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Android External database : Using database in "assets" folder

The best way to create a database application in android is , using an exteranal database . ie, we can create database  using tools like Navicat , SQLite Browser and copy this database into our application .This  method is more flexible and easy than creating a database in our application .

This is a simple application using external database file.Application will insert data into database and show data from the database in a customized list view.
 Screenshots of this application are
MainActivity


This is the first activity of this application . When  Register Here button is pressed it will start Registration Activity
Editing of the entries can be done with a Long Click on the listView items.
you can download the source code of this project from  google drive https://drive.google.com/folderview?id=0BySLpWhqmbbdY3JHMkZRZFN0bEE&usp=sharing
click on the above link ->sign into  your  google account ->add this to your google drive -> open it in google drive and download it.



if you crate a database file using SQlite browser it will look like this




you can download the sample database file from here 
https://drive.google.com/file/d/0BySLpWhqmbbdeG55d0dtbmNabnc/view?usp=sharing

Atfer creating a database file paste it into the assets folder of your project directory.

The main class of this project is DatabaseHeiper.java  this class will copy the database file in the Assets folder  into the appliction.

package com.arun.externaldatabsedemo;

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteDatabase.CursorFactory;
import android.database.sqlite.SQLiteException;
import android.database.sqlite.SQLiteOpenHelper;

public class DataBaseHelper extends SQLiteOpenHelper {
 private static SQLiteDatabase sqliteDb;
 private static DataBaseHelper instance;
 private static final int DATABASE_VERSION = 1;
 
 private Context context;
 static Cursor cursor = null;

 DataBaseHelper(Context context, String name, CursorFactory factory,
   int version) {
  super(context, name, factory, version);
  this.context = context;

 }

 private static void initialize(Context context, String databaseName) {
  if (instance == null) {

   if (!checkDatabase(context, databaseName)) {

    try {
     copyDataBase(context, databaseName);
    } catch (IOException e) {

     System.out.println( databaseName
       + " does not exists ");
    }
   }

   instance = new DataBaseHelper(context, databaseName, null,
     DATABASE_VERSION);
   sqliteDb = instance.getWritableDatabase();

   System.out.println("instance of  " + databaseName + " created ");
  }
 }

 public static final DataBaseHelper getInstance(Context context,
   String databaseName) {
  initialize(context, databaseName);
  return instance;
 }

 public SQLiteDatabase getDatabase() {
  return sqliteDb;
 }

 @Override
 public void onCreate(SQLiteDatabase db) {

 }

 @Override
 public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {

 }

 private static void copyDataBase(Context aContext, String databaseName)
   throws IOException {

  InputStream myInput = aContext.getAssets().open(databaseName);

  String outFileName = getDatabasePath(aContext, databaseName);

  File f = new File("/data/data/" + aContext.getPackageName()
    + "/databases/");
  if (!f.exists())
   f.mkdir();

  OutputStream myOutput = new FileOutputStream(outFileName);

  byte[] buffer = new byte[1024];
  int length;
  while ((length = myInput.read(buffer)) > 0) {
   myOutput.write(buffer, 0, length);
  }

  myOutput.flush();
  myOutput.close();
  myInput.close();

  System.out.println(databaseName + " copied");
 }

 public static boolean checkDatabase(Context aContext, String databaseName) {
  SQLiteDatabase checkDB = null;

  try {
   String myPath = getDatabasePath(aContext, databaseName);

   checkDB = SQLiteDatabase.openDatabase(myPath, null,
     SQLiteDatabase.OPEN_READONLY);

   checkDB.close();
  } catch (SQLiteException e) {

   System.out.println(databaseName + " does not exists");
  }

  return checkDB != null ? true : false;
 }

 private static String getDatabasePath(Context aContext, String databaseName) {
  return "/data/data/" + aContext.getPackageName() + "/databases/"
    + databaseName;
 }

 public static Cursor rawQuery(String query) {
  try {
   if (sqliteDb.isOpen()) {
    sqliteDb.close();
   }
   sqliteDb = instance.getWritableDatabase();

   cursor = null;
   cursor = sqliteDb.rawQuery(query, null);
  } catch (Exception e) {
   System.out.println("DB ERROR  " + e.getMessage());
   e.printStackTrace();
  }
  return cursor;
 }

 public static void execute(String query) {
  try {
   if (sqliteDb.isOpen()) {
    sqliteDb.close();
   }
   sqliteDb = instance.getWritableDatabase();
   sqliteDb.execSQL(query);
  } catch (Exception e) {
   System.out.println("DB ERROR  " + e.getMessage());
   e.printStackTrace();
  }
 }
}

