我对qndroid很新，所以如果这个问题看起来很简单，请原谅我。
我正在尝试使用来自我正在从数据助手类创建的SQLite表中的信息来加载微调器。
该项目似乎加载了o.k.但是，SQLite tabe中没有任何信息加载到微调器中？下面是代码。我感谢所提供的所有帮助。
Notepadv1 CLASS
/*
* Copyright (C) 2008 Google Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.android.demo.notepad1;
import android.app.ListActivity;
import android.database.Cursor;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.ArrayAdapter;
import android.widget.SimpleCursorAdapter;
import android.widget.Spinner;
import android.widget.TextView;
public class Notepadv1 extends ListActivity {
public static final int INSERT_ID = Menu.FIRST;
private int mNoteNumber = 1;
private NotesDbAdapter mDbHelper;
private TextView output;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
try{
setContentView(R.layout.main);
}
catch (Exception e)
{
e.getMessage();
}
mDbHelper = new NotesDbAdapter(this);
mDbHelper.open();
//createNote();
output = (TextView) this.findViewById(R.id.out_text);
output.setText("hello this is finally working");
Spinner spinner = (Spinner) findViewById(R.id.widget38);
Cursor c = mDbHelper.fetchAllNotes();
int firstnameColumnIndex = c.getColumnIndexOrThrow
("building");
ArrayAdapter<CharSequence> adapter = new ArrayAdapter<CharSequence>(
this, android.R.layout.simple_spinner_item);
adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
spinner.setAdapter(adapter);
//spinner.setOnItemSelectedListener(new MyOnItemSelectedListener(this,adapter));
if (c.moveToFirst()) {
do {
adapter.add(c.getString(firstnameColumnIndex)) ;
}
while (c.moveToNext());
if (mDbHelper != null) {
mDbHelper.close();
}
}
//fillData();
}
//@Override
//public boolean onCreateOptionsMenu(Menu menu) {
// boolean result = super.onCreateOptionsMenu(menu);
// menu.add(0, INSERT_ID, 0, R.string.menu_insert);
// return result;
// }
// @Override
// public boolean onOptionsItemSelected(MenuItem item) {
// switch (item.getItemId()) {
// case INSERT_ID:
// createNote();
// return true;
// }
// return super.onOptionsItemSelected(item);
//}
private void createNote() {
String noteName = "Note " + mNoteNumber++;
mDbHelper.fetchNote();
//fillData();
}
private void fillData() {
// Get all of the notes from the database and create the item list
Cursor c = mDbHelper.fetchAllNotes();
startManagingCursor(c);
String[] from = new String[] { NotesDbAdapter.KEY_TITLE };
int[] to = new int[] { R.id.text1 };
// Now create an array adapter and set it to display using our row
SimpleCursorAdapter notes =
new SimpleCursorAdapter(this, R.layout.notes_row, c, from, to);
setListAdapter(notes);
}
}
NotesDbAdapter CLASS
/*
* Copyright (C) 2008 Google Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License"); you may not
* use this file except in compliance with the License. You may obtain a copy of
* the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations under
* the License.
*/
package com.android.demo.notepad1;
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.SQLiteOpenHelper;
import android.util.Log;
/**
* Simple notes database access helper class. Defines the basic CRUD operations
* for the notepad example, and gives the ability to list all notes as well as
* retrieve or modify a specific note.
*
* This has been improved from the first version of this tutorial through the
* addition of better error handling and also using returning a Cursor instead
* of using a collection of inner classes (which is less scalable and not
* recommended).
