我正在尝试将一个arrayadapter设置为来自firebase的listview，但它无效。我正在使用一个片段，它告诉我“v”AKA我的视图是从内部类中访问的，需要声明为final。我已经尝试将“final”放在行的开头，但它不起作用。我是Android Studio的新手，非常感谢您的帮助！
这是我的代码：
public class Mandag extends Fragment {
private ListView listView;
@Override
public View onCreateView(final LayoutInflater inflater, final ViewGroup container, Bundle savedInstanceState) {
View v = inflater.inflate(mandag, container, false);
FirebaseDatabase database = FirebaseDatabase.getInstance();
DatabaseReference myRef = database.getReference("Skular");
final SharedPreferences skuule = getActivity().getSharedPreferences("skule", Context.MODE_PRIVATE);
String Skule = skuule.getString("skule", "");
final SharedPreferences klaasse = getActivity().getSharedPreferences("klasse", Context.MODE_PRIVATE);
String Klasse = klaasse.getString("klasse", "");
myRef.child(Skule).child(Klasse).child("Fag").child("Mandag").addListenerForSingleValueEvent(new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
final List<String> timar = new ArrayList<String>();
for (DataSnapshot areaSnapshot : dataSnapshot.getChildren()) {
String skuleName = areaSnapshot.getValue(String.class);
timar.add(skuleName);
}
ArrayAdapter<String> skularAdapter = new ArrayAdapter<String>(getActivity(), android.R.layout.activity_list_item, timar);
final ListView = (ListView) v.findViewById(R.id.mList);
listView.setAdapter(skularAdapter);
}
@Override
public void onCancelled(DatabaseError databaseError) {
}
});
return v;
}
我的数据库：
{"Skular" : {
"Kvåle_Skule" : {
"9A" : {
"Fag" : {
"Mandag" : {
"Fag1" : "Engelsk",
"Fag2" : "Engelsk",
"Fag3" : "Matte",
"Fag4" : "Kosetime:)",
"Fag5" : "KRLE",
"Fag6" : "Naturfag"
}
},
"Lekser" : {
"Naturfag" : "Les side 31 - 34!",
"Norsk" : "Gjer nåke",
"Samfunsfag" : "Sjå Ein Debatt 8 ganger"
}
},
"9B" : {
"Fag" : {
"Mandag" : {
"Fag1" : "Norsk",
"Fag2" : "Norsk",
"Fag3" : "Matte",
"Fag4" : "Matte",
"Fag5" : "Gym",
"Fag6" : "Gym"
}
},
"Lekser" : {
"Naturfag" : "Les side 31 - 34!",
"Norsk" : "Gjer nåke",
"Samfunsfag" : "Sjå Ein Debatt 2 ganger"
}
},
"9C" : {
"Fag" : {
"Mandag" : {
"Fag1" : "Norsk",
"Fag2" : "Engelsk",
"Fag3" : "Matte",
"Fag4" : "Samfunsfag",
"Fag5" : "KRLE",
"Fag6" : "Naturfag"
}
},
"Lekser" : {
"Naturfag" : "Les side 31 - 34!",
"Norsk" : "Gjer nåke",
"Samfunsfag" : "Sjå Ein Debatt"
}
},
"Picker1" : [ "8", "9", "10" ],
"Picker2" : [ "A", "B", "C" ]
},
},}
谢谢你能提供帮助！
编辑： 我的错误：
10-02 21:45:05.714 5935-5935/com.heli.minvekeplan E/ArrayAdapter: You must supply a resource ID for a TextView
10-02 21:45:05.714 5935-5935/com.heli.minvekeplan D/AndroidRuntime: Shutting down VM
10-02 21:45:05.717 5935-5935/com.heli.minvekeplan E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.heli.minvekeplan, PID: 5935
java.lang.IllegalStateException: ArrayAdapter requires the resource ID to be a TextView
at android.widget.ArrayAdapter.createViewFromResource(ArrayAdapter.java:386)
at android.widget.ArrayAdapter.getView(ArrayAdapter.java:362)
at android.widget.AbsListView.obtainView(AbsListView.java:2347)
at android.widget.ListView.measureHeightOfChildren(ListView.java:1270)
at android.widget.ListView.onMeasure(ListView.java:1182)
at android.view.View.measure(View.java:17637)
at android.widget.RelativeLayout.measureChildHorizontal(RelativeLayout.java:728)
at android.widget.RelativeLayout.onMeasure(RelativeLayout.java:464)
at android.view.View.measure(View.java:17637)
at android.support.v4.view.ViewPager.onMeasure(ViewPager.java:1629)
at android.view.View.measure(View.java:17637)
at android.widget.RelativeLayout.measureChildHorizontal(RelativeLayout.java:728)
at android.widget.RelativeLayout.onMeasure(RelativeLayout.java:464)
at android.view.View.measure(View.java:17637)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5536)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:436)
at android.support.v7.widget.ContentFrameLayout.onMeasure(ContentFrameLayout.java:139)
at android.view.View.measure(View.java:17637)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5536)
at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1436)
at android.widget.LinearLayout.measureVertical(LinearLayout.java:722)
at android.widget.LinearLayout.onMeasure(LinearLayout.java:613)
at android.view.View.measure(View.java:17637)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5536)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:436)
at android.view.View.measure(View.java:17637)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5536)
at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1436)
at android.widget.LinearLayout.measureVertical(LinearLayout.java:722)
