Failed to resume work.

Question

Failed to resume work.

I am new and trying to update ListView after updating my SQLite database. I do not get a compilation error after I revised my onResume() method. I use SimpleCursorAdapter to query, but it does not work. The error received was from logcat and below. Please advise ... examples will help best.

Logcat:

  02-19 21:31:49.933: E/AndroidRuntime(714): java.lang.RuntimeException: Unable to resume activity {com.loginplus.home/com.loginplus.home.LoginList}: java.lang.NullPointerException 02-19 21:31:49.933: E/AndroidRuntime(714): at android.app.ActivityThread.performResumeActivity(ActivityThread.java:2444) 02-19 21:31:49.933: E/AndroidRuntime(714): at android.app.ActivityThread.handleResumeActivity(ActivityThread.java:2472) 02-19 21:31:49.933: E/AndroidRuntime(714): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1986) 02-19 21:31:49.933: E/AndroidRuntime(714): at android.app.ActivityThread.access$600(ActivityThread.java:123) 02-19 21:31:49.933: E/AndroidRuntime(714): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1147) 02-19 21:31:49.933: E/AndroidRuntime(714): at android.os.Handler.dispatchMessage(Handler.java:99) 02-19 21:31:49.933: E/AndroidRuntime(714): at android.os.Looper.loop(Looper.java:137) 02-19 21:31:49.933: E/AndroidRuntime(714): at android.app.ActivityThread.main(ActivityThread.java:4424) 02-19 21:31:49.933: E/AndroidRuntime(714): at java.lang.reflect.Method.invokeNative(Native Method) 02-19 21:31:49.933: E/AndroidRuntime(714): at java.lang.reflect.Method.invoke(Method.java:511) 02-19 21:31:49.933: E/AndroidRuntime(714): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784) 02-19 21:31:49.933: E/AndroidRuntime(714): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551) 02-19 21:31:49.933: E/AndroidRuntime(714): at dalvik.system.NativeStart.main(Native Method) 02-19 21:31:49.933: E/AndroidRuntime(714): Caused by: java.lang.NullPointerException 02-19 21:31:49.933: E/AndroidRuntime(714): at com.loginplus.home.LoginList.onResume(LoginList.java:101) 02-19 21:31:49.933: E/AndroidRuntime(714): at android.app.Instrumentation.callActivityOnResume(Instrumentation.java:1154) 02-19 21:31:49.933: E/AndroidRuntime(714): at android.app.Activity.performResume(Activity.java:4539) 02-19 21:31:49.933: E/AndroidRuntime(714): at android.app.ActivityThread.performResumeActivity(ActivityThread.java:2434)

Activity:

