我正在尝试在片段中创建一个RecyclerView，但我一直在android.support.v7.widget.RecyclerView.onMeasure上获取java.lang.NullPointerException。我仔细查看了其他帖子，然后尝试了所有提示。但是我一直得到同样的错误。这是我的代码。任何帮助将不胜感激。
错误：
java.lang.NullPointerException
at android.support.v7.widget.RecyclerView.onMeasure(RecyclerView.java:1764)
at android.view.View.measure(View.java:17633)
at android.widget.RelativeLayout.measureChildHorizontal(RelativeLayout.java:719)
at android.widget.RelativeLayout.onMeasure(RelativeLayout.java:455)
at android.view.View.measure(View.java:17633)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5412)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:310)
at android.view.View.measure(View.java:17633)
at android.support.v4.view.ViewPager.onMeasure(ViewPager.java:1456)
at android.view.View.measure(View.java:17633)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5412)
at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1410)
at android.widget.LinearLayout.measureVertical(LinearLayout.java:695)
at android.widget.LinearLayout.onMeasure(LinearLayout.java:588)
at android.view.View.measure(View.java:17633)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5412)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:310)
at android.view.View.measure(View.java:17633)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5412)
at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1410)
at android.widget.LinearLayout.measureVertical(LinearLayout.java:695)
at android.widget.LinearLayout.onMeasure(LinearLayout.java:588)
at android.view.View.measure(View.java:17633)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5412)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:310)
at android.view.View.measure(View.java:17633)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5412)
at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1410)
at android.widget.LinearLayout.measureVertical(LinearLayout.java:695)
at android.widget.LinearLayout.onMeasure(LinearLayout.java:588)
at android.view.View.measure(View.java:17633)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5412)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:310)
at com.android.internal.policy.impl.PhoneWindow$DecorView.onMeasure(PhoneWindow.java:2588)
at android.view.View.measure(View.java:17633)
at android.view.ViewRootImpl.performMeasure(ViewRootImpl.java:2347)
at android.view.ViewRootImpl.measureHierarchy(ViewRootImpl.java:1439)
at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1653)
at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1297)
at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:6773)
at android.view.Choreographer$CallbackRecord.run(Choreographer.java:813)
at android.view.Choreographer.doCallbacks(Choreographer.java:613)
at android.view.Choreographer.doFrame(Choreographer.java:583)
at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:799)
at android.os.Handler.handleCallback(Handler.java:733)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:146)
at android.app.ActivityThread.main(ActivityThread.java:5635)
at java.lang.reflect.Method.invokeNative(Native Method)
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(Native Method)
片段：
public class SelectTeamFragment extends Fragment implements AdapterView.OnClickListener {
private RecyclerView listNFLTeams;
RecyclerView.LayoutManager layoutManager;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
View view = inflater.inflate(R.layout.fragment_select_team, container, false);
// 1. get a reference to recyclerView
RecyclerView recyclerView = (RecyclerView) view.findViewById(R.id.my_recycler_view);
recyclerView.setHasFixedSize(true);
// 2. set layoutManger
layoutManager = new LinearLayoutManager(getActivity());
recyclerView.setLayoutManager(layoutManager);
// this is data for recycler view
ItemData itemsData[] = { new ItemData("Help",R.drawable.ic_launcher),
new ItemData("Denver Broncos",R.drawable.ic_launcher),
new ItemData("Atlantic Falcons",R.drawable.ic_launcher),
new ItemData("Detroit Lions",R.drawable.ic_launcher),
new ItemData("Seattle SeaHawks",R.drawable.ic_launcher),
new ItemData("Miami Dolphins",R.drawable.ic_launcher)};
// 3. create an adapter
AdapterTeams mAdapter = new AdapterTeams(itemsData);
// 4. set adapter
recyclerView.setAdapter(mAdapter);
// 5. set item animator to DefaultAnimator
recyclerView.setItemAnimator(new DefaultItemAnimator());
return view;
}
@Override
public void onClick(View v) {
}
}
适配器：
public MyAdapter(ItemData[] itemsData) {
this.itemsData = itemsData;
}
// Create new views (invoked by the layout manager)
@Override
public MyAdapter.ViewHolder onCreateViewHolder(ViewGroup parent,
int viewType) {
// create a new view
View itemLayoutView = LayoutInflater.from(parent.getContext())
.inflate(R.layout.fragment_select_team, parent, false);
// create ViewHolder
ViewHolder viewHolder = new ViewHolder(itemLayoutView);
return viewHolder;
}
// Replace the contents of a view (invoked by the layout manager)
@Override
public void onBindViewHolder(ViewHolder viewHolder, int position) {
// - get data from your itemsData at this position
// - replace the contents of the view with that itemsData
viewHolder.Title.setText(itemsData[position].gettitle());
viewHolder.Icon.setImageResource(itemsData[position].getimage());
}
// inner class to hold a reference to each item of RecyclerView
public static class ViewHolder extends RecyclerView.ViewHolder {
public TextView Title;
public ImageView Icon;
public ViewHolder(View itemLayoutView) {
super(itemLayoutView);
Title = (TextView) itemLayoutView.findViewById(R.id.teamName);
Icon = (ImageView) itemLayoutView.findViewById(R.id.teamLogo);
}
}
// Return the size of your itemsData (invoked by the layout manager)
@Override
public int getItemCount() {
return itemsData.length;
}
}
itemdata：和
public class ItemData {
private String title;
private int image;
public ItemData(String title,int image){
this.title = title;
this.image = image;
}
public String gettitle() {
return title;
}
public int getimage() {
return image;
}
// getters & setters
}
Fragment_select_team.xml：
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="loserpool.nghiadang.loserpool.SelectTeamFragment">
<!-- A RecyclerView with some commonly used attributes -->
<android.support.v7.widget.RecyclerView
android:id="@+id/my_recycler_view"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:scrollbars="vertical">
</android.support.v7.widget.RecyclerView>
</RelativeLayout>
custom_select_team.xml：
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent">
<ImageView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="@+id/teamLogo"
android:layout_alignParentTop="true"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true"
android:src="@drawable/ic_launcher" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="NFL Team"
android:id="@+id/teamName"
android:layout_alignParentTop="true"
android:layout_centerHorizontal="true"
android:textSize="24dp"/>
</RelativeLayout>