getArguments（）返回null当从容器活动传递字符串数组活动到片段

Question

我有一个活动，其中有一个片段，我必须从活动传递字符串数组，当我通过以下代码执行此操作时出现空指针异常请帮助

Main2Activity.java

public class Main2Activity extends AppCompatActivity implements OnMapReadyCallback, AsyncResponse{ 

String[] check = { 
     "KFC bundle", 
     "Pizza Hut b", 
     "Pizza Point b" 
} ; 
@Override 
protected void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.activity_main2); 
    Intent intent = getIntent(); 
    newString = intent.getLongExtra("user_id", newString); 
    Bundle bundle = new Bundle(); 
    bundle.putStringArray("name", check); 
    Log.i("okkkkk", "Name Put: " + check[1]); 
    Deals deals = new Deals(); 
    deals.setArguments(bundle); 
    Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar); 
    setSupportActionBar(toolbar); 
    // Create the adapter that will return a fragment for each of the three 
    // primary sections of the activity. 
    mSectionsPagerAdapter = new SectionsPagerAdapter(getSupportFragmentManager()); 
    // Set up the ViewPager with the sections adapter. 
    mViewPager = (ViewPager) findViewById(R.id.container); 
    mViewPager.setAdapter(mSectionsPagerAdapter); 
    TabLayout tabLayout = (TabLayout) findViewById(R.id.tabs); 
    tabLayout.setupWithViewPager(mViewPager); 
    FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab); 
    fab.setOnClickListener(new View.OnClickListener() { 
     @Override 
     public void onClick(View view) { 
      Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG) 
        .setAction("Action", null).show(); 
     } 
    }); 
} 
    public class SectionsPagerAdapter extends FragmentPagerAdapter { 

    public SectionsPagerAdapter(FragmentManager fm) { 
     super(fm); 
    } 

    @Override 
    public Fragment getItem(int position) { 
     try { 
      switch (position) { 
       case 0: { 
        MapsFragment mapsActivity=new MapsFragment(); 
        return mapsActivity; 
       } 
       case 1: { 
        Deals deals = new Deals(); 
        return deals; 
       } 
      } 
     } 
     catch (Exception e) 
     { 
      Log.i("okkk", "Exception 1 : " + e); 
     } 

Deals.java`

public class Deals extends Fragment { 
    @Nullable 
    @Override 
    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup  container, @Nullable Bundle savedInstanceState) { 
    View view   =LayoutInflater.from(getActivity()).inflate(R.layout.fragment_main2,null); 
     // bundle = this.getArguments(); 
     String[] name = getArguments().getStringArray("name"); 
     Log.i("okkkkk", "Name String: " + name); 
     // String[] deal = getArguments().getStringArray("deal"); 

    ListView listview =(ListView)view.findViewById(R.id.DealsListView); 
    customList adapter = new customList(getActivity(), web, imageId,deal); 
    listview.setAdapter(adapter); 
    return view; 

}` 


java.lang.NullPointerException 
                         at app.com.example.saeed.fypephaseone.Deals.onCreateView(Deals.java:42) 
                         at android.support.v4.app.Fragment.performCreateView(Fragment.java:2074) 
                         at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1104) 
                         at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1286) 
                         at android.support.v4.app.BackStackRecord.run(BackStackRecord.java:758) 
                         at android.support.v4.app.FragmentManagerImpl.execSingleAction(FragmentManager.java:1632) 
                         at android.support.v4.app.BackStackRecord.commitNowAllowingStateLoss(BackStackRecord.java:637) 
                         at android.support.v4.app.FragmentPagerAdapter.finishUpdate(FragmentPagerAdapter.java:143) 
                         at android.support.v4.view.ViewPager.populate(ViewPager.java:1235) 
                         at android.support.v4.view.ViewPager.populate(ViewPager.java:1083) 
                         at android.support.v4.view.ViewPager.onMeasure(ViewPager.java:1609) 
                         at android.view.View.measure(View.java:16842) 

Answer 1

您需要使用实例deals您PagerAdapter的getItem函数内部，而不是创建它没有bundle参数作为一个新片段实例

1）使您deals实例全局

类

public class Main2Activity extends AppCompatActivity implements OnMapReadyCallback, AsyncResponse{ 

String[] check = { 
     "KFC bundle", 
     "Pizza Hut b", 
     "Pizza Point b" 
} ; 
Deals deals; 

@Override 
protected void onCreate(Bundle savedInstanceState) { 
    // code 
    deals = new Deals(); 
    deals.setArguments(bundle); 
    Toolbar toolbar = (Toolbar) findV 
    // code 
} 
// code 

2）使用deals内getItem

@Override 
    public Fragment getItem(int position) { 

     switch (position) { 
      case 0: { 
       MapsFragment mapsActivity=new MapsFragment(); 
       return mapsActivity; 
      } 
      case 1: { 
       return deals; 
      } 
     } 
    return null; 
} 

，或者你可以做到这一点

@Override 
public Fragment getItem(int position) { 
    try { 
     switch (position) { 
      case 0: { 
       MapsFragment mapsActivity=new MapsFragment(); 
       return mapsActivity; 
      } 
      case 1: { 
       Deals deals = new Deals(); 
       Bundle bundle = new Bundle(); 
       bundle.putStringArray("name", check); 
       deals.setArguments(bundle); 
       return deals; 
      } 
     } 
    } 
    catch (Exception e) 
    { 
     Log.i("okkk", "Exception 1 : " + e); 
    }