我在开发Android应用程序时遇到了问题。我试图从我的Android应用程序中检索所有数据，但我不知道如何。这是我的DBAdapter.java类：
package com.example.foodsaver2;
import android.content.ContentValues;
import android.content.Context;
import android.content.SharedPreferences;
import android.database.Cursor;
import android.database.SQLException;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.graphics.AvoidXfermode;
import android.util.Log;
import com.example.*;
public class DBAdapter {
public static final String KEY_ROWID = "rowid";
public static final String KEY_CUSTOMER = "customer";
public static final String KEY_NAME = "name";
public static final String KEY_ADDRESS = "address";
public static final String KEY_ADDRESS1 = "address1";
public static final String KEY_ADDRESS2 = "address2";
public static final String KEY_CITY = "city";
public static final String KEY_STATE = "state";
public static final String KEY_ZIP = "zipCode";
public static final String KEY_SEARCH = "searchData";
public static final String TOTAL_CARB = "carb";
public static final String FIBER = "fiber";
public static final String SUGAR = "sugar";
public static final String PROTEIN = "protein";
public static final String SODIUM = "salt";
public static final String TOTALCALORIES = "calories";
public static Context contextOfApplication;
private static final String TAG = "DBAdapter";
private DatabaseHelper mDbHelper;
public SQLiteDatabase mDb;
private static final String DATABASE_NAME = "Data";
private static final String FTS_VIRTUAL_TABLE = "Info";
private static final int DATABASE_VERSION = 7;
private static final String DATABASE_CREATE1 =
"CREATE VIRTUAL TABLE " + FTS_VIRTUAL_TABLE + " USING fts3(" +
KEY_CUSTOMER + /*"INTEGER," + */ "," +
KEY_NAME + "," +
KEY_ADDRESS1 + "," +
KEY_ADDRESS2 + "," +
KEY_CITY + "," +
KEY_STATE + "," +
KEY_ZIP + "," +
KEY_SEARCH + "," +
TOTAL_CARB + "," +
FIBER + "," +
SUGAR + "," +
PROTEIN + "," +
SODIUM + "," +
TOTALCALORIES + "," +
" UNIQUE (" + KEY_CUSTOMER + "));";
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) {
Log.w(TAG, DATABASE_CREATE1);
db.execSQL(DATABASE_CREATE1);
}
public static Context getContextOfApplication(){
return contextOfApplication;
}
@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 " + FTS_VIRTUAL_TABLE);
onCreate(db);
}
}
public DBAdapter(Context ctx) {
this.mCtx = ctx;
}
public DBAdapter open() throws SQLException {
mDbHelper = new DatabaseHelper(mCtx);
mDb = mDbHelper.getWritableDatabase();
return this;
}
public void close() {
if (mDbHelper != null) {
mDbHelper.close();
}
}
public long createCustomer(String customer, String name, String address1, String address2, String city, String state, String zipCode, String carb, String fiber, String sugar, String protein, String sodium, String calories) {
ContentValues initialValues = new ContentValues();
String searchValue = customer + " " +
name + " " +
address1 + " " +
city + " " +
state + " " +
zipCode;
initialValues.put(KEY_CUSTOMER, customer);
initialValues.put(KEY_NAME, name);
initialValues.put(KEY_ADDRESS1, address1);
initialValues.put(KEY_ADDRESS2, address2);
initialValues.put(KEY_CITY, city);
initialValues.put(KEY_STATE, state);
initialValues.put(KEY_ZIP, zipCode);
initialValues.put(KEY_SEARCH, searchValue);
initialValues.put(TOTAL_CARB, carb);
initialValues.put(FIBER, fiber);
initialValues.put(SUGAR, sugar);
initialValues.put(PROTEIN, protein);
initialValues.put(SODIUM, sodium);
initialValues.put(TOTALCALORIES, calories);
return mDb.insert(FTS_VIRTUAL_TABLE, null, initialValues);
}
public Cursor searchCustomer(String inputText) throws SQLException {
Log.w(TAG, inputText);
String query = "SELECT docid as _id," +
KEY_CUSTOMER + "," +
KEY_NAME + "," +
"(" + KEY_ADDRESS1 + "||" +
"(case when " + KEY_ADDRESS2 + "> '' then '\n' || " + KEY_ADDRESS2 + " else '' end)) as " + KEY_ADDRESS +"," +
KEY_ADDRESS1 + "," +
KEY_ADDRESS2 + "," +
KEY_CITY + "," +
KEY_STATE + "," +
KEY_ZIP + "," +
TOTAL_CARB + "," +
FIBER + "," +
SUGAR + "," +
PROTEIN + "," +
SODIUM + "," +
TOTALCALORIES +
" from " + FTS_VIRTUAL_TABLE +
" where " + KEY_SEARCH + " MATCH '" + inputText + "';";
Log.w(TAG, query);
Cursor mCursor = mDb.rawQuery(query,null);
if (mCursor != null) {
mCursor.moveToFirst();
}
return mCursor;
}
public boolean deleteAllCustomers() {
int doneDelete = 0;
doneDelete = mDb.delete(FTS_VIRTUAL_TABLE, null , null);
Log.w(TAG, Integer.toString(doneDelete));
return doneDelete > 0;
}
}
这是我的SendFeedback.java类，我尝试检索数据。
package com.example.foodsaver2;
import android.app.Activity;
import android.content.Intent;
import android.database.Cursor;
import android.os.Bundle;
import android.preference.PreferenceActivity;
import android.view.View;
import android.widget.Button;
import android.widget.Toast;
/**
* Created by mother on 2/7/14.
