我是Android的新手，并且一直在关注教程来创建应用。我在将数据插入数据库方面遇到了很大困难。我已经尝试了所有我无法想到的东西。数据库类是：
package com.mckallip.BeerOnTheWall;
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;
public class DatabaseUtil{
private static final String TAG = "DatabaseUtil";
/**
* Database Name
*/
private static final String DATABASE_NAME = "Beer_Database";
/**
* Database Version
*/
private static final int DATABASE_VERSION = 1;
/**
* Table Name
*/
private static final String DATABASE_TABLE = "Beer_List";
/**
* Table columns
*/
public static final String KEY_BEER_NAME = "beer_name";
public static final String KEY_BEER_STYLE = "beer_style";
public static final String KEY_BREWERY = "beer_brewery";
public static final String KEY_ABV = "beer_abv";
public static final String KEY_BEER_SCORE = "beer_score";
public static final String KEY_BEER_IMAGE = "beer_image";
public static final String KEY_BEER_COMMENTS = "beer_comments";
public static final String KEY_ROWID = "_id";
/**
* Database creation sql statement
*/
private static final String CREATE_BEER_TABLE =
"CREATE TABLE " + DATABASE_TABLE + " (" + KEY_ROWID + " INTEGER PRIMARY KEY AUTOINCREMENT, " + KEY_BEER_NAME + " TEXT, " + KEY_BEER_STYLE + " TEXT, " + KEY_BREWERY + " TEXT, " + KEY_ABV + " TEXT, " + KEY_BEER_SCORE + "TEXT, " + KEY_BEER_IMAGE + " TEXT, " + KEY_BEER_COMMENTS + "TEXT );";
/**
* Context
*/
private final Context mCtx;
private DatabaseHelper mDbHelper;
private SQLiteDatabase mDb;
/**
* Inner private class. Database Helper class for creating and updating database.
*/
private static class DatabaseHelper extends SQLiteOpenHelper {
DatabaseHelper(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
/**
* onCreate method is called for the 1st time when database doesn't exists.
*/
@Override
public void onCreate(SQLiteDatabase db) {
Log.i(TAG, "Creating DataBase: " + CREATE_BEER_TABLE);
db.execSQL(CREATE_BEER_TABLE);
}
/**
* onUpgrade method is called when database version changes.
*/
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
Log.w(TAG, "Upgrading database from version " + oldVersion + " to "
+ newVersion);
}
}
protected SQLiteDatabase getDataBase(){
return mDb;
}
/**
* Constructor - takes the context to allow the database to be
* opened/created
*
* @param ctx the Context within which to work
*/
public DatabaseUtil(Context ctx) {
this.mCtx = ctx;
}
/**
* This method is used for creating/opening connection
* @return instance of DatabaseUtil
* @throws SQLException
*/
public DatabaseUtil open() throws SQLException {
mDbHelper = new DatabaseHelper(mCtx);
mDb = mDbHelper.getWritableDatabase();
return this;
}
/**
* This method is used for closing the connection.
*/
public void close() {
mDbHelper.close();
}
/**
* This method is used to create/insert new record Beer record.
* @param sbeer_name
* @param sbeer_style
* @param sbeer_score
* @param sbrewery
* @param sabv
* @param simageLoc
* @param scomments
* @return long
*/
public long createBeer(String beer_name, String beer_style,
String beer_score, String brewery, String abv,
String imageLoc, String comments) {
ContentValues initialValues = new ContentValues();
initialValues.put(KEY_BEER_NAME, beer_name);
initialValues.put(KEY_BEER_STYLE, beer_style);
initialValues.put(KEY_BREWERY, brewery);
initialValues.put(KEY_ABV, abv);
initialValues.put(KEY_BEER_SCORE, beer_score);
initialValues.put(KEY_BEER_IMAGE, imageLoc);
initialValues.put(KEY_BEER_COMMENTS, comments);
return mDb.insert(DATABASE_TABLE, null, initialValues);
}
/**
* This method will delete Beer record.
* @param rowId
* @return boolean
*/
public boolean deleteBeer(long rowId) {
return mDb.delete(DATABASE_TABLE, KEY_ROWID + "=" + rowId, null) > 0;
}
/**
* This method will return Cursor holding all the Beer records.
* @return Cursor
*/
public Cursor fetchAllBeers() {
return mDb.query(DATABASE_TABLE, new String[] {KEY_ROWID,
KEY_BEER_NAME, KEY_BEER_STYLE, KEY_BREWERY, KEY_ABV,
KEY_BEER_SCORE, KEY_BEER_IMAGE, KEY_BEER_COMMENTS}, null, null, null, null, null);
}
/**
* This method will return Cursor holding the specific Beer record.
* @param id
* @return Cursor
* @throws SQLException
*/
public Cursor fetchBeer(long id) throws SQLException {
Cursor mCursor =
mDb.query(true, DATABASE_TABLE, new String[] {KEY_ROWID,
KEY_BEER_NAME, KEY_BEER_STYLE, KEY_BREWERY, KEY_ABV,
KEY_BEER_SCORE, KEY_BEER_IMAGE, KEY_BEER_COMMENTS
}, KEY_ROWID + "=" + id, null,
null, null, null, null);
if (mCursor != null) {
mCursor.moveToFirst();
}
return mCursor;
}
/**
* This method will update Beer record.
