Mobile Application Development (202046712) 12202080501057
Practical – 5
Aim: Develop an android application that create, save, update, and
delete data in database.
activity_main.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"
android:padding="16dp">
<EditText
android:id="@+id/editName"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="Name" />
<EditText
android:id="@+id/editEmail"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="Email" />
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Mobile Application Development (202046712) 12202080501057
<Button
android:id="@+id/btnAdd"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Add User" />
<Button
android:id="@+id/btnView"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="View All Users" />
<Button
android:id="@+id/btnUpdate"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Update User by ID" />
<Button
android:id="@+id/btnDelete"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Delete User by ID" />
</LinearLayout>
GCET 2
Mobile Application Development (202046712) 12202080501057
DatabaseHelper.java:
package com.example.prac5;
import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.*;
public class DatabaseHelper extends SQLiteOpenHelper {
public static final String DB_NAME = "Users.db";
public static final String TABLE_NAME = "user_table";
public static final String COL_1 = "ID";
public static final String COL_2 = "NAME";
public static final String COL_3 = "EMAIL";
public DatabaseHelper(Context context) {
super(context, DB_NAME, null, 1);
}
@Override
public void onCreate(SQLiteDatabase db) {
db.execSQL("CREATE TABLE " + TABLE_NAME +
" (ID INTEGER PRIMARY KEY AUTOINCREMENT, NAME TEXT, EMAIL
TEXT)");
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Mobile Application Development (202046712) 12202080501057
@Override
public void onUpgrade(SQLiteDatabase db, int oldV, int newV) {
db.execSQL("DROP TABLE IF EXISTS " + TABLE_NAME);
onCreate(db);
}
public boolean insertData(String name, String email) {
SQLiteDatabase db = this.getWritableDatabase();
ContentValues cv = new ContentValues();
cv.put(COL_2, name);
cv.put(COL_3, email);
long result = db.insert(TABLE_NAME, null, cv);
return result != -1; // returns true if inserted
}
public Cursor getAllData() {
SQLiteDatabase db = this.getWritableDatabase();
return db.rawQuery("SELECT * FROM " + TABLE_NAME, null);
}
public boolean updateData(String id, String name, String email) {
SQLiteDatabase db = this.getWritableDatabase();
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Mobile Application Development (202046712) 12202080501057
ContentValues cv = new ContentValues();
cv.put(COL_2, name);
cv.put(COL_3, email);
int rows = db.update(TABLE_NAME, cv, "ID=?", new String[]{id});
return rows > 0; // true if update successful
}
public Integer deleteData(String id)
{
SQLiteDatabase db = this.getWritableDatabase();
return db.delete(TABLE_NAME, "ID=?", new String[]{id});
}
GCET 5
Mobile Application Development (202046712) 12202080501057
MainActivity.java:
package com.example.prac5;
import android.database.Cursor;
import android.os.Bundle;
import android.view.View;
import android.widget.*;
import androidx.appcompat.app.AlertDialog;
import androidx.appcompat.app.AppCompatActivity;
public class MainActivity extends AppCompatActivity {
DatabaseHelper db;
EditText editName, editEmail;
Button btnAdd, btnView, btnUpdate, btnDelete;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
db = new DatabaseHelper(this);
editName = findViewById(R.id.editName);
editEmail = findViewById(R.id.editEmail);
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Mobile Application Development (202046712) 12202080501057
btnAdd = findViewById(R.id.btnAdd);
btnView = findViewById(R.id.btnView);
btnUpdate = findViewById(R.id.btnUpdate);
btnDelete = findViewById(R.id.btnDelete);
addUser();
viewUsers();
updateUser();
deleteUser();
}
public void addUser() {
btnAdd.setOnClickListener(v -> {
boolean inserted = db.insertData(
editName.getText().toString(),
editEmail.getText().toString());
Toast.makeText(this, inserted ? "User Added!" : "Error Adding User",
Toast.LENGTH_SHORT).show();
});
}
public void viewUsers() {
btnView.setOnClickListener(v -> {
Cursor res = db.getAllData();
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Mobile Application Development (202046712) 12202080501057
if (res.getCount() == 0) {
showMessage("Oops", "No users found");
return;
}
StringBuilder buffer = new StringBuilder();
while (res.moveToNext()) {
buffer.append("ID: ").append(res.getString(0)).append("\n");
buffer.append("Name: ").append(res.getString(1)).append("\n");
buffer.append("Email: ").append(res.getString(2)).append("\n\n");
}
showMessage("All Users", buffer.toString());
});
}
public void updateUser() {
btnUpdate.setOnClickListener(v -> {
final EditText inputId = new EditText(this);
inputId.setHint("Enter ID to Update");
new AlertDialog.Builder(this)
.setTitle("Update User")
.setMessage("Enter ID of user to update")
.setView(inputId)
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Mobile Application Development (202046712) 12202080501057
.setPositiveButton("Update", (dialog, which) -> {
boolean updated = db.updateData(
inputId.getText().toString(),
editName.getText().toString(),
editEmail.getText().toString());
Toast.makeText(this, updated ? "User Updated!" : "User Not
Found", Toast.LENGTH_SHORT).show();
})
.setNegativeButton("Cancel", null)
.show();
});
}
public void deleteUser() {
btnDelete.setOnClickListener(v -> {
final EditText inputId = new EditText(this);
inputId.setHint("Enter ID to Delete");
new AlertDialog.Builder(this)
.setTitle("Delete User")
.setMessage("Enter ID of user to delete")
.setView(inputId)
.setPositiveButton("Delete", (dialog, which) -> {
int deletedRows = db.deleteData(inputId.getText().toString());
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Mobile Application Development (202046712) 12202080501057
Toast.makeText(this, deletedRows > 0 ? "User Deleted!" : "User
Not Found", Toast.LENGTH_SHORT).show();
})
.setNegativeButton("Cancel", null)
.show();
});
}
public void showMessage(String title, String msg) {
new AlertDialog.Builder(this)
.setTitle(title)
.setMessage(msg)
.setPositiveButton("OK", null)
.show();
}
}
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Mobile Application Development (202046712) 12202080501057
Output:
Create/Add Users: View all users/saved users:
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Mobile Application Development (202046712) 12202080501057
Update the users by ID:
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Mobile Application Development (202046712) 12202080501057
Delete the users by ID:
GCET 13
