Die Verwendung von CardView und RecyclerView in meinen Layoutdateien löst eine Ausnahme aus

Question

Also habe ich eine Aufnahme im Material Design von Android Preview L. gemacht. Ich habe sowohl die CardView als auch die RecyclerView Bibliotheken importiert.

Ich verwende die Android Studio Preview Version 0.8.0. Halten Sie die neuesten SDK-Pakete bereit.

Sobald ich sie in meinen Layout-Dateien verwende, löst die Vorschau eine Ausnahme für beide aus. Hier

ist die Ausnahme für die CardView:

java.lang.ClassFormatError: Illegal field name "CardView.Dark" in class android/support/v7/cardview/R$style 
at java.lang.ClassLoader.defineClass1(Native Method) 
at java.lang.ClassLoader.defineClass(ClassLoader.java:792) 
at java.lang.ClassLoader.defineClass(ClassLoader.java:635) 
at org.jetbrains.android.uipreview.ProjectClassLoader.findClass(ProjectClassLoader.java:63) 
at java.lang.ClassLoader.loadClass(ClassLoader.java:424) 
at java.lang.ClassLoader.loadClass(ClassLoader.java:411) 
at java.lang.ClassLoader.loadClass(ClassLoader.java:357) 
at android.support.v7.widget.CardView.initialize(CardView.java:69) 
at android.support.v7.widget.CardView.<init>(CardView.java:60) 
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) 
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:57) 
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) 
at java.lang.reflect.Constructor.newInstance(Constructor.java:526) 
at org.jetbrains.android.uipreview.ViewLoader.createNewInstance(ViewLoader.java:375) 
at org.jetbrains.android.uipreview.ViewLoader.loadView(ViewLoader.java:100) 
at com.android.tools.idea.rendering.LayoutlibCallback.loadView(LayoutlibCallback.java:172) 
at android.view.BridgeInflater.loadCustomView(BridgeInflater.java:207) 
at android.view.BridgeInflater.createViewFromTag(BridgeInflater.java:132) 
at android.view.LayoutInflater.inflate(LayoutInflater.java:478) 
at android.view.LayoutInflater.inflate(LayoutInflater.java:381) 
at com.android.layoutlib.bridge.impl.RenderSessionImpl.inflate(RenderSessionImpl.java:395) 
at com.android.layoutlib.bridge.Bridge.createSession(Bridge.java:329) 
at com.android.ide.common.rendering.LayoutLibrary.createSession(LayoutLibrary.java:332) 
at com.android.tools.idea.rendering.RenderService$3.compute(RenderService.java:575) 
at com.android.tools.idea.rendering.RenderService$3.compute(RenderService.java:564) 
at com.intellij.openapi.application.impl.ApplicationImpl.runReadAction(ApplicationImpl.java:932) 
at com.android.tools.idea.rendering.RenderService.createRenderSession(RenderService.java:564) 
at com.android.tools.idea.rendering.RenderService.render(RenderService.java:691) 
at org.jetbrains.android.uipreview.AndroidLayoutPreviewToolWindowManager.doRender(AndroidLayoutPreviewToolWindowManager.java:586) 
at org.jetbrains.android.uipreview.AndroidLayoutPreviewToolWindowManager.access$1900(AndroidLayoutPreviewToolWindowManager.java:80) 
at org.jetbrains.android.uipreview.AndroidLayoutPreviewToolWindowManager$6$1.run(AndroidLayoutPreviewToolWindowManager.java:528) 
at com.intellij.openapi.progress.impl.ProgressManagerImpl$2.run(ProgressManagerImpl.java:178) 
at com.intellij.openapi.progress.ProgressManager.executeProcessUnderProgress(ProgressManager.java:209) 
at com.intellij.openapi.progress.impl.ProgressManagerImpl.executeProcessUnderProgress(ProgressManagerImpl.java:212) 
at com.intellij.openapi.progress.impl.ProgressManagerImpl.runProcess(ProgressManagerImpl.java:171) 
at org.jetbrains.android.uipreview.AndroidLayoutPreviewToolWindowManager$6.run(AndroidLayoutPreviewToolWindowManager.java:523) 
at com.intellij.util.ui.update.MergingUpdateQueue.execute(MergingUpdateQueue.java:320) 
at com.intellij.util.ui.update.MergingUpdateQueue.execute(MergingUpdateQueue.java:310) 
at com.intellij.util.ui.update.MergingUpdateQueue$2.run(MergingUpdateQueue.java:254) 
at com.intellij.util.ui.update.MergingUpdateQueue.flush(MergingUpdateQueue.java:269) 
at com.intellij.util.ui.update.MergingUpdateQueue.flush(MergingUpdateQueue.java:227) 
at com.intellij.util.ui.update.MergingUpdateQueue.run(MergingUpdateQueue.java:217) 
at com.intellij.util.concurrency.QueueProcessor.runSafely(QueueProcessor.java:238) 
at com.intellij.util.Alarm$Request$1.run(Alarm.java:327) 
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471) 
at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:334) 
at java.util.concurrent.FutureTask.run(FutureTask.java:166) 
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145) 
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615) 
at java.lang.Thread.run(Thread.java:724) 

