Question

我一直在努力让Facebook练习应用程序正常工作，我无法弄清楚为什么我不能引用Facebook SDK中的LoginButton。下面是我在查看定义LoginButton。

的布局时遇到的错误

 <com.facebook.login.widget.LoginButton
        android:id="@+id/login_button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center_horizontal"
        android:layout_marginTop="30dp"
        android:layout_marginBottom="30dp" />

java.lang.NoClassDefFoundError: Could not initialize class
com.facebook.login.widget.LoginButton   at
sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
        at
sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
        at
sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
        at java.lang.reflect.Constructor.newInstance(Constructor.java:408)
        at
org.jetbrains.android.uipreview.ViewLoader.createNewInstance(ViewLoader.java:413)
        at
org.jetbrains.android.uipreview.ViewLoader.loadView(ViewLoader.java:105)
        at
com.android.tools.idea.rendering.LayoutlibCallback.loadView(LayoutlibCallback.java:176)
        at
android.view.BridgeInflater.loadCustomView(BridgeInflater.java:207)
        at
android.view.BridgeInflater.createViewFromTag(BridgeInflater.java:132)
        at
android.view.LayoutInflater.rInflate_Original(LayoutInflater.java:806)
        at
android.view.LayoutInflater_Delegate.rInflate(LayoutInflater_Delegate.java:64)
        at android.view.LayoutInflater.rInflate(LayoutInflater.java:782)    at
android.view.LayoutInflater.inflate(LayoutInflater.java:504)    at
android.view.LayoutInflater.inflate(LayoutInflater.java:385)    at
com.android.layoutlib.bridge.impl.RenderSessionImpl.inflate(RenderSessionImpl.java:400)
        at com.android.layoutlib.bridge.Bridge.createSession(Bridge.java:332)
        at
com.android.ide.common.rendering.LayoutLibrary.createSession(LayoutLibrary.java:350)
        at
com.android.tools.idea.rendering.RenderService$5.compute(RenderService.java:708)
        at
com.android.tools.idea.rendering.RenderService$5.compute(RenderService.java:697)
        at
com.intellij.openapi.application.impl.ApplicationImpl.runReadAction(ApplicationImpl.java:932)
        at
com.android.tools.idea.rendering.RenderService.createRenderSession(RenderService.java:697)
        at
com.android.tools.idea.rendering.RenderService.render(RenderService.java:816)
        at
com.intellij.android.designer.designSurface.AndroidDesignerEditorPanel$6.run(AndroidDesignerEditorPanel.java:480)
        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:511)
        at java.util.concurrent.FutureTask.run(FutureTask.java:266)     at
java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
        at
java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
        at java.lang.Thread.run(Thread.java:745)

Answer 1

如果您使用的是Android Studio，请点按以下链接： Could not initialize LoginButton Facebook-sdk for android。

如果您正在使用Eclipse，那么请交叉检查您是否已在清单中添加了库项目和元数据以及登录活动。

此外，它可能因为使用android sdk中不支持的api而发生。使用更高的api级别再试一次。

无法实例化以下类： - com.facebook.widget.LoginButton

1 个答案: