非常新的android，刚刚完成了数据库教程并遇到了以下问题。任何人都可以看到任何令人眼花缭乱的问题让我解决这个问题吗？
继承我的三个班级：
第一堂课是主要的活动课：
package com.example.sqlite;
import android.app.ListActivity;
import android.content.Intent;
import android.database.Cursor;
import android.os.Bundle;
import android.view.ContextMenu;
import android.view.ContextMenu.ContextMenuInfo;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.view.View;
import android.widget.SimpleCursorAdapter;
import android.widget.AdapterView.AdapterContextMenuInfo;
public class MainActivity extends ListActivity {
private DBAdapter mDBHelper;
private static final int REQUEST_ADD = 1;
private static final int REQUEST_EDIT = 2;
private Cursor mC;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
mDBHelper = new DBAdapter(this);
mDBHelper = mDBHelper.open();
refreshList();
registerForContextMenu(getListView());
}
// Option menu first
@Override
public boolean onCreateOptionsMenu(Menu menu) {
MenuInflater inflater = getMenuInflater();
inflater.inflate (R.menu.mymenu, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
switch(item.getItemId())
{
case R.id.miAdd:
Intent i = new Intent ();
i.setClass(this, Input.class);
i.putExtra(DBAdapter.COL_ID, 0);
startActivityForResult(i, REQUEST_ADD);
return true;
case R.id.miClear:
mDBHelper.deleteAllBookmark();
refreshList();
return true;
default:
return super.onOptionsItemSelected(item);
}
}
@Override
public boolean onContextItemSelected(MenuItem item) {
AdapterContextMenuInfo info = (AdapterContextMenuInfo) item.getMenuInfo();
int position = info.position;
long id = info.id;
switch(item.getItemId())
{
case R.id.miEdit:
Cursor c = mC;
c.moveToPosition(position);
Intent i = new Intent();
i.setClass(this, Input. class);
i.putExtra(DBAdapter.COL_ID, id);
i.putExtra(DBAdapter.COL_TITLE, c.getString(c.getColumnIndexOrThrow(DBAdapter.COL_TITLE)));
i.putExtra(DBAdapter.COL_URL, c.getString(c.getColumnIndexOrThrow(DBAdapter.COL_URL)));
startActivityForResult(i, REQUEST_EDIT);
return true;
case R.id.miDelete:
mDBHelper.deleteBookmark(id);
refreshList();
return true;
default:
return super.onContextItemSelected(item);
}
}
@Override
public void onCreateContextMenu(ContextMenu menu, View v,
ContextMenuInfo menuInfo) {
super.onCreateContextMenu(menu, v, menuInfo);
MenuInflater inflater = getMenuInflater();
inflater.inflate(R.menu.contextmenu, menu);
}
private void refreshList()
{
mC = mDBHelper.GetAllBookmarks();
startManagingCursor(mC);
SimpleCursorAdapter adapter = new SimpleCursorAdapter(this, R.layout.row,
mC, new String[] {DBAdapter.COL_TITLE,DBAdapter.COL_URL},
new int[] {R.id.txtText1, R.id.txtText2});
setListAdapter(adapter);
}
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
switch(requestCode)
{
case REQUEST_ADD:
String url = data.getStringExtra(DBAdapter.COL_URL);
String title = data.getStringExtra(DBAdapter.COL_TITLE);
mDBHelper.createBookmark(title, url);
refreshList();
break;
case REQUEST_EDIT:
String editUrl = data.getStringExtra(DBAdapter.COL_URL);
String editTitle = data.getStringExtra(DBAdapter.COL_TITLE);
long updateId = data.getLongExtra(DBAdapter.COL_ID, 0);
mDBHelper.updateBookmark(updateId, editTitle, editUrl);
break;
default:
super.onActivityResult(requestCode, resultCode, data);
}
}
}
第二类是数据库适配器类：
package com.example.sqlite;
import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
public class DBAdapter {
private static final String DB_NAME = "Bookmark";
private static final String DB_TABLE = "Bookmark";
private static final int DB_VERSION = 1;
private static final String DB_CREATE =
"CREATE TABLE Bookmark (" +
"_id integer PRIMARY KEY AUTOINCREMENT," +
"Title text," +
