Android：在片段内膨胀自定义视图

Posted 2023-04-15

【中文标题】Android：在片段内膨胀自定义视图

【英文标题】：Android: Inflate Custom View inside Fragment

【发布时间】：2016-12-13 01:16:52

【问题描述】：

我有一个应用程序使用片段视图作为其布局的一部分。在这个片段中，我想实例化一个 Paint Canvas，我可以在其中进行自定义绘图。

问题是，当我使用错误 android.view.InflateException: Binary XML file line #15: Binary XML file line #15: Error inflating class com.example.xxxxx.NeckCanvasOverlay 对片段进行充气时，我的应用程序崩溃了

我不确定是什么导致我的 Paint 类不能正确充气。我知道关于如何在片段中使用 findViewById 有一些特殊规则，但我认为我遵守了它们，因为我在片段的视图本身上调用 findViewByid（在我的代码中称为“v”）。

我该如何解决这个问题？

FragmentNeckDisplayMenu.java（片段类）

public class FragmentNeckDisplayMenu extends Fragment 
    private static View v;
    private NeckCanvasOverlay neckHUD;

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) 
        v = inflater.inflate(R.layout.menu_fragment_neck_display,container,false);      //ERROR HERE
        NeckCanvasOverlay neckHUD = (NeckCanvasOverlay) v.findViewById(R.id.neckHUD);   //paint test
        ...
        return v;
    

NeckCanvasOverlay.java（绘画类）

class NeckCanvasOverlay extends View 
    private Paint mPainter;

    public NeckCanvasOverlay(Context context) 
        super(context);
        initView();
    

    private void initView()    //Initializes canvas & paint objects here to save performance
        mPainter = new Paint(Paint.ANTI_ALIAS_FLAG);
        mPainter.setColor(Color.BLUE);
        mPainter.setAlpha(128);
    

    @Override
    public void onDraw(Canvas canvas) 
        super.onDraw(canvas);
        canvas.drawCircle(180, 900, 200, mPainter);
    

menu_fragment_neck_display.xml（片段的布局）

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_
    android:layout_
    android:orientation="vertical"
    android:id="@+id/canvas"
    android:background="@drawable/image">

    <LinearLayout
        android:layout_
        android:layout_
        android:layout_gravity="center"
        android:layout_weight="4">
        !--Custom view for Canvas here -->
        <com.example.xxxxx.NeckCanvasOverlay
            android:id="@+id/neckHUD"
            android:layout_
            android:layout_
            android:background="@drawable/neck_for_menu"/>
    </LinearLayout>

    <Button
        android:id="@+id/menuIcon"
        android:layout_
        android:layout_
        android:layout_marginTop="64dp"
        android:text="Menu"
        android:layout_alignParentLeft="true"
        android:layout_alignParentStart="true"
        android:layout_gravity="bottom"
        android:layout_weight="0.5"/>
</LinearLayout>

