Programação de dispositivos móveis AVA2

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Universidade Veiga de Almeida
Programação de dispositivos móveis AVA1
Prof. Claudio Fico Fonseca
Nova Iguaçu, Rio de Janeiro
2024.1
Vou assumir que escolhemos o objeto "Livro" para fins de exemplo. Aqui está
uma implementação básica que atende aos requisitos mencionados:
1.Definindo a classe Livro:
import android.content.ContentValues;
public class Book {
private int id;
private String title;
private String author;
private int year;
private double price;
private String genre;
public Book(int id, String title, String author, int year, double price, String
genre) {
this.id = id;
this.title = title;
this.author = author;
this.year = year;
this.price = price;
this.genre = genre;
}
// Getters and Setters
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getTitle() {
return title;
}
public void setTitle(String title) {
this.title = title;
}
public String getAuthor() {
return author;
}
public void setAuthor(String author) {
this.author = author;
}
public int getYear() {
return year;
}
public void setYear(int year) {
this.year = year;
}
public double getPrice() {
return price;
}
public void setPrice(double price) {
this.price = price;
}
public String getGenre() {
return genre;
}
public void setGenre(String genre) {
this.genre = genre;
}
@Override
public String toString() {
return title + " by " + author;
}
}
2.Criando DBHelper para o acesso a dados:
import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.content.ContentValues;
import android.database.Cursor;
import java.util.ArrayList;
import java.util.List;
public class DBHelper extends SQLiteOpenHelper {
private static final String DATABASE_NAME = "library.db";
private static final int DATABASE_VERSION = 1;
private static final String TABLE_BOOKS = "books";
private static final String COLUMN_ID = "id";
private static final String COLUMN_TITLE = "title";
private static final String COLUMN_AUTHOR = "author";
private static final String COLUMN_YEAR = "year";
private static final String COLUMN_PRICE = "price";
private static final String COLUMN_GENRE = "genre";
public DBHelper(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
@Override
public void onCreate(SQLiteDatabase db) {
String createTableQuery = "CREATE TABLE " + TABLE_BOOKS + "(" +
COLUMN_ID + " INTEGER PRIMARY KEY AUTOINCREMENT, " +
COLUMN_TITLE + " TEXT, " +
COLUMN_AUTHOR + " TEXT, " +
COLUMN_YEAR + " INTEGER, " +
COLUMN_PRICE + " REAL, " +
COLUMN_GENRE + " TEXT" +
")";
db.execSQL(createTableQuery);
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
db.execSQL("DROP TABLE IF EXISTS " + TABLE_BOOKS);
onCreate(db);
}
// CRUD Operations
public void addBook(Book book) {
SQLiteDatabase db = this.getWritableDatabase();
ContentValues values = new ContentValues();
values.put(COLUMN_TITLE, book.getTitle());
values.put(COLUMN_AUTHOR, book.getAuthor());
values.put(COLUMN_YEAR, book.getYear());
values.put(COLUMN_PRICE, book.getPrice());
values.put(COLUMN_GENRE, book.getGenre());
db.insert(TABLE_BOOKS, null, values);
db.close();
}
public Book getBook(int id) {
SQLiteDatabase db = this.getReadableDatabase();
Cursor cursor = db.query(TABLE_BOOKS, new String[]{COLUMN_ID,
COLUMN_TITLE, COLUMN_AUTHOR, COLUMN_YEAR, COLUMN_PRICE,
COLUMN_GENRE},
COLUMN_ID + "=?", new String[]{String.valueOf(id)}, null, null, null,
null);
if (cursor != null)
cursor.moveToFirst();
Book book = new Book(
cursor.getInt(cursor.getColumnIndex(COLUMN_ID)),
cursor.getString(cursor.getColumnIndex(COLUMN_TITLE)),
cursor.getString(cursor.getColumnIndex(COLUMN_AUTHOR)),
cursor.getInt(cursor.getColumnIndex(COLUMN_YEAR)),
cursor.getDouble(cursor.getColumnIndex(COLUMN_PRICE)),
cursor.getString(cursor.getColumnIndex(COLUMN_GENRE)));
cursor.close();
db.close();
return book;
}
public List getAllBooks() {
List bookList = new ArrayList();
String selectQuery = "SELECT * FROM " + TABLE_BOOKS;
SQLiteDatabase db = this.getWritableDatabase();
Cursor cursor = db.rawQuery(selectQuery, null);
if (cursor.moveToFirst()) {
do {
Book book = new Book(
cursor.getInt(cursor.getColumnIndex(COLUMN_ID)),
cursor.getString(cursor.getColumnIndex(COLUMN_TITLE)),
cursor.getString(cursor.getColumnIndex(COLUMN_AUTHOR)),
cursor.getInt(cursor.getColumnIndex(COLUMN_YEAR)),
cursor.getDouble(cursor.getColumnIndex(COLUMN_PRICE)),
cursor.getString(cursor.getColumnIndex(COLUMN_GENRE)));
bookList.add(book);
} while (cursor.moveToNext());
}
cursor.close();
db.close();
return bookList;
}
public int updateBook(Book book) {
SQLiteDatabase db = this.getWritableDatabase();
ContentValues values = new ContentValues();
values.put(COLUMN_TITLE, book.getTitle());
values.put(COLUMN_AUTHOR, book.getAuthor());
values.put(COLUMN_YEAR, book.getYear());
values.put(COLUMN_PRICE, book.getPrice());
values.put(COLUMN_GENRE, book.getGenre());
return db.update(TABLE_BOOKS, values, COLUMN_ID + " = ?", new
String[]{String.valueOf(book.getId())});
}
public void deleteBook(Book book) {
SQLiteDatabase db = this.getWritableDatabase();
db.delete(TABLE_BOOKS, COLUMN_ID + " = ?", new
String[]{String.valueOf(book.getId())});
db.close();
}
}
3.Banco de dados
import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.content.ContentValues;
import android.database.Cursor;
import java.util.ArrayList;
import java.util.List;
public class DBHelper extends SQLiteOpenHelper {
private static final String DATABASE_NAME = "library.db";
private static final int DATABASE_VERSION = 1;
private static final String TABLE_BOOKS = "books";
private static final String COLUMN_ID = "id";
private static final String COLUMN_TITLE = "title";
private static final String COLUMN_AUTHOR = "author";
private static final String COLUMN_YEAR = "year";
private static final String COLUMN_PRICE = "price";
private static final String COLUMN_GENRE = "genre";
public DBHelper(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
@Override
public void onCreate(SQLiteDatabase db) {
String createTableQuery = "CREATE TABLE " + TABLE_BOOKS + "(" +
COLUMN_ID + " INTEGER PRIMARY KEY AUTOINCREMENT, " +
COLUMN_TITLE + " TEXT, " +
COLUMN_AUTHOR + " TEXT, " +
COLUMN_YEAR + " INTEGER, " +
COLUMN_PRICE + " REAL, " +
COLUMN_GENRE + " TEXT" +
")";
db.execSQL(createTableQuery);
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
db.execSQL("DROP TABLE IF EXISTS " + TABLE_BOOKS);
onCreate(db);
}
// CRUD Operations
public void addBook(Book book) {
SQLiteDatabase db = this.getWritableDatabase();
ContentValues values = new ContentValues();
values.put(COLUMN_TITLE, book.getTitle());
values.put(COLUMN_AUTHOR, book.getAuthor());
values.put(COLUMN_YEAR, book.getYear());
values.put(COLUMN_PRICE, book.getPrice());
values.put(COLUMN_GENRE, book.getGenre());
db.insert(TABLE_BOOKS, null, values);
db.close();
}
public Book getBook(int id) {
SQLiteDatabase db = this.getReadableDatabase();
Cursor cursor = db.query(TABLE_BOOKS, new String[]{COLUMN_ID,
COLUMN_TITLE, COLUMN_AUTHOR, COLUMN_YEAR, COLUMN_PRICE,
COLUMN_GENRE},
COLUMN_ID + "=?", new String[]{String.valueOf(id)}, null, null, null,
null);
if (cursor != null)
cursor.moveToFirst();
Book book = new Book(
cursor.getInt(cursor.getColumnIndex(COLUMN_ID)),
cursor.getString(cursor.getColumnIndex(COLUMN_TITLE)),
cursor.getString(cursor.getColumnIndex(COLUMN_AUTHOR)),
cursor.getInt(cursor.getColumnIndex(COLUMN_YEAR)),
cursor.getDouble(cursor.getColumnIndex(COLUMN_PRICE)),
cursor.getString(cursor.getColumnIndex(COLUMN_GENRE)));
cursor.close();
db.close();
return book;
}
public List getAllBooks() {
List bookList = new ArrayList();
String selectQuery = "SELECT * FROM " + TABLE_BOOKS;
SQLiteDatabase db = this.getWritableDatabase();
Cursor cursor = db.rawQuery(selectQuery, null);
if (cursor.moveToFirst()){
do {
Book book = new Book(
cursor.getInt(cursor.getColumnIndex(COLUMN_ID)),
cursor.getString(cursor.getColumnIndex(COLUMN_TITLE)),
cursor.getString(cursor.getColumnIndex(COLUMN_AUTHOR)),
cursor.getInt(cursor.getColumnIndex(COLUMN_YEAR)),
cursor.getDouble(cursor.getColumnIndex(COLUMN_PRICE)),
cursor.getString(cursor.getColumnIndex(COLUMN_GENRE)));
bookList.add(book);
} while (cursor.moveToNext());
}
cursor.close();
db.close();
return bookList;
}
public int updateBook(Book book) {
