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它以前一直在工作，但突然它沒有，即使我甚至沒有更改代碼......我在我的RecyclerView實例上得到空引用，作爲異常告訴我... 這是我的Java代碼：Android RecyclerView爲空
RecyclerView recyclerView;
RecyclerView.Adapter rvadapter;
RecyclerView.LayoutManager rvLayoutManager;
static ArrayList<String> itemTexte;
File dir;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_recycler_view);
dir = new File(Environment.getExternalStorageDirectory(), "Notizen");
if (!dir.exists()) {
try {
dir.mkdirs();
} catch (Exception e) {
e.printStackTrace();
}
}
itemTexte = new ArrayList<>();
recyclerView = (RecyclerView) findViewById(R.id.recyclerview);
rvLayoutManager = new LinearLayoutManager(RecyclerViewActivity.this);
recyclerView.setLayoutManager(rvLayoutManager);
rvadapter = new RvAdapterKlasse(RecyclerViewActivity.this);
recyclerView.setAdapter(rvadapter);
notizenSetup();
}
的錯誤是在recyclerView.setLayoutManager(rvLayoutManager); 這裏是我的XML：
<?xml version="1.0" encoding="utf-8"?>
<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="at.wurz.david.recyclerviewtemplate.RecyclerViewActivity">
<android.support.v7.widget.RecyclerView
android:layout_height="match_parent"
android:layout_width="match_parent"
android:id="@+id/recyclerview"
/>
</RelativeLayout>
錯誤：
04-09 10:35:23.131 15155-15155/at.wurz.david.recyclerviewtemplate D/AndroidRuntime: Shutting down VM
04-09 10:35:23.133 15155-15155/at.wurz.david.recyclerviewtemplate E/AndroidRuntime: FATAL EXCEPTION: main
Process: at.wurz.david.recyclerviewtemplate, PID: 15155
java.lang.RuntimeException: Unable to start activity ComponentInfo{at.wurz.david.recyclerviewtemplate/at.wurz.david.recyclerviewtemplate.RecyclerViewActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.support.v7.widget.RecyclerView.setLayoutManager(android.support.v7.widget.RecyclerView$LayoutManager)' on a null object reference
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2462)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2524)
at android.app.ActivityThread.access$800(ActivityThread.java:167)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1419)
at android.os.Handler.dispatchMessage(Handler.java:111)
at android.os.Looper.loop(Looper.java:194)
at android.app.ActivityThread.main(ActivityThread.java:5546)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:964)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:759)
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.support.v7.widget.RecyclerView.setLayoutManager(android.support.v7.widget.RecyclerView$LayoutManager)' on a null object reference
at at.wurz.david.recyclerviewtemplate.RecyclerViewActivity.onCreate(RecyclerViewActivity.java:76)
at android.app.Activity.performCreate(Activity.java:5977)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1111)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2415)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2524)
at android.app.ActivityThread.access$800(ActivityThread.java:167)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1419)
at android.os.Handler.dispatchMessage(Handler.java:111)
at android.os.Looper.loop(Looper.java:194)
at android.app.ActivityThread.main(ActivityThread.java:5546)
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:964)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:759)
我搜索了錯誤，但所有主題都至少1歲，並說谷歌已經修復了這個錯誤。
哪裏錯誤堆棧跟蹤？ –
已編輯！如果你可以閱讀它的東西......：D – SomeRandomNameCuzWhyNot
你已經實例化RecyclerView.LayoutManager rvLayoutManager; – Jois