File 000

Android Studio SQLite Database Example

Table Structure

This is the Student table structure that going to use to store student detail information,

we make thing simple so we only create 3 fields as image below 

Id is primary key and also auto increment number

Screen Layout

We will create 2 screens, first screen will display all students in the database which will

look like this

Second screen which is detail screen, when user click on the listview item it will bring

user to new screen which will look like this

Code The Layout

1. Let’s start to create a project and name it SQLiteDB, and the rest of step should be as

standard, if you need guide on this step , please refer this link. These are the basic

setting i’ve set.

2. In src > main > res > layout > activity_main.xml. Add ListView, Button

into activity_main.xml and it will look like this.activity_main.xml

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<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"    android:paddingLeft="@dimen/activity_horizontal_margin"    android:paddingRight="@dimen/activity_horizontal_margin"    android:paddingTop="@dimen/activity_vertical_margin"    android:paddingBottom="@dimen/activity_vertical_margin"    tools:context="com.instinctcoder.sqlitedb.MainActivity$PlaceholderFragment">     <Button        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:text="Add"        android:id="@+id/btnAdd"        android:layout_alignParentBottom="true"        android:layout_alignParentLeft="true"        android:layout_alignParentStart="true" />     <ListView        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:id="@android:id/list"        android:layout_centerHorizontal="true"        android:layout_alignParentTop="true"        android:layout_above="@+id/btnAdd" />     <Button        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:text="List All"        android:id="@+id/btnGetAll"        android:layout_alignParentBottom="true"        android:layout_toRightOf="@+id/btnAdd" /> </RelativeLayout>

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You need to change the ListView id to android:id=”@+id/listView” if you choose to

extends ListActivity in your class or else you will get error –> Your content must have a

ListView whose id attribute is ‘android.R.id.list’

3. Add another activity and we named it StudentDetail.java. The go to src >

main > res > layout > activity_student_detail.xml. Add Button, TextView

into activity_student_detail.xml and it will look like this.activity_student_detail.xml

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<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"    android:paddingLeft="@dimen/activity_horizontal_margin"    android:paddingRight="@dimen/activity_horizontal_margin"    android:paddingTop="@dimen/activity_vertical_margin"    android:paddingBottom="@dimen/activity_vertical_margin"    tools:context="com.instinctcoder.sqlitedb.StudentDetail$PlaceholderFragment">     <TextView        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:textAppearance="?android:attr/textAppearanceMedium"        android:text="Name"        android:id="@+id/textView"        android:layout_alignParentTop="true"        android:layout_alignParentLeft="true"        android:layout_alignParentStart="true"        android:layout_marginTop="30dp" />     <TextView        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:textAppearance="?android:attr/textAppearanceMedium"        android:text="Email"        android:id="@+id/textView2"        android:layout_below="@+id/textView"        android:layout_alignParentLeft="true"        android:layout_alignParentStart="true"        android:layout_marginTop="29dp" />     <TextView        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:textAppearance="?android:attr/textAppearanceMedium"        android:text="Age"        android:id="@+id/textView3"        android:layout_below="@+id/textView2"        android:layout_alignParentLeft="true"        android:layout_alignParentStart="true"        android:layout_marginTop="29dp" />

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     <EditText        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:inputType="textPersonName"        android:ems="10"        android:id="@+id/editTextName"        android:layout_above="@+id/textView2"        android:layout_toRightOf="@+id/textView"        android:layout_alignParentRight="true"        android:layout_alignParentEnd="true" />     <EditText        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:inputType="textEmailAddress"        android:ems="10"        android:id="@+id/editTextEmail"        android:layout_above="@+id/textView3"        android:layout_toRightOf="@+id/textView"        android:layout_alignRight="@+id/editTextName"        android:layout_alignEnd="@+id/editTextName" />     <EditText        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:inputType="number"        android:ems="10"        android:id="@+id/editTextAge"        android:layout_alignBottom="@+id/textView3"        android:layout_alignLeft="@+id/editTextEmail"        android:layout_alignStart="@+id/editTextEmail"        android:layout_alignRight="@+id/editTextEmail"        android:layout_alignEnd="@+id/editTextEmail" />     <Button        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:text="Save"        android:id="@+id/btnSave"        android:layout_alignParentBottom="true"        android:layout_toLeftOf="@+id/btnClose" />     <Button        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:text="Close"        android:id="@+id/btnClose"        android:layout_alignParentBottom="true"        android:layout_alignParentRight="true"        android:layout_alignParentEnd="true" />     <Button        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:text="Delete"        android:id="@+id/btnDelete"        android:layout_alignTop="@+id/btnSave"        android:layout_toLeftOf="@+id/btnSave" /> </RelativeLayout>