The functions public static Cursor rawQuery(String query) is used for select database operation,

 public static Cursor rawQuery(String query) {
  try {
   if (sqliteDb.isOpen()) {
    sqliteDb.close();
   }
   sqliteDb = instance.getWritableDatabase();

   cursor = null;
   cursor = sqliteDb.rawQuery(query, null);
  } catch (Exception e) {
   System.out.println("DB ERROR  " + e.getMessage());
   e.printStackTrace();
  }
  return cursor;
 }
public static void execute(String query) is used for insert. update, delete operations. 
public static void execute(String query) {
  try {
   if (sqliteDb.isOpen()) {
    sqliteDb.close();
   }
   sqliteDb = instance.getWritableDatabase();
   sqliteDb.execSQL(query);
  } catch (Exception e) {
   System.out.println("DB ERROR  " + e.getMessage());
   e.printStackTrace();
  }
 }
MainActivity.java
The mainAcitivy is the first activity of this sample aplication Which shows a list of registered employees. 

package com.arun.externaldatabsedemo;

import java.util.ArrayList;

import android.app.Activity;
import android.content.Intent;
import android.database.Cursor;
import android.os.Bundle;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemLongClickListener;
import android.widget.Button;
import android.widget.ListView;

public class MainActivity extends Activity {
 private DataBaseHelper dataBaseHelper;
 private ListView lvEmployee;
 private Button btRegister;
 private static final String DB_NAME = "EMPLOYEE_DB";

 @Override
 protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_main);
  dataBaseHelper = DataBaseHelper.getInstance(this, DB_NAME);
  lvEmployee = (ListView) findViewById(R.id.lv_employee);
  btRegister = (Button) findViewById(R.id.btn_register);

  showEmployeeDetails();

  lvEmployee.setOnItemLongClickListener(new OnItemLongClickListener() {

   @Override
   public boolean onItemLongClick(AdapterView<?> arg0, View arg1,
     int position, long arg3) {
    EmployeeListItems listItems = (EmployeeListItems) arg0
      .getItemAtPosition(position);
    String employeeId = listItems.getEmpId();
    Bundle passData = new Bundle();
    passData.putString("empID", employeeId);
    Intent Editintent = new Intent(MainActivity.this,
      EmployeEdit.class);
    Editintent.putExtras(passData);
    startActivity(Editintent);

    return false;
   }
  });

  btRegister.setOnClickListener(new OnClickListener() {

   @Override
   public void onClick(View v) {
    Intent intent = new Intent(MainActivity.this,
      EmployeeRegistration.class);
    startActivity(intent);

   }
  });
 }

 private void showEmployeeDetails() {

  ArrayList<EmployeeListItems> employeeList = new ArrayList<EmployeeListItems>();
  employeeList.clear();
  String query = "SELECT * FROM employe";
  Cursor c1 = DataBaseHelper.rawQuery(query);

  if (c1 != null && c1.getCount() != 0) {
   if (c1.moveToFirst()) {
    do {
     EmployeeListItems employeeListItems = new EmployeeListItems();

     employeeListItems.setEmpId(c1.getString(c1
       .getColumnIndex("employee_id")));
     employeeListItems.setFirstName(c1.getString(c1
       .getColumnIndex("first_name")));
     employeeListItems.setLastName(c1.getString(c1
       .getColumnIndex("last_name")));
     employeeListItems.setPhoneNO(c1.getString(c1
       .getColumnIndex("phone_no")));
     employeeList.add(employeeListItems);

    } while (c1.moveToNext());
   }
  }
  c1.close();

  EmployeeListAdapter employeeListAdapter = new EmployeeListAdapter(
    MainActivity.this, employeeList);
  lvEmployee.setAdapter(employeeListAdapter);

 }

 @Override
 public boolean onCreateOptionsMenu(Menu menu) {
  // Inflate the menu; this adds items to the action bar if it is present.
  getMenuInflater().inflate(R.menu.main, menu);
  return true;
 }

}
Customized ListView is used here so Customized Adapter class(EmployeeListAdapter.java) and a bean class(EmployeeListItems.java) is used

