
     twitterSite.requestFocus(View.FOCUS_DOWN); 
     twitterSite.setOnTouchListener(new View.OnTouchListener() { 

      public boolean onTouch(View v, MotionEvent event) { 
       switch (event.getAction()) { 
        case MotionEvent.ACTION_DOWN: 
        case MotionEvent.ACTION_UP: 
         if (!v.hasFocus()) { 
          v.requestFocus(); 
         } 
         break; 
       } 
       return false; 
      } 
     }); 
     twitterSite.loadUrl(mReqToken.getAuthenticationURL()); 
     setContentView(twitterSite); 

    } catch (TwitterException e) { 
     Log.e("HelloWorld", "Error in activity", e); 
     Toast.makeText(this, "Twitter Login error, try again later", Toast.LENGTH_SHORT).show(); 
    } 
} 

스택 트레이스

09-26 08:21:12.123: ERROR/AndroidRuntime(171): Uncaught handler: thread main exiting due to uncaught exception 
09-26 08:21:12.312: ERROR/AndroidRuntime(171): java.lang.NullPointerException 
09-26 08:21:12.312: ERROR/AndroidRuntime(171):  at android.app.Activity.setContentView(Activity.java:1631) 
09-26 08:21:12.312: ERROR/AndroidRuntime(171):  at com.blundell.tut.ttt.TweetToTwitterActivity.loginNewUser(TweetToTwitterActivity.java:184) 
09-26 08:21:12.312: ERROR/AndroidRuntime(171):  at com.reason.max.Reason$3.onClick(Reason.java:239) 
09-26 08:21:12.312: ERROR/AndroidRuntime(171):  at android.view.View.performClick(View.java:2344) 
09-26 08:21:12.312: ERROR/AndroidRuntime(171):  at android.view.View.onTouchEvent(View.java:4133) 
09-26 08:21:12.312: ERROR/AndroidRuntime(171):  at android.widget.TextView.onTouchEvent(TextView.java:6510) 
09-26 08:21:12.312: ERROR/AndroidRuntime(171):  at android.view.View.dispatchTouchEvent(View.java:3672) 
09-26 08:21:12.312: ERROR/AndroidRuntime(171):  at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:882) 
09-26 08:21:12.312: ERROR/AndroidRuntime(171):  at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:882) 
09-26 08:21:12.312: ERROR/AndroidRuntime(171):  at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:882) 
09-26 08:21:12.312: ERROR/AndroidRuntime(171):  at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:882) 
09-26 08:21:12.312: ERROR/AndroidRuntime(171):  at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:882) 
09-26 08:21:12.312: ERROR/AndroidRuntime(171):  at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:882) 
09-26 08:21:12.312: ERROR/AndroidRuntime(171):  at com.android.internal.policy.impl.PhoneWindow$DecorView.superDispatchTouchEvent(PhoneWindow.java:1712) 
09-26 08:21:12.312: ERROR/AndroidRuntime(171):  at com.android.internal.policy.impl.PhoneWindow.superDispatchTouchEvent(PhoneWindow.java:1202) 
09-26 08:21:12.312: ERROR/AndroidRuntime(171):  at android.app.Dialog.dispatchTouchEvent(Dialog.java:609) 
09-26 08:21:12.312: ERROR/AndroidRuntime(171):  at com.android.internal.policy.impl.PhoneWindow$DecorView.dispatchTouchEvent(PhoneWindow.java:1696) 
09-26 08:21:12.312: ERROR/AndroidRuntime(171):  at android.view.ViewRoot.handleMessage(ViewRoot.java:1658) 
09-26 08:21:12.312: ERROR/AndroidRuntime(171):  at android.os.Handler.dispatchMessage(Handler.java:99) 
09-26 08:21:12.312: ERROR/AndroidRuntime(171):  at android.os.Looper.loop(Looper.java:123) 
09-26 08:21:12.312: ERROR/AndroidRuntime(171):  at android.app.ActivityThread.main(ActivityThread.java:4203) 
09-26 08:21:12.312: ERROR/AndroidRuntime(171):  at java.lang.reflect.Method.invokeNative(Native Method) 
09-26 08:21:12.312: ERROR/AndroidRuntime(171):  at java.lang.reflect.Method.invoke(Method.java:521) 
09-26 08:21:12.312: ERROR/AndroidRuntime(171):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:791) 
09-26 08:21:12.312: ERROR/AndroidRuntime(171):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:549) 
09-26 08:21:12.312: ERROR/AndroidRuntime(171):  at dalvik.system.NativeStart.main(Native Method) 

Answer 1

setContentView

  TweetToTwitterActivity twitter = new TweetToTwitterActivity(); 
      twitter.loginNewUser(v, context); 

는 Activity 클래스하는 방법이다. 그래서 함수가 액티비티 클래스에 없다면 당신은 컨텐트를 설정해야하는 액티비티를 언급해야한다.

((Activity) context).setContentView(twitterSite); 

이유가 있기 때문에 Activity에 컨텍스트를 입력해야합니다.

Answer 2

onCreate() 방법 UR 첫번째 라인

super.onCreate(savedInstanceState);