SQLiteDatabase db = this.getWritableDatabase();
ContentValues values = new ContentValues();
values.put(COLUMN_TITLE, book.getTitle());
values.put(COLUMN_AUTHOR, book.getAuthor());
values.put(COLUMN_YEAR, book.getYear());
values.put(COLUMN_PRICE, book.getPrice());
values.put(COLUMN_GENRE, book.getGenre());
return db.update(TABLE_BOOKS, values, COLUMN_ID + " = ?", new
String[]{String.valueOf(book.getId())});
}
public void deleteBook(Book book) {
SQLiteDatabase db = this.getWritableDatabase();
db.delete(TABLE_BOOKS, COLUMN_ID + " = ?", new
String[]{String.valueOf(book.getId())});
db.close();
}
}
4. Main activity
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ListView;
import androidx.appcompat.app.AppCompatActivity;
import java.util.ArrayList;
import java.util.List;
public class MainActivity extends AppCompatActivity {
private ListView listViewBooks;
private EditText editTextTitle, editTextAuthor, editTextYear, editTextPrice,
editTextGenre;
private Button buttonAdd, buttonUpdate, buttonDelete, buttonClear;
private List bookList;
private ArrayAdapter bookAdapter;
private DBHelper dbHelper;
private Book selectedBook;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
dbHelper = new DBHelper(this);
listViewBooks = findViewById(R.id.listViewBooks);
editTextTitle = findViewById(R.id.editTextTitle);
editTextAuthor = findViewById(R.id.editTextAuthor);
editTextYear = findViewById(R.id.editTextYear);
editTextPrice = findViewById(R.id.editTextPrice);
editTextGenre = findViewById(R.id.editTextGenre);
buttonAdd = findViewById(R.id.buttonAdd);
buttonUpdate = findViewById(R.id.buttonUpdate);
buttonDelete = findViewById(R.id.buttonDelete);
buttonClear = findViewById(R.id.buttonClear);
bookList = new ArrayList();
bookAdapter = new ArrayAdapter(this,
android.R.layout.simple_list_item_1, bookList);
listViewBooks.setAdapter(bookAdapter);
listViewBooks.setOnItemClickListener(new
AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView adapterView, View view, int
position, long l) {
selectedBook = bookList.get(position);
editTextTitle.setText(selectedBook.getTitle());
editTextAuthor.setText(selectedBook.getAuthor());
editTextYear.setText(String.valueOf(selectedBook.getYear()));
editTextPrice.setText(String.valueOf(selectedBook.getPrice()));
editTextGenre.setText(selectedBook.getGenre());
}
});
buttonAdd.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
String title = editTextTitle.getText().toString();
String author = editTextAuthor.getText().toString();
int year = Integer.parseInt(editTextYear.getText().toString());
double price =
Double.parseDouble(editTextPrice.getText().toString());
String genre = editTextGenre.getText().toString();
Book book = new Book(0, title, author, year, price, genre);
dbHelper.addBook(book);
refreshBookList();
clearFields();
}
});
buttonUpdate.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
if (selectedBook != null) {
String title = editTextTitle.getText().toString();
String author = editTextAuthor.getText().toString();
int year = Integer.parseInt(editTextYear.getText().toString());
double price =
Double.parseDouble(editTextPrice.getText().toString());
String genre = editTextGenre.getText().toString();
selectedBook.setTitle(title);
selectedBook.setAuthor(author);
selectedBook.setYear(year);
selectedBook.setPrice(price);
selectedBook.setGenre(genre);
dbHelper.updateBook(selectedBook);
refreshBookList();
clearFields();
selectedBook = null;
}
}
});
buttonDelete.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
if (selectedBook != null) {
dbHelper.deleteBook(selectedBook);
refreshBookList();
clearFields();
selectedBook = null;
}
}
});
buttonClear.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
clearFields();
selectedBook = null;
}
});
refreshBookList();
}
private void refreshBookList() {
bookList.clear();
bookList.addAll(dbHelper.getAllBooks());
bookAdapter.notifyDataSetChanged();
}
private void clearFields() {
editTextTitle.setText("");
editTextAuthor.setText("");
editTextYear.setText("");
editTextPrice.setText("");
editTextGenre.setText("");
}
}
5.Código da interface XML