* @param id
* @param name
* @param standard
* @return boolean
*/
public boolean updateBeer(int id, String beer_name, String beer_style,
String beer_score, String brewery, String abv, String imageLoc,
String comments) {
ContentValues args = new ContentValues();
args.put(KEY_BEER_NAME, beer_name);
args.put(KEY_BEER_STYLE, beer_style);
args.put(KEY_BREWERY, brewery);
args.put(KEY_BEER_SCORE, beer_score);
args.put(KEY_ABV, abv);
args.put(KEY_BEER_IMAGE, imageLoc);
args.put(KEY_BEER_COMMENTS, comments);
return mDb.update(DATABASE_TABLE, args, KEY_ROWID + "=" + id, null) > 0;
}
}
添加数据的类是：
package com.mckallip.BeerOnTheWall;
import android.content.Context;
import android.content.Intent;
import android.database.sqlite.SQLiteDatabase;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Spinner;
import android.widget.TextView;
import android.widget.Toast;
public class AddBeerActivity extends BeerOnTheWallActivity {
private EditText et1;
private EditText et2;
private EditText et3;
private EditText et4;
private Spinner score_spin;
private EditText et5;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.add_beer);
mDatabase.open();
Context e = getApplicationContext();
String test = "read only";
if (mDatabase.getDataBase().isReadOnly()){
test = "Not ReadOnly" + mDatabase.getDataBase().getPath();
}
Toast t = Toast.makeText(e, test, 2);
t.show();
et1 = (EditText) findViewById(R.id.add_beer_name);
et2 = (EditText)findViewById(R.id.add_beer_style);
et3 = (EditText) findViewById(R.id.add_brewery);
et4 = (EditText) findViewById(R.id.add_abv);
score_spin = (Spinner) findViewById(R.id.score_spinner);
et5 = (EditText) findViewById(R.id.add_comments);
((Button)findViewById(R.id.add_submit)).setOnClickListener(new OnClickListener() {
public void onClick( View v ){
if (mDatabase.getDataBase().isReadOnly())mDatabase.open();
long beer_Id = mDatabase.createBeer( et1.toString(), et2.toString(), score_spin.toString(), et3.toString(), et4.toString(), "image", et5.toString() );
Context context = getApplicationContext();
CharSequence text = "Your beer was added at database position " + beer_Id;
if ( beer_Id == -1 ){
text = "There was an error and the beer could not be added.";
}
Toast toast = Toast.makeText(context, text, 2);
toast.show();
// reset form
if ( beer_Id != -1 ){
et1.setText(null);
et2.setText(null);
et3.setText(null);
et4.setText(null);
et5.setText(null);
}
}
});
// Handle Go to List button
final Button gotoList = (Button) findViewById(R.id.beer_list);
gotoList.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
// Go to other activity that displays beer list
Intent intent = new Intent(AddBeerActivity.this, BeerListActivity.class);
startActivity(intent);
}
});
}
}
我添加了toast作为尝试和调试它的方法。第一个声称它是只读的，我无法弄清楚为什么或如何使它可写。
另外，我将BeerOnTheWallActivity中的DatabaseUtil实例化为静态变量，因为......
public class BeerOnTheWallActivity extends Activity {
protected DatabaseUtil mDatabase = null;
//protected Cursor mCursor = null;
//protected SQLiteDatabase mDB = null;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
mDatabase = new DatabaseUtil(this.getApplicationContext());
mDatabase.open();
}
当我按下按钮添加数据时，错误日志指出：
07-14 00：31：45.549：ERROR / Database（31512）：插入beer_abv = android.widget.EditText@47a27ea8时出错beer_style=android.widget.EditText@47a25d28 beer_score=android.widget.Spinner@47a2a768 beer_name = android.widget.EditText@47a245a8 beer_comments=android.widget.EditText@47a2b560 beer_image = image beer_brewery=android.widget.EditText@47a26de8
07-14 00：31：45.549：ERROR / Database（31512）：android.database.sqlite.SQLiteException：table Beer_List没有名为beer_score的列:,编译时：INSERT INTO Beer_List（beer_abv，beer_style，beer_score，beer_name ，beer_comments，beer_image，beer_brewery）价值观（？，？，？，？，？，？，？）;
我认为就是这样。任何帮助将不胜感激。
答案 0 :(得分：2)
请查看以下
您的代码是
private static final String CREATE_BEER_TABLE =
"CREATE TABLE " + DATABASE_TABLE + " (" + KEY_ROWID + " INTEGER PRIMARY KEY AUTOINCREMENT, " + KEY_BEER_NAME + " TEXT, " + KEY_BEER_STYLE + " TEXT, " + KEY_BREWERY + " TEXT, " + KEY_ABV + " TEXT, " + KEY_BEER_SCORE + "TEXT, " + KEY_BEER_IMAGE + " TEXT, " + KEY_BEER_COMMENTS + "TEXT );";
已更改为使用此
private static final String CREATE_BEER_TABLE =
"CREATE TABLE " + DATABASE_TABLE + " (" + KEY_ROWID + " INTEGER PRIMARY KEY AUTOINCREMENT, " + KEY_BEER_NAME + " TEXT, " + KEY_BEER_STYLE + " TEXT, " + KEY_BREWERY + " TEXT, " + KEY_ABV + " TEXT, " + KEY_BEER_SCORE + " TEXT, " + KEY_BEER_IMAGE + " TEXT, " + KEY_BEER_COMMENTS + " TEXT );";
答案 1 :(得分：1)
这是错误的
long beer_Id = mDatabase.createBeer( et1.toString(), et2.toString(), score_spin.toString(), et3.toString(), et4.toString(), "image", et5.toString() );
在这里，你没有得到e1文本。试试e1.getText().toString()
这会导致这些错误：
07-14 00：31：45.549：ERROR / Database（31512）：插入错误 beer_abv=android.widget.EditText@47a27ea8 beer_style=android.widget.EditText@47a25d28 beer_score=android.widget.Spinner@47a2a768 beer_name=android.widget.EditText@47a245a8 beer_comments=android.widget.EditText@47a2b560 beer_image = image beer_brewery=android.widget.EditText@47a26de8