無法將數據從活動傳遞到片段

我會先說我是Android編程的新手，在閱讀了無數帖子後，仍然無法確定我在嘗試做什麼時出錯將一些參數從Fragment傳遞到Activity，任何幫助都會非常有幫助。無法將數據從活動傳遞到片段

我的動態類：

public class MainActivity extends AppCompatActivity implements View.OnClickListener { 

    public static final MasterFragment newInstance(String numberOfItems) { 
     MasterFragment masterFragment = new MasterFragment(); 
     Bundle bundle = new Bundle(); 
     bundle.putString("numberOfItems", numberOfItems); 
     masterFragment.setArguments(bundle); 
     return masterFragment; 
    } 

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

     if (savedInstanceState != null) { 
      MasterFragment masterFragment = new MasterFragment(); 
      masterFragment.setArguments(getIntent().getExtras()); 
     } 

     Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar); 
     setSupportActionBar(toolbar); 

     /*getting some buttons here 

     */ 

     //not sure if relevant, but just in case I'll add this here too 
     getSupportActionBar().setDisplayShowHomeEnabled(true); 
     getSupportActionBar().setIcon(R.drawable.ic_menu_white_24dp); 

     if (toolbar != null) { 
      toolbar.setOnClickListener(new View.OnClickListener() { 
       @Override 
       public void onClick(View v) { 
        SlidingPaneLayout mSlidingLayout; 
        mSlidingLayout = (SlidingPaneLayout) findViewById(R.id.mainSlidingPaneLayout); 

        if (mSlidingLayout.isOpen()) { 
         mSlidingLayout.closePane(); 
         getSupportActionBar().setIcon(R.drawable.ic_menu_white_24dp); 
        } else { 
         mSlidingLayout.openPane(); 
         getSupportActionBar().setIcon(R.drawable.ic_arrow_back_white_24dp); 
        } 
       } 
      }); 
     } 
    } 

    @Override 
    public void onClick(View v) { 
     Intent intent = new Intent(getApplicationContext(), ProductsScrollingActivity 
       .class); 

     ArrayList<String> products = new ArrayList<String>(); 
     switch (v.getId()) { 
      case R.id.baby: { 
       //getting the products ArrayList here 
       break; 
      } 
     } 
     intent.putExtra("products", products); 
     startActivity(intent); 
    } 
}

我的片段類：

public class MasterFragment extends ListFragment { 

    String noOfItems; 

    @Override 
    public View onCreateView (LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { 
     View view = inflater.inflate(R.layout.fragment_master, container); 
     noOfItems = getArguments().getString("numberOfItems", "0"); 
     setListAdapter(new MenuListAdapter(R.layout.row_menu_action_item, getActivity(), MenuActionItem.values(), noOfItems)); 
     return view; 
    } 
}

我content_main.xml：

<?xml version="1.0" encoding="utf-8"?> 
<android.support.v4.widget.SlidingPaneLayout 
    xmlns:android="http://schemas.android.com/apk/res/android" 
    xmlns:app="http://schemas.android.com/apk/res-auto" 
    xmlns:tools="http://schemas.android.com/tools" 
    android:layout_width="match_parent" 
    android:layout_height="match_parent" 
    android:paddingBottom="@dimen/activity_vertical_margin" 
    android:paddingLeft="@dimen/activity_horizontal_margin" 
    android:paddingRight="@dimen/activity_horizontal_margin" 
    android:paddingTop="@dimen/activity_vertical_margin" 
    android:background="#ffffff" 
    android:orientation="horizontal" 
    android:id="@+id/mainSlidingPaneLayout" 
    app:layout_behavior="@string/appbar_scrolling_view_behavior" 
    tools:context="com.example.MainActivity" 
    tools:showIn="@layout/activity_main"> 

    <!--Master fragment--> 
    <fragment 
     android:id="@+id/fragment_master" 
     android:name="com.example.MasterFragment" 
     android:layout_width="@dimen/mini_drawer_fragment_width" 
     android:layout_height="match_parent" 
     tools:layout="@layout/fragment_master"> 
    </fragment> 

    <!-- A ScrollView goes here with some other stuff--> 
</android.support.v4.widget.SlidingPaneLayout>

