==================== Problem Description ====================
I have defined a method for querying the database (Selectallrecrod), saving the queried value in a list<string>, using unit tests, this method is feasible and can execute the result. ListView I use the Arrayadapter adapter, I write the data can be used, but a use of the Selectallrecrod method returned by the list error, null pointer exception. I want to know if you want to query the database, is to use the adapter is not must for simplecursoradapter, I think it should not be.
The Java code is as follows:
public class Towfragment extends fragment{private listview listview = null;private Mydao Mydao = null;private List<stri Ng> listData = null; @Overridepublic View Oncreateview (layoutinflater inflater, ViewGroup container,bundle Savedinstancestate) {View view = Inflater.inflate (R.layout.tow, container, false); listview = (ListView) View.findviewbyid (r.id.listview); Mydao = new Mydao (getactivity ()); listData = Mydao.selectedallrecord (); Listview.setadapter (New arrayadapter<string> (Getactivity (), Android. R.layout.simple_expandable_list_item_1, ListData)); return view;}}
The error log is as follows:
06-21 07:48:17.486:e/androidruntime (16659): FATAL exception:main
06-21 07:48:17.486:e/androidruntime (16659): java.lang.NullPointerException
06-21 07:48:17.486:e/androidruntime (16659): at Android.widget.ArrayAdapter.createViewFromResource (Arrayadapter.ja va:394)
06-21 07:48:17.486:e/androidruntime (16659): at Android.widget.ArrayAdapter.getView (arrayadapter.java:362)
06-21 07:48:17.486:e/androidruntime (16659): at Android.widget.AbsListView.obtainView (abslistview.java:2159)
06-21 07:48:17.486:e/androidruntime (16659): at Android.widget.ListView.measureHeightOfChildren (listview.java:1246 )
06-21 07:48:17.486:e/androidruntime (16659): at Android.widget.ListView.onMeasure (listview.java:1158)
06-21 07:48:17.486:e/androidruntime (16659): at Android.view.View.measure (view.java:15518)
06-21 07:48:17.486:e/androidruntime (16659): at Android.view.ViewGroup.measureChildWithMargins (viewgroup.java:4825 )
06-21 07:48:17.486:e/androidruntime (16659): at Android.widget.LinearLayout.measureChildBeforeLayout (LinearLayout. java:1404)
06-21 07:48:17.486:e/androidruntime (16659): at Android.widget.LinearLayout.measureVertical (linearlayout.java:695)
06-21 07:48:17.486:e/androidruntime (16659): at Android.widget.LinearLayout.onMeasure (linearlayout.java:588)
06-21 07:48:17.486:e/androidruntime (16659): at Android.view.View.measure (view.java:15518)
06-21 07:48:17.486:e/androidruntime (16659): at Android.view.ViewGroup.measureChildWithMargins (viewgroup.java:4825 )
06-21 07:48:17.486:e/androidruntime (16659): at Android.widget.FrameLayout.onMeasure (framelayout.java:310)
06-21 07:48:17.486:e/androidruntime (16659): at Android.view.View.measure (view.java:15518)
06-21 07:48:17.486:e/androidruntime (16659): at Android.support.v4.view.ViewPager.onMeasure (viewpager.java:1389)
06-21 07:48:17.486:e/androidruntime (16659): at Android.view.View.measure (view.java:15518)
06-21 07:48:17.486:e/androidruntime (16659): at Android.view.ViewGroup.measureChildWithMargins (viewgroup.java:4825 )
06-21 07:48:17.486:e/androidruntime (16659): at Android.widget.FrameLayout.onMeasure (framelayout.java:310)
06-21 07:48:17.486:e/androidruntime (16659): at Android.view.View.measure (view.java:15518)
06-21 07:48:17.486:e/androidruntime (16659): at Android.widget.LinearLayout.measureVertical (linearlayout.java:847)
06-21 07:48:17.486:e/androidruntime (16659): at Android.widget.LinearLayout.onMeasure (linearlayout.java:588)
06-21 07:48:17.486:e/androidruntime (16659): at Android.view.View.measure (view.java:15518)
06-21 07:48:17.486:e/androidruntime (16659): at Android.view.ViewGroup.measureChildWithMargins (viewgroup.java:4825 )
06-21 07:48:17.486:e/androidruntime (16659): at Android.widget.FrameLayout.onMeasure (framelayout.java:310)
06-21 07:48:17.486:e/androidruntime (16659): at Com.android.internal.policy.impl.phonewindow$decorview.onmeasure (P honewindow.java:2176)
06-21 07:48:17.486:e/androidruntime (16659): at Android.view.View.measure (view.java:15518)
06-21 07:48:17.486:e/androidruntime (16659): at Android.view.ViewRootImpl.performMeasure (viewrootimpl.java:1874)
06-21 07:48:17.486:e/androidruntime (16659): at Android.view.ViewRootImpl.measureHierarchy (viewrootimpl.java:1089)
06-21 07:48:17.486:e/androidruntime (16659): at Android.view.ViewRootImpl.performTraversals (viewrootimpl.java:1265 )
06-21 07:48:17.486:e/androidruntime (16659): at Android.view.ViewRootImpl.doTraversal (viewrootimpl.java:989)
06-21 07:48:17.486:e/androidruntime (16659): At Android.view.viewrootimpl$traversalrunnable.run (ViewRootImpl.java: 4351)
06-21 07:48:17.486:e/androidruntime (16659): at Android.view.choreographer$callbackrecord.run (Choreographer.java:7 49)
06-21 07:48:17.486:e/androidruntime (16659): at Android.view.Choreographer.doCallbacks (choreographer.java:562)
06-21 07:48:17.486:e/androidruntime (16659): at Android.view.Choreographer.doFrame (choreographer.java:532)
06-21 07:48:17.486:e/androidruntime (16659): at Android.view.choreographer$framedisplayeventreceiver.run (Choreogra pher.java:735)
06-21 07:48:17.486:e/androidruntime (16659): at Android.os.Handler.handleCallback (handler.java:725)
06-21 07:48:17.486:e/androidruntime (16659): at Android.os.Handler.dispatchMessage (handler.java:92)
06-21 07:48:17.486:e/androidruntime (16659): at Android.os.Looper.loop (looper.java:137)
06-21 07:48:17.486:e/androidruntime (16659): at Android.app.ActivityThread.main (activitythread.java:5041)
06-21 07:48:17.486:e/androidruntime (16659): at Java.lang.reflect.Method.invokeNative (Native Method)
06-21 07:48:17.486:e/androidruntime (16659): at Java.lang.reflect.Method.invoke (method.java:511)
06-21 07:48:17.486:e/androidruntime (16659): at Com.android.internal.os.zygoteinit$methodandargscaller.run (ZygoteI nit.java:793)
06-21 07:48:17.486:e/androidruntime (16659): at Com.android.internal.os.ZygoteInit.main (zygoteinit.java:560)
06-21 07:48:17.486:e/androidruntime (16659): at Dalvik.system.NativeStart.main (Native Method)
06-21 07:48:21.626:e/inputdispatcher (296): Channel ' 41055180 com.ccniit.zhh.main/com.ccniit.zhh.main.mainactivity ( Server) ' ~ Channel is unrecoverably broken and'll be disposed!
==================== Solution 1====================
The problem isn't at the level of code you posted.
We need to track and debug.
Read the value of the database displayed on the ListView