*/
public class SendFeedback extends Activity {
private DBAdapter mDbHelper;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.send_feedback);
mDbHelper = new DBAdapter(this);
mDbHelper.open();
}
public void send (View v) {
Cursor c = mDbHelper.getData();
GmailSender sender = new GmailSender("omitted for privacy", "omitted for privacy");
try {
sender.sendMail("This is Subject",
"This is Body",
"omitted for privacy",
"omitted for privacy");
Toast.makeText(getApplicationContext(), "Sent!", Toast.LENGTH_SHORT).show();
} catch (Exception e) {
Toast.makeText(getApplicationContext(), "Cannot send message!", Toast.LENGTH_SHORT).show();
}
}
}
我不知道该怎么做。我已经搜索了互联网和SO一段时间，但我找不到解决方案。我对SQLiteDatabases也没有任何经验。关于这个问题的任何帮助表示赞赏。
答案 0 :(得分：0)
这是关于android上sqlite数据库的一个很好的教程： http://www.vogella.com/tutorials/AndroidSQLite/article.html
看看这个摘录：
public List<Comment> getAllComments() {
List<Comment> comments = new ArrayList<Comment>();
Cursor cursor = database.query(MySQLiteHelper.TABLE_COMMENTS, allColumns, null, null, null, null, null);
cursor.moveToFirst();
while (!cursor.isAfterLast()) {
Comment comment = cursorToComment(cursor);
comments.add(comment);
cursor.moveToNext();
}
// make sure to close the cursor
cursor.close();
return comments;
}
和
private Comment cursorToComment(Cursor cursor) {
Comment comment = new Comment();
comment.setId(cursor.getLong(0));
comment.setComment(cursor.getString(1));
return comment;
}
因此对于您的应用，您可以：
public List getAllComments（）{ 列出customers = new ArrayList（）;
Cursor cursor = database.query(FTS_VIRTUAL_TABLE, new String[]{"KEY_CUSTOMER", "KEY_NAME " , etc..}, null, null, null, null, null);
cursor.moveToFirst();
while (!cursor.isAfterLast()) {
Customer customer = cursorToCustomer(cursor);
customers.add(comment);
cursor.moveToNext();
}
// make sure to close the cursor
cursor.close();
return customers;
}
和
private Customer cursorToCustomer(Cursor cursor) {
Customer customer = new Customer();
customer.setCustomer(cursor.getString(0));
customer.setName(cursor.getString(1));
customer.setAddress1(cursor.getString(2));
customer.setAddress2(cursor.getString(3));
customer.setCity(cursor.getString(4));
customer.setState(cursor.getString(5));
customer.setZipCode(cursor.getString(6));
customer.setSearchValue(cursor.getString(7));
customer.setCarb(cursor.getString(8));
customer.setFiber(cursor.getString(9));
customer.setSugar(cursor.getString(10));
customer.setProtein(cursor.getString(11));
customer.setSodium(cursor.getString(12));
customer.setCalories(cursor.getString(13));
return comment;
}
PS：您需要创建自己的“客户”类来保存此处显示的数据