android - 错误 : <item> tag requires a 'drawable' attribute or child tag defining a drawable

Question

我在可绘制文件夹中创建了一个状态列表选择器文件 item_bg_selector.xml，如下所示:

<selector xmlns:android="http://schemas.android.com/apk/res/android">
  <item android:state_selected="true" 
      android:drawable="@drawable/item_background_selected" />
  <item android:state_focused="true" 
      android:drawable="@drawable/item_background_selected" />
  <item android:state_pressed="true" 
      android:drawable="@drawable/item_background_selected" />
  <item android:drawable="@android:color/transparent"/>
</selector>

然后我定义一个样式元素

<style name="Item">
    <item name="android:layout_width">wrap_content</item>
    <item name="android:layout_height">wrap_content</item>
    <item name="android:background">@drawable/item_bg_selector</item>
</style>

然后我尝试像这样创建一个 ImageButton :

    <ImageButton style="@style/Item"
        android:id="@id/btn_home"
    android:src="@drawable/home_button" />

Eclipse 在 Event Details 窗口中不断给我以下错误:

Failed to parse file /path/to/projectdir/res/drawable/item_bg_selector.xml

异常跟踪如下:

org.xmlpull.v1.XmlPullParserException: Binary XML file line #16: <item> tag requires a 'drawable' attribute or child tag defining a drawable
    at android.graphics.drawable.StateListDrawable.inflate(StateListDrawable.java:167)
    at android.graphics.drawable.Drawable.createFromXmlInner(Drawable.java:787)
    at android.graphics.drawable.Drawable.createFromXml(Drawable.java:728)
    at com.android.layoutlib.bridge.impl.ResourceHelper.getDrawable(ResourceHelper.java:208)
    at com.android.layoutlib.bridge.android.BridgeTypedArray.getDrawable(BridgeTypedArray.java:731)
    at android.view.View.<init>(View.java:1885)
    at android.widget.ImageView.<init>(ImageView.java:112)
    at android.widget.ImageButton.<init>(ImageButton.java:85)
    at android.widget.ImageButton.<init>(ImageButton.java:81)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:39)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27)
    at java.lang.reflect.Constructor.newInstance(Constructor.java:513)
    at android.view.LayoutInflater.createView(LayoutInflater.java:500)
    at com.android.layoutlib.bridge.android.BridgeInflater.onCreateView(BridgeInflater.java:84)
    at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:563)
    at com.android.layoutlib.bridge.android.BridgeInflater.createViewFromTag(BridgeInflater.java:129)
    at android.view.LayoutInflater.rInflate(LayoutInflater.java:618)
    at android.view.LayoutInflater.rInflate(LayoutInflater.java:621)
    at android.view.LayoutInflater.inflate(LayoutInflater.java:407)
    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:325)
    at com.android.ide.eclipse.adt.internal.editors.layout.gle2.RenderService.createRenderSession(RenderService.java:372)
    at com.android.ide.eclipse.adt.internal.editors.layout.gle2.GraphicalEditorPart.renderWithBridge(GraphicalEditorPart.java:1317)
    at com.android.ide.eclipse.adt.internal.editors.layout.gle2.GraphicalEditorPart.recomputeLayout(GraphicalEditorPart.java:1071)
    at com.android.ide.eclipse.adt.internal.editors.layout.gle2.GraphicalEditorPart.activated(GraphicalEditorPart.java:897)
    at com.android.ide.eclipse.adt.internal.editors.layout.LayoutEditor.pageChange(LayoutEditor.java:384)
    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.Display.sendEvent(Display.java:3783)
    at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1375)
    at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1398)
    at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1383)
    at org.eclipse.swt.widgets.Widget.notifyListeners(Widget.java:1195)
    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.Display.sendEvent(Display.java:3783)
    at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1375)
    at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1398)
    at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1383)
    at org.eclipse.swt.widgets.Widget.notifyListeners(Widget.java:1195)
    at org.eclipse.swt.widgets.Display.runDeferredEvents(Display.java:3629)
    at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3284)
    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(NativeMethodAccessorImpl.java:39)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:597)
    at org.eclipse.equinox.launcher.Main.invokeFramework(Main.java:620)
    at org.eclipse.equinox.launcher.Main.basicRun(Main.java:575)
    at org.eclipse.equinox.launcher.Main.run(Main.java:1408)

现在，问题是错误在哪里？可绘制对象存在于文件夹中。标签具有可绘制属性。我已经交叉检查了将近 15 次，但仍然无法找到问题所在。我相信这是一个非常简单的问题(如果有的话)。任何解决此问题的方法也值得赞赏。

加法: 此外，item_bg_selector.xml 中的第 16 行对应于我发布的文件中从顶部算起的第三行。那就是

<selector xmlns:android="http://schemas.android.com/apk/res/android">
  <item android:state_selected="true" 
line16 ----> android:drawable="@drawable/item_background_selected" />

Answer 1

错误与您的 xml 格式有关，您正在设置类似

android:background="@drawable/item_bg_selector"

错误告诉你的是它应该是这样的

android:drawable="@drawable/item_bg_selector"