傳遞整數片段片段 - sectionsPageAdapter，ViewPager

Question

我所試圖做的事：

我有承載兩個片段的活動 - CreateActivity.java承載Fragment1.java和Fragment2.java。

當在Fragment1中點擊ListFragment中的項目時，我想切換到查看Fragment2並根據Fragment1中列表中單擊的位置顯示一些信息。

我試圖通過列表中的「位置」的價值，像這樣：在片段1 ListFragment項目

用戶點擊這個代碼，然後將「位置」向CreateActivity.java值：

OnMemeSelectedListener mCallback; 

public interface OnListSelectedListener { 
    public void onArticleSelected(int position); 
} 

public void onAttach(Activity activity) { 
    super.onAttach(activity); 
    try { 
     mCallback = (OnListSelectedListener) activity; 
    } catch (ClassCastException e) { 
     throw new ClassCastException(activity.toString() 
       + " must implement OnHeadlineSelectedListener"); 
    } 
} 

@Override 
public void onListItemClick(ListView l, View v, int position, long id) { 
    super.onListItemClick(l, v, position, id); 
    mCallback.onArticleSelected(position); 
} 

在CreateActivity.java下面的方法被調用，以獲得整數「位置」：

@Override 
public void onArticleSelected(int position) { 
    // Fragment2 newFragment = new Fragment2(); 
    Bundle args = new Bundle(); 
    args.putInt(Fragment2.ARG_POSITION, position); 
    Fragment2 fragobj = new Fragment2(); 
    fragobj.setArguments(args); 
    Log.w("myApp", "" + position); 
    //Switch to Fragment2 Tab 
    mViewPager.setCurrentItem(1); 
} 

截至這是完全的工作作爲日誌輸出正確的位置列表。現在獲得Fragment2.class我寫了下面這行的整數：

int Position = getArguments().getInt(ARG_POSITION, position); 