完整堆栈跟踪（编辑：包含完整跟踪）

   08-06 21:47:24.894 26334-26334/com.example.xxxxx E/ACRA: ACRA caught a InflateException for com.example.xxxxx
                                                             android.view.InflateException: Binary XML file line #15: Binary XML file line #15: Error inflating class com.example.gu.NeckCanvasOverlay
                                                                 at android.view.LayoutInflater.inflate(LayoutInflater.java:551)
                                                                 at android.view.LayoutInflater.inflate(LayoutInflater.java:429)
                                                                 at com.example.xxxxx.FragmentNeckDisplayMenu.onCreateView(FragmentNeckDisplayMenu.java:32)
                                                                 at android.support.v4.app.Fragment.performCreateView(Fragment.java:1962)
                                                                 at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1067)
                                                                 at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1248)
                                                                 at android.support.v4.app.BackStackRecord.run(BackStackRecord.java:738)
                                                                 at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1613)
                                                                 at android.support.v4.app.FragmentManagerImpl.executePendingTransactions(FragmentManager.java:570)
                                                                 at android.support.v4.app.FragmentPagerAdapter.finishUpdate(FragmentPagerAdapter.java:141)
                                                                 at android.support.v4.view.ViewPager.populate(ViewPager.java:1106)
                                                                 at android.support.v4.view.ViewPager.populate(ViewPager.java:952)
                                                                 at android.support.v4.view.ViewPager.setOffscreenPageLimit(ViewPager.java:733)
                                                                 at com.example.xxxxx.PlayFrets.configMenu(PlayFrets.java:150)
                                                                 at com.example.xxxxx.AsyncTask_NoteFileLoader.onPostExecute(AsyncTask_NoteFileLoader.java:125)
                                                                 at com.example.xxxxx.AsyncTask_NoteFileLoader.onPostExecute(AsyncTask_NoteFileLoader.java:9)
                                                                 at android.os.AsyncTask.finish(AsyncTask.java:651)
                                                                 at android.os.AsyncTask.access$500(AsyncTask.java:180)
                                                                 at android.os.AsyncTask$InternalHandler.handleMessage(AsyncTask.java:668)
                                                                 at android.os.Handler.dispatchMessage(Handler.java:102)
                                                                 at android.os.Looper.loop(Looper.java:158)
                                                                 at android.app.ActivityThread.main(ActivityThread.java:7229)
                                                                 at java.lang.reflect.Method.invoke(Native Method)
                                                                 at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1230)
                                                                 at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1120)
                                                              Caused by: android.view.InflateException: Binary XML file line #15: Error inflating class com.example.gu.NeckCanvasOverlay
                                                                 at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:788)
                                                                 at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:716)
                                                                 at android.view.LayoutInflater.rInflate(LayoutInflater.java:847)
                                                                 at android.view.LayoutInflater.rInflateChildren(LayoutInflater.java:810)
                                                                 at android.view.LayoutInflater.rInflate(LayoutInflater.java:855)
                                                                 at android.view.LayoutInflater.rInflateChildren(LayoutInflater.java:810)
                                                                 at android.view.LayoutInflater.inflate(LayoutInflater.java:527)
                                                                 at android.view.LayoutInflater.inflate(LayoutInflater.java:429) 
                                                                 at com.example.xxxxx.FragmentNeckDisplayMenu.onCreateView(FragmentNeckDisplayMenu.java:32) 
                                                                 at android.support.v4.app.Fragment.performCreateView(Fragment.java:1962) 
                                                                 at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1067) 
                                                                 at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1248) 
                                                                 at android.support.v4.app.BackStackRecord.run(BackStackRecord.java:738) 
                                                                 at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1613) 
                                                                 at android.support.v4.app.FragmentManagerImpl.executePendingTransactions(FragmentManager.java:570) 
                                                                 at android.support.v4.app.FragmentPagerAdapter.finishUpdate(FragmentPagerAdapter.java:141) 
                                                                 at android.support.v4.view.ViewPager.populate(ViewPager.java:1106) 
                                                                 at android.support.v4.view.ViewPager.populate(ViewPager.java:952) 
                                                                 at android.support.v4.view.ViewPager.setOffscreenPageLimit(ViewPager.java:733) 
                                                                 at com.example.xxxxx.PlayFrets.configMenu(PlayFrets.java:150) 
                                                                 at com.example.xxxxx.AsyncTask_NoteFileLoader.onPostExecute(AsyncTask_NoteFileLoader.java:125) 
                                                                 at com.example.xxxxx.AsyncTask_NoteFileLoader.onPostExecute(AsyncTask_NoteFileLoader.java:9) 
                                                                 at android.os.AsyncTask.finish(AsyncTask.java:651) 
                                                                 at android.os.AsyncTask.access$500(AsyncTask.java:180) 
                                                                 at android.os.AsyncTask$InternalHandler.handleMessage(AsyncTask.java:668) 
                                                                 at android.os.Handler.dispatchMessage(Handler.java:102) 
                                                                 at android.os.Looper.loop(Looper.java:158) 
                                                                 at android.app.ActivityThread.main(ActivityThread.java:7229) 
                                                                 at java.lang.reflect.Method.invoke(Native Method) 
                                                                 at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1230) 
                                                                 at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1120) 
                                                              Caused by: java.lang.ClassNotFoundException: Didn't find class "com.example.gu.NeckCanvasOverlay" on path: DexPathList[[zip file "/data/app/com.example.xxxxx-2/base.apk"],nativeLibraryDirectories=[/data/app/com.example.xxxxx-2/lib/arm64, /vendor/lib64, /system/lib64]]