"url text);";
private static final String DB_UPGRADE = "DROP TABLE IF EXCISTS Bookmark";
public static final String COL_TITLE = "Title";
public static final String COL_URL = "url";
public static final String COL_ID = "id";
private SQLiteDatabase mDB;
private DBHelper mDBHelper;
private Context mCtx;
private static class DBHelper extends SQLiteOpenHelper
{
public DBHelper (Context context)
{
super (context, DB_NAME, null, DB_VERSION);
}
public void onCreate(SQLiteDatabase db)
{
db.execSQL(DB_CREATE);
}
public void onUpgrade(SQLiteDatabase db, int newVersion, int oldVersion)
{
db.execSQL(DB_UPGRADE);
}
}
public DBAdapter(Context ctx)
{
mCtx = ctx;
}
public DBAdapter open()
{
mDBHelper = new DBHelper(mCtx);
mDB = mDBHelper.getWritableDatabase();
return this;
}
public DBAdapter close()
{
mDBHelper.close();
return this;
}
public long createBookmark(String title, String url)
{
ContentValues v = new ContentValues();
v.put(COL_TITLE, title);
v.put(COL_URL, url);
return mDB.insert(DB_TABLE, null, v);
}
public boolean deleteBookmark(long id)
{
return mDB.delete(DB_TABLE, COL_ID + "=" + id, null)>0;
}
public boolean deleteAllBookmark()
{
return mDB.delete(DB_TABLE,null,null)>0;
}
public Cursor GetAllBookmarks()
{
return mDB.query(DB_TABLE,
new String[] {COL_ID, COL_TITLE, COL_URL},
null, null, null, null, null);
}
public Cursor GetBookmark(long id)
{
Cursor mCursor = mDB.query(true, DB_TABLE,
new String[] {COL_ID, COL_TITLE, COL_URL},
COL_ID + "=" + id,
null, null, null, null, null);
if (mCursor != null)
mCursor.moveToFirst();
return mCursor;
}
public boolean updateBookmark(long id, String title, String url)
{
ContentValues v = new ContentValues();
v.put(COL_TITLE, title);
v.put(COL_URL, url);
return mDB.update(DB_TABLE, v, COL_ID + "=" + id, null)>0;
}
}
第3类是输入类：
package com.example.sqlite;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
public class Input extends Activity {
private EditText txtTitle;
private EditText txtURL;
private Button btnOK;
private long id;
private boolean bUpdateMode = false;
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.input);
txtTitle = (EditText) findViewById(R.id.txtTitle);
txtURL = (EditText) findViewById(R.id.txtURL);
btnOK = (Button) findViewById(R.id.btnOK);
Intent i = this.getIntent();
id = i.getLongExtra(DBAdapter.COL_ID, 0);
if (id == 0)
{
bUpdateMode = false;
}
else
{
bUpdateMode = true;
String title = i.getStringExtra(DBAdapter.COL_TITLE);
String url = i.getStringExtra(DBAdapter.COL_URL);
txtTitle.setText(title);
txtURL.setText(url);
}
btnOK.setOnClickListener(new View.OnClickListener()
{
public void onClick (View V)
{
Intent i = new Intent ();
i.putExtra(DBAdapter.COL_URL, txtURL.getText().toString());
i.putExtra(DBAdapter.COL_TITLE, txtTitle.getText().toString());
if(bUpdateMode)
i.putExtra(DBAdapter.COL_ID, id);
setResult(RESULT_OK, i);
finish();
}
});
}
}
logcat的：
12-26 18:25:20.360: I/Database(271): sqlite returned: error code = 1, msg = no such column: id
12-26 18:25:20.379: D/AndroidRuntime(271): Shutting down VM
12-26 18:25:20.379: W/dalvikvm(271): threadid=1: thread exiting with uncaught exception (group=0x4001d800)
12-26 18:25:20.419: E/AndroidRuntime(271): FATAL EXCEPTION: main
12-26 18:25:20.419: E/AndroidRuntime(271): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.sqlite/com.example.sqlite.MainActivity}: android.database.sqlite.SQLiteException: no such column: id: , while compiling: SELECT id, Title, url FROM Bookmark
12-26 18:25:20.419: E/AndroidRuntime(271): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2663)
12-26 18:25:20.419: E/AndroidRuntime(271): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2679)
