I am pretty new in android application development and I am trying to get on of the rows from a SQLite db to show up as a Listactivity, but this is not working and the program terminates unexpectedly. Here is the code:
package ankur.test.app;
import android.app.ListActivity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.ArrayAdapter;
import android.widget.ListView;
public class testMenu extends ListActivity{
HotOrNot Infor = new HotOrNot(this);
{
Infor.open();
}
String[] result = Infor.getList();
{
Infor.close();
}
@Override
protected void onCreate(Bundle ankurtestlist) {
// TODO Auto-generated method stub
super.onCreate(ankurtestlist);
setListAdapter(new ArrayAdapter<String>(testMenu.this, android.R.layout.simple_list_item_2, result));
}
@Override
protected void onListItemClick(ListView l, View v, int position, long id) {
// TODO Auto-generated method stub
super.onListItemClick(l, v, position, id);
Object cheese = result[position];
/* try{
Class ourClass = Class.forName("ankur.test.app."+ cheese);
Intent ourIntent = new Intent(testMenu.this, ourClass);
startActivity(ourIntent);
}catch(ClassNotFoundException e){
e.printStackTrace();
}*/
}
}and this is the method in another class:
public String[] getList() {
// TODO Auto-generated method stub
String[] columns = new String[]{ KEY_ROWID, KEY_NAME, KEY_HOTNESS};
Cursor c = ourDatabase.query(DATABASE_TABLE, columns, null, null, null, null, null);
ArrayList name = new ArrayList();
int i = 0;
int iName = c.getColumnIndex(KEY_NAME);
for (c.moveToFirst(); !c.isAfterLast(); c.moveToNext()){
name.add(c.getString(iName));
i++;
}
String[] result = (String[]) name.toArray();
return result;
}Here are the logcat results:
02-06 14:53:10.383: D/AndroidRuntime(3963): Shutting down VM
02-06 14:53:10.383: W/dalvikvm(3963): threadid=1: thread exiting with uncaught exception (group=0x4001d800)
02-06 14:53:10.403: E/AndroidRuntime(3963): FATAL EXCEPTION: main
02-06 14:53:10.403: E/AndroidRuntime(3963): java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{ankur.test.app/ankur.test.app.testMenu}: java.lang.NullPointerException
02-06 14:53:10.403: E/AndroidRuntime(3963): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2585)
02-06 14:53:10.403: E/AndroidRuntime(3963): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2679)
02-06 14:53:10.403: E/AndroidRuntime(3963): at android.app.ActivityThread.access$2300(ActivityThread.java:125)
02-06 14:53:10.403: E/AndroidRuntime(3963): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2033)
02-06 14:53:10.403: E/AndroidRuntime(3963): at android.os.Handler.dispatchMessage(Handler.java:99)
02-06 14:53:10.403: E/AndroidRuntime(3963): at android.os.Looper.loop(Looper.java:123)
02-06 14:53:10.403: E/AndroidRuntime(3963): at android.app.ActivityThread.main(ActivityThread.java:4627)
02-06 14:53:10.403: E/AndroidRuntime(3963): at java.lang.reflect.Method.invokeNative(Native Method)
02-06 14:53:10.403: E/AndroidRuntime(3963): at java.lang.reflect.Method.invoke(Method.java:521)
02-06 14:53:10.403: E/AndroidRuntime(3963): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
02-06 14:53:10.403: E/AndroidRuntime(3963): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
02-06 14:53:10.403: E/AndroidRuntime(3963): at dalvik.system.NativeStart.main(Native Method)
02-06 14:53:10.403: E/AndroidRuntime(3963): Caused by: java.lang.NullPointerException
02-06 14:53:10.403: E/AndroidRuntime(3963): at android.content.ContextWrapper.openOrCreateDatabase(ContextWrapper.java:203)