堆棧跟蹤：

java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example/com.example.MainActivity}: android.view.InflateException: Binary XML file line #25: Binary XML file line #20: Error inflating class fragment 
                        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2416) 
                        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2476) 
                        at android.app.ActivityThread.-wrap11(ActivityThread.java) 
                        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1344) 
                        at android.os.Handler.dispatchMessage(Handler.java:102) 
                        at android.os.Looper.loop(Looper.java:148) 
                        at android.app.ActivityThread.main(ActivityThread.java:5417) 
                        at java.lang.reflect.Method.invoke(Native Method) 
                        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726) 
                        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616) 
                       Caused by: android.view.InflateException: Binary XML file line #25: Binary XML file line #20: Error inflating class fragment 
                        at android.view.LayoutInflater.inflate(LayoutInflater.java:539) 
                        at android.view.LayoutInflater.inflate(LayoutInflater.java:423) 
                        at android.view.LayoutInflater.inflate(LayoutInflater.java:374) 
                        at android.support.v7.app.AppCompatDelegateImplV7.setContentView(AppCompatDelegateImplV7.java:256) 
                        at android.support.v7.app.AppCompatActivity.setContentView(AppCompatActivity.java:109) 
                        at com.example.MainActivity.onCreate(MainActivity.java:59) 
                        at android.app.Activity.performCreate(Activity.java:6237) 
                        at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1107) 
                        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2369) 
                        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2476)  
                        at android.app.ActivityThread.-wrap11(ActivityThread.java)  
                        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1344)  
                        at android.os.Handler.dispatchMessage(Handler.java:102)  
                        at android.os.Looper.loop(Looper.java:148)  
                        at android.app.ActivityThread.main(ActivityThread.java:5417)  
                        at java.lang.reflect.Method.invoke(Native Method)  
                        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)  
                        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)  
                       Caused by: android.view.InflateException: Binary XML file line #20: Error inflating class fragment 
                        at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:782) 
                        at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:704) 
                        at android.view.LayoutInflater.rInflate(LayoutInflater.java:835) 
                        at android.view.LayoutInflater.rInflateChildren(LayoutInflater.java:798) 
                        at android.view.LayoutInflater.parseInclude(LayoutInflater.java:971) 
                        at android.view.LayoutInflater.rInflate(LayoutInflater.java:831) 
                        at android.view.LayoutInflater.rInflateChildren(LayoutInflater.java:798) 
                        at android.view.LayoutInflater.inflate(LayoutInflater.java:515) 
                        at android.view.LayoutInflater.inflate(LayoutInflater.java:423)  
                        at android.view.LayoutInflater.inflate(LayoutInflater.java:374)  
                        at android.support.v7.app.AppCompatDelegateImplV7.setContentView(AppCompatDelegateImplV7.java:256)  
                        at android.support.v7.app.AppCompatActivity.setContentView(AppCompatActivity.java:109)  
                        at com.example.MainActivity.onCreate(MainActivity.java:59)  
                        at android.app.Activity.performCreate(Activity.java:6237)  
                        at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1107)  
                        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2369)  
                        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2476)  
                        at android.app.ActivityThread.-wrap11(ActivityThread.java)  
                        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1344)  
                        at android.os.Handler.dispatchMessage(Handler.java:102)  
                        at android.os.Looper.loop(Looper.java:148)  
                        at android.app.ActivityThread.main(ActivityThread.java:5417)  
                        at java.lang.reflect.Method.invoke(Native Method)  
                        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)  
                        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)  
                       Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.String android.os.Bundle.getString(java.lang.String, java.lang.String)' on a null object reference 
                        at com.example.MasterFragment.onCreateView(MasterFragment.java:26) 
                        at android.support.v4.app.Fragment.performCreateView(Fragment.java:1962) 
                        at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1036) 
                        at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1226) 
                        at android.support.v4.app.FragmentManagerImpl.addFragment(FragmentManager.java:1328) 
                        at android.support.v4.app.FragmentManagerImpl.onCreateView(FragmentManager.java:2284) 
                        at android.support.v4.app.FragmentController.onCreateView(FragmentController.java:111) 
                        at android.support.v4.app.FragmentActivity.dispatchFragmentsOnCreateView(FragmentActivity.java:314) 
                        at android.support.v4.app.BaseFragmentActivityHoneycomb.onCreateView(BaseFragmentActivityHoneycomb.java:31) 
                        at android.support.v4.app.FragmentActivity.onCreateView(FragmentActivity.java:79) 
                        at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:754) 
                        at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:704)  
                        at android.view.LayoutInflater.rInflate(LayoutInflater.java:835)  
                        at android.view.LayoutInflater.rInflateChildren(LayoutInflater.java:798)  
                        at android.view.LayoutInflater.parseInclude(LayoutInflater.java:971)  
                        at android.view.LayoutInflater.rInflate(LayoutInflater.java:831)  
                        at android.view.LayoutInflater.rInflateChildren(LayoutInflater.java:798)  
                        at android.view.LayoutInflater.inflate(LayoutInflater.java:515)  
                        at android.view.LayoutInflater.inflate(LayoutInflater.java:423)  
                        at android.view.LayoutInflater.inflate(LayoutInflater.java:374)  
                        at android.support.v7.app.AppCompatDelegateImplV7.setContentView(AppCompatDelegateImplV7.java:256)  
                        at android.support.v7.app.AppCompatActivity.setContentView(AppCompatActivity.java:109)  
                        at com.example.MainActivity.onCreate(MainActivity.java:59)  
                        at android.app.Activity.performCreate(Activity.java:6237)  
                        at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1107)  
                        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2369)  
                        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2476)  
                        at android.app.ActivityThread.-wrap11(ActivityThread.java)  
                        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1344)  
                        at android.os.Handler.dispatchMessage(Handler.java:102)  
                        at android.os.Looper.loop(Looper.java:148)  
                        at android.app.ActivityThread.main(ActivityThread.java:5417)  
                        at java.lang.reflect.Method.invoke(Native Method)  
                        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)  
                        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)

來源

2016-03-15 Cosmin

你嘗試從Bundle中獲取字符串，但是您從不將它設置爲'getArguments（）。getString（「numberOfItems」，「0」）;'因爲您從不調用'newInstance（）'方法 – GVillani82

您有'if（savedInstanceState ！= null）{'。所以savedInstanceState第一次爲空，除非您旋轉活動被破壞並重新創建的屏幕。這是故意的嗎？ – Raghunandan

我建議你從代碼中添加片段，而不是在xml中定義它們。 – Greensy

當你用XML定義一個片段時，你無法在片段膨脹之前設置片段上的參數 - 所以在片段的onViewCreated代碼中，getArguments（）爲null，這會導致崩潰。如果你想將參數添加到您的片段，更換<fragment>標籤在XML與FrameLayout裏，在您的活動定義片段（如你正在做的話），並將其與FragmentManager添加到的FrameLayout：

getSupportFragmentManager().beginTransaction() 
    .add(R.id.fragment_container, /*id of your frame layout*/ 
     fragment /*instance of the fragment created in your activity*/) 
    .commit();

來源

2016-03-15 15:33:14

這確實有用。謝謝。 – Cosmin

無法將數據從活動傳遞到片段

回答

相關問題