Android:在片段内添加自定义视图 [英] Android: Inflate Custom View inside Fragment
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问题描述
我有一个使用片段视图作为其布局一部分的应用程序.在此片段中，我想实例化一个Paint Canvas，在其中可以进行自定义绘图.
I have an application that uses a fragment view as part of its layout. Within this fragment, I want to instantiate a Paint Canvas where i can do custom drawing.
问题是，当我用错误android.view.InflateException: Binary XML file line #15: Binary XML file line #15: Error inflating class com.example.xxxxx.NeckCanvasOverlay
我不确定是什么导致我的Paint类无法正确膨胀.我知道有关于如何在片段中使用findViewById的特殊规则，但是我认为我坚持这些规则，因为我是在片段的视图本身上调用findViewByid(在我的代码中称为"v").
I'm not sure what's causing my Paint class not to inflate properly. I know there are special rules about how you use findViewById inside a fragment, but I thought I was adhering to them since i'm calling findViewByid on the fragment's view itself (called "v" in my code).
如何解决此问题?
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_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:id="@+id/canvas"
android:background="@drawable/image">
<LinearLayout
android:layout_width="148dp"
android:layout_height="0dp"
android:layout_gravity="center"
android:layout_weight="4">
!--Custom view for Canvas here -->
<com.example.xxxxx.NeckCanvasOverlay
android:id="@+id/neckHUD"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:background="@drawable/neck_for_menu"/>
</LinearLayout>
<Button
android:id="@+id/menuIcon"
android:layout_width="wrap_content"
android:layout_height="0dp"
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(包括的完整跟踪)
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)
推荐答案
直接的问题是ClassNotFoundException.在布局中处理自定义View时，常见的原因是布局XML中的类名不正确，这似乎是这里的问题.确保XML标记具有用于自定义View类的正确，完全合格的类名，该类名将从文件顶部开始是该类的package，并位于该类名之前.
The immediate problem is a ClassNotFoundException. When dealing with custom Views in a layout, a common cause for this is an incorrect class name in the layout XML, which seems to have been the issue here. Ensure that the XML tag has the correct, fully-qualified class name for the custom View class, which will be the class's package from the top of the file, prepended to the class name.
此外，将从布局中放大的View实例化为带有两个参数的构造函数，该构造函数使用Context和AttributeSet.您的类定义至少需要具有该构造函数才能允许通胀，否则您将得到NoSuchMethodException.同样，如果您只是扩展View，那么如果您将构造函数链接起来，它将使事情变得简单一些.例如:
Additionally, Views inflated from your layout will be instantiated with a two-argument constructor that takes a Context and an AttributeSet. Your class definition needs to have at least that constructor to allow inflation, or you'll get a NoSuchMethodException. Also, it would make things a little simpler if you'd chain your constructors, if you're just extending View. For example:
public NeckCanvasOverlay(Context context) {
this(context, null);
}
public NeckCanvasOverlay(Context context, AttributeSet attrs) {
super(context, attrs);
initView();
}
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