Transfer data from SQL database to populate spinner - Java Discussion Boards

Re: PLEASE HELP JAVA

Member 1477360615-Mar-20 10:11

Member 14773606

15-Mar-20 10:11

Try to use another loop...

Re: PLEASE HELP JAVA

Richard MacCutchan15-Mar-20 12:26

Richard MacCutchan

15-Mar-20 12:26

What?

Re: PLEASE HELP JAVA

MallardsReach13-Mar-20 3:12

MallardsReach

13-Mar-20 3:12

Here's what I came up with not sating it's the correct way as I am only just starting with Java but it works.

Java

import java.util.Random;

public class TwoDiceGame {
    public static void main(String[] args){
        // Declare a counter variable to count the loop time
        int count = 0, total = 0;
        
        for(int i=0;i<100;i++){
           Random rNums = new Random(); // create a new object of Random class
            int rNums_die1 = rNums.nextInt(6)+1; 
            int rNums_die2 = rNums.nextInt(6)+1;
			
            if(rNums_die1 + rNums_die2 >= 10){
				total ++;
		         count ++;
			}
			else{
				 count++;
			}
		}
		System.out.println ("Out of 100 rolls of the two dice, the total of both the dice greater than or equal to 10 was " + total + " times");
    }
  }

Re: PLEASE HELP JAVA

Richard MacCutchan13-Mar-20 4:30

Richard MacCutchan

13-Mar-20 4:30

Nice but ...
... you should create the Random object once only, before the for loop. Random classes tend to be pseudo rather than 'true' random number generators, and as such will generally produce the same sequence each time. You can improve on this by adding a seed value to the constructor as described at Random (Java Platform SE 8 )[^], but it is still best to create it only once, before using it in a loop.

Re: PLEASE HELP JAVA

MallardsReach13-Mar-20 6:33

MallardsReach

13-Mar-20 6:33

Thanks again Richard, as I have said I am only starting out with Java and saw this post so thought it would give me something to have a go at. Will look at the link you have provided.

Re: PLEASE HELP JAVA

Richard MacCutchan13-Mar-20 6:49

Richard MacCutchan

13-Mar-20 6:49

If you also want to see some excellent learning materials then take a look at The Java™ Tutorials[^].

Re: PLEASE HELP JAVA

MallardsReach13-Mar-20 7:15

MallardsReach

13-Mar-20 7:15

Will look at the tutorials.
Tried the random seed and always got the same number every time I ran the program
So did this and it seems to work, at least I get different result each time.

Java

Random rnd = new Random(); // create a new object of Random class
rnd.setSeed(System.currentTimeMillis());

Transfer data from SQL database to populate spinner

Member 1475169121-Feb-20 5:55

Member 14751691

21-Feb-20 5:55

Hello Everyone! I have found some code and developed a database that you can enter a student's name and their parents phone number. However, I am stuck. I need the data from the SQL database to populate and spinner, but I don't even know where to begin with coding that. I would appreciate any help that could be given. Here is the code I am currently using (I did get this code online and tailored it to work with my version of Android Studio. (I am using version 3.5)

The following code is in MainActivity.java

package codebind.example.sqliteoperations;

import android.os.Bundle;
import android.view.View;
import android.widget.EditText;

import androidx.appcompat.app.AppCompatActivity;

public class MainActivity extends AppCompatActivity {
    EditText Name, Pass , updateold, updatenew, delete;
    myDbAdapter helper;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Name= (EditText) findViewById(R.id.editName);
        Pass= (EditText) findViewById(R.id.editPass);
        updateold= (EditText) findViewById(R.id.editText3);
        updatenew= (EditText) findViewById(R.id.editText5);
        delete = (EditText) findViewById(R.id.editText6);

        helper = new myDbAdapter(this);
    }
    public void addUser(View view)
    {
        String t1 = Name.getText().toString();
        String t2 = Pass.getText().toString();
        if(t1.isEmpty() || t2.isEmpty())
        {
            Message.message(getApplicationContext(),"Enter Both Name and Password");
        }
        else
        {
            long id = helper.insertData(t1,t2);
            if(id<=0)
            {
                Message.message(getApplicationContext(),"Insertion Unsuccessful");
                Name.setText("");
                Pass.setText("");
            } else
            {
                Message.message(getApplicationContext(),"Insertion Successful");
                Name.setText("");
                Pass.setText("");
            }
        }
    }

    public void viewdata(View view)
    {
        String data = helper.getData();
        Message.message(this,data);
    }

    public void update( View view)
    {
        String u1 = updateold.getText().toString();
        String u2 = updatenew.getText().toString();
        if(u1.isEmpty() || u2.isEmpty())
        {
            Message.message(getApplicationContext(),"Enter Data");
        }
        else
        {
            int a= helper.updateName( u1, u2);
            if(a<=0)
            {
                Message.message(getApplicationContext(),"Unsuccessful");
                updateold.setText("");
                updatenew.setText("");
            } else {
                Message.message(getApplicationContext(),"Updated");
                updateold.setText("");
                updatenew.setText("");
            }
        }

    }
    public void delete( View view)
    {
        String uname = delete.getText().toString();
        if(uname.isEmpty())
        {
            Message.message(getApplicationContext(),"Enter Data");
        }
        else{
            int a= helper.delete(uname);
            if(a<=0)
            {
                Message.message(getApplicationContext(),"Unsuccessful");
                delete.setText("");
            }
            else
            {
                Message.message(this, "DELETED");
                delete.setText("");
            }
        }
    }
}

The following code is in myDbAdapter.java

package codebind.example.sqliteoperations;

import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;


public class myDbAdapter {
    myDbHelper myhelper;
    public myDbAdapter(Context context)
    {
        myhelper = new myDbHelper(context);
    }

    public long insertData(String name, String pass)
    {
        SQLiteDatabase dbb = myhelper.getWritableDatabase();
        ContentValues contentValues = new ContentValues();
        contentValues.put(myDbHelper.NAME, name);
        contentValues.put(myDbHelper.MyPASSWORD, pass);
        long id = dbb.insert(myDbHelper.TABLE_NAME, null , contentValues);
        return id;
    }

    public String getData()
    {
        SQLiteDatabase db = myhelper.getWritableDatabase();
        String[] columns = {myDbHelper.UID,myDbHelper.NAME,myDbHelper.MyPASSWORD};
        Cursor cursor =db.query(myDbHelper.TABLE_NAME,columns,null,null,null,null,null);
        StringBuffer buffer= new StringBuffer();
        while (cursor.moveToNext())
        {
            int cid =cursor.getInt(cursor.getColumnIndex(myDbHelper.UID));
            String name =cursor.getString(cursor.getColumnIndex(myDbHelper.NAME));
            String  password =cursor.getString(cursor.getColumnIndex(myDbHelper.MyPASSWORD));
            buffer.append(cid+ "   " + name + "   " + password +" \n");
        }
        return buffer.toString();
    }

    public  int delete(String uname)
    {
        SQLiteDatabase db = myhelper.getWritableDatabase();
        String[] whereArgs ={uname};

        int count =db.delete(myDbHelper.TABLE_NAME ,myDbHelper.NAME+" = ?",whereArgs);
        return  count;
    }

    public int updateName(String oldName , String newName)
    {
        SQLiteDatabase db = myhelper.getWritableDatabase();
        ContentValues contentValues = new ContentValues();
        contentValues.put(myDbHelper.NAME,newName);
        String[] whereArgs= {oldName};
        int count =db.update(myDbHelper.TABLE_NAME,contentValues, myDbHelper.NAME+" = ?",whereArgs );
        return count;
    }

    static class myDbHelper extends SQLiteOpenHelper
    {
        private static final String DATABASE_NAME = "myDatabase";    // Database Name
        private static final String TABLE_NAME = "myTable";   // Table Name
        private static final int DATABASE_Version = 1;    // Database Version
        private static final String UID="_id";     // Column I (Primary Key)
        private static final String NAME = "Name";    //Column II
        private static final String MyPASSWORD= "Password";    // Column III
        private static final String CREATE_TABLE = "CREATE TABLE "+TABLE_NAME+
                " ("+UID+" INTEGER PRIMARY KEY AUTOINCREMENT, "+NAME+" VARCHAR(255) ,"+ MyPASSWORD+" VARCHAR(225));";
        private static final String DROP_TABLE ="DROP TABLE IF EXISTS "+TABLE_NAME;
        private Context context;

        public myDbHelper(Context context) {
            super(context, DATABASE_NAME, null, DATABASE_Version);
            this.context=context;
        }

        public void onCreate(SQLiteDatabase db) {

            try {
                db.execSQL(CREATE_TABLE);
            } catch (Exception e) {
                Message.message(context,""+e);
            }
        }

        @Override
        public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
            try {
                Message.message(context,"OnUpgrade");
                db.execSQL(DROP_TABLE);
                onCreate(db);
            }catch (Exception e) {
                Message.message(context,""+e);
            }
        }
    }
}

The following code is in Message.java

package codebind.example.sqliteoperations;

import android.content.Context;
import android.widget.Toast;

public class Message {
    public static void message(Context context, String message) {
        Toast.makeText(context, message, Toast.LENGTH_LONG).show();
    }
}

The following code is in activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"

    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/activity_main"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="#4B1414">

    <TextView
        android:id="@+id/textView"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_alignParentStart="true"
        android:layout_alignParentLeft="true"
        android:layout_alignParentTop="true"
        android:layout_marginTop="12dp"
        android:gravity="center"
        android:text="Student Name"
        android:textColor="#FFFFFF"
        android:textSize="18sp"
        android:textStyle="bold|italic" />

    <EditText
        android:id="@+id/editName"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_below="@+id/textView"
        android:layout_alignParentEnd="true"
        android:layout_alignParentRight="true"
        android:ems="10"
        android:gravity="center_vertical|center"
        android:hint="Enter Name"
        android:inputType="textPersonName"
        android:textColor="#FFFFFF"
        android:textStyle="bold|italic" />

    <TextView
        android:id="@+id/textView2"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_below="@+id/editName"
        android:layout_alignParentEnd="true"
        android:layout_alignParentRight="true"
        android:layout_marginTop="13dp"
        android:gravity="center"
        android:hint="Enter Password"
        android:text="Parent Number"
        android:textColor="#FFFFFF"
        android:textSize="18sp"
        android:textStyle="bold|italic" />

    <Button
        android:id="@+id/button2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignBaseline="@+id/button"
        android:layout_alignEnd="@+id/button4"
        android:layout_alignRight="@+id/button4"
        android:layout_alignBottom="@+id/button"
        android:onClick="viewdata"
        android:text="View Data"
        android:textSize="18sp"
        android:textStyle="bold|italic" />

    <Button
        android:id="@+id/button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@+id/editPass"
        android:layout_alignParentStart="true"
        android:layout_alignParentLeft="true"
        android:layout_marginStart="28dp"
        android:layout_marginLeft="28dp"
        android:layout_marginTop="23dp"
        android:onClick="addUser"
        android:text="Add User"
        android:textSize="18sp"
        android:textStyle="bold|italic" />

    <Button
        android:id="@+id/button3"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@+id/editText3"
        android:layout_alignStart="@+id/button4"
        android:layout_alignLeft="@+id/button4"
        android:layout_marginTop="13dp"
        android:onClick="update"
        android:text="Update"
        android:textStyle="normal|bold" />

    <EditText
        android:id="@+id/editText6"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignTop="@+id/button4"
        android:layout_alignParentStart="true"
        android:layout_alignParentLeft="true"
        android:layout_toStartOf="@+id/button2"
        android:layout_toLeftOf="@+id/button2"
        android:ems="10"
        android:freezesText="false"
        android:hint="Enter Name to Delete Data"
        android:inputType="textPersonName" />

    <Button
        android:id="@+id/button4"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentEnd="true"
        android:layout_alignParentRight="true"
        android:layout_alignParentBottom="true"
        android:layout_marginEnd="21dp"
        android:layout_marginRight="21dp"
        android:layout_marginBottom="41dp"
        android:onClick="delete"
        android:text="Delete"
        android:textStyle="normal|bold"
        tools:ignore="RelativeOverlap" />

    <EditText
        android:id="@+id/editText3"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@+id/button"
        android:layout_alignParentStart="true"
        android:layout_alignParentLeft="true"
        android:layout_marginStart="7dp"
        android:layout_marginLeft="7dp"
        android:layout_marginTop="47dp"
        android:ems="10"
        android:hint="Current Name"
        android:inputType="textPersonName"
        android:textColor="#FFFFFF"
        android:textSize="14sp"
        android:textStyle="bold|italic" />

    <EditText
        android:id="@+id/editPass"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_below="@+id/textView2"
        android:layout_alignParentStart="true"
        android:layout_alignParentLeft="true"
        android:layout_marginTop="11dp"
        android:ems="10"
        android:gravity="center_vertical|center"
        android:hint="Enter Number"
        android:inputType="textPassword"
        android:textAllCaps="false"
        android:textSize="18sp"
        android:textStyle="normal|bold" />

    <EditText
        android:id="@+id/editText5"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignStart="@+id/editText3"
        android:layout_alignLeft="@+id/editText3"
        android:layout_alignTop="@+id/button3"
        android:layout_marginTop="32dp"
        android:ems="10"
        android:hint="New Name"
        android:inputType="textPersonName"
        android:textSize="14sp"
        android:textStyle="bold|italic" />

</RelativeLayout>

Thanks you for all your help!

Re: Transfer data from SQL database to populate spinner

Richard MacCutchan21-Feb-20 6:10

Richard MacCutchan

21-Feb-20 6:10

You need to put the data into an object that the spinner can use to populate itself, like an ArrayAdapter. See Spinners | Android Developers[^].

Re: Transfer data from SQL database to populate spinner

Member 1475169121-Feb-20 7:38

Member 14751691

21-Feb-20 7:38

Thank you. How would I go about doing that? I am fairly new to android studio and this is all new to me.

Re: Transfer data from SQL database to populate spinner

Richard MacCutchan21-Feb-20 22:08

Richard MacCutchan

21-Feb-20 22:08

Read the documentation for the classes that you are trying to use. Also look at some of the Android tutorials here on CodeProject: https://www.codeproject.com/KB/android/[^]

Re: Transfer data from SQL database to populate spinner

Member 1475169122-Feb-20 14:38

Member 14751691

22-Feb-20 14:38

Thank you very much!

Json Manager Project (Need Critique/Possible Tips)

Member 147385357-Feb-20 16:20

Member 14738535

7-Feb-20 16:20

Hi Guys,
This is my first post in this community. And I hope I am not screwing up.

Anyways I built a package to process Json data as a string into objects as nodes stored in nodes in a tree. It is far from complete, but the parsing and node tree building methods are set and the manager class is commenting.

This is also important to me as I am building a portfolio, and I i would be grateful if someone can take another look to see if anything can be done more efficiently and possible let me know where i went wrong with commenting and examples of how you would do it.

Anyways the main class link in github is bellow:
JVJsonManager/Json.java at master · Clowcadia/JVJsonManager · GitHub[^]

Re: Json Manager Project (Need Critique/Possible Tips)

Richard MacCutchan7-Feb-20 22:06

Richard MacCutchan

7-Feb-20 22:06

Sorry, this forum is for technical questions. Also, most people here have day jobs so their time is limited. But Java already has built in support for JSON: java json - Google Search[^].

Re: Json Manager Project (Need Critique/Possible Tips)

Member 147385358-Feb-20 3:56

Member 14738535

8-Feb-20 3:56

Thank you for response, I am aware of the existing Json libraries out there, the reason i made my own is to populate my portfolio with something as i think a starter portfolio will tend to end up rewriting the wheel . (I am sure this is the case most of the time anyways, as most application for most functions are already existent). As for this is not the correct community for this, does anyone have suggestions where I could get some advice?

How to optimize the time complexity of counting a word

neelayak7-Feb-20 3:28

neelayak

7-Feb-20 3:28

So i am working on a hacker rank question and able to make it work but in certain cases it takes way too much time

Java

<pre>static long repeatedString1(String u, long n) {
		String[] a = u.split("");
		int s = a.length;
		int t = (int) n;
		int r = (t / s) + 1;
		String d = new String(new char[t]).replace("\0", u);
		String[] m = d.split("");
		long p = 0;
		if (s == 1) {
			p = t;
		} else {
			for (int i = 0; i < t; i++) {

				if (m[i].equals("a")) {
					p++;
				}
			}
		}
		return p;
	}

any sugessions how i can make it fast?
The question is i will given a randon string and i have to count no of "a" in the string where "n" is the no of words that will be repeated.https://www.hackerrank.com/challenges/repeated-string/problem?h_l=interview&playlist_slugs%5B%5D=interview-preparation-kit&playlist_slugs%5B%5D=warmup[^]

Re: How to optimize the time complexity of counting a word

Richard MacCutchan7-Feb-20 4:08

Richard MacCutchan

7-Feb-20 4:08

I am not sure why you are splitting the string into an array of characters. You can do a simple count by iterating over the elements of the string testing for 'a'. You can use the string length and the number value to calculate how many times the string is repeated. Using that information should lead you to a faster solution. Just remember to allow for a truncated string at the end. And your code would be much easier to understand if you used meaningful names for your variables rather than single letters.

Re: How to optimize the time complexity of counting a word

neelayak7-Feb-20 4:21

neelayak

7-Feb-20 4:21

Thx Sir, In the question there are different case like "ababacc", "aba","a" So what i am doing is i split the words into an array and then add the words as per the letter. there is one more approach that i want to ask will that will more efficiently or not

So i will divide the n from the array size of the string and then (string.length- reminder) and I will have the no of times it is divisible and i will also calculate the no of "a" present in the word

Re: How to optimize the time complexity of counting a word

Richard MacCutchan7-Feb-20 4:41

Richard MacCutchan

7-Feb-20 4:41

Like I said, there is no need to split the string. Just count the number of 'a's in the string. From that number, the length of the string, and the repeat count, you can easily calculate the total.

Message Closed

20-Jan-20 14:21

bekagaw653

20-Jan-20 14:21

Message Closed

Member 1471420112-Jan-20 9:03

Member 14714201

12-Jan-20 9:03

No post

modified 13-Jan-20 9:36am.

Re: Java task zigzag

Richard MacCutchan12-Jan-20 22:11

Richard MacCutchan

12-Jan-20 22:11

Please read Forum Guidelines - PLEASE READ - Java Discussion Boards[^], then edit your message and post proper details of your problem.

Re: Java task zigzag

ZurdoDev13-Jan-20 1:05

ZurdoDev

13-Jan-20 1:05

Many people would want to help but we're all pretty bad at mind reading. At least most people on this site think that about me.

Social Media - A platform that makes it easier for the crazies to find each other.

Everyone is born right handed. Only the strongest overcome it.
Fight for left-handed rights and hand equality.

Re: Java task zigzag

Richard MacCutchan13-Jan-20 1:33

Richard MacCutchan

13-Jan-20 1:33

I think I know what you are thinking now ...

bus reservation and ticketting system

Member 1469715023-Dec-19 10:20

Member 14697150

23-Dec-19 10:20

hello guys!
I need a java project on BUS RESERVATION AND TICKETTING SYSTEM done by object oriented concepts.
so if any one to help me please send me a source code!

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