我试图在我的电视应用中实现搜索，但是当我在搜索时按下提交按钮时，它会崩溃并显示以下消息：
java.lang.NullPointerException: Attempt to invoke virtual method 'int android.support.v17.leanback.widget.ObjectAdapter.size()' on a null object reference
at android.support.v17.leanback.app.SearchFragment.focusOnResults(SearchFragment.java:581)
at android.support.v17.leanback.app.SearchFragment.queryComplete(SearchFragment.java:567)
at android.support.v17.leanback.app.SearchFragment.access$1300(SearchFragment.java:63)
at android.support.v17.leanback.app.SearchFragment$4.onKeyboardDismiss(SearchFragment.java:257)
at android.support.v17.leanback.widget.SearchBar$6$2.run(SearchBar.java:257)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5221)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:899)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694)
以下是我SearchFragment的实现：
public class SearchTVFragment extends SearchFragment implements SearchFragment.SearchResultProvider{
private static final int SEARCH_DELAY_MS = 300;
private static final String TAG = SearchTVFragment.class.getSimpleName();
final private ArrayObjectAdapter mRowsAdapter = new ArrayObjectAdapter(new ListRowPresenter());
final ScheduledExecutorService scheduledExecutorService = Executors.newScheduledThreadPool(1);
ScheduledFuture<List<VideoEntryWrapper>> searchResult;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setSpeechRecognitionCallback(new SpeechRecognitionCallback() {
@Override
public void recognizeSpeech() {
}
});
setSearchResultProvider(this);
Toast.makeText(getActivity(),"Search onCreate", Toast.LENGTH_SHORT).show();
}
@Override
public ArrayObjectAdapter getResultsAdapter() {
return mRowsAdapter;
}
@Override
public boolean onQueryTextChange(String newQuery) {
return false;
}
@Override
public boolean onQueryTextSubmit(String query) {
return processQuery(query);
}
boolean processQuery(String query){
Log.debug(TAG,"processQuery : "+query);
if(searchResult != null){
searchResult.cancel(true);
}
searchResult = scheduledExecutorService.schedule(new SearchVideoTask(query, 0, 20)
, SEARCH_DELAY_MS, TimeUnit.MILLISECONDS);
processResponse(searchResult);
return true;
}
private void processResponse(final ScheduledFuture<List<VideoEntryWrapper>> searchRes){
new AsyncTask<Void,Void,List<VideoEntryWrapper>>(){
@Override
protected List<VideoEntryWrapper> doInBackground(Void... params) {
try {
Log.debug(TAG,">> processResponse");
List<VideoEntryWrapper> videoEntryWrappers = searchRes.get();
Log.debug(TAG,"<< processResponse");
return videoEntryWrappers;
} catch (CancellationException|InterruptedException e) {
Log.debug(TAG,"<< processResponse cancelled");
} catch (ExecutionException e) {
Log.error(TAG,"<< processResponse error : "+e.getMessage());
}
return null;
}
@Override
protected void onPostExecute(List<VideoEntryWrapper> videoEntryWrappers) {
if(videoEntryWrappers != null){
Log.debug(TAG,">> view response");
ArrayObjectAdapter listRowAdapter = new ArrayObjectAdapter(new SongEntryPresenter());
for (VideoEntryWrapper videoEntryWrapper: videoEntryWrappers){
listRowAdapter.add(videoEntryWrapper);
}
mRowsAdapter.add(new ListRow(listRowAdapter));
Log.debug(TAG,"<< view response");
} else {
Log.debug(TAG,">> no data to view response");
}
}
}.execute();
}
}
这里有什么问题？如果我使用null方法提供适配器，为什么适配器为getResultsAdapter()？
日志转储：
3 1660-1671/com.mypackage.name I/art﹕ WaitForGcToComplete blocked for 3.066s for cause HeapTrim
02-10 16:59:23.428 1660-1660/com.mypackage.name D/InputEventConsistencyVerifier﹕ TouchEvent: Source was not SOURCE_CLASS_POINTER.
