我有一个菜单，它维护一个CustomSearchView. 因为我想在 3 个选项卡（片段）之间切换，MainActivity所以我制作了 3 个与每个选项卡相关的菜单 .xml 文件。对于女巫操作栏的菜单，我使用onPrepareOptionMenu以下内容：
@Override
public boolean onPrepareOptionsMenu(Menu menu) {
if (menu != null && menu.hasVisibleItems())
menu.clear();
switch ((int) viewPager.getCurrentItem()) {
case 0:
Log.d(TAG, "onPrepareOptionsMenu " + viewPager.getChildCount()
+ " " + viewPager.getCurrentItem());
getMenuInflater().inflate(R.menu.searching_menu, menu); //line 99
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB) {
SearchManager searchManager = (SearchManager) getSystemService(Context.SEARCH_SERVICE);
MenuItem item = menu.findItem(R.id.searchview);
customSearchView = (CustomSearchView) item.getActionView(); //line 103
customSearchView.setSearchableInfo(searchManager
.getSearchableInfo(getComponentName()));
customSearchView.setSaveSearchTextState(true);
customSearchView.setIconifiedByDefault(false);
customSearchView
.setOnStatefulQueryTextListener(new android.widget.SearchView.OnQueryTextListener() {
@Override
public boolean onQueryTextChange(String query) {
searchingFragment.loadResultFound(query);
return true;
}
@Override
public boolean onQueryTextSubmit(String query) {
return true;
}
});
}
mSearchBySpinner = (Spinner) menu.findItem(R.id.search_by_spinner);
View view = ((MenuItem) mSearchBySpinner).getActionView();
if (view instanceof Spinner) {
Spinner spinner = (Spinner) view;
spinner.setAdapter(ArrayAdapter.createFromResource(
getApplicationContext(), R.array.searchby,
android.R.layout.simple_spinner_dropdown_item));
}
break;
case 1:
Log.d(TAG, "onPrepareOptionsMenu " + viewPager.getChildCount()
+ " " + viewPager.getCurrentItem());
getMenuInflater().inflate(R.menu.sort_menu, menu);
break;
case 2:
Log.d(TAG, "onPrepareOptionsMenu " + viewPager.getChildCount()
+ " " + viewPager.getCurrentItem());
getMenuInflater().inflate(R.menu.favorite_menu, menu);
break;
}
setMenu(menu);
return super.onPrepareOptionsMenu(menu);
}
这是 search_menu：
<menu xmlns:android="http://schemas.android.com/apk/res/android" >
<item
android:id="@+id/searchview"
android:actionViewClass="com.haanz.K4Droid.ui.CustomSearchView"
android:icon="@android:drawable/ic_search_category_default"
android:orderInCategory="99"
android:showAsAction="collapseActionView|ifRoom"
android:title="@string/searching"/>
<item
android:id="@+id/search_by_spinner"
android:actionViewClass="android.widget.Spinner"
android:orderInCategory="100"
android:showAsAction="always"
android:title="spinner"/>
<item
android:id="@+id/info"
android:icon="@android:drawable/ic_dialog_info"
android:orderInCategory="98"
android:showAsAction="collapseActionView"
android:title="@string/searching"/>
</menu>
当我在设备上运行项目时，它会抛出一个像这样的 Logcat：
08-30 11:11:05.483: D/MainActivity(13881): onPrepareOptionsMenu 2 0
08-30 11:11:05.488: W/MenuInflater(13881): Cannot instantiate class: com.haanz.K4Droid.ui.CustomSearchView
08-30 11:11:05.488: W/MenuInflater(13881): java.lang.ClassNotFoundException: com.haanz.K4Droid.ui.CustomSearchView
08-30 11:11:05.488: W/MenuInflater(13881): at dalvik.system.BaseDexClassLoader.findClass(BaseDexClassLoader.java)
08-30 11:11:05.488: W/MenuInflater(13881): at java.lang.ClassLoader.loadClass(ClassLoader.java)
08-30 11:11:05.488: W/MenuInflater(13881): at java.lang.ClassLoader.loadClass(ClassLoader.java)
08-30 11:11:05.488: W/MenuInflater(13881): at android.view.MenuInflater$MenuState.newInstance(MenuInflater.java)
08-30 11:11:05.488: W/MenuInflater(13881): at android.view.MenuInflater$MenuState.setItem(MenuInflater.java)
08-30 11:11:05.488: W/MenuInflater(13881): at android.view.MenuInflater$MenuState.addItem(MenuInflater.java)
08-30 11:11:05.488: W/MenuInflater(13881): at android.view.MenuInflater.parseMenu(MenuInflater.java)
08-30 11:11:05.488: W/MenuInflater(13881): at android.view.MenuInflater.inflate(MenuInflater.java)
08-30 11:11:05.488: W/MenuInflater(13881): at com.haanz.K4Droid.ui.MainActivity.onPrepareOptionsMenu(MainActivity.java:99)
