我有一个活动,其中有一个片段,当我通过以下代码执行此操作时,我必须从活动中传递字符串数组,发生空指针异常,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)
最佳答案
您需要在deals
的PagerAdapter
函数中使用实例getItem
,而不是创建一个没有bundle
作为参数的新Fragment实例。
1.)使您的deals
实例成为全局类
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.)在
deals
内使用getItem
@Override
public Fragment getItem(int position) {
switch (position) {
case 0: {
MapsFragment mapsActivity=new MapsFragment();
return mapsActivity;
}
case 1: {
return deals;
}
}
return null;
}
或者你可以这样做
@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);
}
关于java - 当将字符串数组从容器Activity传递到 fragment 时,getArguments()返回null,我们在Stack Overflow上找到一个类似的问题:https://stackoverflow.com/questions/42302122/