in android.support.v17.leanback.widget.SearchEditText{3b6b36a3 VFED..CL .F.P.... 32,18-799,57 #7f0e0192 app:id/lb_search_text_editor}
0: sent at 952267000000, MotionEvent { action=ACTION_DOWN, id[0]=0, x[0]=767.0, y[0]=39.0, toolType[0]=TOOL_TYPE_UNKNOWN, buttonState=0, metaState=0, flags=0x0, edgeFlags=0x0, pointerCount=1, historySize=0, eventTime=952267, downTime=952267, deviceId=0, source=0x0 }
-- recent events --
1: sent at 952082381000, MotionEvent { action=ACTION_UP, id[0]=0, x[0]=125.0, y[0]=18.0, toolType[0]=TOOL_TYPE_FINGER, buttonState=0, metaState=0, flags=0x0, edgeFlags=0x0, pointerCount=1, historySize=0, eventTime=952082, downTime=951974, deviceId=0, source=0x1002 }
2: sent at 951974040000, MotionEvent { action=ACTION_DOWN, id[0]=0, x[0]=125.0, y[0]=18.0, toolType[0]=TOOL_TYPE_FINGER, buttonState=0, metaState=0, flags=0x0, edgeFlags=0x0, pointerCount=1, historySize=0, eventTime=951974, downTime=951974, deviceId=0, source=0x1002 }
02-10 16:59:23.431 1660-1660/com.mypackage.name D/InputEventConsistencyVerifier﹕ TouchEvent: Source was not SOURCE_CLASS_POINTER.
in android.support.v17.leanback.widget.SearchEditText{3b6b36a3 VFED..CL .F.P.... 32,18-799,57 #7f0e0192 app:id/lb_search_text_editor}
0: sent at 952465000000, MotionEvent { action=ACTION_UP, id[0]=0, x[0]=767.0, y[0]=39.0, toolType[0]=TOOL_TYPE_UNKNOWN, buttonState=0, metaState=0, flags=0x0, edgeFlags=0x0, pointerCount=1, historySize=0, eventTime=952465, downTime=952465, deviceId=0, source=0x0 }
-- recent events --
1: sent at 952267000000, MotionEvent { action=ACTION_DOWN, id[0]=0, x[0]=767.0, y[0]=39.0, toolType[0]=TOOL_TYPE_UNKNOWN, buttonState=0, metaState=0, flags=0x80000000, edgeFlags=0x0, pointerCount=1, historySize=0, eventTime=952267, downTime=952267, deviceId=0, source=0x0 }
2: sent at 952082381000, MotionEvent { action=ACTION_UP, id[0]=0, x[0]=125.0, y[0]=18.0, toolType[0]=TOOL_TYPE_FINGER, buttonState=0, metaState=0, flags=0x0, edgeFlags=0x0, pointerCount=1, historySize=0, eventTime=952082, downTime=951974, deviceId=0, source=0x1002 }
3: sent at 951974040000, MotionEvent { action=ACTION_DOWN, id[0]=0, x[0]=125.0, y[0]=18.0, toolType[0]=TOOL_TYPE_FINGER, buttonState=0, metaState=0, flags=0x0, edgeFlags=0x0, pointerCount=1, historySize=0, eventTime=951974, downTime=951974, deviceId=0, source=0x1002 }
02-10 16:59:23.905 1660-1672/com.mypackage.name I/art﹕ Background sticky concurrent mark sweep GC freed 26600(1800KB) AllocSpace objects, 54(1086KB) LOS objects, 13% free, 12MB/14MB, paused 2.427ms total 1.699s
02-10 16:59:24.101 1660-1660/com.mypackage.name E/RecyclerView﹕ No adapter attached; skipping layout
02-10 16:59:25.639 1660-1672/com.mypackage.name I/art﹕ Background partial concurrent mark sweep GC freed 25993(1512KB) AllocSpace objects, 63(1464KB) LOS objects, 25% free, 11MB/15MB, paused 3.207ms total 340.306ms
02-10 16:59:28.745 1660-1672/com.mypackage.name I/art﹕ Background sticky concurrent mark sweep GC freed 5324(417KB) AllocSpace objects, 13(240KB) LOS objects, 1% free, 15MB/15MB, paused 2.204ms total 229.996ms
02-10 16:59:29.129 1660-1672/com.mypackage.name I/art﹕ Background partial concurrent mark sweep GC freed 11273(526KB) AllocSpace objects, 24(606KB) LOS objects, 21% free, 14MB/18MB, paused 9.062ms total 355.074ms
02-10 16:59:29.132 1660-1671/com.mypackage.name I/art﹕ WaitForGcToComplete blocked for 226.367ms for cause HeapTrim
02-10 16:59:31.354 1660-1672/com.mypackage.name I/art﹕ Background sticky concurrent mark sweep GC freed 15296(1193KB) AllocSpace objects, 48(1120KB) LOS objects, 10% free, 16MB/18MB, paused 3.980ms total 118.393ms
