Java 当我切换到另一个包含回收器视图的活动时，应用程序崩溃
单击主活动中的图像视图切换到第二个活动时 崩溃。在实现回收视图之前，我可以切换到第二个活动。 我猜布局管理器有点问题Java 当我切换到另一个包含回收器视图的活动时，应用程序崩溃,java,android,android-studio,android-recyclerview,Java,Android,Android Studio,Android Recyclerview,单击主活动中的图像视图切换到第二个活动时 崩溃。在实现回收视图之前，我可以切换到第二个活动。 我猜布局管理器有点问题 activity_second.xml <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="match_parent" android:orientatio
activity_second.xml
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<android.support.v7.widget.RecyclerView
android:id="@+id/recyclerView"
android:layout_width="match_parent"
android:layout_height="match_parent" />
在第二个活动中，改变
setContentView(R.layout.activity_main);
在第二个activity java类中，oncreate方法正在扩展activity主布局，而您的recyclerView位于activity_second.xml中
因此更改setcontentview请发布错误的完整日志。@Vucko忘了添加它。现在检查它是否已编辑。
public class SecondActivity extends ActionBarActivity {
public ArrayList<HashMap<String, String>> mDataSource;
protected RecyclerView mRecyclerView;
protected RecyclerView.LayoutManager mLayoutManager;
protected HomeItemAdapter mAdapter;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
//Initialize Data Source
initDataset();
// BEGIN_INCLUDE(initializeRecyclerView)
mRecyclerView = (RecyclerView) findViewById(R.id.recyclerView);
//The LayoutManager defines how elements are laid out.
mLayoutManager = new GridLayoutManager(this, 3);
mRecyclerView.setLayoutManager(mLayoutManager);
mAdapter = new HomeItemAdapter(this, mDataSource);
// Set CustomAdapter as the adapter for RecyclerView.
mRecyclerView.setAdapter(mAdapter);
// END_INCLUDE(initializeRecyclerView)
}
private void initDataset() {
mDataSource = new ArrayList();
HashMap<String, String> h1 = new HashMap();
h1.put("name", "FIFTH HARMONY");
h1.put("city", "Reflection");
h1.put("image_url","http://www.azlyrics.com/hot/fifthharmony_B00MS4BUUU.jpg");
mDataSource.add(h1);
h1 = new HashMap();
h1.put("name", "PAPA ROACH");
h1.put("city", "F.E.A.R.");
h1.put("image_url","http://www.azlyrics.com/hot/919y0earTjL.jpg");
mDataSource.add(h1);
h1 = new HashMap();
h1.put("name", "Ellie Goulding");
h1.put("city", "ドラえもん");
h1.put("image_url","http://cdn1.umg3.net/12/files/2013/07/EG_HD_stan.jpg");
mDataSource.add(h1);
h1 = new HashMap();
h1.put("name", "SAYWECANFLY");
h1.put("city", "Between The Roses");
h1.put("image_url","http://www.azlyrics.com/hot/61-TWobzipL.jpg");
mDataSource.add(h1);
h1 = new HashMap();
h1.put("name", "NE-YO");
h1.put("city", "Non-Fiction");
h1.put("image_url","http://www.azlyrics.com/hot/81kBXMLAHkL.jpg");
mDataSource.add(h1);
h1 = new HashMap();
h1.put("name", "Frozen");
h1.put("city", "Frozen Heart Lyrics");
h1.put("image_url","http://www.stlyrics.com/images/ama/frozen_6430.jpg");
mDataSource.add(h1);
h1 = new HashMap();
h1.put("name", "2NE1");
h1.put("city", "K-Pop Superstar");
h1.put("image_url","http://www.billboard.com/files/styles/promo_310/public/media/cl_2ne1_instagram_kpop2014_650-430a.png");
mDataSource.add(h1);
h1 = new HashMap();
h1.put("name", "PAPA ROACH");
h1.put("city", "F.E.A.R.");
h1.put("image_url","http://www.azlyrics.com/hot/919y0earTjL.jpg");
mDataSource.add(h1);
h1 = new HashMap();
h1.put("name", "SAYWECANFLY");
h1.put("city", "Between The Roses");
h1.put("image_url","http://www.azlyrics.com/hot/61-TWobzipL.jpg");
mDataSource.add(h1);
h1 = new HashMap();
h1.put("name", "NE-YO");
h1.put("city", "Non-Fiction");
h1.put("image_url","http://www.azlyrics.com/hot/81kBXMLAHkL.jpg");
mDataSource.add(h1);
h1 = new HashMap();
h1.put("name", "Frozen");
h1.put("city", "Frozen Heart Lyrics");
h1.put("image_url","http://www.stlyrics.com/images/ama/frozen_6430.jpg");
mDataSource.add(h1);
h1 = new HashMap();
h1.put("name", "2NE1");
h1.put("city", "K-Pop Superstar");
h1.put("image_url","http://www.billboard.com/files/styles/promo_310/public/media/cl_2ne1_instagram_kpop2014_650-430a.png");
mDataSource.add(h1);
}
}
Process: com.example.sensei.mist, PID: 2193
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.sensei.mist/com.example.sensei.mist.SecondActivity}: 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:2325)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2387)
at android.app.ActivityThread.access$800(ActivityThread.java:151)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1303)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5254)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698)
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.support.v7.widget.RecyclerView.setLayoutManager(android.support.v7.widget.RecyclerView$LayoutManager)' on a null object reference
at com.example.sensei.mist.SecondActivity.onCreate(SecondActivity.java:33)
at android.app.Activity.performCreate(Activity.java:5990)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1106)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2278)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2387)
at android.app.ActivityThread.access$800(ActivityThread.java:151)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1303)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5254)
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:903)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698)
setContentView(R.layout.activity_main);
setContentView(R.layout.activity_second);