【发布时间】:2015-06-30 07:18:24
【问题描述】:
我目前正在从 Android Programming: The Big Nerd Ranch Guide 学习 Android。有一个名为 CriminalIntent 的应用程序引入了 Fragments 的概念。我按照作者所说的步骤进行操作,但仍然出现运行时异常。这是代码
//由其他Activity扩展的单个抽象Activity类
incorporating fragments
public abstract class SingleFragmentActivity extends Activity {
protected abstract Fragment createFragment();
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_fragment);
FragmentManager fm = getFragmentManager();
Fragment fragment = fm.findFragmentById(R.id.fragmentContainer);
if (fragment == null) {
fragment = createFragment();
fm.beginTransaction()
.add(R.id.fragmentContainer, fragment)
.commit();
}
}
}
//这里是扩展上述类的List活动
public class CrimeListActivity extends SingleFragmentActivity {
@Override
protected Fragment createFragment() {
return new CrimeListFragment();
}
}
//这里是ListActivity使用的Fragment
public class CrimeListFragment extends ListFragment {
private ArrayList<Crime> mCrimes;
public CrimeListFragment() {
// Required empty public constructor
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
getActivity().setTitle(R.string.crimes_title);
mCrimes = CrimeLab.get(getActivity()).getCrimes();
ArrayAdapter<Crime> adapter =
new ArrayAdapter<Crime>(getActivity(),
android.R.layout.simple_list_item_1,
mCrimes);
setListAdapter(adapter);
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
return inflater.inflate(R.layout.fragment_crime_list, container, false);
}
}
现在,布局:
//activity_fragment.xml
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/fragmentContainer"
android:layout_width="match_parent"
android:layout_height="match_parent"/>
还有,
//fragment_crime_list.xml
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.example.criminalintent.CrimeListFragment">
<TextView android:layout_width="match_parent" android:layout_height="match_parent"
android:text="@string/hello_blank_fragment" />
</FrameLayout>
我尝试调试,但发现异常发生在主Activity启动过程中。
06-30 12:45:37.350 20494-20494/? I/art﹕ Not late-enabling -Xcheck:jni (already on)
06-30 12:45:37.398 20494-20494/? D/AndroidRuntime﹕ Shutting down VM
06-30 12:45:37.398 20494-20494/? E/AndroidRuntime﹕ FATAL EXCEPTION: main
Process: com.example.criminalintent, PID: 20494
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.criminalintent/com.example.criminalintent.CrimeListActivity}: java.lang.RuntimeException: Content has view with id attribute 'android.R.id.list' that is not a ListView class
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2325)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2390)
at android.app.ActivityThread.access$800(ActivityThread.java:151)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1303)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5257)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698)
Caused by: java.lang.RuntimeException: Content has view with id attribute 'android.R.id.list' that is not a ListView class
at android.app.ListFragment.ensureList(ListFragment.java:402)
at android.app.ListFragment.onViewCreated(ListFragment.java:203)
at android.app.FragmentManagerImpl.moveToState(FragmentManager.java:908)
at android.app.FragmentManagerImpl.moveToState(FragmentManager.java:1067)
at android.app.BackStackRecord.run(BackStackRecord.java:834)
at android.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1452)
at android.app.Activity.performStart(Activity.java:6005)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2288)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2390)
at android.app.ActivityThread.access$800(ActivityThread.java:151)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1303)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5257)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698)
【问题讨论】:
-
发布 fragment_crime_list.xml
标签: android listview android-fragments