我在蓝色的月亮中遇到这个错误，似乎无法重现它或找出问题所在：
java.lang.NullPointerException
at com.example.mike.beerportfoliomaterial.BeerPage.onSaveInstanceState(BeerPage.java:221)
at android.support.v4.app.Fragment.performSaveInstanceState(Fragment.java:1933)
at android.support.v4.app.FragmentManagerImpl.saveFragmentBasicState(FragmentManager.java:1642)
at android.support.v4.app.FragmentManagerImpl.saveAllState(FragmentManager.java:1710)
at android.support.v4.app.FragmentActivity.onSaveInstanceState(FragmentActivity.java:524)
at com.example.mike.beerportfoliomaterial.MainDrawer2.onSaveInstanceState(MainDrawer2.java:193)
at android.app.Activity.performSaveInstanceState(Activity.java:1253)
at android.app.Instrumentation.callActivityOnSaveInstanceState(Instrumentation.java:1229)
at android.app.ActivityThread.handleRelaunchActivity(ActivityThread.java:4175)
at android.app.ActivityThread.access$1000(ActivityThread.java:174)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1327)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:146)
at android.app.ActivityThread.main(ActivityThread.java:5731)
at java.lang.reflect.Method.invokeNative(Method.java)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1291)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1107)
at dalvik.system.NativeStart.main(NativeStart.java)
BeerPage java代码是：
public class BeerPage extends Fragment {
public BeerPage(){}
String beerId = "";
String breweryId = "";
SearchView searchView;
private UiLifecycleHelper uiHelper;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.beer_page, container, false);
Spinner spinner = (Spinner) rootView.findViewById(R.id.statsSpin);
ArrayAdapter<CharSequence> adapter = ArrayAdapter.createFromResource(getActivity(),
R.array.beerpage, android.R.layout.simple_spinner_item);
adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item); // The drop down view
spinner.setAdapter(adapter);
spinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
@Override
public void onItemSelected(AdapterView<?> parentView, View selectedItemView, int position, long id) {
switch (position) {
case 0:
break;
case 1:
// do whatever stuff you wanna do here
Fragment Fragment_one;
FragmentManager man= getActivity().getSupportFragmentManager();
FragmentTransaction tran = man.beginTransaction();
Fragment_one = new TasteTags2();
tran.replace(R.id.main, Fragment_one);//tran.
tran.addToBackStack(null);
tran.commit();
break;
case 2:
Fragment Fragment_two;
FragmentManager mantwo= getActivity().getSupportFragmentManager();
FragmentTransaction trantwo = mantwo.beginTransaction();
Fragment_two = new TasteNotePage();
trantwo.replace(R.id.main, Fragment_two);//tran.
trantwo.addToBackStack(null);
trantwo.commit();
break;
case 3:
Fragment Fragment_three;
FragmentManager manthree= getActivity().getSupportFragmentManager();
FragmentTransaction tranthree = manthree.beginTransaction();
Fragment_three = new FoodPairingsPage();
tranthree.replace(R.id.main, Fragment_three);//tran.
tranthree.addToBackStack(null);
tranthree.commit();
break;
case 4:
Fragment Fragment_four;
FragmentManager manfour= getActivity().getSupportFragmentManager();
FragmentTransaction tranfour = manfour.beginTransaction();
Fragment_four = new ListPage();
tranfour.replace(R.id.main, Fragment_four);//tran.
tranfour.addToBackStack(null);
tranfour.commit();
break;
}
}
@Override
public void onNothingSelected(AdapterView<?> parentView) {
// your code here
}
});
//body code goes here
//get user information
SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(getActivity());
String userName = prefs.getString("userName", null);
String userID = prefs.getString("userID", null);
final String beerId = prefs.getString("beerID", null);
breweryId = prefs.getString("breweryID", null);
final String breweryName = prefs.getString("breweryName", null);
final String styleName = prefs.getString("styleName", null);
final String beerName = prefs.getString("lastBeer", null);
TextView bt = (TextView)rootView.findViewById(R.id.beerBreweryName);
bt.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
// do whatever stuff you wanna do here
Fragment Fragment_one;
FragmentManager man= getActivity().getSupportFragmentManager();
FragmentTransaction tran = man.beginTransaction();
Fragment_one = new BreweryPage2();
((ActionBarActivity)getActivity()).getSupportActionBar().setTitle(breweryName);
//set beer to get style from
SharedPreferences preferences = PreferenceManager.getDefaultSharedPreferences(getActivity());
SharedPreferences.Editor editor = preferences.edit();
editor.putString("breweryID",breweryId);
editor.commit();
tran.replace(R.id.main, Fragment_one);//tran.
tran.addToBackStack(null);
tran.commit();
}
});
TextView bt2 = (TextView)rootView.findViewById(R.id.beerStyleName);
bt2.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
// do whatever stuff you wanna do here
((ActionBarActivity)getActivity()).getSupportActionBar().setTitle(styleName);
Fragment Fragment_two;
FragmentManager man= getActivity().getSupportFragmentManager();
FragmentTransaction tran = man.beginTransaction();
//set beer to get style from
SharedPreferences preferences = PreferenceManager.getDefaultSharedPreferences(getActivity());
SharedPreferences.Editor editor = preferences.edit();
editor.putString("style",beerId);
editor.commit();
Fragment_two = new StylePage2();
tran.replace(R.id.main, Fragment_two);//tran.
tran.addToBackStack(null);
tran.commit();
}
});
String url = "myURL";
new GetBeerDataJSON2(getActivity(), beerId).execute(url);
//facebook stuff
uiHelper = new UiLifecycleHelper(getActivity(), null);
uiHelper.onCreate(savedInstanceState);
return rootView;
}
//facebook stuff
@Override
public void onResume() {
super.onResume();
uiHelper.onResume();
}
@Override
public void onSaveInstanceState(Bundle outState) {
super.onSaveInstanceState(outState);
uiHelper.onSaveInstanceState(outState);
}
@Override
public void onPause() {
super.onPause();
uiHelper.onPause();
}
@Override
public void onDestroy() {
super.onDestroy();
uiHelper.onDestroy();
}
@Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
uiHelper.onActivityResult(requestCode, resultCode, data, new FacebookDialog.Callback() {
@Override
public void onError(FacebookDialog.PendingCall pendingCall, Exception error, Bundle data) {
Log.e("Activity", String.format("Error: %s", error.toString()));
}
@Override
public void onComplete(FacebookDialog.PendingCall pendingCall, Bundle data) {
Log.i("Activity", "Success!");
}
});
}
}
答案 0 :(得分：2)
您可能希望在onCreate回调中移动uiHelper实例化，因为崩溃可能来自onCreateView之前调用的onSaveInstanceState。
答案 1 :(得分：0)
如果您未正确处理配置更改，则会出现此错误。因此，如果您的应用不支持多个方向，即纵向和横向，则必须在清单文件中指定每个活动的方向。
+------------------+
| sum_col_array |
+------------------+
| ["12","15","18"] |
+------------------+