*/
public class NotesDbAdapter {
public static final String KEY_TITLE = "building";
public static final String KEY_BODY = "body";
public static final String KEY_ROWID = "_id";
private static final String TAG = "NotesDbAdapter";
private DatabaseHelper mDbHelper;
private SQLiteDatabase mDb;
/**
* Database creation sql statement
*/
private static final String DATABASE_CREATE =
"create table campus (_id integer primary key autoincrement, building varchar(20), lat double, lon double);";
private static final String DATABASE_NAME = "example";
private static final String DATABASE_TABLE = "campus";
private static final int DATABASE_VERSION = 2;
private final Context mCtx;
private static class DatabaseHelper extends SQLiteOpenHelper {
DatabaseHelper(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
@Override
public void onCreate(SQLiteDatabase db) {
db.execSQL(DATABASE_CREATE);
db.execSQL( "insert into campus values('Calcutta House',51.515838,-0.07361); "
+ "insert into campus values('Central House',51.514113,-0.074981); "
+ "insert into campus values('Commercial Road',51.514948,-0.068468); "
+ "insert into campus values('Goulston Street',51.516627,-0.075244); "
+ "insert into campus values('Jewry Steet',51.51294,-0.076612); "
+ "insert into campus values('Students Union',51.51533,-0.074096); "
+ "insert into campus values('Whitechapel High Street',51.514756,-0.073262); "
+ "insert into campus values('The Womens Library',51.515838,-0.07361);");
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
Log.w(TAG, "Upgrading database from version " + oldVersion + " to "
+ newVersion + ", which will destroy all old data");
db.execSQL("DROP TABLE IF EXISTS notes");
onCreate(db);
}
}
/**
* Constructor - takes the context to allow the database to be
* opened/created
*
* @param ctx the Context within which to work
*/
public NotesDbAdapter(Context ctx) {
this.mCtx = ctx;
}
/**
* Open the notes database. If it cannot be opened, try to create a new
* instance of the database. If it cannot be created, throw an exception to
* signal the failure
*
* @return this (self reference, allowing this to be chained in an
* initialization call)
* @throws SQLException if the database could be neither opened or created
*/
public NotesDbAdapter open() throws SQLException {
mDbHelper = new DatabaseHelper(mCtx);
mDb = mDbHelper.getWritableDatabase();
return this;
}
public void close() {
mDbHelper.close();
}
/**
* Create a new note using the title and body provided. If the note is
* successfully created return the new rowId for that note, otherwise return
* a -1 to indicate failure.
*
* @param title the title of the note
* @param body the body of the note
* @return rowId or -1 if failed
*/
public long createNote(String title, String body) {
ContentValues initialValues = new ContentValues();
initialValues.put(KEY_TITLE, title);
initialValues.put(KEY_BODY, body);
return mDb.insert(DATABASE_TABLE, null, initialValues);
}
/**
* Delete the note with the given rowId
*
* @param rowId id of note to delete
* @return true if deleted, false otherwise
*/
public boolean deleteNote(long rowId) {
return mDb.delete(DATABASE_TABLE, KEY_ROWID + "=" + rowId, null) > 0;
}
/**
* Return a Cursor over the list of all notes in the database
*
* @return Cursor over all notes
*/
public Cursor fetchAllNotes() {
return mDb.query(DATABASE_TABLE, new String[] {"building", "lon",
"lat"}, null, null, null, null, null);
}
/**
* Return a Cursor positioned at the note that matches the given rowId
*
* @param rowId id of note to retrieve
* @return Cursor positioned to matching note, if found
* @throws SQLException if note could not be found/retrieved
*/
public Cursor fetchNote() throws SQLException {
Cursor mCursor =
mDb.query(true, DATABASE_TABLE, new String[] {"building",
"lon", "lat"}, "building = 'Commercial Road'", null,
null, null, null, null);
if (mCursor != null) {
mCursor.moveToFirst();
}
return mCursor;
}
/**
* Update the note using the details provided. The note to be updated is
* specified using the rowId, and it is altered to use the title and body
* values passed in
*
* @param rowId id of note to update
* @param title value to set note title to
* @param body value to set note body to
* @return true if the note was successfully updated, false otherwise
*/
public boolean updateNote(long rowId, String title, String body) {
ContentValues args = new ContentValues();
args.put(KEY_TITLE, title);
args.put(KEY_BODY, body);
return mDb.update(DATABASE_TABLE, args, KEY_ROWID + "=" + rowId, null) > 0;
}
}
主xml文件
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android=
"http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent">
<TextView android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text=" " />
<TextView android:id="@+id/out_text"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/no_notes"/>
<Spinner
android:id="@+id/widget38"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
>
</Spinner>
</LinearLayout>
谢谢，
答案 0 :(得分：1)
试试这段代码。
它对我有用。
AdapterCountries = new ArrayAdapter<CharSequence>(this,
android.R.layout.simple_spinner_item);
AdapterCountries
.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
spin.setAdapter(AdapterCountries);
spin.setOnItemSelectedListener(new MyOnItemSelectedListener());
allElementDetails.clear();
db1.open();
// long id;
Cursor cursor = db1.getAllTitles1();
while (cursor.moveToNext())
{
results=cursor.getString(2);
AdapterCountries.add(results);
}
db1.close();
在我的适配器类
中public Cursor getAllTitles1()
{
return db.query(DATABASE_TABLE1, new String[] {
KEY_ROWID,
DISHNAME,
CATEGORY,
DESCRIPTION,
IMAGE},
null,
null,
null,
null,
null);
}