  public class LoginList extends Activity implements OnClickListener, OnItemClickListener { private ListView loginList; private Button webLogin; private ListAdapter loginListAdapter; private ArrayList<LoginDetails> loginArrayList; List<String> arrayList = new ArrayList<String>(); @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); arrayList = populateList(); loginListAdapter = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, populateList()); setContentView(R.layout.login_listview); loginList = (ListView) findViewById(R.id.loginlist); loginList.setOnItemClickListener(this); webLogin = (Button) findViewById(R.id.button3); webLogin.setOnClickListener(this); } @Override public void onClick (View v) { Intent webLoginIntent = new Intent (this, LoginPlusActivity.class); startActivity(webLoginIntent); } public List<String> populateList (){ List<String> webNameList = new ArrayList<String>(); dataStore openHelperClass = new dataStore (this); SQLiteDatabase sqliteDatabase = openHelperClass.getReadableDatabase(); Cursor cursor = sqliteDatabase.query(dataStore.TABLE_NAME_INFOTABLE, null, null, null, null, null, dataStore.COLUMN_NAME_SITE, null); startManagingCursor(cursor); while (cursor.moveToNext()){ String sName = cursor.getString(cursor.getColumnIndex(dataStore.COLUMN_NAME_SITE)); String wUrl = cursor.getString(cursor.getColumnIndex(dataStore.COLUMN_NAME_ADDRESS)); String uName = cursor.getString(cursor.getColumnIndex(dataStore.COLUMN_NAME_USERNAME)); String pWord = cursor.getString(cursor.getColumnIndex(dataStore.COLUMN_NAME_PASSWORD)); String lNotes = cursor.getString(cursor.getColumnIndex(dataStore.COLUMN_NAME_NOTES)); LoginDetails lpDetails = new LoginDetails(); lpDetails.setsName(sName); lpDetails.setwUrl(wUrl); lpDetails.setuName(uName); lpDetails.setpWord(pWord); lpDetails.setlNotes(lNotes); loginArrayList.add(lpDetails); webNameList.add(sName); } sqliteDatabase.close(); return webNameList; } @Override protected void onResume() { super.onResume(); loginArrayList.clear(); arrayList.clear(); arrayList = populateList(); dataStore refreshHelper = new dataStore (this); SQLiteDatabase sqliteDatabase = refreshHelper.getWritableDatabase(); Cursor cursor = sqliteDatabase.query(dataStore.TABLE_NAME_INFOTABLE, null, null, null, null, null, dataStore.COLUMN_NAME_SITE, null); String[]columns = new String[] { dataStore.COLUMN_NAME_SITE, dataStore.COLUMN_NAME_ADDRESS, dataStore.COLUMN_NAME_USERNAME, dataStore.COLUMN_NAME_PASSWORD, dataStore.COLUMN_NAME_NOTES }; int[] to = new int[]{R.id.rusName, R.id.ruwUrl, R.id.ruuName, R.id.rupWord, R.id.ruNotes}; SimpleCursorAdapter loginListAdapter = new SimpleCursorAdapter(this, android.R.layout.simple_list_item_1, cursor, columns, to); loginListAdapter.notifyDataSetChanged(); } @Override public void onItemClick(AdapterView<?> arg0 , View arg1, int arg2, long arg3) { Toast.makeText(getApplicationContext(), "Selected ID :" + arg2, Toast.LENGTH_SHORT).show(); Intent updateDeleteLoginInfo = new Intent (this, UpdateDeleteLoginList.class); LoginDetails clickedObject = loginArrayList.get(arg2); Bundle loginBundle = new Bundle(); loginBundle.putString("clickedWebSite",clickedObject.getsName()); loginBundle.putString("clickedWebAddress",clickedObject.getwUrl()); loginBundle.putString("clickedUserName",clickedObject.getuName()); loginBundle.putString("clickedPassWord",clickedObject.getpWord()); loginBundle.putString("clickedNotes",clickedObject.getlNotes()); updateDeleteLoginInfo.putExtras(loginBundle); startActivityForResult(updateDeleteLoginInfo, 0); } }

RennoDiniro EditResults:

Logcat:

  02-21 23:40:18.419: E/AndroidRuntime(705): FATAL EXCEPTION: main 02-21 23:40:18.419: E/AndroidRuntime(705): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.loginplus.home/com.loginplus.home.LoginList}: java.lang.NullPointerException 02-21 23:40:18.419: E/AndroidRuntime(705): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1956) 02-21 23:40:18.419: E/AndroidRuntime(705): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1981) 02-21 23:40:18.419: E/AndroidRuntime(705): at android.app.ActivityThread.access$600(ActivityThread.java:123) 02-21 23:40:18.419: E/AndroidRuntime(705): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1147) 02-21 23:40:18.419: E/AndroidRuntime(705): at android.os.Handler.dispatchMessage(Handler.java:99) 02-21 23:40:18.419: E/AndroidRuntime(705): at android.os.Looper.loop(Looper.java:137) 02-21 23:40:18.419: E/AndroidRuntime(705): at android.app.ActivityThread.main(ActivityThread.java:4424) 02-21 23:40:18.419: E/AndroidRuntime(705): at java.lang.reflect.Method.invokeNative(Native Method) 02-21 23:40:18.419: E/AndroidRuntime(705): at java.lang.reflect.Method.invoke(Method.java:511) 02-21 23:40:18.419: E/AndroidRuntime(705): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784) 02-21 23:40:18.419: E/AndroidRuntime(705): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551) 02-21 23:40:18.419: E/AndroidRuntime(705): at dalvik.system.NativeStart.main(Native Method) 02-21 23:40:18.419: E/AndroidRuntime(705): Caused by: java.lang.NullPointerException 02-21 23:40:18.419: E/AndroidRuntime(705): at com.loginplus.home.LoginList.populateList(LoginList.java:88) 02-21 23:40:18.419: E/AndroidRuntime(705): at com.loginplus.home.LoginList.onCreate(LoginList.java:37) 02-21 23:40:18.419: E/AndroidRuntime(705): at android.app.Activity.performCreate(Activity.java:4465) 02-21 23:40:18.419: E/AndroidRuntime(705): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1049) 02-21 23:40:18.419: E/AndroidRuntime(705): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1920)