                                                                 at dalvik.system.BaseDexClassLoader.findClass(BaseDexClassLoader.java:56)
                                                                 at java.lang.ClassLoader.loadClass(ClassLoader.java:511)
                                                                 at java.lang.ClassLoader.loadClass(ClassLoader.java:469)
                                                                 at android.view.LayoutInflater.createView(LayoutInflater.java:595)
                                                                 at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:776)
                                                                 at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:716) 
                                                                 at android.view.LayoutInflater.rInflate(LayoutInflater.java:847) 
                                                                 at android.view.LayoutInflater.rInflateChildren(LayoutInflater.java:810) 
                                                                 at android.view.LayoutInflater.rInflate(LayoutInflater.java:855) 
                                                                 at android.view.LayoutInflater.rInflateChildren(LayoutInflater.java:810) 
                                                                 at android.view.LayoutInflater.inflate(LayoutInflater.java:527) 
                                                                 at android.view.LayoutInflater.inflate(LayoutInflater.java:429) 
                                                                 at com.example.xxxxx.FragmentNeckDisplayMenu.onCreateView(FragmentNeckDisplayMenu.java:32) 
                                                                 at android.support.v4.app.Fragment.performCreateView(Fragment.java:1962) 
                                                                 at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1067) 
                                                                 at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1248) 
                                                                 at android.support.v4.app.BackStackRecord.run(BackStackRecord.java:738) 
                                                                 at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1613) 
                                                                 at android.support.v4.app.FragmentManagerImpl.executePendingTransactions(FragmentManager.java:570) 
                                                                 at android.support.v4.app.FragmentPagerAdapter.finishUpdate(FragmentPagerAdapter.java:141) 
                                                                 at android.support.v4.view.ViewPager.populate(ViewPager.java:1106) 
                                                                 at android.support.v4.view.ViewPager.populate(ViewPager.java:952) 
                                                                 at android.support.v4.view.ViewPager.setOffscreenPageLimit(ViewPager.java:733) 
                                                                 at com.example.xxxxx.PlayFrets.configMenu(PlayFrets.java:150) 
                                                                 at com.example.xxxxx.AsyncTask_NoteFileLoader.onPostExecute(AsyncTask_NoteFileLoader.java:125) 
                                                                 at com.example.xxxxx.AsyncTask_NoteFileLoader.onPostExecute(AsyncTask_NoteFileLoader.java:9) 
                                                                 at android.os.AsyncTask.finish(AsyncTask.java:651) 
                                                                 at android.os.AsyncTask.access$500(AsyncTask.java:180) 
                                                                 at android.os.AsyncTask$InternalHandler.handleMessage(AsyncTask.java:668) 
                                                                 at android.os.Handler.dispatchMessage(Handler.java:102) 
                                                                 at android.os.Looper.loop(Looper.java:158) 
                                                                 at android.app.ActivityThread.main(ActivityThread.java:7229) 
                                                                 at java.lang.reflect.Method.invoke(Native Method) 
                                                                 at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1230) 
                                                                 at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1120) 
                                                                Suppressed: java.lang.ClassNotFoundException: com.example.gu.NeckCanvasOverlay
                                                                 at java.lang.Class.classForName(Native Method)
                                                                 at java.lang.BootClassLoader.findClass(ClassLoader.java:781)
                                                                 at java.lang.BootClassLoader.loadClass(ClassLoader.java:841)
                                                                 at java.lang.ClassLoader.loadClass(ClassLoader.java:504)
                                                                        ... 33 more
                                                              Caused by: java.lang.NoClassDefFoundError: Class not found using the boot class loader; no stack trace available
08-06 21:47:24.954 26334-27123/? E/AndroidRuntime: FATAL EXCEPTION: main
                                                   Process: com.example.xxxxx, PID: 26334
                                                   android.view.InflateException: Binary XML file line #15: Binary XML file line #15: Error inflating class com.example.gu.NeckCanvasOverlay
                                                       at android.view.LayoutInflater.inflate(LayoutInflater.java:551)
                                                       at android.view.LayoutInflater.inflate(LayoutInflater.java:429)
                                                       at com.example.xxxxx.FragmentNeckDisplayMenu.onCreateView(FragmentNeckDisplayMenu.java:32)
                                                       at android.support.v4.app.Fragment.performCreateView(Fragment.java:1962)
                                                       at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1067)
                                                       at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1248)
                                                       at android.support.v4.app.BackStackRecord.run(BackStackRecord.java:738)
                                                       at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1613)
                                                       at android.support.v4.app.FragmentManagerImpl.executePendingTransactions(FragmentManager.java:570)
                                                       at android.support.v4.app.FragmentPagerAdapter.finishUpdate(FragmentPagerAdapter.java:141)
                                                       at android.support.v4.view.ViewPager.populate(ViewPager.java:1106)
                                                       at android.support.v4.view.ViewPager.populate(ViewPager.java:952)
                                                       at android.support.v4.view.ViewPager.setOffscreenPageLimit(ViewPager.java:733)
                                                       at com.example.xxxxx.PlayFrets.configMenu(PlayFrets.java:150)
                                                       at com.example.xxxxx.AsyncTask_NoteFileLoader.onPostExecute(AsyncTask_NoteFileLoader.java:125)
                                                       at com.example.xxxxx.AsyncTask_NoteFileLoader.onPostExecute(AsyncTask_NoteFileLoader.java:9)
                                                       at android.os.AsyncTask.finish(AsyncTask.java:651)
                                                       at android.os.AsyncTask.access$500(AsyncTask.java:180)
