我创建了一个用于测试的应用程序two edittexts (Email and password）和 2 个按钮（submit and viewdata）。我正在调试这个应用程序，它工作正常。
我想通过添加一个来更新此应用程序Edittext (Name）并升级SQLite Database in onUpgrade()方法。代码如下所示。
public class DatabaseHelper extends SQLiteOpenHelper {
private static final String DATABASE_NAME="upgrade";
private static final int DATABASE_VERSION=2;
//details table details
public static final String TABLE_NAME_Details="details";
public static final String USERNAME="USERNAME";
public static final String PASSWORD="PASSWORD";
public static final String Name="Name"; //newly added column in version 2
public static final String TABLE_NAME_Details_temp="temp";
public static final String USERNAME_temp="USERNAME";
public static final String PASSWORD_temp="PASSWORD";
public static final String Name_temp="Name";
//create table statements for version 2
public static final String Create_Table_Details = "CREATE TABLE "
+ TABLE_NAME_Details + " (" + USERNAME + " TEXT PRIMARY KEY,"
+ PASSWORD + " TEXT ,"
+ Name + " TEXT"
+")";
/* creation for version 1
private static final String Create_Table_Details = "CREATE TABLE " +
TABLE_NAME_Details + "("
+ USERNAME + " TEXT PRIMARY KEY,"
+ PASSWORD + " TEXT"
+ ")";*/
//Alter table statements FOR onUpgrade()
//private static final String ALTER_Details = "ALTER TABLE " +
TABLE_NAME_Details + " ADD COLUMN" + Name + " TEXT";
public DatabaseHelper(Context context)
{
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
@Override
public void onCreate(SQLiteDatabase db) {
try{
db.execSQL(Create_Table_Details);
Log.d("database","installed successfully");
}catch (Exception e)
{
e.printStackTrace();
Log.e("/test","Exception due to"+e.toString());
}
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion)
{
String TEMP_CREATE_CONTACTS_TABLE = "CREATE TABLE " +
TABLE_NAME_Details_temp + "("
+ USERNAME_temp + " TEXT," + PASSWORD_temp + " TEXT )";
db.execSQL(TEMP_CREATE_CONTACTS_TABLE);
db.execSQL("INSERT INTO " + TABLE_NAME_Details_temp + " SELECT " +
USERNAME + ", "
+ PASSWORD + " FROM " + TABLE_NAME_Details);
db.execSQL("DROP TABLE "+ TABLE_NAME_Details);
String CREATE_CONTACTS_TABLE = "CREATE TABLE " + TABLE_NAME_Details + "("
+ USERNAME + " TEXT," + PASSWORD + " TEXT," + Name + " TEXT )";
db.execSQL(CREATE_CONTACTS_TABLE);
db.execSQL("INSERT INTO " + TABLE_NAME_Details + " SELECT " +
USERNAME_temp + ", "
+ PASSWORD_temp + ", " + Name_temp + ", " + null + " FROM " +
TABLE_NAME_Details_temp);
db.execSQL("DROP TABLE " + TABLE_NAME_Details);
}
public boolean insertData(String username, String password,String name)
{
try{
SQLiteDatabase db = this.getWritableDatabase();
ContentValues contentValues=new ContentValues();
contentValues.put(USERNAME,username);
contentValues.put(PASSWORD,password);
contentValues.put(Name,name);
long result=db.insertOrThrow(TABLE_NAME_Details, null, contentValues);
if(result==-1)
return false;
else
return true;
}catch(Exception e)
{
e.printStackTrace();
Log.e("/test","Exception due to"+e.toString());
return false;
}
}
//update value
public boolean updatePassword(String LoggedUsername)
{
SQLiteDatabase db = null;
try {
db = this.getWritableDatabase();
ContentValues values = new ContentValues();
values.put(PASSWORD, "test");
if (db.isOpen()) {
db.update(TABLE_NAME_Details, values, USERNAME + "='" +
LoggedUsername+"'",null);
return true;
}
else
return false;
} catch (Exception e) {
Log.d("eEmp/DBUpdateUser ", e.toString());
return false;
}
}
//getting data from database
public Cursor getAllData()
{
SQLiteDatabase db = this.getWritableDatabase();
Cursor res = db.rawQuery("select * from "+TABLE_NAME_Details,null);
return res;
}
}
我安装了第一个版本并且工作正常，然后卸载了。
卸载后，安装第二版本并存储数据。它也工作正常。
当我尝试在调试模式下使用第二版本更新第一个版本时，应用程序更新成功，并且在第一个版本中输入的数据可见。当我尝试将数据存储在第二个版本中时，数据没有插入到 sqlite 数据库中。为什么？
调试时，调用了 insert 方法，但这里if(result==-1)我得到 -1 而不是 1。因此，数据控制来自该方法，并且数据没有插入到数据库中。
例如：在第一个版本中：我输入了用户名：stackoverflow和密码stackoverflow。
我将应用程序更新到第二版本并更新成功。现在我输入用户名：hello密码：hello name:hello然后单击提交按钮。
之后如果我点击viewdata按钮：显示用户名：stackoverflow密码stackoverflow名称：空。但不显示第二版本中插入的数据。
任何帮助，将不胜感激。请帮我提供正确的解决方案。
谢谢。