08-30 11:11:05.488: W/MenuInflater(13881): at android.app.Activity.onPreparePanel(Activity.java)
08-30 11:11:05.488: W/MenuInflater(13881): at android.support.v4.app.FragmentActivity.onPreparePanel(FragmentActivity.java:469)
08-30 11:11:05.488: W/MenuInflater(13881): at com.android.internal.policy.impl.PhoneWindow.preparePanel(PhoneWindow.java)
08-30 11:11:05.488: W/MenuInflater(13881): at com.android.internal.policy.impl.PhoneWindow.invalidatePanelMenu(PhoneWindow.java)
08-30 11:11:05.488: W/MenuInflater(13881): at com.android.internal.policy.impl.PhoneWindow$1.run(PhoneWindow.java)
08-30 11:11:05.488: W/MenuInflater(13881): at android.os.Handler.handleCallback(Handler.java)
08-30 11:11:05.488: W/MenuInflater(13881): at android.os.Handler.dispatchMessage(Handler.java)
08-30 11:11:05.488: W/MenuInflater(13881): at android.os.Looper.loop(Looper.java)
08-30 11:11:05.488: W/MenuInflater(13881): at android.app.ActivityThread.main(ActivityThread.java)
08-30 11:11:05.488: W/MenuInflater(13881): at java.lang.reflect.Method.invokeNative(Native Method)
08-30 11:11:05.488: W/MenuInflater(13881): at java.lang.reflect.Method.invoke(Method.java)
08-30 11:11:05.488: W/MenuInflater(13881): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java)
08-30 11:11:05.488: W/MenuInflater(13881): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java)
08-30 11:11:05.488: W/MenuInflater(13881): at dalvik.system.NativeStart.main(Native Method)
08-30 11:11:05.498: W/dalvikvm(13881): threadid=1: thread exiting with uncaught exception (group=0x419f24d0)
08-30 11:11:05.498: E/AndroidRuntime(13881): FATAL EXCEPTION: main
08-30 11:11:05.498: E/AndroidRuntime(13881): java.lang.NullPointerException
08-30 11:11:05.498: E/AndroidRuntime(13881): at com.haanz.K4Droid.ui.MainActivity.onPrepareOptionsMenu(MainActivity.java:104)
08-30 11:11:05.498: E/AndroidRuntime(13881): at android.app.Activity.onPreparePanel(Activity.java)
08-30 11:11:05.498: E/AndroidRuntime(13881): at android.support.v4.app.FragmentActivity.onPreparePanel(FragmentActivity.java:469)
08-30 11:11:05.498: E/AndroidRuntime(13881): at com.android.internal.policy.impl.PhoneWindow.preparePanel(PhoneWindow.java)
08-30 11:11:05.498: E/AndroidRuntime(13881): at com.android.internal.policy.impl.PhoneWindow.invalidatePanelMenu(PhoneWindow.java)
08-30 11:11:05.498: E/AndroidRuntime(13881): at com.android.internal.policy.impl.PhoneWindow$1.run(PhoneWindow.java)
08-30 11:11:05.498: E/AndroidRuntime(13881): at android.os.Handler.handleCallback(Handler.java)
08-30 11:11:05.498: E/AndroidRuntime(13881): at android.os.Handler.dispatchMessage(Handler.java)
08-30 11:11:05.498: E/AndroidRuntime(13881): at android.os.Looper.loop(Looper.java)
08-30 11:11:05.498: E/AndroidRuntime(13881): at android.app.ActivityThread.main(ActivityThread.java)
08-30 11:11:05.498: E/AndroidRuntime(13881): at java.lang.reflect.Method.invokeNative(Native Method)
08-30 11:11:05.498: E/AndroidRuntime(13881): at java.lang.reflect.Method.invoke(Method.java)
08-30 11:11:05.498: E/AndroidRuntime(13881): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java)
08-30 11:11:05.498: E/AndroidRuntime(13881): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java)
08-30 11:11:05.498: E/AndroidRuntime(13881): at dalvik.system.NativeStart.main(Native Method)
08-30 11:11:05.518: D/Process(13881): killProcess, pid=13881
08-30 11:11:05.518: D/Process(13881): dalvik.system.VMStack.getThreadStackTrace(Native Method)
08-30 11:11:05.518: D/Process(13881): java.lang.Thread.getStackTrace(Thread.java)
08-30 11:11:05.518: D/Process(13881): android.os.Process.killProcess(Process.java)
08-30 11:11:05.518: D/Process(13881): com.android.internal.os.RuntimeInit$UncaughtHandler.uncaughtException(RuntimeInit.java)
08-30 11:11:05.518: D/Process(13881): java.lang.ThreadGroup.uncaughtException(ThreadGroup.java)
08-30 11:11:05.518: D/Process(13881): java.lang.ThreadGroup.uncaughtException(ThreadGroup.java)
谁能告诉我为什么会发生这种情况？当它大喊“无法实例化类：com.Haanz.K4Droid.ui.CustomSearchView ”时，我找不到任何东西。任何帮助将不胜感激。