02-10 16:59:32.953 1660-1672/com.mypackage.name I/art﹕ Background sticky concurrent mark sweep GC freed 2874(255KB) AllocSpace objects, 14(363KB) LOS objects, 3% free, 17MB/18MB, paused 12.077ms total 66.367ms
02-10 16:59:34.865 1660-1672/com.mypackage.name I/art﹕ Background partial concurrent mark sweep GC freed 16826(947KB) AllocSpace objects, 44(1077KB) LOS objects, 18% free, 17MB/21MB, paused 1.929ms total 678.420ms
02-10 16:59:36.906 1660-1672/com.mypackage.name I/art﹕ Background sticky concurrent mark sweep GC freed 12683(1028KB) AllocSpace objects, 45(1056KB) LOS objects, 9% free, 19MB/21MB, paused 2.011ms total 168.397ms
02-10 16:59:38.322 1660-1660/com.mypackage.name E/RecyclerView﹕ No adapter attached; skipping layout
02-10 16:59:38.539 1660-1660/com.mypackage.name D/AndroidRuntime﹕ Shutting down VM
02-10 16:59:38.919 1660-1672/com.mypackage.name I/art﹕ Background sticky concurrent mark sweep GC freed 4319(368KB) AllocSpace objects, 8(144KB) LOS objects, 1% free, 20MB/21MB, paused 2.288ms total 249.723ms
02-10 16:59:39.101 1660-1672/com.mypackage.name I/art﹕ Background partial concurrent mark sweep GC freed 12459(582KB) AllocSpace objects, 36(956KB) LOS objects, 17% free, 19MB/23MB, paused 2.706ms total 173.491ms
02-10 16:59:40.871 1660-1672/com.mypackage.name I/art﹕ Background sticky concurrent mark sweep GC freed 26845(1677KB) AllocSpace objects, 36(837KB) LOS objects, 8% free, 20MB/22MB, paused 2.210ms total 128.916ms
02-10 16:59:41.121 1660-1660/com.mypackage.name E/AndroidRuntime﹕ FATAL EXCEPTION: main
Process: com.mypackage.name, PID: 1660
java.lang.NullPointerException: Attempt to invoke virtual method 'int android.support.v17.leanback.widget.ObjectAdapter.size()' on a null object reference
at android.support.v17.leanback.app.SearchFragment.focusOnResults(SearchFragment.java:581)
at android.support.v17.leanback.app.SearchFragment.queryComplete(SearchFragment.java:567)
at android.support.v17.leanback.app.SearchFragment.access$1300(SearchFragment.java:63)
at android.support.v17.leanback.app.SearchFragment$4.onKeyboardDismiss(SearchFragment.java:257)
at android.support.v17.leanback.widget.SearchBar$6$2.run(SearchBar.java:257)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5221)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:899)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694)
02-10 16:59:43.968 1660-1660/com.mypackage.name I/Process﹕ Sending signal. PID: 1660 SIG: 9
02-10 16:59:45.723 1798-1798/com.mypackage.name I/MultiDex﹕ VM with version 2.1.0 has multidex support
02-10 16:59:45.724 1798-1798/com.mypackage.name I/MultiDex﹕ install
02-10 16:59:45.724 1798-1798/com.mypackage.name I/MultiDex﹕ VM has multidex support, MultiDex support library is disabled.
02-10 16:59:46.337 1798-1798/com.mypackage.name I/MyAppApplication﹕ >> onCreate
02-10 16:59:46.349 1798-1798/com.mypackage.name D/DeviceUtils﹕ >> getAdvertisingId
02-10 16:59:46.354 1798-1798/com.mypackage.name D/DeviceUtils﹕ << getAdvertisingId
02-10 16:59:46.377 1798-1814/com.mypackage.name D/DeviceUtils﹕ >> getAdvertisingId try fetching id
02-10 16:59:46.381 1798-1814/com.mypackage.name D/DeviceUtils﹕ >> getAdvertisingId inSyncBlock id not exist
02-10 16:59:46.396 1798-1814/com.mypackage.name D/DeviceUtils﹕ >> getAdId
02-10 16:59:46.471 1798-1798/com.mypackage.name I/Crashlytics﹕ Initializing Crashlytics 1.1.13.29
02-10 16:59:47.100 1798-1798/com.mypackage.name I/MyAppApplication﹕ << onCreate
02-10 16:59:52.300 1798-1798/com.mypackage.name D/InstallationTableWrapper﹕ Save installation successful
答案 0 :(得分：0)
我也在寻找答案。分辨率很简单。你和我忘了告诉Class将此类设置为默认搜索响应。
添加：
setSearchResultProvider(this);
在onCreate中修复此问题。多数民众赞成。