我正在尝试从数据库中读取数据。我手动导入了数据库，sqlite现在只想在 android 应用程序中建立连接，并希望读取行并将它们显示在文本字段中，但是我使用的代码要么每次都使数据库成为新的，要么正在创建表再次在该数据库中，我得到一个运行时错误。
我的代码是：
package com.example.dbexample;
import java.util.ArrayList;
import java.util.List;
import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
public class DatabaseHandler extends SQLiteOpenHelper {
// All Static variables
// Database Version
private static final int DATABASE_VERSION = 1;
// Database Name
private static final String DATABASE_NAME = "TranslatesManager";
// Translates table name
private static final String TABLE_TRANSLATOR = "Words";
// Translates Table Columns names
private static final String KEY_ID = "id";
private static final String KEY_ENGLISHNAME = "Englishname";
private static final String KEY_URDUNAME = "Urduname";
public DatabaseHandler(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
// Creating Tables
@Override
public void onCreate(SQLiteDatabase db) {
/* String CREATE_TranslateS_TABLE = "CREATE TABLE " + TABLE_TRANSLATOR + "("
+ KEY_ID + " INTEGER PRIMARY KEY," + KEY_ENGLISHNAME + " TEXT,"
+ KEY_URDUNAME + " TEXT" + ")";
db.execSQL(CREATE_TranslateS_TABLE);
*/
}
// Upgrading database
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
// Drop older table if existed
// db.execSQL("DROP TABLE IF EXISTS " + TABLE_TRANSLATOR);
// Create tables again
//onCreate(db);
}
// Adding new Translate
void addTranslate(Translate Translate) {
SQLiteDatabase db = this.getWritableDatabase();
ContentValues values = new ContentValues();
values.put(KEY_ENGLISHNAME, Translate.getName()); // Translate Name
values.put(KEY_URDUNAME, Translate.getUrduName()); // Translate Phone
// Inserting Row
db.insert(TABLE_TRANSLATOR, null, values);
db.close(); // Closing database connection
}
// Getting single Translate
Translate getTranslate(int id) {
SQLiteDatabase db = this.getReadableDatabase();
Cursor cursor = db.query(TABLE_TRANSLATOR, new String[] { KEY_ID,
KEY_ENGLISHNAME, KEY_URDUNAME }, KEY_ID + "=?",
new String[] { String.valueOf(id) }, null, null, null, null);
if (cursor != null)
cursor.moveToFirst();
Translate Translate = new Translate(Integer.parseInt
(cursor.getString(0)),cursor.getString(1), cursor.getString(2));
// return Translate
return Translate;
}
// Getting All Translates
public List<Translate> getAllTranslates() {
List<Translate> TranslateList = new ArrayList<Translate>();
// Select All Query
String selectQuery = "SELECT * FROM " + TABLE_TRANSLATOR;
SQLiteDatabase db = this.getWritableDatabase();
Cursor cursor = db.rawQuery(selectQuery, null);
// looping through all rows and adding to list
if (cursor.moveToFirst()) {
do {
Translate Translate = new Translate();
Translate.setID(Integer.parseInt(cursor.getString(0)));
Translate.setName(cursor.getString(1));
Translate.setUrduName(cursor.getString(2));
// Adding Translate to list
TranslateList.add(Translate);
} while (cursor.moveToNext());
}
// return Translate list
return TranslateList;
}
// Updating single Translate
public int updateTranslate(Translate Translate) {
SQLiteDatabase db = this.getWritableDatabase();
ContentValues values = new ContentValues();
values.put(KEY_ENGLISHNAME, Translate.getName());
values.put(KEY_URDUNAME, Translate.getUrduName());
// updating row
return db.update(TABLE_TRANSLATOR, values, KEY_ID + " = ?",
new String[] { String.valueOf(Translate.getID()) });
}
// Deleting single Translate
public void deleteTranslate(Translate Translate) {
SQLiteDatabase db = this.getWritableDatabase();
db.delete(TABLE_TRANSLATOR, KEY_ID + " = ?",
new String[] { String.valueOf(Translate.getID()) });
db.close();
}
// Getting Translates Count
public int getTranslatesCount() {
String countQuery = "SELECT * FROM " + TABLE_TRANSLATOR;
SQLiteDatabase db = this.getReadableDatabase();
Cursor cursor = db.rawQuery(countQuery, null);
cursor.close();
// return count
return cursor.getCount();
}
}
翻译者是类。它只有 id、englishname、urduname 字段。
请更正此文件或查找错误，以便我知道如何从sqlLiteDatabase文本框中读取。
我的主要活动代码是：
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main_db);
DatabaseHandler db = new DatabaseHandler(this);
// Inserting Translates
/// Log.d("Insert: ", "Inserting ..");
//db.addTranslate(new Translate("Ravi", "9100000000"));
//db.addTranslate(new Translate("Srinivas", "9199999999"));
//db.addTranslate(new Translate("Tommy", "9522222222"));
//db.addTranslate(new Translate("Karthik", "9533333333"));
// Reading all Translates
Log.d("Reading: ", "Reading all Translates..");
List<Translate> Translates = db.getAllTranslates();
for (Translate cn : Translates) {
String log = "Id: "+cn.getID()+" ,Name: " + cn.getName() +
" ,Phone: " + cn.getUrduName();
// Writing Translates to log
Log.d("Name: ", log);
}
TextView t1 = (TextView) findViewById(R.id.textView1);
TextView t2 = (TextView) findViewById(R.id.textView4);
TextView t3 = (TextView) findViewById(R.id.textView3);
for (Translate cn : Translates)
{
t1.setText(Integer.toString(cn.getID()));
t2.setText(cn.getName());
t3.setText(cn.getUrduName());
}
}
请让我知道问题出在哪里。