我正在使用一个Android应用程序,使用recyclerview和cardview,一切都很好,但是当我旋转屏幕时,应用程序停止,我在
中得到一个nullPointerExceptionrecyclerView.setLayoutManager(mLayoutManager);
这是一个完整的例外:
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.news.press/com.news.press.activities.MainActivity}: 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:3150)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3260)
at android.app.ActivityThread.handleRelaunchActivity(ActivityThread.java:5200)
at android.app.ActivityThread.access$1100(ActivityThread.java:218)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1740)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:145)
at android.app.ActivityThread.main(ActivityThread.java:6934)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1404)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1199)
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.support.v7.widget.RecyclerView.setLayoutManager(android.support.v7.widget.RecyclerView$LayoutManager)' on a null object reference
at com.news.press.activities.MainActivity.onCreate(MainActivity.java:88)
at android.app.Activity.performCreate(Activity.java:6609)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1134)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3103)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3260)
at android.app.ActivityThread.handleRelaunchActivity(ActivityThread.java:5200)
at android.app.ActivityThread.access$1100(ActivityThread.java:218)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1740)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:145)
at android.app.ActivityThread.main(ActivityThread.java:6934)
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:1404)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1199)
这是我的xml布局
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:id="@+id/content_main"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_behavior="@string/appbar_scrolling_view_behavior"
tools:context="com.news.press.activities.MainActivity"
android:layoutDirection="rtl"
android:textDirection="rtl">
<android.support.v7.widget.RecyclerView
android:id="@+id/recycler_view"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:clipToPadding="false"
android:scrollbars="none"
/>
</RelativeLayout>
更新
我的Java代码
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(
this, drawer, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close);
drawer.setDrawerListener(toggle);
toggle.syncState();
NavigationView navigationView = (NavigationView) findViewById(R.id.nav_view);
navigationView.setNavigationItemSelectedListener(this);
/**
* setting homepage Content
*/
recyclerView = (RecyclerView) findViewById(R.id.recycler_view);
articlesList = new ArrayList<>();
adapter = new ArticleAdapter(this, articlesList);
RecyclerView.LayoutManager mLayoutManager = new GridLayoutManager(this,1);
recyclerView.setLayoutManager(mLayoutManager);
recyclerView.addItemDecoration(new GridSpacingItemDecoration(1, dpToPx(1), true));
recyclerView.setItemAnimator(new DefaultItemAnimator());
recyclerView.setAdapter(adapter);
prepareArticles();
}
答案 0 :(得分:-1)
对我来说,一切似乎都很清楚。
你能否检查一下你没有其他的陆地布局。 也许这个其他布局没有Recyclerview?