Und hier ist die Ausnahme für RecyclerView:

java.lang.NullPointerException 
at android.support.v7.widget.RecyclerView.onMeasure(RecyclerView.java:1310) 
at android.view.View.measure(View.java:16987) 
at android.widget.RelativeLayout.measureChildHorizontal(RelativeLayout.java:722) 
at android.widget.RelativeLayout.onMeasure(RelativeLayout.java:458) 
at android.view.View.measure(View.java:16987) 
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5257) 
at android.widget.FrameLayout.onMeasure(FrameLayout.java:314) 
at android.view.View.measure(View.java:16987) 
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5257) 
at com.android.internal.widget.ActionBarOverlayLayout.onMeasure(ActionBarOverlayLayout.java:447) 
at android.view.View.measure(View.java:16987) 
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5257) 
at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1436) 
at android.widget.LinearLayout.measureHorizontal(LinearLayout.java:1083) 
at android.widget.LinearLayout.onMeasure(LinearLayout.java:615) 
at android.view.View.measure(View.java:16987) 
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5257) 
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:16987) 
at android.widget.LinearLayout.measureVertical(LinearLayout.java:875) 
at android.widget.LinearLayout.onMeasure(LinearLayout.java:613) 
at android.view.View.measure(View.java:16987) 
at com.android.layoutlib.bridge.impl.RenderSessionImpl.measureView(RenderSessionImpl.java:621) 
at com.android.layoutlib.bridge.impl.RenderSessionImpl.render(RenderSessionImpl.java:521) 
at com.android.layoutlib.bridge.Bridge.createSession(Bridge.java:331) 
at com.android.ide.common.rendering.LayoutLibrary.createSession(LayoutLibrary.java:332) 
at com.android.tools.idea.rendering.RenderService$3.compute(RenderService.java:575) 
at com.android.tools.idea.rendering.RenderService$3.compute(RenderService.java:564) 
at com.intellij.openapi.application.impl.ApplicationImpl.runReadAction(ApplicationImpl.java:932) 
at com.android.tools.idea.rendering.RenderService.createRenderSession(RenderService.java:564) 
at com.android.tools.idea.rendering.RenderService.render(RenderService.java:691) 
at org.jetbrains.android.uipreview.AndroidLayoutPreviewToolWindowManager.doRender(AndroidLayoutPreviewToolWindowManager.java:586) 
at org.jetbrains.android.uipreview.AndroidLayoutPreviewToolWindowManager.access$1900(AndroidLayoutPreviewToolWindowManager.java:80) 
at org.jetbrains.android.uipreview.AndroidLayoutPreviewToolWindowManager$6$1.run(AndroidLayoutPreviewToolWindowManager.java:528) 
at com.intellij.openapi.progress.impl.ProgressManagerImpl$2.run(ProgressManagerImpl.java:178) 
at com.intellij.openapi.progress.ProgressManager.executeProcessUnderProgress(ProgressManager.java:209) 
at com.intellij.openapi.progress.impl.ProgressManagerImpl.executeProcessUnderProgress(ProgressManagerImpl.java:212) 
at com.intellij.openapi.progress.impl.ProgressManagerImpl.runProcess(ProgressManagerImpl.java:171) 
at org.jetbrains.android.uipreview.AndroidLayoutPreviewToolWindowManager$6.run(AndroidLayoutPreviewToolWindowManager.java:523) 
at com.intellij.util.ui.update.MergingUpdateQueue.execute(MergingUpdateQueue.java:320) 
at com.intellij.util.ui.update.MergingUpdateQueue.execute(MergingUpdateQueue.java:310) 
at com.intellij.util.ui.update.MergingUpdateQueue$2.run(MergingUpdateQueue.java:254) 
at com.intellij.util.ui.update.MergingUpdateQueue.flush(MergingUpdateQueue.java:269) 
at com.intellij.util.ui.update.MergingUpdateQueue.flush(MergingUpdateQueue.java:227) 
at com.intellij.util.ui.update.MergingUpdateQueue.run(MergingUpdateQueue.java:217) 
at com.intellij.util.concurrency.QueueProcessor.runSafely(QueueProcessor.java:238) 
at com.intellij.util.Alarm$Request$1.run(Alarm.java:327) 
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471) 
at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:334) 
at java.util.concurrent.FutureTask.run(FutureTask.java:166) 
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145) 
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615) 
at java.lang.Thread.run(Thread.java:724) 