02-06 14:53:10.403: E/AndroidRuntime(3963): at android.database.sqlite.SQLiteOpenHelper.getWritableDatabase(SQLiteOpenHelper.java:98)
02-06 14:53:10.403: E/AndroidRuntime(3963): at ankur.test.app.HotOrNot.open(HotOrNot.java:62)
02-06 14:53:10.403: E/AndroidRuntime(3963): at ankur.test.app.testMenu.<init>(testMenu.java:14)
02-06 14:53:10.403: E/AndroidRuntime(3963): at java.lang.Class.newInstanceImpl(Native Method)
02-06 14:53:10.403: E/AndroidRuntime(3963): at java.lang.Class.newInstance(Class.java:1429)
02-06 14:53:10.403: E/AndroidRuntime(3963): at android.app.Instrumentation.newActivity(Instrumentation.java:1021)
02-06 14:53:10.403: E/AndroidRuntime(3963): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2577)
02-06 14:53:10.403: E/AndroidRuntime(3963): ... 11 moreHere is the HotOrNot class:
package ankur.test.app;
import java.util.ArrayList;
import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.SQLException;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteDatabase.CursorFactory;
import android.database.sqlite.SQLiteOpenHelper;
public class HotOrNot {
public static final String KEY_ROWID = "_id";
public static final String KEY_NAME = "persons_name";
public static final String KEY_HOTNESS = "persons_hotness";
private static final String DATABASE_NAME = "HotOrNotdb";
private static final String DATABASE_TABLE = "peopleTable";
private static final int DATABASE_VERSION = 1;
private DbHelper ourHelper;
private final Context ourContext;
private SQLiteDatabase ourDatabase;
private static class DbHelper extends SQLiteOpenHelper{
public DbHelper(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
// TODO Auto-generated constructor stub
}
@Override
public void onCreate(SQLiteDatabase db) {
// TODO Auto-generated method stub
db.execSQL("CREATE TABLE " + DATABASE_TABLE + " (" +
KEY_ROWID + " INTEGER PRIMARY KEY AUTOINCREMENT, " +
KEY_NAME + " TEXT NOT NULL, " +
KEY_HOTNESS + " TEXT NOT NULL);"
);
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
// TODO Auto-generated method stub
db.execSQL("DROP TABLE IF EXIST " + DATABASE_TABLE);
onCreate(db);
}
}
public HotOrNot(Context c){
ourContext = c;
}
public HotOrNot open() throws SQLException{
ourHelper = new DbHelper(ourContext);
ourDatabase = ourHelper.getWritableDatabase();
return this;
}
public void close(){
ourHelper.close();
}
public long createEntry(String name, String hotness) {
// TODO Auto-generated method stub
ContentValues cv = new ContentValues();
cv.put(KEY_NAME, name);
cv.put(KEY_HOTNESS, hotness);
return ourDatabase.insert(DATABASE_TABLE, null, cv);
}
public String getData() {
// TODO Auto-generated method stub
String[] columns = new String[]{ KEY_ROWID, KEY_NAME, KEY_HOTNESS};
Cursor c = ourDatabase.query(DATABASE_TABLE, columns, null, null, null, null, null);
String result = "";
int iRow = c.getColumnIndex(KEY_ROWID);
int iName = c.getColumnIndex(KEY_NAME);
int iHotness = c.getColumnIndex(KEY_HOTNESS);
for (c.moveToFirst(); !c.isAfterLast(); c.moveToNext()){
result = result + c.getString(iRow) + " " + c.getString(iName) + " " + c.getString(iHotness) + "\n";
}
return result;
}
public String[] getList() {
// TODO Auto-generated method stub
String[] column = new String[]{KEY_NAME};
Cursor d = ourDatabase.query(DATABASE_TABLE, column, null, null, null, null, null);
ArrayList name = new ArrayList();
int iName = d.getColumnIndex(KEY_NAME);
for (d.moveToFirst(); !d.isAfterLast(); d.moveToNext()){
name.add(d.getString(iName));
}
String[] result = (String[]) name.toArray();
return result;
}
}Any help would be appreciated.
Thanks