4. When user click on the list item we want to show student detail activity. So we need

an unique id to retrieve student detail and this id must come from listview. To do this we

have 2 options

The easiest way (if you like ;)) you could put id and name into listview

item, and show it to the user (bad UI design -_-‘) and when user click at

the code split the selected item and pass to student detail activity to

retrieve the record. (i.e. ID_studentname will appear on the listview

item)

Create a new simple layout to help us to retrieve student detail by

student id and hide the student id in listview item from user. (I like this,

or you should do this way :)).

So to do with 2nd approach we need to create a new layout and name

it view_student_entry.xml, and the code will look like belowview_student_entry.xml

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<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:orientation="vertical" android:layout_width="match_parent"    android:layout_height="match_parent">    <TextView        android:id="@+id/student_Id"        android:layout_width="fill_parent"        android:layout_height="wrap_content"        android:visibility="gone" />     <TextView        android:id="@+id/student_name"        android:layout_width="fill_parent"        android:layout_height="wrap_content"        android:paddingLeft="6dip"        android:paddingTop="6dip"        android:textSize="22sp"        android:textStyle="bold" /> </LinearLayout>

Code

1. Now let’s start code on table structure portion first – create table in Android. Base on

the table structure image above, we will create a file name Student.java , and the

code in this file will look like thisStudent.java

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package com.instinctcoder.sqlitedb;public class Student {    // Labels table name    public static final String TABLE = "Student";     // Labels Table Columns names    public static final String KEY_ID = "id";    public static final String KEY_name = "name";    public static final String KEY_email = "email";    public static final String KEY_age = "age";     // property help us to keep data    public int student_ID;    public String name;    public String email;    public int age;}

2. In order for us to create a table for need to use these classes SQLiteDatabase,

SQLiteDatabase is the class for us to perform CRUD function, and SQLiteOpenHelper,

SQLiteOpenHelper is a helper class to manage database creation and version

management. We’ll create a class and name it DBHelper.java and code in this file

will look like this, to ease on understand code line by line i put comment in code. DBHelper.java

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package com.instinctcoder.sqlitedb; import android.content.Context;import android.database.sqlite.SQLiteDatabase;import android.database.sqlite.SQLiteOpenHelper; public class DBHelper  extends SQLiteOpenHelper {    //version number to upgrade database version    //each time if you Add, Edit table, you need to change the

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    //version number.    private static final int DATABASE_VERSION = 4;     // Database Name    private static final String DATABASE_NAME = "crud.db";     public DBHelper(Context context ) {        super(context, DATABASE_NAME, null, DATABASE_VERSION);    }     @Override    public void onCreate(SQLiteDatabase db) {        //All necessary tables you like to create will create here         String CREATE_TABLE_STUDENT = "CREATE TABLE " + Student.TABLE  + "("                + Student.KEY_ID  + " INTEGER PRIMARY KEY AUTOINCREMENT ,"                + Student.KEY_name + " TEXT, "                + Student.KEY_age + " INTEGER, "                + Student.KEY_email + " TEXT )";         db.execSQL(CREATE_TABLE_STUDENT);     }     @Override    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {        // Drop older table if existed, all data will be gone!!!        db.execSQL("DROP TABLE IF EXISTS " + Student.TABLE);         // Create tables again        onCreate(db);     }  }

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3. With above 2 steps, student table will be created when app get started and now we

could code the CRUD functions! Create StudentRepo.java, the purpose of this class

is to perform CRUD on the Student table. The code in this file will look like this.StudentRepo.java

