将我的自定义视图添加到XML布局会引发exception

我正在尝试创建我的第一个自定义View子类GraphView并将其添加到我的布局XML文件中。

我发现了这个问题并试图将它应用到我的项目中,但似乎有些错误,因为Eclipse IDE告诉我:

 de.muza3000.graph.GraphView failed to instantiate. 

并抛出exception:

 java.lang.NoSuchMethodException: de.muza3000.graph.GraphView.(android.content.Context, android.util.AttributeSet) 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(Unknown Source) at com.android.ide.eclipse.adt.internal.editors.layout.ProjectCallback.loadView(Unknown Source) at android.view.BridgeInflater.loadCustomView(BridgeInflater.java:198) at android.view.BridgeInflater.createViewFromTag(BridgeInflater.java:126) at android.view.LayoutInflater.rInflate(LayoutInflater.java:618) at android.view.LayoutInflater.inflate(LayoutInflater.java:407) at android.view.LayoutInflater.inflate(LayoutInflater.java:296) at com.android.layoutlib.bridge.Bridge.computeLayout(Bridge.java:396) at com.android.ide.common.rendering.LayoutLibrary.createLegacySession(LayoutLibrary.java:382) at com.android.ide.common.rendering.LayoutLibrary.createSession(LayoutLibrary.java:276) at com.android.ide.eclipse.adt.internal.editors.layout.gle2.GraphicalEditorPart.renderWithBridge(Unknown Source) at com.android.ide.eclipse.adt.internal.editors.layout.gle2.GraphicalEditorPart.renderWithBridge(Unknown Source) at com.android.ide.eclipse.adt.internal.editors.layout.gle2.GraphicalEditorPart.recomputeLayout(Unknown Source) at com.android.ide.eclipse.adt.internal.editors.layout.gle2.GraphicalEditorPart.activated(Unknown Source) at com.android.ide.eclipse.adt.internal.editors.layout.LayoutEditor.pageChange(Unknown Source) at org.eclipse.ui.part.MultiPageEditorPart$2.widgetSelected(MultiPageEditorPart.java:290) at org.eclipse.swt.widgets.TypedListener.handleEvent(TypedListener.java:234) at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java:84) at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1053) at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1077) at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1062) at org.eclipse.swt.widgets.Widget.notifyListeners(Widget.java:774) at org.eclipse.swt.custom.CTabFolder.setSelection(CTabFolder.java:2743) at org.eclipse.swt.custom.CTabFolder.onMouse(CTabFolder.java:1429) at org.eclipse.swt.custom.CTabFolder$1.handleEvent(CTabFolder.java:257) at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java:84) at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1053) at org.eclipse.swt.widgets.Display.runDeferredEvents(Display.java:4066) at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3657) at org.eclipse.ui.internal.Workbench.runEventLoop(Workbench.java:2640) at org.eclipse.ui.internal.Workbench.runUI(Workbench.java:2604) at org.eclipse.ui.internal.Workbench.access$4(Workbench.java:2438) at org.eclipse.ui.internal.Workbench$7.run(Workbench.java:671) at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:332) at org.eclipse.ui.internal.Workbench.createAndRunWorkbench(Workbench.java:664) at org.eclipse.ui.PlatformUI.createAndRunWorkbench(PlatformUI.java:149) at org.eclipse.ui.internal.ide.application.IDEApplication.start(IDEApplication.java:115) at org.eclipse.equinox.internal.app.EclipseAppHandle.run(EclipseAppHandle.java:196) at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.runApplication(EclipseAppLauncher.java:110) at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.start(EclipseAppLauncher.java:79) at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:369) at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:179) 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:619) at org.eclipse.equinox.launcher.Main.basicRun(Main.java:574) at org.eclipse.equinox.launcher.Main.run(Main.java:1407) 

这是我的布局:

      

我的代码:

 package de.muza3000.graph; import android.content.Context; import android.util.AttributeSet; import android.view.View; public class GraphView extends View { GraphView(Context context, AttributeSet attrs, int defStyle) { super(context, attrs, defStyle); } GraphView(Context context, AttributeSet attrs) { super(context, attrs); } GraphView(Context context) { super(context); } } 

将构造函数的访问修饰符更改为public。