12-26 18:25:20.419: E/AndroidRuntime(271): at android.app.ActivityThread.access$2300(ActivityThread.java:125)
12-26 18:25:20.419: E/AndroidRuntime(271): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2033)
12-26 18:25:20.419: E/AndroidRuntime(271): at android.os.Handler.dispatchMessage(Handler.java:99)
12-26 18:25:20.419: E/AndroidRuntime(271): at android.os.Looper.loop(Looper.java:123)
12-26 18:25:20.419: E/AndroidRuntime(271): at android.app.ActivityThread.main(ActivityThread.java:4627)
12-26 18:25:20.419: E/AndroidRuntime(271): at java.lang.reflect.Method.invokeNative(Native Method)
12-26 18:25:20.419: E/AndroidRuntime(271): at java.lang.reflect.Method.invoke(Method.java:521)
12-26 18:25:20.419: E/AndroidRuntime(271): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
12-26 18:25:20.419: E/AndroidRuntime(271): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
12-26 18:25:20.419: E/AndroidRuntime(271): at dalvik.system.NativeStart.main(Native Method)
12-26 18:25:20.419: E/AndroidRuntime(271): Caused by: android.database.sqlite.SQLiteException: no such column: id: , while compiling: SELECT id, Title, url FROM Bookmark
12-26 18:25:20.419: E/AndroidRuntime(271): at android.database.sqlite.SQLiteCompiledSql.native_compile(Native Method)
12-26 18:25:20.419: E/AndroidRuntime(271): at android.database.sqlite.SQLiteCompiledSql.compile(SQLiteCompiledSql.java:91)
12-26 18:25:20.419: E/AndroidRuntime(271): at android.database.sqlite.SQLiteCompiledSql.<init>(SQLiteCompiledSql.java:64)
12-26 18:25:20.419: E/AndroidRuntime(271): at android.database.sqlite.SQLiteProgram.<init>(SQLiteProgram.java:80)
12-26 18:25:20.419: E/AndroidRuntime(271): at android.database.sqlite.SQLiteQuery.<init>(SQLiteQuery.java:46)
12-26 18:25:20.419: E/AndroidRuntime(271): at android.database.sqlite.SQLiteDirectCursorDriver.query(SQLiteDirectCursorDriver.java:42)
12-26 18:25:20.419: E/AndroidRuntime(271): at android.database.sqlite.SQLiteDatabase.rawQueryWithFactory(SQLiteDatabase.java:1345)
12-26 18:25:20.419: E/AndroidRuntime(271): at android.database.sqlite.SQLiteDatabase.queryWithFactory(SQLiteDatabase.java:1229)
12-26 18:25:20.419: E/AndroidRuntime(271): at android.database.sqlite.SQLiteDatabase.query(SQLiteDatabase.java:1184)
12-26 18:25:20.419: E/AndroidRuntime(271): at android.database.sqlite.SQLiteDatabase.query(SQLiteDatabase.java:1264)
12-26 18:25:20.419: E/AndroidRuntime(271): at com.example.sqlite.DBAdapter.GetAllBookmarks(DBAdapter.java:105)
12-26 18:25:20.419: E/AndroidRuntime(271): at com.example.sqlite.MainActivity.refreshList(MainActivity.java:141)
12-26 18:25:20.419: E/AndroidRuntime(271): at com.example.sqlite.MainActivity.onCreate(MainActivity.java:33)
12-26 18:25:20.419: E/AndroidRuntime(271): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
12-26 18:25:20.419: E/AndroidRuntime(271): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2627)
12-26 18:25:20.419: E/AndroidRuntime(271): ... 11 more
12-26 18:25:32.789: I/Process(271): Sending signal. PID: 271 SIG: 9
答案 0 :(得分：2)
SQLiteException: no such column: id: , while compiling: SELECT id, Title, url FROM Bookmark
您正在尝试选择"id"，但您的列名为"_id"：
private static final String DB_CREATE =
"CREATE TABLE Bookmark (" +
"_id integer PRIMARY KEY AUTOINCREMENT," +
"Title text," +
"url text);";
您需要更改COL_ID以包含下划线：
public static final String COL_ID = "_id";
答案 1 :(得分：2)
正如日志所说：
引起：android.database.sqlite.SQLiteException：没有这样的列： id：，同时编译：SELECT id，Title，url FROM Bookmark
表示当前表中不存在“id列。更改您的
public static final String COL_ID = "id";
到
public static final String COL_ID = "_id";