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package com.instinctcoder.sqlitedb; import android.content.ContentValues;import android.content.Context;import android.database.Cursor;import android.database.sqlite.SQLiteDatabase;import java.util.ArrayList;import java.util.HashMap; public class StudentRepo {    private DBHelper dbHelper;     public StudentRepo(Context context) {        dbHelper = new DBHelper(context);    }     public int insert(Student student) {         //Open connection to write data        SQLiteDatabase db = dbHelper.getWritableDatabase();        ContentValues values = new ContentValues();        values.put(Student.KEY_age, student.age);        values.put(Student.KEY_email,student.email);        values.put(Student.KEY_name, student.name);         // Inserting Row        long student_Id = db.insert(Student.TABLE, null, values);        db.close(); // Closing database connection        return (int) student_Id;    }     public void delete(int student_Id) {         SQLiteDatabase db = dbHelper.getWritableDatabase();        // It's a good practice to use parameter ?, instead of concatenate string        db.delete(Student.TABLE, Student.KEY_ID + "= ?", new String[] { String.valueOf(student_Id) });        db.close(); // Closing database connection    }     public void update(Student student) {         SQLiteDatabase db = dbHelper.getWritableDatabase();        ContentValues values = new ContentValues();         values.put(Student.KEY_age, student.age);        values.put(Student.KEY_email,student.email);        values.put(Student.KEY_name, student.name);

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         // It's a good practice to use parameter ?, instead of concatenate string        db.update(Student.TABLE, values, Student.KEY_ID + "= ?", new String[] { String.valueOf(student.student_ID) });        db.close(); // Closing database connection    }     public ArrayList<HashMap<String, String>>  getStudentList() {        //Open connection to read only        SQLiteDatabase db = dbHelper.getReadableDatabase();        String selectQuery =  "SELECT  " +                Student.KEY_ID + "," +                Student.KEY_name + "," +                Student.KEY_email + "," +                Student.KEY_age +                " FROM " + Student.TABLE;         //Student student = new Student();        ArrayList<HashMap<String, String>> studentList = new ArrayList<HashMap<String, String>>();         Cursor cursor = db.rawQuery(selectQuery, null);        // looping through all rows and adding to list         if (cursor.moveToFirst()) {            do {                HashMap<String, String> student = new HashMap<String, String>();                student.put("id", cursor.getString(cursor.getColumnIndex(Student.KEY_ID)));                student.put("name", cursor.getString(cursor.getColumnIndex(Student.KEY_name)));                studentList.add(student);             } while (cursor.moveToNext());        }         cursor.close();        db.close();        return studentList;     }     public Student getStudentById(int Id){        SQLiteDatabase db = dbHelper.getReadableDatabase();        String selectQuery =  "SELECT  " +                Student.KEY_ID + "," +                Student.KEY_name + "," +                Student.KEY_email + "," +                Student.KEY_age +                " FROM " + Student.TABLE                + " WHERE " +                Student.KEY_ID + "=?";// It's a good practice to use parameter ?, instead of concatenate string         int iCount =0;        Student student = new Student();         Cursor cursor = db.rawQuery(selectQuery, new String[] { String.valueOf(Id) } );         if (cursor.moveToFirst()) {            do {                student.student_ID =cursor.getInt(cursor.getColumnIndex(Student.KEY_ID));                student.name =cursor.getString(cursor.getColumnIndex(Student.KEY_name));                student.email  =cursor.getString(cursor.getColumnIndex(Student.KEY_email));                student.age =cursor.getInt(cursor.getColumnIndex(Student.KEY_age));             } while (cursor.moveToNext());        }

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         cursor.close();        db.close();        return student;    } }

4. When user click on the listview item we will display student detail information on

detail screen, we will have this code to do the job for us. Go to src > main > java >

StudentDetail.java. and copy this code into the class.StudentDetail.java

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package com.instinctcoder.sqlitedb; import android.content.Intent;import android.support.v7.app.ActionBarActivity;import android.support.v7.app.ActionBar;import android.support.v4.app.Fragment;import android.os.Bundle;import android.view.LayoutInflater;import android.view.Menu;import android.view.MenuItem;import android.view.View;import android.view.ViewGroup;import android.os.Build;import android.widget.ArrayAdapter;import android.widget.Button;import android.widget.EditText;import android.widget.ListView;import android.widget.Toast; import java.util.ArrayList; public class StudentDetail extends ActionBarActivity implements android.view.View.OnClickListener{     Button btnSave ,  btnDelete;    Button btnClose;    EditText editTextName;    EditText editTextEmail;    EditText editTextAge;    private int _Student_Id=0; 

