Q:

showing data in listview from database in android studio

So I tried creating a database and the data is getting saved on the database but I wanted to get the data in the list view on the mainactivity so I tried here's the Main Activity
 import android.content.Intent;
 import android.database.Cursor;
 import android.database.sqlite.SQLiteDatabase;
 import android.database.sqlite.SQLiteOpenHelper;
 import android.support.design.widget.FloatingActionButton;
 import android.support.v7.app.AppCompatActivity;
 import android.os.Bundle;
 import android.view.View;
 import android.widget.ArrayAdapter;
 import android.widget.ListAdapter;
 import android.widget.ListView;
 import android.widget.Toast;

 import java.util.ArrayList;
 import java.util.List;

 import static com.frolicfreak.bhushan.memo.DatabaseHelper.Table_Name;

public class MainActivity extends AppCompatActivity implements View.OnClickListener{

FloatingActionButton fab;
DatabaseHelper db;

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

    db =new DatabaseHelper(this);

    fab= (FloatingActionButton)findViewById(R.id.fab);
    fab.setOnClickListener(this);

    ListView listView = (ListView)findViewById(R.id.list);

    ArrayList<String> theList =new ArrayList<>();
    Cursor data= db.getAllData();

    if (data.getCount()==0){
        return;
    }
    else
    {
        while(data.moveToNext()){
            theList.add(getString(1));
            ListAdapter listAdapter=new ArrayAdapter<>(this,android.R.layout.simple_list_item_1,theList);
            listView.setAdapter(listAdapter);
        }
    }
}

@Override
public void onClick(View v) {

    Intent intent= new Intent(this,Main2Activity.class);
    startActivity(intent);

}

}
now I executed this activity and there is an error in the android monitor
  08-25 02:13:23.179 4125-4125/com.frolicfreak.bhushan.memo E/AndroidRuntime: FATAL EXCEPTION: main
                                                                        Process: com.frolicfreak.bhushan.memo, PID: 4125
                                                                        java.lang.RuntimeException: Unable to start activity ComponentInfo{com.frolicfreak.bhushan.memo/com.frolicfreak.bhushan.memo.MainActivity}: android.content.res.Resources$NotFoundException: String resource ID #0x1
                                                                            at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2416)
                                                                            at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2476)
                                                                            at android.app.ActivityThread.-wrap11(ActivityThread.java)
                                                                            at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1344)
                                                                            at android.os.Handler.dispatchMessage(Handler.java:102)
                                                                            at android.os.Looper.loop(Looper.java:148)
                                                                            at android.app.ActivityThread.main(ActivityThread.java:5417)
                                                                            at java.lang.reflect.Method.invoke(Native Method)
                                                                            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
                                                                            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
                                                                         Caused by: android.content.res.Resources$NotFoundException: String resource ID #0x1
                                                                            at android.content.res.Resources.getText(Resources.java:312)
                                                                            at android.content.res.Resources.getString(Resources.java:400)
                                                                            at android.content.Context.getString(Context.java:409)
                                                                            at com.frolicfreak.bhushan.memo.MainActivity.onCreate(MainActivity.java:47)
                                                                            at android.app.Activity.performCreate(Activity.java:6237)
                                                                            at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1107)
                                                                            at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2369)
                                                                            at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2476) 
                                                                            at android.app.ActivityThread.-wrap11(ActivityThread.java) 
                                                                            at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1344) 
                                                                            at android.os.Handler.dispatchMessage(Handler.java:102) 
                                                                            at android.os.Looper.loop(Looper.java:148) 
                                                                            at android.app.ActivityThread.main(ActivityThread.java:5417) 
                                                                            at java.lang.reflect.Method.invoke(Native Method) 
                                                                            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726) 
                                                                            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616) 

the application is getting crashed even in the main launch activity 
so please help me solving this problem
yes the database helper file is extended 
DatabaseHelper java file is as follows
    package com.frolicfreak.bhushan.memo;

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

    import java.util.ArrayList;

    /**
 * Created by BHUSHAN on 24-08-2017.
*/

     public class DatabaseHelper extends SQLiteOpenHelper {

public static final String Database_Name = "Memo.db";
public static final String Table_Name = "Memo";
public static final String col1 = "ID";
public static final String col2 = "data";

public DatabaseHelper(Context context) {
    super(context, Database_Name, null, 1);
}

@Override
public void onCreate(SQLiteDatabase db) {

    db.execSQL("create table " + Table_Name + "(ID integer primary key autoincrement, data text)");

}

@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
    db.execSQL("drop table if exists " + Table_Name);
    onCreate(db);
}

public boolean insertData(String data, String Data) {
    SQLiteDatabase db = this.getWritableDatabase();
    ContentValues contentValues = new ContentValues();
    contentValues.put(col2, Data);
    long result = db.insert(Table_Name, null, contentValues);
    if (result==-1)
        return false;
    else
        return true;
}

public Cursor getAllData() {

    SQLiteDatabase db = this.getWritableDatabase();
    Cursor res = db.rawQuery("SELECT * FROM " + Table_Name, null);
    return res;
}

}

A:

First try to edit line of your code 
theList.add(getString(1)) to theList.add(data.getString(1))
If after that it does not work give more code of you DBhelper class.