EmployeeListAdapter.java
package com.arun.externaldatabsedemo;

import java.util.ArrayList;

import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.TextView;

public class EmployeeListAdapter extends BaseAdapter {

 Context context;
 ArrayList<EmployeeListItems> employeeList;

 public EmployeeListAdapter(Context context,
   ArrayList<EmployeeListItems> employeeList) {

  this.context = context;
  this.employeeList = employeeList;
 }

 @Override
 public int getCount() {

  return employeeList.size();
 }

 @Override
 public Object getItem(int position) {

  return employeeList.get(position);
 }

 @Override
 public long getItemId(int position) {

  return position;
 }

 @Override
 public View getView(int position, View convertView, ViewGroup parent) {
  EmployeeListItems employeeListItems = employeeList.get(position);

  if (convertView == null) {
   LayoutInflater inflater = (LayoutInflater) context
     .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
   convertView = inflater.inflate(R.layout.employee_list_row, null);

  }
  TextView tvSlNo = (TextView) convertView.findViewById(R.id.tv_slno);
  tvSlNo.setText(employeeListItems.getEmpId());
  TextView tvFirstName = (TextView) convertView
    .findViewById(R.id.tv_first_name);
  tvFirstName.setText(employeeListItems.getFirstName());
  TextView tvLastName = (TextView) convertView
    .findViewById(R.id.tv_last_name);
  tvLastName.setText(employeeListItems.getLastName());
  TextView tvPhone = (TextView) convertView.findViewById(R.id.tv_phone);
  tvPhone.setText(employeeListItems.getPhoneNO());

  return convertView;
 }

}

EmployeeListItems.java

package com.arun.externaldatabsedemo;

public class EmployeeListItems {
 private String EmpId;
 private String FirstName;
 private String LastName;
 private String PhoneNO;

 public String getEmpId() {
  return EmpId;
 }

 public void setEmpId(String empId) {
  EmpId = empId;
 }

 public String getFirstName() {
  return FirstName;
 }

 public void setFirstName(String firstName) {
  FirstName = firstName;
 }

 public String getLastName() {
  return LastName;
 }

 public void setLastName(String lastName) {
  LastName = lastName;
 }

 public String getPhoneNO() {
  return PhoneNO;
 }

 public void setPhoneNO(String phoneNO) {
  PhoneNO = phoneNO;
 }

}

EmployeeRegistration.java

This class is used for new employee registration . The activity is loaded when Register Here button is clicked


package com.arun.externaldatabsedemo;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;

public class EmployeeRegistration extends Activity {
 private Button btSubmit;
 private Button btCancel;
 private EditText etEmpId;
 private EditText etfirstName;
 private EditText etlastaName;
 private EditText etPhone;

 @Override
 protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.new_registration);
  btSubmit = (Button) findViewById(R.id.bt_submit);
  btCancel = (Button) findViewById(R.id.bt_reg_cancel);
  etEmpId = (EditText) findViewById(R.id.et_id);
  etfirstName = (EditText) findViewById(R.id.et_first_name);
  etlastaName = (EditText) findViewById(R.id.et_last_name);
  etPhone = (EditText) findViewById(R.id.et_phone);

  btSubmit.setOnClickListener(new OnClickListener() {

   @Override
   public void onClick(View v) {

    String insertQuery = "INSERT INTO employe VALUES('"
      + etEmpId.getText().toString() + "'," + "'"
      + etfirstName.getText().toString() + "','"
      + etlastaName.getText().toString() + "','"
      + etPhone.getText().toString() + "')";

    DataBaseHelper.execute(insertQuery);
    Intent intent = new Intent(EmployeeRegistration.this,
      MainActivity.class);
    startActivity(intent);

   }
  });

  btCancel.setOnClickListener(new OnClickListener() {

   @Override
   public void onClick(View v) {

    finish();
   }
  });

 }

}
EmployeEdit.java

This Class is used to edit employee details . By Long clicking ListView items we can edit it.


package com.arun.externaldatabsedemo;

import android.app.Activity;
import android.content.Intent;
import android.database.Cursor;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;

public class EmployeEdit extends Activity {

 private Button btCancel;
 private Button btDone;
 private EditText etfirstName;
 private EditText etlastaName;
 private EditText etPhone;
 private String employeeId;

 @Override
 protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.edit_employee);
  btDone = (Button) findViewById(R.id.bt_done);
  btCancel = (Button) findViewById(R.id.bt_cancel);
  etfirstName = (EditText) findViewById(R.id.et_edit_first_name);
  etlastaName = (EditText) findViewById(R.id.et_edit_last_name);
  etPhone = (EditText) findViewById(R.id.et_edit_phone);
  Bundle getData = getIntent().getExtras();
  employeeId = getData.getString("empID");

  setEditTextFields();

  btDone.setOnClickListener(new OnClickListener() {

   @Override
   public void onClick(View v) {
    String UpdateQuery = " UPDATE employe set first_name='"
      + etfirstName.getText().toString() + "' ,"
      + "last_name='" + etlastaName.getText().toString()
      + "' , phone_no='" + etPhone.getText().toString()
      + "' where employee_id='" + employeeId + "' ";

