How to update a value using SQLite in android

hei Daniel ,

i will make a simple code for you.

first,I will create a class which function to create a database sqlite / open db sqlite / drop table , i name it DataBaseHelper, the code :

----------------------------------------------------------------------------------- database helper --------------------------------------------------------------------------------------------------
/**
* Created by Rezky on 2016/04/08.
*/
public class DataBaseHelper extends SQLiteOpenHelper {

private static final int DATABASE_VERSION = 1;
private static final String DATABASE_NAME = "myDb"; //You can change with your db name
private static final String TABLE_NAME = "contacts";

public static final String CREATE_TBL1 = "create table contacts (id integer primary key not null , uname text not null , pass text not null)";

private static DataBaseHelper instance;

public static synchronized DataBaseHelper getHelper(Context context) {
    if (instance == null)
        instance = new DataBaseHelper(context);
    return instance;
}

public DataBaseHelper(Context context) {
    super(context, DATABASE_NAME, null, DATABASE_VERSION);
}

@Override
public void onOpen(SQLiteDatabase db) {
    super.onOpen(db);
    if (!db.isReadOnly()) {
        // Enable foreign key constraints
        db.execSQL("PRAGMA foreign_keys=ON;");
    }
}

@Override
public void onCreate(SQLiteDatabase db) {
    db.execSQL(CREATE_TBL1);     
}

@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
    Log.w("db upgrade",
                "Upgrading the database from version " + oldVersion + " to " + newVersion);
    // clear all data
    db.execSQL("DROP TABLE IF EXISTS " + CREATE_TBL1);     
}

}

---------------------------------------------------------------------- end of database helper --------------------------------------------------------------------------------

after that , i will create a class which will use database helper. this class will be function for manipulate data on database sqlite. i name it "SqliteManipulate", the code :

note : you can change this code according your needs
----------------------------------------------------------------------------------- SqliteManipulate --------------------------------------------------------------------------------------------------

public class SqliteManipulate {
public static final String TAG = "NotificationDataDAO";

private SQLiteDatabase mDatabase;
private DataBaseHelper mDbHelper;
private Context mContext;
private String[] mAllColumns ={"id ","uname","pass "};

public SqliteManipulate (Context mContext){
    this.mContext = mContext;
    mDbHelper = new DataBaseHelper(mContext);

    // open the database
    try {
        open();
    } catch (SQLException e) {
        Log.e(TAG, "SQLException on openning database " + e.getMessage());
        e.printStackTrace();
    }
}

public void open() throws SQLiteException{
    mDatabase = mDbHelper.getWritableDatabase();
}

public void close() {
    mDbHelper.close();
}

//basic code for inserting data , this code based on your data
public long insDataUser(String Username, String Password){
ContentValues mValues = new ContentValues();

        mValues.put("uname", Username);
        mValues.put("pass", Password);
        long res=mDatabase.insert("contacts", null, mValues); //contacts is your table name (you can change it with you tables name)


      return res;
}

//basic code for updating data, this code based on your data
public boolean updatePassword(String Username ,String Password) {
Cursor mCursor = mDatabase.query("contacts",mAllColumns, "uname = " + mUsername ,null,null,null,null); //contacts is table name, this code query data from table contacts with value columnusername equals variabel Username

    try {

        if (mCursor != null) {
            mCursor.moveToFirst();
            while (!mCursor.isAfterLast()) {

                ContentValues values = new ContentValues();
                values.put("uname",mCursor.getString(1));
                values.put("pass", mCursor.getString(2));
                mDatabase.update("contacts", values, "id = ?",
                        new String[]{String.valueOf(mCursor.getString(0))});

                mCursor.moveToNext();
            }
            mCursor.close();

            return true;

        }else{
            return false;
        }

    } catch (SQLException e) {
        return false;
    }
}

//this code for clear all data from table contacts
public boolean deleteAllData() {
int doneDelete = 0;
doneDelete = mDatabase.delete("contacts", null, null);
return doneDelete > 0;
}

}

---------------------------------------------------------------------- end of SqliteManipulate --------------------------------------------------------------------------------

and then, in your activity, write this code :

if (!newpass1str.equals(newpass2str)) {
// Show Toast Message
Toast pass = Toast.makeText(ChangePassword.this, "Passwords Do Not Match!", Toast.LENGTH_SHORT);
pass.show();

        // Clears Text fields if passwords do not match
        newPass1.setText("");
        newPass2.setText("");
    } else {
        // Code to update password goes here
         SqliteManipulate mDao = new SqliteManipulate (getApplicationContext());
         boolean isUpdate = mDao .updatePassword(newunamestr,newPass1);

        if (isUpdate){
          Toast created = Toast.makeText(ChangePassword.this, "Password Successfuly Changed", Toast.LENGTH_SHORT);
          created.show();
        }
    }

All of this code based from my project, I've not yet tested it. so if you get an error, tell me

hopefully i can help you.