Action class:

  public class LoginList extends Activity implements OnClickListener, OnItemClickListener { private ListView loginList; private Button webLogin; private ListAdapter loginListAdapter; private ArrayList<LoginDetails> loginArrayList; List<String> arrayList = new ArrayList<String>(); @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); loginListAdapter = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, populateList()); arrayList = populateList(); setContentView(R.layout.login_listview); loginList = (ListView) findViewById(R.id.loginlist); loginList.setOnItemClickListener(this); webLogin = (Button) findViewById(R.id.button3); webLogin.setOnClickListener(this); } @Override public void onClick (View v) { Intent webLoginIntent = new Intent (this, LoginPlusActivity.class); startActivity(webLoginIntent); } public List<String> populateList (){ List<String> webNameList = new ArrayList<String>(); dataStore openHelperClass = new dataStore (this); SQLiteDatabase sqliteDatabase = openHelperClass.getReadableDatabase(); Cursor cursor = sqliteDatabase.query(dataStore.TABLE_NAME_INFOTABLE, null, null, null, null, null, dataStore.COLUMN_NAME_SITE, null); startManagingCursor(cursor); while (cursor.moveToNext()){ String sName = cursor.getString(cursor.getColumnIndex(dataStore.COLUMN_NAME_SITE)); String wUrl = cursor.getString(cursor.getColumnIndex(dataStore.COLUMN_NAME_ADDRESS)); String uName = cursor.getString(cursor.getColumnIndex(dataStore.COLUMN_NAME_USERNAME)); String pWord = cursor.getString(cursor.getColumnIndex(dataStore.COLUMN_NAME_PASSWORD)); String lNotes = cursor.getString(cursor.getColumnIndex(dataStore.COLUMN_NAME_NOTES)); LoginDetails lpDetails = new LoginDetails(); lpDetails.setsName(sName); lpDetails.setwUrl(wUrl); lpDetails.setuName(uName); lpDetails.setpWord(pWord); lpDetails.setlNotes(lNotes); loginArrayList.add(lpDetails); webNameList.add(sName); } sqliteDatabase.close(); return webNameList; } @Override protected void onResume() { super.onResume(); try{ loginArrayList = new ArrayList<LoginDetails>(); arrayList = new ArrayList<String>(); loginArrayList.clear(); arrayList.clear(); arrayList = populateList(); dataStore refreshHelper = new dataStore (this); SQLiteDatabase sqliteDatabase = refreshHelper.getWritableDatabase(); Cursor cursor = sqliteDatabase.query(dataStore.TABLE_NAME_INFOTABLE, null, null, null, null, null, dataStore.COLUMN_NAME_SITE, null); String[]columns = new String[] { dataStore.COLUMN_NAME_SITE, dataStore.COLUMN_NAME_ADDRESS, dataStore.COLUMN_NAME_USERNAME, dataStore.COLUMN_NAME_PASSWORD, dataStore.COLUMN_NAME_NOTES }; int[] to = new int[]{R.id.rusName, R.id.ruwUrl, R.id.ruuName, R.id.rupWord, R.id.ruNotes}; SimpleCursorAdapter loginListAdapter = new SimpleCursorAdapter(this, android.R.layout.simple_list_item_1, cursor, columns, to); loginListAdapter.notifyDataSetChanged(); }catch(Exception e) { e.printStackTrace(); } } @Override public void onItemClick(AdapterView<?> arg0 , View arg1, int arg2, long arg3) { Toast.makeText(getApplicationContext(), "Selected ID :" + arg2, Toast.LENGTH_SHORT).show(); Intent updateDeleteLoginInfo = new Intent (this, UpdateDeleteLoginList.class); LoginDetails clickedObject = loginArrayList.get(arg2); Bundle loginBundle = new Bundle(); loginBundle.putString("clickedWebSite",clickedObject.getsName()); loginBundle.putString("clickedWebAddress",clickedObject.getwUrl()); loginBundle.putString("clickedUserName",clickedObject.getuName()); loginBundle.putString("clickedPassWord",clickedObject.getpWord()); loginBundle.putString("clickedNotes",clickedObject.getlNotes()); updateDeleteLoginInfo.putExtras(loginBundle); startActivityForResult(updateDeleteLoginInfo, 0); } }

+7

android nullpointerexception android-listview simplecursoradapter onresume

user1165694 Feb 12 '13 at 18:56

source share

7 answers

Vikalp Patel · Answer 1 · 2013-02-15T20:33:32+0000

Create an adapter using a cursor that points to the desired data, as well as layout information.

