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昨天我建我的应用程序，它工作得很好，然后我又试了一次以后，它只是想出了一个错误信息Unfortuneately应用程序已停止日食
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03-04 08:32:17.238: D/AndroidRuntime(836): Shutting down VM
03-04 08:32:17.238: W/dalvikvm(836): threadid=1: thread exiting with uncaught exception (group=0x40a71930)
03-04 08:32:17.248: E/AndroidRuntime(836): FATAL EXCEPTION: main
03-04 08:32:17.248: E/AndroidRuntime(836): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.android.fragments/com.example.android.fragments.MainActivity}: java.lang.ClassCastException: [email protected] must implement OnHeadlineSelectedListener
03-04 08:32:17.248: E/AndroidRuntime(836): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2180)
03-04 08:32:17.248: E/AndroidRuntime(836): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230)
03-04 08:32:17.248: E/AndroidRuntime(836): at android.app.ActivityThread.access$600(ActivityThread.java:141)
03-04 08:32:17.248: E/AndroidRuntime(836): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1234)
03-04 08:32:17.248: E/AndroidRuntime(836): at android.os.Handler.dispatchMessage(Handler.java:99)
03-04 08:32:17.248: E/AndroidRuntime(836): at android.os.Looper.loop(Looper.java:137)
03-04 08:32:17.248: E/AndroidRuntime(836): at android.app.ActivityThread.main(ActivityThread.java:5041)
03-04 08:32:17.248: E/AndroidRuntime(836): at java.lang.reflect.Method.invokeNative(Native Method)
03-04 08:32:17.248: E/AndroidRuntime(836): at java.lang.reflect.Method.invoke(Method.java:511)
03-04 08:32:17.248: E/AndroidRuntime(836): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
03-04 08:32:17.248: E/AndroidRuntime(836): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
03-04 08:32:17.248: E/AndroidRuntime(836): at dalvik.system.NativeStart.main(Native Method)
03-04 08:32:17.248: E/AndroidRuntime(836): Caused by: java.lang.ClassCastException: [email protected] must implement OnHeadlineSelectedListener
03-04 08:32:17.248: E/AndroidRuntime(836): at com.example.android.fragments.MainActivity$HeadlinesFragment.onAttach(MainActivity.java:178)
03-04 08:32:17.248: E/AndroidRuntime(836): at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:825)
03-04 08:32:17.248: E/AndroidRuntime(836): at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1080)
03-04 08:32:17.248: E/AndroidRuntime(836): at android.support.v4.app.BackStackRecord.run(BackStackRecord.java:622)
03-04 08:32:17.248: E/AndroidRuntime(836): at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1416)
03-04 08:32:17.248: E/AndroidRuntime(836): at android.support.v4.app.FragmentActivity.onStart(FragmentActivity.java:505)
03-04 08:32:17.248: E/AndroidRuntime(836): at android.app.Instrumentation.callActivityOnStart(Instrumentation.java:1164)
03-04 08:32:17.248: E/AndroidRuntime(836): at android.app.Activity.performStart(Activity.java:5114)
03-04 08:32:17.248: E/AndroidRuntime(836): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2153)
03-04 08:32:17.248: E/AndroidRuntime(836): ... 11 more
03-04 08:35:24.997: E/Trace(892): error opening trace file: No such file or directory (2)
03-04 08:35:25.628: D/AndroidRuntime(892): Shutting down VM
03-04 08:35:25.628: W/dalvikvm(892): threadid=1: thread exiting with uncaught exception (group=0x40a71930)
03-04 08:35:25.638: E/AndroidRuntime(892): FATAL EXCEPTION: main
03-04 08:35:25.638: E/AndroidRuntime(892): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.android.fragments/com.example.android.fragments.MainActivity}: java.lang.ClassCastException: [email protected] must implement OnHeadlineSelectedListener
03-04 08:35:25.638: E/AndroidRuntime(892): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2180)
03-04 08:35:25.638: E/AndroidRuntime(892): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230)
03-04 08:35:25.638: E/AndroidRuntime(892): at android.app.ActivityThread.access$600(ActivityThread.java:141)
03-04 08:35:25.638: E/AndroidRuntime(892): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1234)
03-04 08:35:25.638: E/AndroidRuntime(892): at android.os.Handler.dispatchMessage(Handler.java:99)
03-04 08:35:25.638: E/AndroidRuntime(892): at android.os.Looper.loop(Looper.java:137)
03-04 08:35:25.638: E/AndroidRuntime(892): at android.app.ActivityThread.main(ActivityThread.java:5041)
03-04 08:35:25.638: E/AndroidRuntime(892): at java.lang.reflect.Method.invokeNative(Native Method)
03-04 08:35:25.638: E/AndroidRuntime(892): at java.lang.reflect.Method.invoke(Method.java:511)
03-04 08:35:25.638: E/AndroidRuntime(892): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
03-04 08:35:25.638: E/AndroidRuntime(892): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
03-04 08:35:25.638: E/AndroidRuntime(892): at dalvik.system.NativeStart.main(Native Method)