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    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_student_detail);         btnSave = (Button) findViewById(R.id.btnSave);        btnDelete = (Button) findViewById(R.id.btnDelete);        btnClose = (Button) findViewById(R.id.btnClose);         editTextName = (EditText) findViewById(R.id.editTextName);        editTextEmail = (EditText) findViewById(R.id.editTextEmail);        editTextAge = (EditText) findViewById(R.id.editTextAge);         btnSave.setOnClickListener(this);        btnDelete.setOnClickListener(this);        btnClose.setOnClickListener(this);          _Student_Id =0;        Intent intent = getIntent();        _Student_Id =intent.getIntExtra("student_Id", 0);        StudentRepo repo = new StudentRepo(this);        Student student = new Student();        student = repo.getStudentById(_Student_Id);         editTextAge.setText(String.valueOf(student.age));        editTextName.setText(student.name);        editTextEmail.setText(student.email);    }      @Override    public boolean onCreateOptionsMenu(Menu menu) {                // Inflate the menu; this adds items to the action bar if it is present.        getMenuInflater().inflate(R.menu.student_detail, menu);        return true;    }     @Override    public boolean onOptionsItemSelected(MenuItem item) {        // Handle action bar item clicks here. The action bar will        // automatically handle clicks on the Home/Up button, so long        // as you specify a parent activity in AndroidManifest.xml.        int id = item.getItemId();        if (id == R.id.action_settings) {            return true;        }        return super.onOptionsItemSelected(item);    }     public void onClick(View view) {        if (view == findViewById(R.id.btnSave)){            StudentRepo repo = new StudentRepo(this);            Student student = new Student();            student.age= Integer.parseInt(editTextAge.getText().toString());            student.email=editTextEmail.getText().toString();            student.name=editTextName.getText().toString();            student.student_ID=_Student_Id;             if (_Student_Id==0){               _Student_Id = repo.insert(student);                 Toast.makeText(this,"New Student Insert",Toast.LENGTH_SHORT).show();            }else{ 

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                repo.update(student);                Toast.makeText(this,"Student Record updated",Toast.LENGTH_SHORT).show();            }        }else if (view== findViewById(R.id.btnDelete)){            StudentRepo repo = new StudentRepo(this);            repo.delete(_Student_Id);            Toast.makeText(this, "Student Record Deleted", Toast.LENGTH_SHORT);            finish();        }else if (view== findViewById(R.id.btnClose)){            finish();        }      } }

5. We have almost all pieces in place to display data for us in listview. So we continue

in MainActivity.java, paste this code into file.MainActivity.java

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package com.instinctcoder.sqlitedb; import android.app.ListActivity;import android.content.Intent;import android.support.v7.app.ActionBarActivity;import android.support.v7.app.ActionBar;import android.support.v4.app.Fragment;import android.os.Bundle;import android.view.LayoutInflater;import android.view.Menu;import android.view.MenuItem;import android.view.View;import android.view.ViewGroup;import android.os.Build;import android.widget.AdapterView;import android.widget.Button;import android.widget.ListAdapter;import android.widget.ListView;import android.widget.SimpleAdapter;import android.widget.TextView;import android.widget.Toast; import java.util.ArrayList;import java.util.HashMap; public class MainActivity extends ListActivity  implements android.view.View.OnClickListener{

