相关疑难解决方法(0)

我有一个非常令人沮丧的错误,我无法解释.我创建了一个Android应用程序,用于Android AppCompat使其与旧版本兼容.这是我的主要活动布局文件:

<android.support.v4.widget.DrawerLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/drawer_layout"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <!-- As the main content view, the view below consumes the entire
         space available using match_parent in both dimensions. -->
    <FrameLayout
        android:id="@+id/container"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />

    <!-- android:layout_gravity="start" tells DrawerLayout to treat
         this as a sliding drawer on the left side for left-to-right
         languages and on the right side for right-to-left languages.
         If you're not building against API 17 or higher, use
         android:layout_gravity="left" instead. -->

    <!-- The drawer is given …

我有一个res/layout/main.xml包括这些元素和其他:

<some.package.MyCustomView android:id="@+id/foo" (some other params) />
<TextView android:id="@+id/boring" (some other params) />

在我的Activity的onCreate中,我这样做:

setContentView(R.layout.main);
TextView boring = (TextView) findViewById(R.id.boring);
// ...find other elements...
MyCustomView foo = (MyCustomView) findViewById(R.id.foo);
if (foo == null) { Log.d(TAG, "epic fail"); }

其他元素成功找到,但foo返回null.MyCustomView有一个构造函数,MyCustomView(Context c, AttributeSet a)并且Log.d(...)该构造函数的末尾在"史诗失败"之前的logcat中成功出现.

为什么是foonull？

我制作了一个应用程序,其中我在我的位置显示了带有GPS位置标记的Google地图.此地图位于第一个选项卡上,我还有另外两个选项卡,如下图所示

现在我面临一个问题,即当我从选项卡1移动到选项卡2然后再转到选项卡1时它完美地工作,但是当我移动到选项卡3然后移回选项卡1或选项卡2时,应用程序崩溃并给出以下内容例外情况LogCat:

01-27 18:35:26.190 9414-9414/com.example.accurat.faisal E/AndroidRuntime: FATAL EXCEPTION: main
  Process: com.example.accurat.faisal, PID: 9414
  android.view.InflateException: Binary XML file line #26: Binary XML file line #26: Error inflating class fragment
      at android.view.LayoutInflater.inflate(LayoutInflater.java:551)
      at android.view.LayoutInflater.inflate(LayoutInflater.java:429)
      at com.example.accurat.faisal.MyLocation.onCreateView(MyLocation.java:62)
      at android.support.v4.app.Fragment.performCreateView(Fragment.java:2184)
      at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1298)
      at android.support.v4.app.FragmentManagerImpl.moveFragmentsToInvisible(FragmentManager.java:2323)
      at android.support.v4.app.FragmentManagerImpl.executeOpsTogether(FragmentManager.java:2136)
      at android.support.v4.app.FragmentManagerImpl.optimizeAndExecuteOps(FragmentManager.java:2092)
      at android.support.v4.app.FragmentManagerImpl.execSingleAction(FragmentManager.java:1969)
      at android.support.v4.app.BackStackRecord.commitNowAllowingStateLoss(BackStackRecord.java:620)
      at android.support.v4.app.FragmentPagerAdapter.finishUpdate(FragmentPagerAdapter.java:143)
      at android.support.v4.view.ViewPager.populate(ViewPager.java:1268)
      at android.support.v4.view.ViewPager.populate(ViewPager.java:1116)
      at android.support.v4.view.ViewPager$3.run(ViewPager.java:273)
      at android.view.Choreographer$CallbackRecord.run(Choreographer.java:911)
      at android.view.Choreographer.doCallbacks(Choreographer.java:686)
      at android.view.Choreographer.doFrame(Choreographer.java:619)
      at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:897)
      at android.os.Handler.handleCallback(Handler.java:739)
      at android.os.Handler.dispatchMessage(Handler.java:95)
      at android.os.Looper.loop(Looper.java:148)
      at android.app.ActivityThread.main(ActivityThread.java:7325)
      at java.lang.reflect.Method.invoke(Native Method)
      at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1230)
      at …