03-04 08:35:25.638: E/AndroidRuntime(892): Caused by: java.lang.ClassCastException: [email protected] must implement OnHeadlineSelectedListener
03-04 08:35:25.638: E/AndroidRuntime(892): at com.example.android.fragments.MainActivity$HeadlinesFragment.onAttach(MainActivity.java:178)
03-04 08:35:25.638: E/AndroidRuntime(892): at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:825)
03-04 08:35:25.638: E/AndroidRuntime(892): at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1080)
03-04 08:35:25.638: E/AndroidRuntime(892): at android.support.v4.app.BackStackRecord.run(BackStackRecord.java:622)
03-04 08:35:25.638: E/AndroidRuntime(892): at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1416)
03-04 08:35:25.638: E/AndroidRuntime(892): at android.support.v4.app.FragmentActivity.onStart(FragmentActivity.java:505)
03-04 08:35:25.638: E/AndroidRuntime(892): at android.app.Instrumentation.callActivityOnStart(Instrumentation.java:1164)
03-04 08:35:25.638: E/AndroidRuntime(892): at android.app.Activity.performStart(Activity.java:5114)
03-04 08:35:25.638: E/AndroidRuntime(892): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2153)
03-04 08:35:25.638: E/AndroidRuntime(892): ... 11 more
Android清单
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.android.fragments"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk android:minSdkVersion="11" android:targetSdkVersion="17" />
<application
android:icon="@drawable/ic_launcher"
android:label="@string/app_name" >
<activity
android:name="com.example.android.fragments.MainActivity"
android:label="@string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
</manifest>
MainActivity.java
public class MainActivity extends FragmentActivity {
public interface OnHeadlineSelectedListener {
/** Called by HeadlinesFragment when a list item is selected */
public void onArticleSelected(int position);
}
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.news_articles);
// Check whether the activity is using the layout version with
// the fragment_container FrameLayout. If so, we must add the first fragment
if (findViewById(R.id.fragment_container) != null) {
// However, if we're being restored from a previous state,
// then we don't need to do anything and should return or else
// we could end up with overlapping fragments.
if (savedInstanceState != null) {
return;
}
// Create an instance of ExampleFragment
HeadlinesFragment firstFragment = new HeadlinesFragment();
// In case this activity was started with special instructions from an Intent,
// pass the Intent's extras to the fragment as arguments
firstFragment.setArguments(getIntent().getExtras());
// Add the fragment to the 'fragment_container' FrameLayout
getSupportFragmentManager().beginTransaction()
.add(R.id.fragment_container, firstFragment).commit();
}
}
public void onArticleSelected(int position) {
// The user selected the headline of an article from the HeadlinesFragment
// Capture the article fragment from the activity layout
ArticleFragment articleFrag = (ArticleFragment)
getSupportFragmentManager().findFragmentById(R.id.article_fragment);
if (articleFrag != null) {
// If article frag is available, we're in two-pane layout...
// Call a method in the ArticleFragment to update its content
articleFrag.updateArticleView(position);
} else {
// If the frag is not available, we're in the one-pane layout and must swap frags...
// Create fragment and give it an argument for the selected article
ArticleFragment newFragment = new ArticleFragment();
Bundle args = new Bundle();
args.putInt(ArticleFragment.ARG_POSITION, position);
newFragment.setArguments(args);
FragmentTransaction transaction = getSupportFragmentManager().beginTransaction();
// Replace whatever is in the fragment_container view with this fragment,
// and add the transaction to the back stack so the user can navigate back
transaction.replace(R.id.fragment_container, newFragment);
transaction.addToBackStack(null);
// Commit the transaction
transaction.commit();
}
}
public class ArticleFragment extends Fragment {
final static String ARG_POSITION = "position";
int mCurrentPosition = -1;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// If activity recreated (such as from screen rotate), restore
// the previous article selection set by onSaveInstanceState().
// This is primarily necessary when in the two-pane layout.
if (savedInstanceState != null) {
mCurrentPosition = savedInstanceState.getInt(ARG_POSITION);
}
// Inflate the layout for this fragment
return inflater.inflate(R.layout.article_view, container, false);
}
@Override
public void onStart() {
super.onStart();
// During startup, check if there are arguments passed to the fragment.
// onStart is a good place to do this because the layout has already been
// applied to the fragment at this point so we can safely call the method
// below that sets the article text.
