Android XML文件java.lang.nullpointerexception

Question

我正在建立一个全新的Android项目。它不是我的第一个Android应用程序，所以我更沮丧的是无法摆脱这个错误...

我使用的是一个XML文件，目前只有3个项目，并且XML标签中没有错误：

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/container"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".gaming..MainActivity" >

    <ImageView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:background="@drawable/fondipad"
        android:contentDescription="@string/FondDesc"

        />

    <RelativeLayout 
        android:layout_height="300dp" 
        android:layout_width="fill_parent"
        android:background="@drawable/cadremenu">

    </RelativeLayout> 
    </RelativeLayout>

很简单，是吗？ 但是，视觉选项卡不会渲染cadremenu drawable（但是＆＃34;喜欢＆＃34;确实如此）......但是cadremenu.png位于drawable文件夹中！ 我可以启动应用程序，但只渲染背景... 我真的不知道该怎么做...... xml文件返回此异常

java.lang.NullPointerException
    at android.graphics.Bitmap_Delegate.createBitmap(Bitmap_Delegate.java:598)
    at android.graphics.Bitmap_Delegate.createBitmap(Bitmap_Delegate.java:120)
    at android.graphics.Bitmap_Delegate.createBitmap(Bitmap_Delegate.java:102)
    at com.android.layoutlib.bridge.impl.ResourceHelper.getDrawable(ResourceHelper.java:233)
    at android.content.res.BridgeTypedArray.getDrawable(BridgeTypedArray.java:782)
    at android.view.View.<init>(View.java:3554)
    at android.view.View.<init>(View.java:3484)
    at android.view.ViewGroup.<init>(ViewGroup.java:464)
    at android.widget.RelativeLayout.<init>(RelativeLayout.java:236)
    at sun.reflect.GeneratedConstructorAccessor37.newInstance(Unknown Source)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27)
    at java.lang.reflect.Constructor.newInstance(Constructor.java:513)
    at android.view.LayoutInflater.createView(LayoutInflater.java:594)
    at android.view.BridgeInflater.onCreateView(BridgeInflater.java:86)
    at android.view.LayoutInflater.onCreateView(LayoutInflater.java:669)
    at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:694)
    at android.view.BridgeInflater.createViewFromTag(BridgeInflater.java:131)
    at android.view.LayoutInflater.rInflate_Original(LayoutInflater.java:755)
    at android.view.LayoutInflater_Delegate.rInflate(LayoutInflater_Delegate.java:64)
    at android.view.LayoutInflater.rInflate(LayoutInflater.java:727)
    at android.view.LayoutInflater.inflate(LayoutInflater.java:492)
    at android.view.LayoutInflater.inflate(LayoutInflater.java:373)
    at com.android.layoutlib.bridge.impl.RenderSessionImpl.inflate(RenderSessionImpl.java:399)
    at com.android.layoutlib.bridge.Bridge.createSession(Bridge.java:336)
    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:504)
    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:292)
    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:4136)
    at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1458)
    at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1481)
    at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1466)
    at org.eclipse.swt.widgets.Widget.notifyListeners(Widget.java:1271)
    at org.eclipse.swt.custom.CTabFolder.setSelection(CTabFolder.java:3028)
    at org.eclipse.swt.custom.CTabFolder.onMouse(CTabFolder.java:1749)
    at org.eclipse.swt.custom.CTabFolder$1.handleEvent(CTabFolder.java:278)
    at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java:84)
    at org.eclipse.swt.widgets.Display.sendEvent(Display.java:4136)
    at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1458)
    at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1481)
    at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1466)
    at org.eclipse.swt.widgets.Widget.notifyListeners(Widget.java:1271)
    at org.eclipse.swt.widgets.Display.runDeferredEvents(Display.java:3982)
    at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3621)
    at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine$9.run(PartRenderingEngine.java:1053)
    at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:332)
    at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.run(PartRenderingEngine.java:942)
    at org.eclipse.e4.ui.internal.workbench.E4Workbench.createAndRunUI(E4Workbench.java:86)
    at org.eclipse.ui.internal.Workbench$5.run(Workbench.java:588)
    at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:332)
    at org.eclipse.ui.internal.Workbench.createAndRunWorkbench(Workbench.java:543)
    at org.eclipse.ui.PlatformUI.createAndRunWorkbench(PlatformUI.java:149)
    at org.eclipse.ui.internal.ide.application.IDEApplication.start(IDEApplication.java:124)
    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:353)
    at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:180)
    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:629)
    at org.eclipse.equinox.launcher.Main.basicRun(Main.java:584)
    at org.eclipse.equinox.launcher.Main.run(Main.java:1438)

欢迎任何帮助！

编辑：我已经尝试删除，放回抽屉，项目，......清理项目，重建......我甚至尝试删除＆amp;重新安装每个ADT组件

Answer 1

正如@laato建议的那样，我检查了我的drawable / cadremenu文件。我在项目中复制/粘贴/覆盖了文件，然后一切正常！实际上我的所有其他资源都遇到了同样的问题，例如我的资源文件夹是否已损坏或类似的情况。

谢谢你们 希望有一天有人会在这里找到帮助

Answer 2

此异常通常由于 损坏的drawables 而发生。确保您能够打开并查看已链接的所有可绘制内容。

如果您碰巧看到此类错误消息或无法查看您的drawable，请尝试使用原始文件再次替换它，或者如果您已下载它，请尝试重新下载。

Answer 3

因为没有显示的drawable本身在RelativeLayout中，你需要在cadremenu布局中放置一些位置属性，以便Android知道放置它的位置。例如，尝试：

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/container"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="monteil.gaming.hundredious.MainActivity" >

<ImageView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:background="@drawable/fondipad"
    android:contentDescription="@string/FondDesc"

    />

<RelativeLayout 
    android:layout_height="300dp" 
    android:layout_width="fill_parent"
    **android:layout_alignParentTop="true"**
    android:background="@drawable/cadremenu">

</RelativeLayout> 
</RelativeLayout>