 SimpleCursorAdapter mAdapter = new SimpleCursorAdapter(this, android.R.layout.simple_list_item_1, cursor, columns, to);

In your case, when you use R.layout.simple_list_item_1

columns will be null or Particular column data which you get from cursor

to will be android.R.id.text1

For example,

  Cursor cursor = getContentResolver().query(People.CONTENT_URI, new String[]{People._ID, People.NAME, People.NUMBER}, null, null, null); startManagingCursor(cursor); // THE DESIRED COLUMNS TO BE BOUND String[] columns = new String[] { People.NAME, People.NUMBER }; // THE XML DEFINED VIEWS WHICH THE DATA WILL BE BOUND TO int[] to = new int[] { R.id.name_entry, R.id.number_entry }; SimpleCursorAdapter mAdapter = new SimpleCursorAdapter(this,R.layout.list_example_entry, cursor, columns, to);

stoilkov · Answer 2 · 2013-02-22T08:54:52+0000

Obviously, you are not initializing the ArrayList. But .. for your case, consider using Loader . ApiDemos has complete examples (listed at the bottom of Loader ).

rennoDeniro · Answer 3 · 2013-02-22T00:55:23+0000

Note You never create an instance of loginArrayList , so when you try to access it in your onResume() , it is zero, so it fails. Ignore this before accessing it.

UPDATE 02/22/2013:

Ahh, you forgot to instantiate loginArrayList when the application starts up first.

In onCreate() place the following code immediately after super.OnCreate(...)

 loginArrayList = new ArrayList<LoginDetails>();

It looks like this:

 loginArrayList = new ArrayList<LoginDetails>(); loginListAdapter = new ArrayAdapter<String>(this,android.R.layout.simple_list_item_1,populateList()); arrayList = populateList(); setContentView(R.layout.login_listview); //rest of your code...

A quick setup for your application to work is as follows, but note that fixing this whole problem will require a deeper analysis of what information is lost during pause and resume.

Inside onResume() do

 try{ // your code }catch(Exception e) { //Have the printStackTrace to the problems see what going on without crashing. //e.printStackTrace(); }

But this still does not fix the problem,

In onResume() . Follow these steps:

When you first get the data, store it in the database.
In onResume (), recreate the list and update it with the data stored in the database.

So, to get started

 @Override protected void onResume() { super.onResume(); loginArrayList = new ArrayList<LoginDetails>(); arrayList = new ArrayList<String>(); arrayList = populateList(); // any other code you require to be done after the list is populated. }

Good luck.

hwrdprkns · Answer 4 · 2013-02-12T19:00:38+0000

The cursor seems to be null, a quick way to fix this and get your application to work:

 SimpleCursorAdapter mAdapter = new SimpleCursorAdapter(this, android.R.layout.simple_list_item_1, cursor,null,null); mAdapter.notifyDataSetChanged();

to

 if (cursor != null) { SimpleCursorAdapter mAdapter = new SimpleCursorAdapter(this, android.R.layout.simple_list_item_1, cursor,null,null); mAdapter.notifyDataSetChanged(); }

Otherwise, it seems that your cursor may be null, and you may request the wrong projection.

Delyan · Answer 5 · 2013-02-15T20:15:53+0000

You need to provide a mapping from column names to resource identifiers in the SimpleCursorAdapter constructor — the from and to parameters for which you pass zero.

Sagi antebi · Answer 6 · 2013-02-16T19:52:49+0000

The problem is a guided course -

 startManagingCursor(cursor);

Try saving the cursor yourself, instead of using an activity-driven cursor that is out of date.

I am heading the same issue 2 days ago with onResume calls after cursor control.

Phil · Answer 7 · 2013-02-20T19:07:42+0000

You never initialize loginArrayList (and therefore it is null ).

Failed to resume work.

More articles: