Why Doesn't my add button work?

Question

Im writing a simple android program that takes input names of subjects and then prints them while adding them in sqlite database. But my add button isn't working at all. Help me! im following thenewBoston course on youtube where Bucky gets the job done!

My Mainactivity file

package com.akhilvaid21gmail.attendanceapp;

import android.content.Intent;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.Button;

public class MainActivity extends AppCompatActivity {



    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        Button button=(Button) findViewById(R.id.moveOnButton);
        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                goToSecondActivity();

            }
        });

    }

private void goToSecondActivity()
{
    Intent intent=new Intent(this,Display.class);
    startActivity(intent);





}

My main_activity_xml Xml file

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.akhilvaid21gmail.attendanceapp.MainActivity">

    <TextView
        android:id="@+id/textView"
        android:layout_width="194dp"
        android:layout_height="225dp"
        android:text="Hello There!         Welcome to the Attendance App!"
        android:textColor="@android:color/holo_orange_dark"
        android:textSize="24sp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintHorizontal_bias="0.573"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.251" />

    <Button
        android:id="@+id/moveOnButton"
        android:layout_width="167dp"
        android:layout_height="76dp"
        android:layout_marginBottom="8dp"
        android:layout_marginEnd="8dp"
        android:layout_marginStart="8dp"
        android:layout_marginTop="8dp"
        android:text="Check Attendance?"
        android:textColor="@color/colorAccent"
        android:textSize="18sp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.502"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.498" />

</android.support.constraint.ConstraintLayout>

My Display.java file

package com.akhilvaid21gmail.attendanceapp;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.EditText;
import android.widget.TextView;

public class Display extends AppCompatActivity {



    EditText Input;
    TextView myText;
    myDBHandler dbHandler;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_display);


        Input=(EditText)findViewById(R.id.inputText);

        myText= (TextView) findViewById(R.id.displayText);
        dbHandler= new myDBHandler(this,null,null,1);
        printDatabase();

    }
    //Print Database
    public void printDatabase()
    {
        String dbString=dbHandler.databaseToString();
        myText.setText(dbString);
        Input.setText("");

    }

    public void addButtonClicked(View view)
    {
        Attendance_Register attendance_register =new Attendance_Register(Input.getText().toString());
        dbHandler.addProduct(attendance_register);
    }
    //delete
    public void deleteButtonClicked(View view)
    {
        String InputText=Input.getText().toString();
        dbHandler.deleteSubject(InputText);

    }

}

my Display.xml file

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.akhilvaid21gmail.attendanceapp.Display">

    <Button
        android:id="@+id/addButton"
        android:layout_width="wrap_content"
        android:layout_height="43dp"
        android:layout_marginBottom="8dp"
        android:layout_marginEnd="8dp"
        android:layout_marginStart="8dp"
        android:layout_marginTop="8dp"
        android:onClick="addButtonClicked"
        android:text="Add"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.153"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.314" />

    <Button
        android:id="@+id/deleteButton"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginBottom="8dp"
        android:layout_marginEnd="8dp"
        android:layout_marginStart="8dp"
        android:layout_marginTop="8dp"
        android:onClick="deleteButtonClicked"
        android:text="Delete"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.753"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.317" />

    <EditText
        android:id="@+id/inputText"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginBottom="8dp"
        android:layout_marginEnd="8dp"
        android:layout_marginStart="8dp"
        android:layout_marginTop="8dp"
        android:ems="10"
        android:hint="Enter your Subjects Name"
        android:inputType="textPersonName"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.503"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.017" />

    <TextView
        android:id="@+id/displayText"
        android:layout_width="174dp"
        android:layout_height="194dp"
        android:layout_marginBottom="8dp"
        android:layout_marginEnd="8dp"
        android:layout_marginStart="8dp"
        android:layout_marginTop="8dp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.754" />
</android.support.constraint.ConstraintLayout>

my myDBHandler file

package com.akhilvaid21gmail.attendanceapp;

/**
 * Created by Akhil on 27-Feb-18.
 */

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


public class myDBHandler extends SQLiteOpenHelper{

    private static final int DATABASE_VERSION=1;

    private static final String DATABASE_NAME="Attendance.db";
    public static final String TABLE_ATTENDANCE="Attendance";
    public static final String COLUMN_ID="_id";
    public static final String COLUMN_SUBJECTNAME="Subject Name";
    public myDBHandler(Context context, String name, SQLiteDatabase.CursorFactory factory, int version) {
        super(context, DATABASE_NAME, factory, DATABASE_VERSION);
    }