at android.widget.LinearLayout.onMeasure(LinearLayout.java:613)
at android.view.View.measure(View.java:17637)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5536)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:436)
at com.android.internal.policy.impl.PhoneWindow$DecorView.onMeasure(PhoneWindow.java:2618)
at android.view.View.measure(View.java:17637)
at android.view.ViewRootImpl.performMeasure(ViewRootImpl.java:2019)
at android.view.ViewRootImpl.measureHierarchy(ViewRootImpl.java:1177)
at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1383)
at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1065)
at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:5901)
at android.view.Choreographer$CallbackRecord.run(Choreographer.java:767)
at android.view.Choreographer.doCallbacks(Choreographer.java:580)
at android.view.Choreographer.doFrame(Choreographer.java:550)
at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:753)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:211)
at android.app.ActivityThread.main(ActivityThread.java:5389)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1020)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:815)
Caused by: java.lang.ClassCastException: android.widget.LinearLayout cannot be cast to android.widget.TextView
at android.widget.ArrayAdapter.createViewFromResource(ArrayAdapter.java:379)
at android.widget.ArrayAdapter.getView(ArrayAdapter.java:362)
at android.widget.AbsListView.obtainView(AbsListView.java:2347)
at android.widget.ListView.measureHeightOfChildren(ListView.java:1270)
at android.widget.ListView.onMeasure(ListView.java:1182)
at android.view.View.measure(View.java:17637)
at android.widget.RelativeLayout.measureChildHorizontal(RelativeLayout.java:728)
at android.widget.RelativeLayout.onMeasure(RelativeLayout.java:464)
at android.view.View.measure(View.java:17637)
at android.support.v4.view.ViewPager.onMeasure(ViewPager.java:1629)
at android.view.View.measure(View.java:17637)
at android.widget.RelativeLayout.measureChildHorizontal(RelativeLayout.java:728)
at android.widget.RelativeLayout.onMeasure(RelativeLayout.java:464)
at android.view.View.measure(View.java:17637)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5536)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:436)
at android.support.v7.widget.ContentFrameLayout.onMeasure(ContentFrameLayout.java:139)
at android.view.View.measure(View.java:17637)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5536)
at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1436)
at android.widget.LinearLayout.measureVertical(LinearLayout.java:722)
at android.widget.LinearLayout.onMeasure(LinearLayout.java:613)
at android.view.View.measure(View.java:17637)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5536)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:436)
at android.view.View.measure(View.java:17637)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5536)
at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1436)
at android.widget.LinearLayout.measureVertical(LinearLayout.java:722)
at android.widget.LinearLayout.onMeasure(LinearLayout.java:613)
at android.view.View.measure(View.java:17637)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5536)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:436)
at com.android.internal.policy.impl.PhoneWindow$DecorView.onMeasure(PhoneWindow.java:2618)
at android.view.View.measure(View.java:17637)
at android.view.ViewRootImpl.performMeasure(ViewRootImpl.java:2019)
at android.view.ViewRootImpl.measureHierarchy(ViewRootImpl.java:1177)
at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1383)
at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1065)
at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:5901)
at android.view.Choreographer$CallbackRecord.run(Choreographer.java:767)
at android.view.Choreographer.doCallbacks(Choreographer.java:580)
at android.view.Choreographer.doFrame(Choreographer.java:550)
at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:753)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:211)
at android.app.ActivityThread.main(ActivityThread.java:5389)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1020)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:815)
答案 0 :(得分：0)
您在行
中的匿名类中使用变量v
final ListView = (ListView) v.findViewById(R.id.mList);
此外，我没有看到ListView变量的名称，它应该是：
final ListView listView = (ListView) v.findViewById(R.id.mList);
将该行移到匿名类之外，例如在此行下面：
String Klasse = klaasse.getString("klasse", "");
并保持最终状态，或者你可以按照以下方式进行View决赛：
final View v = inflater.inflate(mandag, container, false);