但是我在開始CreateActivity.java得到NullPointError在我的日誌：

08-31 17:45:04.102: E/AndroidRuntime(14779): FATAL EXCEPTION: main 
08-31 17:45:04.102: E/AndroidRuntime(14779): java.lang.NullPointerException 
08-31 17:45:04.102: E/AndroidRuntime(14779): at com.meme.hdmeme.Fragment2.onCreateView(Fragment2.java:59) 
08-31 17:45:04.102: E/AndroidRuntime(14779): at android.support.v4.app.Fragment.performCreateView(Fragment.java:1478) 
08-31 17:45:04.102: E/AndroidRuntime(14779): at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:927) 
08-31 17:45:04.102: E/AndroidRuntime(14779): at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1104) 
08-31 17:45:04.102: E/AndroidRuntime(14779): at android.support.v4.app.BackStackRecord.run(BackStackRecord.java:682) 
08-31 17:45:04.102: E/AndroidRuntime(14779): at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1460) 
08-31 17:45:04.102: E/AndroidRuntime(14779): at android.support.v4.app.FragmentManagerImpl.executePendingTransactions(FragmentManager.java:472) 
08-31 17:45:04.102: E/AndroidRuntime(14779): at android.support.v4.app.FragmentPagerAdapter.finishUpdate(FragmentPagerAdapter.java:141) 
08-31 17:45:04.102: E/AndroidRuntime(14779): at android.support.v4.view.ViewPager.populate(ViewPager.java:1068) 
08-31 17:45:04.102: E/AndroidRuntime(14779): at android.support.v4.view.ViewPager.populate(ViewPager.java:914) 
08-31 17:45:04.102: E/AndroidRuntime(14779): at android.support.v4.view.ViewPager.onMeasure(ViewPager.java:1436) 
08-31 17:45:04.102: E/AndroidRuntime(14779): at android.view.View.measure(View.java:15518) 
08-31 17:45:04.102: E/AndroidRuntime(14779): at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:4825) 
08-31 17:45:04.102: E/AndroidRuntime(14779): at android.widget.FrameLayout.onMeasure(FrameLayout.java:310) 
08-31 17:45:04.102: E/AndroidRuntime(14779): at android.view.View.measure(View.java:15518) 
08-31 17:45:04.102: E/AndroidRuntime(14779): at android.widget.LinearLayout.measureVertical(LinearLayout.java:847) 
08-31 17:45:04.102: E/AndroidRuntime(14779): at android.widget.LinearLayout.onMeasure(LinearLayout.java:588) 
08-31 17:45:04.102: E/AndroidRuntime(14779): at android.view.View.measure(View.java:15518) 
08-31 17:45:04.102: E/AndroidRuntime(14779): at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:4825) 
08-31 17:45:04.102: E/AndroidRuntime(14779): at android.widget.FrameLayout.onMeasure(FrameLayout.java:310) 
08-31 17:45:04.102: E/AndroidRuntime(14779): at com.android.internal.policy.impl.PhoneWindow$DecorView.onMeasure(PhoneWindow.java:2313) 
08-31 17:45:04.102: E/AndroidRuntime(14779): at android.view.View.measure(View.java:15518) 
08-31 17:45:04.102: E/AndroidRuntime(14779): at android.view.ViewRootImpl.performMeasure(ViewRootImpl.java:1874) 
08-31 17:45:04.102: E/AndroidRuntime(14779): at android.view.ViewRootImpl.measureHierarchy(ViewRootImpl.java:1089) 
08-31 17:45:04.102: E/AndroidRuntime(14779): at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1265) 
08-31 17:45:04.102: E/AndroidRuntime(14779): at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:989) 
08-31 17:45:04.102: E/AndroidRuntime(14779): at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:4351) 
08-31 17:45:04.102: E/AndroidRuntime(14779): at android.view.Choreographer$CallbackRecord.run(Choreographer.java:749) 
08-31 17:45:04.102: E/AndroidRuntime(14779): at android.view.Choreographer.doCallbacks(Choreographer.java:562) 
08-31 17:45:04.102: E/AndroidRuntime(14779): at android.view.Choreographer.doFrame(Choreographer.java:532) 
08-31 17:45:04.102: E/AndroidRuntime(14779): at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:735) 
08-31 17:45:04.102: E/AndroidRuntime(14779): at android.os.Handler.handleCallback(Handler.java:725) 
08-31 17:45:04.102: E/AndroidRuntime(14779): at android.os.Handler.dispatchMessage(Handler.java:92) 
08-31 17:45:04.102: E/AndroidRuntime(14779): at android.os.Looper.loop(Looper.java:137) 
08-31 17:45:04.102: E/AndroidRuntime(14779): at android.app.ActivityThread.main(ActivityThread.java:5195) 
08-31 17:45:04.102: E/AndroidRuntime(14779): at java.lang.reflect.Method.invokeNative(Native Method) 
08-31 17:45:04.102: E/AndroidRuntime(14779): at java.lang.reflect.Method.invoke(Method.java:511) 
08-31 17:45:04.102: E/AndroidRuntime(14779): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:795) 
08-31 17:45:04.102: E/AndroidRuntime(14779): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:562) 
08-31 17:45:04.102: E/AndroidRuntime(14779): at dalvik.system.NativeStart.main(Native Method) 

我一直停留在這幾個小時和無法找到一個解決方法，在所有59行（導致NPE）是：

int Position = getArguments().getInt(ARG_POSITION, position); 

我必須創建之前就設置Fragment2的論點？我想在這個活動中創建這個數據之後傳遞給Fragment2，有什麼想法嗎？

感謝

Answer 1

看起來你在呼喚你onCreateView 。那時候還沒有任何爭論。

覆蓋Fragment2中的setArguments，並將相關代碼顯示出您從第一個Fragment中獲取的內容。

這有可能進入你的Fragment2：

@Override 
    public void setArguments(Bundle args) { 
     super.setArguments(args); 
     int Position = args.getInt(ARG_POSITION, position); 

     // now adjust what ever you want to display 
    }