    DataBaseHelper.execute(UpdateQuery);
    Intent intent = new Intent(EmployeEdit.this, MainActivity.class);
    startActivity(intent);

   }
  });
  btCancel.setOnClickListener(new OnClickListener() {

   @Override
   public void onClick(View v) {
    finish();

   }
  });
 }

 private void setEditTextFields() {

  String query = "SELECT * FROM employe where  employee_id='"
    + employeeId + "' ";
  Cursor c1 = DataBaseHelper.rawQuery(query);
  if (c1 != null && c1.getCount() != 0) {
   if (c1.moveToFirst()) {
    do {

     etfirstName.setText(c1.getString(c1
       .getColumnIndex("first_name")));
     etlastaName.setText(c1.getString(c1
       .getColumnIndex("last_name")));
     etPhone.setText(c1.getString(c1.getColumnIndex("phone_no")));

    } while (c1.moveToNext());
   }
  }
  c1.close();
 }

}

Layout files  are the following

activity_main.xml

 
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

    xmlns:tools="http://schemas.android.com/tools"

    android:id="@+id/LinearLayout1"

    android:layout_width="match_parent"

    android:layout_height="match_parent"

    android:orientation="vertical"

  

    tools:context=".MainActivity" >



    <LinearLayout

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:layout_marginLeft="10dp"

        android:layout_marginTop="10dp" >



        <TextView

           

            android:layout_width="50dp"

            android:layout_height="wrap_content"

            android:text="slno"

            android:textColor="#000" />



        <TextView

            android:layout_width="80dp"

            android:layout_height="wrap_content"

            android:text="FirstName"

            android:textColor="#000" />



        <TextView

           

            android:layout_width="80dp"

            android:layout_height="wrap_content"

            android:text="Lastname"

            android:textColor="#000" />



        <TextView

            android:layout_width="match_parent"

            android:layout_height="wrap_content"

            android:text="phoneNo"

            android:textColor="#000" />



    </LinearLayout>



    <ListView

        android:id="@+id/lv_employee"

        android:layout_width="match_parent"

        android:layout_height="wrap_content"

        android:layout_marginBottom="10dp"

        android:layout_marginLeft="10dp" >



    </ListView>



    <Button

        android:id="@+id/btn_register"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:layout_marginTop="20dp"

        android:text="@string/register" />





</LinearLayout>


new_registration.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" >

    <TableLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content" >

        <TableRow
            android:id="@+id/tableRow1"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content" >

            <TextView
                android:id="@+id/textView1"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="@string/emp_id" />

            <EditText
                android:id="@+id/et_id"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:ems="10" >

                <requestFocus />
            </EditText>
        </TableRow>

        <TableRow
            android:id="@+id/tableRow2"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content" >

            <TextView
                android:id="@+id/TextView01"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="First Name" />

            <EditText
                android:id="@+id/et_first_name"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:ems="10" />
        </TableRow>

        <TableRow
            android:id="@+id/tableRow3"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content" >

            <TextView
                android:id="@+id/TextView02"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="Last Name" />

            <EditText
                android:id="@+id/et_last_name"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:ems="10" />
        </TableRow>

        <TableRow
            android:id="@+id/tableRow4"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content" >

            <TextView
                android:id="@+id/TextView03"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="Phone" />

            <EditText
                android:id="@+id/et_phone"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:ems="10" />
        </TableRow>
    </TableLayout>

    <RelativeLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="20dp" >

        <Button
            android:id="@+id/bt_submit"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_alignParentRight="true"
            android:layout_alignParentTop="true"
            android:layout_marginRight="70dp"
            android:text="@string/submit" />

        <Button
            android:id="@+id/bt_reg_cancel"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_alignParentTop="true"
            android:layout_marginRight="31dp"
            android:layout_toLeftOf="@+id/bt_submit"
            android:text="cancel" />
    </RelativeLayout>

</LinearLayout>


edit_employee.xml 


<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" >

    <TableLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content" >

        <TableRow
            android:id="@+id/tableRow2"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content" >

            <TextView
                android:id="@+id/TextView01"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="First Name" />

            <EditText
                android:id="@+id/et_edit_first_name"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:ems="10" />
        </TableRow>

        <TableRow
            android:id="@+id/tableRow3"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content" >

            <TextView
                android:id="@+id/TextView02"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="Last Name" />

            <EditText
                android:id="@+id/et_edit_last_name"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:ems="10" />
        </TableRow>