Bundle args = getArguments();
if (args != null) {
// Set article based on argument passed in
updateArticleView(args.getInt(ARG_POSITION));
} else if (mCurrentPosition != -1) {
// Set article based on saved instance state defined during onCreateView
updateArticleView(mCurrentPosition);
}
}
public void updateArticleView(int position) {
TextView article = (TextView) getActivity().findViewById(R.id.Article);
article.setText(Articles[position]);
mCurrentPosition = position;
}
@Override
public void onSaveInstanceState(Bundle outState) {
super.onSaveInstanceState(outState);
// Save the current article selection in case we need to recreate the fragment
outState.putInt(ARG_POSITION, mCurrentPosition);
}
}
public class HeadlinesFragment extends ListFragment {
OnHeadlineSelectedListener mCallback;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// We need to use a different list item layout for devices older than Honeycomb
int layout = Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB ?
android.R.layout.simple_list_item_activated_1 : android.R.layout.simple_list_item_1;
// Create an array adapter for the list view, using the Ipsum headlines array
setListAdapter(new ArrayAdapter<String>(getActivity(), layout, Headlines));
}
@Override
public void onStart() {
super.onStart();
// When in two-pane layout, set the listview to highlight the selected list item
// (We do this during onStart because at the point the listview is available.)
if (getFragmentManager().findFragmentById(R.id.article_fragment) != null) {
getListView().setChoiceMode(ListView.CHOICE_MODE_SINGLE);
}
}
@Override
public void onAttach(Activity activity) {
super.onAttach(activity);
// This makes sure that the container activity has implemented
// the callback interface. If not, it throws an exception.
try {
mCallback = (OnHeadlineSelectedListener) activity;
} catch (ClassCastException e) {
throw new ClassCastException(activity.toString()
+ " must implement OnHeadlineSelectedListener");
}
}
@Override
public void onListItemClick(ListView l, View v, int position, long id) {
// Notify the parent activity of selected item
mCallback.onArticleSelected(position);
// Set the item as checked to be highlighted when in two-pane layout
getListView().setItemChecked(position, true);
}
}
ArrayAdapter<String> adapter;
static String Headlines[] = {
"3D Studio Max 2014",
"Adobe Creative Suite 6",
"Agilent Agent",
"Android SDK",
"Audacity",
"C Map Tools",
"Cedar and Easy 68k",
"Context",
"CryEngine 3",
"Derive V5.0",
"Dreamweaver CS6",
"Eclipse",
"Face Modeller",
"Flash CS6",
"Image J",
"Linux",
"Matlab R2012A (Computing Toolbase)",
"Matlab R2012A (Maths)",
"Microsoft Project",
"Microsoft SQL Sever Lite",
"MinecraftEDU",
"MiniTab 16",
"MonoGame",
"NetBeans 7.3.1",
"Office 2013",
"Oracle Client",
"Photoshop CS6",
"Premiere CS6",
"Python 3.3.2",
"QT 5.1",
"R-Studio",
"Rational Architect",
"Steam",
"SWI Pro Log",
"Unreal UDK",
"Visio 2012",
"Visual Studio 2012",
"Win A&D 7 Desktop",
"Windows Mobile SDK",
"Weka ML",
"XNA Game Studio"};
static String Articles []= { "MEA 27\n MEA 34\n",
"MEA 27\n MEA 34\n",
"MEA 27\n MEA 34\n",
"MEA 27\n MEA 34\n",
"MEA 27\n MEA 34\n",
"MEA 27\n MEA 34\n",
"MEA 27\n MEA 34\n",
"MEA 27\n MEA 34\n",
"MEA 27\n MEA 34\n",
"MEA 27\n MEA 34\n",
"MEA 27\n MEA 34\n",
"MEA 27\n MEA 34\n",
"MEA 27\n MEA 34\n",
"MEA 27\n MEA 34\n",
"MEA 27\n MEA 34\n",
"MEA 27\n MEA 34\n",
"MEA 27\n MEA 34\n",
"MEA 27\n MEA 34\n",
"MEA 27\n MEA 34\n",
"MEA 27\n MEA 34\n",
"MEA 27\n MEA 34\n",
"MEA 27\n MEA 34\n",
"MEA 27\n MEA 34\n",
"MEA 27\n MEA 34\n",
"MEA 27\n MEA 34\n",
"MEA 27\n MEA 34\n",
"MEA 27\n MEA 34\n",
"MEA 27\n MEA 34\n",
"MEA 27\n MEA 34\n",
"MEA 27\n MEA 34\n",
"MEA 27\n MEA 34\n",
"MEA 27\n MEA 34\n",
"MEA 27\n MEA 34\n",
"MEA 27\n MEA 34\n",
"MEA 27\n MEA 34\n",
"MEA 27\n MEA 34\n",
"MEA 27\n MEA 34\n",
"MEA 27\n MEA 34\n",
"MEA 27\n MEA 34\n",
"MEA 27\n MEA 34\n",
"MEA 27\n MEA 34\n",
};
}
article_view.xml
<?xml version="1.0" encoding="utf-8"?>
<TextView xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/Article"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:padding="16dp"
android:textSize="18sp" />
news_article.xml
<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/fragment_container"
android:layout_width="match_parent"
android:layout_height="match_parent" />
第一线看起来不错，即mCallback =（OnHeadlineSelectedListener）活动 – Raghunandan
@Raghunandan这是抛出的线，因为缺少'implements'声明 –
我试过了，它提出错误消息'MainActivity不能扩展/实现它自己或其自己的成员类型之一' – user3092467