我试图在数组列表中显示我的 sqlite 数据库的数据，但代码有问题，我找不到它。这是我的应用程序的代码：
public class Event extends Fragment implements OnClickListener {
Intent intent;
TextView eventId;
EventController controller = new EventController(getActivity());
Button show;
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.event, container, false);
ArrayList<HashMap<String, String>> eventList = controller
.getAllEvents();
if (eventList.size() != 0) {
ListView lv = (ListView) rootView.findViewById(R.id.list);
lv.setOnItemClickListener(new OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
eventId = (TextView) view.findViewById(R.id.eventId);
String valEventId = eventId.getText().toString();
Intent objIndent = new Intent(getActivity(),
EditEvent.class);
objIndent.putExtra("eventId", valEventId);
startActivity(objIndent);
}
});
ListAdapter adapter = new SimpleAdapter(getActivity(), eventList,
R.layout.view_event_entry, new String[] { "eventId",
"eventName" }, new int[] { R.id.eventId,
R.id.eventName });
lv.setAdapter(adapter);
}
show = (Button)rootView.findViewById(R.id.button1);
show.setOnClickListener(this);
return rootView;
}
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
Intent objIntent = new Intent(getActivity(), AddEvent.class);
startActivity(objIntent);
}
而 LogCat ，也许问题是空指针异常：
10-27 03:37:20.418: E/AndroidRuntime(29577): FATAL EXCEPTION: main
10-27 03:37:20.418: E/AndroidRuntime(29577): java.lang.NullPointerException
10-27 03:37:20.418: E/AndroidRuntime(29577): at android.database.sqlite.SQLiteOpenHelper.getDatabaseLocked(SQLiteOpenHelper.java:224)
10-27 03:37:20.418: E/AndroidRuntime(29577): at android.database.sqlite.SQLiteOpenHelper.getWritableDatabase(SQLiteOpenHelper.java:164)
10-27 03:37:20.418: E/AndroidRuntime(29577): at com.example.hapshare.EventController.getAllEvents(EventController.java:70)
10-27 03:37:20.418: E/AndroidRuntime(29577): at com.example.hapshare.Event.onCreateView(Event.java:41)
10-27 03:37:20.418: E/AndroidRuntime(29577): at android.support.v4.app.Fragment.performCreateView(Fragment.java:1478)
10-27 03:37:20.418: E/AndroidRuntime(29577): at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:927)
10-27 03:37:20.418: E/AndroidRuntime(29577): at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1104)
10-27 03:37:20.418: E/AndroidRuntime(29577): at android.support.v4.app.BackStackRecord.run(BackStackRecord.java:682)
10-27 03:37:20.418: E/AndroidRuntime(29577): at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1460)
10-27 03:37:20.418: E/AndroidRuntime(29577): at android.support.v4.app.FragmentManagerImpl.executePendingTransactions(FragmentManager.java:472)
10-27 03:37:20.418: E/AndroidRuntime(29577): at android.support.v4.app.FragmentPagerAdapter.finishUpdate(FragmentPagerAdapter.java:141)
这是我的数据库 EventController 的代码：
public class EventController extends SQLiteOpenHelper {
private static final String LOGCAT = null;
public EventController(Context applicationcontext) {
super(applicationcontext, "androidsqlite.db", null, 1);
Log.d(LOGCAT,"Created");
}
@Override
//create table for the database
public void onCreate(SQLiteDatabase database) {
String query;
query = "CREATE TABLE events ( eventId INTEGER PRIMARY KEY, eventName TEXT)";
database.execSQL(query);
Log.d(LOGCAT,"events Created");
}
@Override
//drop the database and reset if required
public void onUpgrade(SQLiteDatabase database, int version_old, int current_version) {
String query;
query = "DROP TABLE IF EXISTS events";
database.execSQL(query);
onCreate(database);
}
public void insertEvent(HashMap<String, String> queryValues) {
SQLiteDatabase database = this.getWritableDatabase();
ContentValues values = new ContentValues();
values.put("eventName", queryValues.get("eventName"));
database.insert("events", null, values);
database.close();
}
public int updateEvent(HashMap<String, String> queryValues) {
SQLiteDatabase database = this.getWritableDatabase();
ContentValues values = new ContentValues();
values.put("eventName", queryValues.get("eventName"));
return database.update("events", values, "eventId" + " = ?", new String[] { queryValues.get("eventId") });
//String updateQuery = "Update words set txtWord='"+word+"' where txtWord='"+ oldWord +"'";
//Log.d(LOGCAT,updateQuery);
//database.rawQuery(updateQuery, null);
//return database.update("words", values, "txtWord = ?", new String[] { word });
}
public void deleteEvent(String id) {
Log.d(LOGCAT,"delete");
SQLiteDatabase database = this.getWritableDatabase();
String deleteQuery = "DELETE FROM events where eventId='"+ id +"'";
Log.d("query",deleteQuery);
database.execSQL(deleteQuery);
}
public ArrayList<HashMap<String, String>> getAllEvents() {
ArrayList<HashMap<String, String>> wordList;
wordList = new ArrayList<HashMap<String, String>>();
String selectQuery = "SELECT * FROM events";
SQLiteDatabase database = this.getWritableDatabase();
Cursor cursor = database.rawQuery(selectQuery, null);
if (cursor.moveToFirst()) {
do {
HashMap<String, String> map = new HashMap<String, String>();
map.put("eventId", cursor.getString(0));
map.put("eventName", cursor.getString(1));
wordList.add(map);
} while (cursor.moveToNext());
}
// return contact list
return wordList;
}
public HashMap<String, String> getEventInfo(String id) {
HashMap<String, String> wordList = new HashMap<String, String>();
SQLiteDatabase database = this.getReadableDatabase();
String selectQuery = "SELECT * FROM events where eventId='"+id+"'";
Cursor cursor = database.rawQuery(selectQuery, null);
if (cursor.moveToFirst()) {
do {
//HashMap<String, String> map = new HashMap<String, String>();
wordList.put("eventName", cursor.getString(1));
//wordList.add(map);
} while (cursor.moveToNext());
}
return wordList;
}
有没有人知道我做错了什么？谢谢