        <TableRow
            android:id="@+id/tableRow4"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content" >

            <TextView
                android:id="@+id/TextView03"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="Phone" />

            <EditText
                android:id="@+id/et_edit_phone"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:ems="10" />
        </TableRow>
    </TableLayout>

    <RelativeLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="20dp" >

        <Button
            android:id="@+id/bt_done"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_alignParentRight="true"
            android:layout_alignParentTop="true"
            android:layout_marginRight="24dp"
            android:text="@string/done" />

        <Button
            android:id="@+id/bt_cancel"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_alignParentTop="true"
            android:layout_marginRight="33dp"
            android:layout_toLeftOf="@+id/bt_done"
            android:text="@string/cancel" />
    </RelativeLayout>

</LinearLayout>


employee_list_row.xml 


<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

    android:id="@+id/LinearLayout1"

    android:layout_width="match_parent"

    android:layout_height="match_parent"

    android:layout_marginLeft="10dp"

    android:orientation="horizontal" >



    <TextView

        android:id="@+id/tv_slno"

        android:layout_width="50dp"

        android:layout_height="wrap_content"

        android:text="slno"

        android:textColor="#000" />



    <TextView

        android:id="@+id/tv_first_name"

        android:layout_width="80dp"

        android:layout_height="wrap_content"

        android:text="TextView"

        android:textColor="#000" />



    <TextView

        android:id="@+id/tv_last_name"

        android:layout_width="80dp"

        android:layout_height="wrap_content"

        android:text="TextView"

        android:textColor="#000" />



    <TextView

        android:id="@+id/tv_phone"

        android:layout_width="match_parent"

        android:layout_height="wrap_content"

        android:text="TextView"

        android:textColor="#000" />



</LinearLayout>

Comments

  1. PAKISTANI DRAMA25 April 2016 at 03:08

    https://drive.google.com/folderview?id=0BySLpWhqmbbdY3JHMkZRZFN0bEE&usp=sharing
    DOWNLOADED THIS FILES BUT HOW TO OPEN THIS PROJECT IN ANDROID STUDIO 2.0

    ReplyDelete
    Replies
    1. Arunkrishna26 April 2016 at 07:19

      The sample code is done in eclipse so it will show issues in android studio. Use this below link
      http://developer.android.com/sdk/installing/migrate.html

      Delete

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If you are running a keytool command  keytool -list -v -keystore C:\Users\arun\.android\debug.keystore -alias androiddebugkey -storepass android    and getting an error   'keytool' is not recognized as an internal or external command  If you are using any other commad like java,javac , etc.. and getting an error " is not recognized as an internal or external command"  you can also use this same steps  you are getting this error because keytool.exe , executable file which exists in the bin directory of your JDK  is not added to Path in your Environmental variables. To resolve this issue 1 .first we need to find the bin Directory of our jdk    Usually this will be in  C:\Program Files\Java\jre1.8.0_221\bin (jre1.8.0_221 - change this to your latest version , ). you can see keytool.exe file in the bin directory . (If you installed jdk in a different directory Find your Jdk installation folder and  use that path.) 2 . we need to add this bin directory
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Simple Calculator With ViewModel and LIveData

This is a simple calculator with basic mathematical operations. You can download full source code of this project from Github https://github.com/arunkfedex/SimpleCalculator We are using ViewModel and LiveData so we need to add those dependencies in build.gradle file. build.gradle plugins { id 'com.android.application' id 'kotlin-android' } android { compileSdk 30 defaultConfig { applicationId "com.arun.androidtutsforu.simplecalculator" minSdk 21 targetSdk 30 versionCode 1 versionName "1.0" testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner" } buildTypes { release { minifyEnabled false proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro' } } compileOptions { sourceCompatibility JavaVersion.VERSION_1_8 ta
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Simple Calculator in Android

You can view new updated simple calculator with ViemModel and LiveData in my new blog    https://androidtuts4u.blogspot.com/2021/10/simple-calculator-with-viewmodel-and.html To create a calculator first  we need to create the layout of the calculator. Layout  is created  using XML file given below <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"     xmlns:tools="http://schemas.android.com/tools"     android:layout_width="match_parent"     android:layout_height="match_parent" >  <EditText     android:id="@+id/result_id"       android:layout_width="fill_parent"     android:layout_height="120dp"   />  <Button    android:id="@+id/Btn7_id"      android:layout_width="70dp"    android:layout_height="60dp"    android:layout_below="@id/result_id"    android:text="7"    android:onClick="btn7Clicked"  
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