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我有三個按鈕用於保存，加載和刪除數據庫中的數據。無法從數據庫中獲取數據
TotalResults.java
package com.example.simplegame;
android.os.Bundle;
import android.app.Activity;
import android.content.Intent;
import android.util.Log;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.TextView;
public class TotalResults extends Activity {
DatabaseManager db = new DatabaseManager(this);
String name;
int score;
TextView result;
TextView saved;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_total_results);
result = (TextView) findViewById (R.id.textResult);
saved = (TextView) findViewById (R.id.textLoad);
Button save = (Button) findViewById (R.id.buttonSave);
Button load = (Button) findViewById (R.id.buttonLoad);
Intent intent = getIntent();
name = intent.getExtras().getString("name");
score = intent.getExtras().getInt("score");
result.setText("Name: "+name+" , Score: "+score);
save.setOnClickListener(new OnClickListener(){
public void onClick(View v) {
db.addContact(new PlayerData(name,score));
Log.d("Insert: ", "Inserting ..");
}
});
load.setOnClickListener(new OnClickListener(){
public void onClick(View v) {
String showName = db.getContact(0).getName();
int showScore = db.getContact(0).getscore();
saved.setText("Player Name: "+showName+" Player Score: "+showScore);
}
});
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.total_results, menu);
return true;
}
}
和DatabaseManager.java
package com.example.simplegame;
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 DatabaseManager extends SQLiteOpenHelper {
// All Static variables
// Database Version
private static final int DATABASE_VERSION = 1;
// Database Name
private static final String DATABASE_NAME = "contactsManager";
// Contacts table name
private static final String TABLE_CONTACTS = "contacts";
// Contacts Table Columns names
private static final String KEY_ID = "id";
private static final String KEY_NAME = "name";
private static final String KEY_PH_NO = "phone_number";
public DatabaseManager(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
// Creating Tables
@Override
public void onCreate(SQLiteDatabase db) {
String CREATE_CONTACTS_TABLE = "CREATE TABLE " + TABLE_CONTACTS + "("
+ KEY_ID + " INTEGER PRIMARY KEY," + KEY_NAME + " TEXT,"
+ KEY_PH_NO + " TEXT" + ")";
db.execSQL(CREATE_CONTACTS_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_CONTACTS);
// Create tables again
onCreate(db);
}
/**
* All CRUD(Create, Read, Update, Delete) Operations
*/
// Adding new contact
void addContact(PlayerData contact) {
SQLiteDatabase db = this.getWritableDatabase();
ContentValues values = new ContentValues();
values.put(KEY_NAME, contact.getName()); // Contact Name
values.put(KEY_PH_NO, contact.getscore()); // Contact Phone
// Inserting Row
db.insert(TABLE_CONTACTS, null, values);
db.close(); // Closing database connection
}
// Getting single contact
PlayerData getContact(int id) {
SQLiteDatabase db = this.getReadableDatabase();
Cursor cursor = db.query(TABLE_CONTACTS, new String[] { KEY_ID,
KEY_NAME, KEY_PH_NO }, KEY_ID + "=?",
new String[] { String.valueOf(id) }, null, null, null, null);
if (cursor != null)
cursor.moveToFirst();
PlayerData contact = new PlayerData(Integer.parseInt(cursor.getString(0)),
cursor.getString(1), cursor.getInt(2));
cursor.close();
// return contact
return contact;
}
// Getting All Contacts
public List<PlayerData> getAllContacts() {
List<PlayerData> contactList = new ArrayList<PlayerData>();
// Select All Query
String selectQuery = "SELECT * FROM " + TABLE_CONTACTS;
SQLiteDatabase db = this.getWritableDatabase();
Cursor cursor = db.rawQuery(selectQuery, null);
// looping through all rows and adding to list
if (cursor.moveToFirst()) {
do {
PlayerData contact = new PlayerData();
contact.setID(Integer.parseInt(cursor.getString(0)));
contact.setName(cursor.getString(1));
contact.setscore(cursor.getInt(2));
// Adding contact to list
contactList.add(contact);
} while (cursor.moveToNext());
}
// return contact list
return contactList;
}
// Updating single contact
public int updateContact(PlayerData contact) {
SQLiteDatabase db = this.getWritableDatabase();
ContentValues values = new ContentValues();
values.put(KEY_NAME, contact.getName());
values.put(KEY_PH_NO, contact.getscore());
// updating row
return db.update(TABLE_CONTACTS, values, KEY_ID + " = ?",
new String[] { String.valueOf(contact.getID()) });
}
// Deleting single contact
public void deleteContact(PlayerData contact) {
SQLiteDatabase db = this.getWritableDatabase();
db.delete(TABLE_CONTACTS, KEY_ID + " = ?",
new String[] { String.valueOf(contact.getID()) });
db.close();
}
// Getting contacts Count
public int getContactsCount() {
String countQuery = "SELECT * FROM " + TABLE_CONTACTS;
SQLiteDatabase db = this.getReadableDatabase();
Cursor cursor = db.rawQuery(countQuery, null);
cursor.close();
// return count
return cursor.getCount();
}
}
它插入數據，但是強制停止如果我點擊負載按鈕和logcat的說：
08-30 18:48:41.616: E/AndroidRuntime(760): android.database.CursorIndexOutOfBoundsException: Index 0 requested, with a size of 0
08-30 18:48:41.616: E/AndroidRuntime(760): at com.example.simplegame.DatabaseManager.getContact(DatabaseManager.java:79)
請幫忙。提前致謝！
這是我的堆棧跟蹤。 http://shrib.com/inserdata – Jeongbebs