                                                       at android.os.AsyncTask$InternalHandler.handleMessage(AsyncTask.java:668)
                                                       at android.os.Handler.dispatchMessage(Handler.java:102)
                                                       at android.os.Looper.loop(Looper.java:158)
                                                       at android.app.ActivityThread.main(ActivityThread.java:7229)
                                                       at java.lang.reflect.Method.invoke(Native Method)
                                                       at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1230)
                                                       at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1120)
                                                    Caused by: android.view.InflateException: Binary XML file line #15: Error inflating class com.example.gu.NeckCanvasOverlay
                                                       at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:788)
                                                       at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:716)
                                                       at android.view.LayoutInflater.rInflate(LayoutInflater.java:847)
                                                       at android.view.LayoutInflater.rInflateChildren(LayoutInflater.java:810)
                                                       at android.view.LayoutInflater.rInflate(LayoutInflater.java:855)
                                                       at android.view.LayoutInflater.rInflateChildren(LayoutInflater.java:810)
                                                       at android.view.LayoutInflater.inflate(LayoutInflater.java:527)
                                                       at android.view.LayoutInflater.inflate(LayoutInflater.java:429) 
                                                       at com.example.xxxxx.FragmentNeckDisplayMenu.onCreateView(FragmentNeckDisplayMenu.java:32) 
                                                       at android.support.v4.app.Fragment.performCreateView(Fragment.java:1962) 
                                                       at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1067) 
                                                       at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1248) 
                                                       at android.support.v4.app.BackStackRecord.run(BackStackRecord.java:738) 
                                                       at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1613) 
                                                       at android.support.v4.app.FragmentManagerImpl.executePendingTransactions(FragmentManager.java:570) 
                                                       at android.support.v4.app.FragmentPagerAdapter.finishUpdate(FragmentPagerAdapter.java:141) 
                                                       at android.support.v4.view.ViewPager.populate(ViewPager.java:1106) 
                                                       at android.support.v4.view.ViewPager.populate(ViewPager.java:952) 
                                                       at android.support.v4.view.ViewPager.setOffscreenPageLimit(ViewPager.java:733) 
                                                       at com.example.xxxxx.PlayFrets.configMenu(PlayFrets.java:150) 
                                                       at com.example.xxxxx.AsyncTask_NoteFileLoader.onPostExecute(AsyncTask_NoteFileLoader.java:125) 
                                                       at com.example.xxxxx.AsyncTask_NoteFileLoader.onPostExecute(AsyncTask_NoteFileLoader.java:9) 
                                                       at android.os.AsyncTask.finish(AsyncTask.java:651) 
                                                       at android.os.AsyncTask.access$500(AsyncTask.java:180) 
                                                       at android.os.AsyncTask$InternalHandler.handleMessage(AsyncTask.java:668) 
                                                       at android.os.Handler.dispatchMessage(Handler.java:102) 
                                                       at android.os.Looper.loop(Looper.java:158) 
                                                       at android.app.ActivityThread.main(ActivityThread.java:7229) 
                                                       at java.lang.reflect.Method.invoke(Native Method) 
                                                       at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1230) 
                                                       at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1120) 
                                                    Caused by: java.lang.ClassNotFoundException: Didn't find class "com.example.gu.NeckCanvasOverlay" on path: DexPathList[[zip file "/data/app/com.example.xxxxx-2/base.apk"],nativeLibraryDirectories=[/data/app/com.example.xxxxx-2/lib/arm64, /vendor/lib64, /system/lib64]]
                                                       at dalvik.system.BaseDexClassLoader.findClass(BaseDexClassLoader.java:56)
                                                       at java.lang.ClassLoader.loadClass(ClassLoader.java:511)
                                                       at java.lang.ClassLoader.loadClass(ClassLoader.java:469)
                                                       at android.view.LayoutInflater.createView(LayoutInflater.java:595)
                                                       at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:776)
                                                       at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:716) 
                                                       at android.view.LayoutInflater.rInflate(LayoutInflater.java:847) 
                                                       at android.view.LayoutInflater.rInflateChildren(LayoutInflater.java:810) 
                                                       at android.view.LayoutInflater.rInflate(LayoutInflater.java:855) 
                                                       at android.view.LayoutInflater.rInflateChildren(LayoutInflater.java:810) 
                                                       at android.view.LayoutInflater.inflate(LayoutInflater.java:527) 
                                                       at android.view.LayoutInflater.inflate(LayoutInflater.java:429) 
                                                       at com.example.xxxxx.FragmentNeckDisplayMenu.onCreateView(FragmentNeckDisplayMenu.java:32) 
                                                       at android.support.v4.app.Fragment.performCreateView(Fragment.java:1962) 
                                                       at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1067) 
                                                       at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1248) 
                                                       at android.support.v4.app.BackStackRecord.run(BackStackRecord.java:738) 
                                                       at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1613) 
                                                       at android.support.v4.app.FragmentManagerImpl.executePendingTransactions(FragmentManager.java:570) 
                                                       at android.support.v4.app.FragmentPagerAdapter.finishUpdate(FragmentPagerAdapter.java:141) 
                                                       at android.support.v4.view.ViewPager.populate(ViewPager.java:1106) 
                                                       at android.support.v4.view.ViewPager.populate(ViewPager.java:952) 
                                                       at android.support.v4.view.ViewPager.setOffscreenPageLimit(ViewPager.java:733) 
                                                       at com.example.xxxxx.PlayFrets.configMenu(PlayFrets.java:150) 
                                                       at com.example.xxxxx.AsyncTask_NoteFileLoader.onPostExecute(AsyncTask_NoteFileLoader.java:125) 