    @Override
    public void onCreate(SQLiteDatabase sqLiteDatabase) {
        String query="CREATE TABLE "+   TABLE_ATTENDANCE+"("+
                COLUMN_ID+" INTEGER PRIMARY KEY AUTOINCREMENT ,"+
               COLUMN_SUBJECTNAME+" TEXT "+
                ");";

            sqLiteDatabase.execSQL(query);
    }

    @Override
    public void onUpgrade(SQLiteDatabase sqLiteDatabase, int i, int i1) {
        sqLiteDatabase.execSQL("DROP TABLE IF EXISTS " + TABLE_ATTENDANCE);
        onCreate(sqLiteDatabase);

    }

    //Add new row to database
    public void addProduct( Attendance_Register attendance)
    {
        ContentValues values = new ContentValues();
        //,COLUMN_DAYS_PRESENT,attendance.getDays_present(),COLUMN_DAYS_ABSENT,attendance.getDays_absent()
        values.put(COLUMN_SUBJECTNAME,attendance.get_subjectName());
        SQLiteDatabase sqLiteDatabase = getWritableDatabase();
        sqLiteDatabase.insert(TABLE_ATTENDANCE,null,values);
        sqLiteDatabase.close();


    }

    //Delete row from database
    public void deleteSubject(String subjectname)
    {
        SQLiteDatabase sqLiteDatabase = getWritableDatabase();
        sqLiteDatabase.execSQL("DELETE FROM "+TABLE_ATTENDANCE+" WHERE "+ COLUMN_SUBJECTNAME+ "=\"" + subjectname+"\";");



    }


   // Print Data Base as a String
    public String databaseToString()
    {
        String dbString="";

        SQLiteDatabase sqLiteDatabase = getWritableDatabase();
        String query="SELECT * FROM "+TABLE_ATTENDANCE+" WHERE 1";
        //CURSOR POINT TO A LOCATION IN YOUR RESULTS
        Cursor c=sqLiteDatabase.rawQuery(query,null);
        //Move to first row
        c.moveToFirst();
            while(!c.isAfterLast())
            {
                if(c.getString(c.getColumnIndex("Subject Name "))!=null){
                    dbString+=c.getString((c.getColumnIndex("Subject Name")));
                    dbString+="\n";
                    c.moveToNext();
                }
            }

        sqLiteDatabase.close();
            return dbString;
    }




}

My attendance_register file

package com.akhilvaid21gmail.attendanceapp;

/**
 * Created by Akhil on 27-Feb-18.
 */

public class Attendance_Register {

    private int _id;

    private String _subjectName;

    public Attendance_Register(){

    }


    public Attendance_Register(String _subjectName) {
        this._subjectName = _subjectName;
    }

    public void set_id(int _id) {
        this._id = _id;
    }


    public void set_subjectName(String _subjectName) {
        this._subjectName = _subjectName;
    }


    public int get_id() {
        return _id;
    }


    public String get_subjectName() {
        return _subjectName;
    }

}

I think this [answer](https://stackoverflow.com/a/4153842/2148666) will help you — Nicolás Carrasco-Stevenson, Feb 27 '18 at 12:53
Possible duplicate of [How exactly does the android:onClick XML attribute differ from setOnClickListener?](https://stackoverflow.com/questions/4153517/how-exactly-does-the-androidonclick-xml-attribute-differ-from-setonclicklistene) — Nicolás Carrasco-Stevenson, Feb 27 '18 at 12:54
"...and then prints them while adding them in sqlite database." - You're not actually printing them after you add them in `addButtonClicked()`. You only add them to the database. Did you mean to call `printDatabase()` again there? — Mike M., Feb 27 '18 at 13:10

Aravindraj · Accepted Answer · 2018-02-27T12:42:29.310

1

You are not referencing Button declared in xml inside java file(Display.java)

Button button1 = (Button) findViewById(R.id.addbutton);

edited Feb 27 '18 at 12:42

answered Feb 27 '18 at 12:36

Aravindraj

590
5
23

1

I have put addButtonClicked as value in 'onClick' Property of the button – Akhil Vaid Feb 27 '18 at 12:38
1.Set id for that Button in xml with android:id="@+id/addbutton" , if you haven't yet .2.Use findViewById inside Display.java as I mentioned. – Aravindraj Feb 27 '18 at 12:40

score 0 · Answer 2 · edited Feb 27 '18 at 13:05

0

change

EditText Input; to EditText inputText;

variable name should start by small letter as suggest by the convention.

for complete result please share in detail, i didn't get you out.

edited Feb 27 '18 at 13:05

vincrichaud

2,218
17
34

answered Feb 27 '18 at 12:39

Milan Hirpara

534
4
18

Why Doesn't my add button work?

2 Answers2