首先，我很遗憾地提出这个问题，因为其他几个月和几年前已经有人问过这个问题。但是，我无法找到解决方案。
我正在关注Google Play服务教程，在我的一个XML布局中包含G +登录按钮，用于我的一个使用Google Play服务的应用。意味着将以下内容添加到我的布局：
<com.google.android.gms.common.SignInButton
android:id="@+id/sign_in_button"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
但我无法这样做，因为eclipse总是告诉我：
无法实例化以下类： - com.google.android.gms.common.SignInButton
异常堆栈跟踪如下所示：
java.lang.VerifyError: Expecting a stackmap frame at branch target 15
Exception Details:
Location:
com/google/android/gms/common/SignInButton.z(Landroid/content/Context;)V @4: ifnull
Reason:
Expected stackmap frame at this location.
Bytecode:
0000000: 2ab4 0016 c600 0b2a 2ab4 0016 b600 252a
0000010: 2b2a b400 182a b400 15b8 0029 b500 16a7
0000020: 001c 4d12 0512 04b8 001a 572a 2b2a b400
0000030: 182a b400 15b8 0021 b500 162a 2ab4 0016
0000040: b600 222a b400 162a b600 24b6 001b 2ab4
0000050: 0016 2ab6 001c b1
Exception Handler Table:
bci [15, 31] => handler: 34
at java.lang.Class.getDeclaredConstructors0(Native Method)
at java.lang.Class.privateGetDeclaredConstructors(Unknown Source)
at java.lang.Class.getConstructor0(Unknown Source)
at java.lang.Class.getConstructor(Unknown Source)
at com.android.ide.eclipse.adt.internal.editors.layout.ProjectCallback.instantiateClass(ProjectCallback.java:367)
at com.android.ide.eclipse.adt.internal.editors.layout.ProjectCallback.loadView(ProjectCallback.java:194)
at com.android.layoutlib.bridge.android.BridgeInflater.loadCustomView(BridgeInflater.java:205)
at com.android.layoutlib.bridge.android.BridgeInflater.createViewFromTag(BridgeInflater.java:133)
at android.view.LayoutInflater.rInflate(LayoutInflater.java:623)
at android.view.LayoutInflater.rInflate(LayoutInflater.java:626)
at android.view.LayoutInflater.rInflate(LayoutInflater.java:626)
at android.view.LayoutInflater.rInflate(LayoutInflater.java:626)
at android.view.LayoutInflater.inflate(LayoutInflater.java:408)
at android.view.LayoutInflater.inflate(LayoutInflater.java:296)
at com.android.layoutlib.bridge.impl.RenderSessionImpl.inflate(RenderSessionImpl.java:279)
at com.android.layoutlib.bridge.Bridge.createSession(Bridge.java:318)
at com.android.ide.common.rendering.LayoutLibrary.createSession(LayoutLibrary.java:332)
at com.android.ide.eclipse.adt.internal.editors.layout.gle2.RenderService.createRenderSession(RenderService.java:517)
at com.android.ide.eclipse.adt.internal.editors.layout.gle2.GraphicalEditorPart.renderWithBridge(GraphicalEditorPart.java:1584)
at com.android.ide.eclipse.adt.internal.editors.layout.gle2.GraphicalEditorPart.recomputeLayout(GraphicalEditorPart.java:1309)
at com.android.ide.eclipse.adt.internal.editors.layout.gle2.GraphicalEditorPart.activated(GraphicalEditorPart.java:1066)
at com.android.ide.eclipse.adt.internal.editors.layout.LayoutEditorDelegate.delegatePageChange(LayoutEditorDelegate.java:686)
at com.android.ide.eclipse.adt.internal.editors.common.CommonXmlEditor.pageChange(CommonXmlEditor.java:360)
at org.eclipse.ui.part.MultiPageEditorPart$2.widgetSelected(MultiPageEditorPart.java:294)
at org.eclipse.swt.widgets.TypedListener.handleEvent(TypedListener.java:248)
at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java:84)
at org.eclipse.swt.widgets.Display.sendEvent(Display.java:4353)
at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1061)
at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1085)
at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1070)
at org.eclipse.swt.widgets.Widget.notifyListeners(Widget.java:782)
at org.eclipse.swt.custom.CTabFolder.setSelection(CTabFolder.java:3110)
at org.eclipse.swt.custom.CTabFolder.onMouse(CTabFolder.java:1794)
at org.eclipse.swt.custom.CTabFolder$1.handleEvent(CTabFolder.java:283)
at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java:84)
at org.eclipse.swt.widgets.Display.sendEvent(Display.java:4353)
at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1061)
at org.eclipse.swt.widgets.Display.runDeferredEvents(Display.java:4172)
at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3761)
at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine$9.run(PartRenderingEngine.java:1151)
at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:332)
at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.run(PartRenderingEngine.java:1032)
at org.eclipse.e4.ui.internal.workbench.E4Workbench.createAndRunUI(E4Workbench.java:148)
at org.eclipse.ui.internal.Workbench$5.run(Workbench.java:636)
at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:332)
at org.eclipse.ui.internal.Workbench.createAndRunWorkbench(Workbench.java:579)
at org.eclipse.ui.PlatformUI.createAndRunWorkbench(PlatformUI.java:150)
at org.eclipse.ui.internal.ide.application.IDEApplication.start(IDEApplication.java:135)
at org.eclipse.equinox.internal.app.EclipseAppHandle.run(EclipseAppHandle.java:196)
at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.runApplication(EclipseAppLauncher.java:134)
at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.start(EclipseAppLauncher.java:104)
at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:382)
at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:236)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at org.eclipse.equinox.launcher.Main.invokeFramework(Main.java:648)
at org.eclipse.equinox.launcher.Main.basicRun(Main.java:603)
at org.eclipse.equinox.launcher.Main.run(Main.java:1465)
at org.eclipse.equinox.launcher.Main.main(Main.java:1438)
我尝试了所有可能找到的解决方案，但没有任何效果。
现在我只是以编程方式添加“登录”按钮，它可以按预期工作。但我不知道为什么我不能简单地通过XML添加按钮。 Google Play服务目前已设置为库，我的项目将其作为一个库使用。
堆栈跟踪的开头是：
Exception Details:
Location:
com/google/android/gms/common/SignInButton.z(Landroid/content/Context;)V @4: ifnull
当我尝试通过XML添加按钮时无法找到和/或获取应用程序上下文时，我是否正确解释了这一点，这可能是错误吗？在这种情况下，将Google Play服务lib与我的项目合并应解决它，不是吗？但这会使项目不必要地膨胀。任何替代方案？
答案 0 :(得分：0)
仅清理项目并关闭Eclipse。然后你应该重新打开Elipse，按钮应该工作