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     Button btnAdd,btnGetAll;    TextView student_Id;     @Override    public void onClick(View view) {        if (view== findViewById(R.id.btnAdd)){             Intent intent = new Intent(this,StudentDetail.class);            intent.putExtra("student_Id",0);            startActivity(intent);         }else {             StudentRepo repo = new StudentRepo(this);             ArrayList<HashMap<String, String>> studentList =  repo.getStudentList();            if(studentList.size()!=0) {                ListView lv = getListView();                lv.setOnItemClickListener(new AdapterView.OnItemClickListener() {                    @Override                    public void onItemClick(AdapterView<?> parent, View view,int position, long id) {                        student_Id = (TextView) view.findViewById(R.id.student_Id);                        String studentId = student_Id.getText().toString();                        Intent objIndent = new Intent(getApplicationContext(),StudentDetail.class);                        objIndent.putExtra("student_Id", Integer.parseInt( studentId));                        startActivity(objIndent);                    }                });                ListAdapter adapter = new SimpleAdapter( MainActivity.this,studentList, R.layout.view_student_entry, new String[] { "id","name"}, new int[] {R.id.student_Id, R.id.student_name});                setListAdapter(adapter);            }else{                Toast.makeText(this,"No student!",Toast.LENGTH_SHORT).show();            }         }    }     @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);         btnAdd = (Button) findViewById(R.id.btnAdd);        btnAdd.setOnClickListener(this);         btnGetAll = (Button) findViewById(R.id.btnGetAll);        btnGetAll.setOnClickListener(this);     }     @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;    }     @Override    public boolean onOptionsItemSelected(MenuItem item) {        // Handle action bar item clicks here. The action bar will        // automatically handle clicks on the Home/Up button, so long        // as you specify a parent activity in AndroidManifest.xml.

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        int id = item.getItemId();        if (id == R.id.action_settings) {            return true;        }        return super.onOptionsItemSelected(item);    } }

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6. That’s all, Run! You should see the below result. 

If everything go smooth, database will be created in this path “data > data > SQLiteDB >

databases > crud.db”, if you like to browse data and table structure of the database you

could refer to How to browse Android Emulator SQLite Database

Updated on 18 Mar 2015

This step is optional and only for those who are using eclipse

I noticed some reader had stuck in the StudentDetail.java file when they use Eclipse to

try out this tutorial, the reason why you click “Add” and failed is because you need to

import android-support-v4.jar and android-support-v7-appcompat.jar into your

workspace, the detail you could follow this link

Alternatively, you use the this source code which build in Eclipse IDE

23.0.2.1259578 and the only different with the Android Studio version is below codeStudentDetail.java

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package com.instinctcoder.sqlitedb; import android.app.Activity;

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import android.content.Intent;import android.os.Bundle;import android.view.Menu;import android.view.MenuItem;import android.view.View;import android.widget.Button;import android.widget.EditText;import android.widget.Toast; public class StudentDetail extends Activity implements android.view.View.OnClickListener{     Button btnSave ,  btnDelete;    Button btnClose;    EditText editTextName;    EditText editTextEmail;    EditText editTextAge;    private int _Student_Id=0;        @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_student_detail);                btnSave = (Button) findViewById(R.id.btnSave);        btnDelete = (Button) findViewById(R.id.btnDelete);        btnClose = (Button) findViewById(R.id.btnClose);         editTextName = (EditText) findViewById(R.id.editTextName);        editTextEmail = (EditText) findViewById(R.id.editTextEmail);        editTextAge = (EditText) findViewById(R.id.editTextAge);         btnSave.setOnClickListener(this);        btnDelete.setOnClickListener(this);        btnClose.setOnClickListener(this);         _Student_Id =0;        Intent intent = getIntent();        _Student_Id =intent.getIntExtra("student_Id", 0);        StudentRepo repo = new StudentRepo(this);        Student student = new Student();        student = repo.getStudentById(_Student_Id);         editTextAge.setText(String.valueOf(student.age));        editTextName.setText(student.name);        editTextEmail.setText(student.email);    }     @Override    public void onClick(View view) {        // TODO Auto-generated method stub         if (view == findViewById(R.id.btnSave)){                StudentRepo repo = new StudentRepo(this);                Student student = new Student();                student.age= Integer.parseInt(editTextAge.getText().toString());                student.email=editTextEmail.getText().toString();                student.name=editTextName.getText().toString();                student.student_ID=_Student_Id;                     if (_Student_Id==0){                   _Student_Id = repo.insert(student);                         Toast.makeText(this,"New Student Insert",Toast.LENGTH_SHORT).show();                }else{                         repo.update(student);

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                    Toast.makeText(this,"Student Record updated",Toast.LENGTH_SHORT).show();                }            }else if (view== findViewById(R.id.btnDelete)){                StudentRepo repo = new StudentRepo(this);                repo.delete(_Student_Id);                Toast.makeText(this, "Student Record Deleted", Toast.LENGTH_SHORT);                finish();            }else if (view== findViewById(R.id.btnClose)){                finish();            }    }}

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