【问题讨论】：

在堆栈跟踪中进一步查看根本原因。这可能是因为您缺少必要的构造函数来为您的自定义View 膨胀。您需要一个带有 Context 和 AttributeSet 的双参数构造函数。

你可以在这个链接上看到答案***.com/questions/17599450/…

你确定你的包名到处都是正确的吗？你在某些地方有com.example.xxxxx，在其他地方有com.example.gu。这只是搜索/替换编辑错误吗？在布局和类中仔细检查，然后尝试清理/重建您的项目。

我不知道你的意思是什么，但你得到了一个ClassNotFoundException 代表com.example.gu.NeckCanvasOverlay。您在布局 XML 中指定的任何类都不存在于您的 apk 中。无论您现在的类和包名称是什么，您都需要确保在 XML 中正确引用了该类。

好发现，这实际上是问题所在！与自定义视图对应的类在我的布局的 XML 文件中命名错误。如果你发布它，我会接受这个作为答案。

【参考方案1】：

直接的问题是ClassNotFoundException。在布局中处理自定义 Views 时，常见原因是布局 XML 中的类名不正确，这似乎是这里的问题。确保 XML 标记具有自定义 View 类的正确、完全限定的类名，这将是文件顶部的类的 package，附加到类名之前。

此外，从您的布局中膨胀的Views 将使用一个带有Context 和AttributeSet 的两个参数的构造函数进行实例化。您的类定义至少需要具有允许膨胀的构造函数，否则您将获得NoSuchMethodException。此外，如果您将构造函数链接起来，如果您只是扩展View，它会使事情变得更简单。例如：

public NeckCanvasOverlay(Context context) 
    this(context, null);


public NeckCanvasOverlay(Context context, AttributeSet attrs) 
    super(context, attrs);
    initView();

【参考方案2】：

为自定义View 包含所有三个构造函数会更安全。例如，为您的NeckCanvasOverlay 包含以下构造函数。

public NeckCanvasOverlay(Context context) 
        super(context);
        initView();
    

    public NeckCanvasOverlay(Context context, AttributeSet attrs) 
        super(context, attrs);
        initView();
    

    public NeckCanvasOverlay(Context context, AttributeSet attrs, int defStyle) 
        super(context, attrs, defStyle);
        initView();
    

我希望这会有所帮助。试一试，如果遇到同样的错误，请告诉我。