Dies macht fast unmöglich Gebäude Layout, diese beiden (erstaunlich) View s verwenden, die Ich bin sehr neugierig.

Gibt es bereits eine Lösung dafür, oder wird das tatsächlich erwartete Verhalten als "benutzerdefiniert" View s, in gewissem Sinne gesehen?

Answer 1

Dies ist ein Fehler in Android Studio. Das Vorschau-Tool weiß nicht, wie die Widgets initialisiert werden. Ich glaube schon, weil die gleiche Ausnahme von Ihrer App ausgelöst wird, wenn Sie vergessen, recyclerView.setLayoutManager() in Ihrem Code aufzurufen.

Answer 2

Ich benutze Eclipse und konfrontiert das gleiche Problem. Wie von user7610 vorgeschlagen, müssen Sie recyclerView.setLayoutManager() aufrufen, um darüber zu kommen.

Hier ist, wie ich es gelöst ..

erstellen Membervariable ..

RecyclerView.LayoutManager mLayoutManager; 

In onCreate() oder onCreateView()

recyclerView = (RecyclerView) view 
       .findViewById(R.id.business_recycler_view); 
recyclerView.setHasFixedSize(true); 

mLayoutManager = new LinearLayoutManager(getActivity()); 
recyclerView.setLayoutManager(mLayoutManager); 

Das ist mein NullPointerException gelöst.

Answer 3

Wenn jemand das gleiche Problem stellt sich diesen Code für Recycler Blick in Inneren Fragmente Verwendung

@Override 
    public View onCreateView(LayoutInflater inflater, ViewGroup container, 
          Bundle savedInstanceState) { 
     // Inflate the layout for this fragment 
     View rootView = inflater.inflate(R.layout.fragment_timeline, container, false); 

     mRecyclerView = (RecyclerView) rootView.findViewById(R.id.my_recycler_view); 

     // use this setting to improve performance if you know that changes 
     // in content do not change the layout size of the RecyclerView 

     mRecyclerView.setHasFixedSize(true); 
     // use a linear layout manager 
     mLayoutManager = new LinearLayoutManager(getActivity()); 
     mRecyclerView.setLayoutManager(mLayoutManager); 


     String[] abc = {"hi","how are you","this is recycler"}; 
     // specify an adapter (see also next example) 
     mAdapter = new RecyclerViewAdapter(abc); 
     mRecyclerView.setAdapter(mAdapter); 
     return rootView; 
    } 

Answer 4

ich ähnliches Problem gefunden. Als solche, wenn wir nur das Layout aufblasen, das aus RecyclerView besteht, dann wird beim Ausführen von setcontentView ein Fehler ausgegeben, weil der Layout-Manager nicht auf Recyclerview Definiert in Layout-Datei eingestellt ist.

RecyclerView recyclerView = (RecyclerView) findViewById(R.id.searchResultsList); 
LinearLayoutManager layoutmanager = new LinearLayoutManager(this); 
layoutmanager.setOrientation(LinearLayoutManager.VERTICAL); 
recyclerView.setLayoutManager(layoutmanager);