ios swift中的简单删除操作
import UIKit
import SQLite3
let kCell = "Cell"
class ViewController: UIViewController {
@IBOutlet weak var tfHeroName: UITextField!
@IBOutlet weak var tfPowerRanking: UITextField!
@IBOutlet weak var btnSave: UIButton!
var db: OpaquePointer?
private let refreshControl = UIRefreshControl()
@IBOutlet weak var tableView: UITableView!
var heroList = [Hero]()
override func viewDidLoad() {
super.viewDidLoad()
//SetupPullTorefresh
// Add Refresh Control to Table View
if #available(iOS 10.0, *) {
tableView.refreshControl = refreshControl
} else {
tableView.addSubview(refreshControl)
}
// Configure Refresh Control
refreshControl.addTarget(self, action: #selector(refreshListData(_:)), for: .valueChanged)
refreshControl.tintColor = #colorLiteral(red: 0.8078431487, green: 0.02745098062, blue: 0.3333333433, alpha: 1)
refreshControl.attributedTitle = NSAttributedString(string: "Loading...")
//database file address
let fileURL = try! FileManager.default.url(for: .documentDirectory, in: .userDomainMask, appropriateFor: nil, create: false)
.appendingPathComponent("HeroesDatabase.sqlite")
//opening database
if sqlite3_open(fileURL.path, &db) != SQLITE_OK {
print("error opening database")
}
//creating table
if sqlite3_exec(db, "CREATE TABLE IF NOT EXISTS Heroes (id INTEGER PRIMARY KEY AUTOINCREMENT, name TEXT, powerrank INTEGER)", nil, nil, nil) != SQLITE_OK {
let errmsg = String(cString: sqlite3_errmsg(db)!)
print("error creating table: \(errmsg)")
}
readValues()
}
@IBAction func tapOnBtnSave(_ sender: Any) {
let name = tfHeroName.text?.trimmingCharacters(in: .whitespacesAndNewlines)
let poweRanking = tfPowerRanking.text?.trimmingCharacters(in: .whitespacesAndNewlines)
if name!.isEmpty {
tfHeroName.layer.borderColor = #colorLiteral(red: 0.8058760762, green: 0.2736578584, blue: 0.1300437152, alpha: 1)
}
if poweRanking!.isEmpty {
tfPowerRanking.layer.borderColor = #colorLiteral(red: 0.8058760762, green: 0.2736578584, blue: 0.1300437152, alpha: 1)
}
//creating a statement
var stmt: OpaquePointer?
//the insert query
let queryString = "INSERT INTO Heroes (name, powerrank) VALUES (?,?)"
//preparing the query
if sqlite3_prepare(db, queryString, -1, &stmt, nil) != SQLITE_OK {
let errmsg = String(cString: sqlite3_errmsg(db)!)
print("error preparing insert: \(errmsg)")
return
}
//binding the parameters
if sqlite3_bind_text(stmt, 1, name, -1, nil) != SQLITE_OK{
let errmsg = String(cString: sqlite3_errmsg(db)!)
print("failure binding name: \(errmsg)")
return
}
if sqlite3_bind_int(stmt, 2, (poweRanking! as NSString).intValue) != SQLITE_OK {
let errmsg = String(cString: sqlite3_errmsg(db))
print("failure binding name: \(errmsg)")
}
//executing the query to insert values
if sqlite3_step(stmt) != SQLITE_DONE {
let errmsg = String(cString: sqlite3_errmsg(db)!)
print("failure binding name: \(errmsg)")
}
//emptying the textfields
tfHeroName.text = ""
tfPowerRanking.text = ""
}
//MARK: Read Operation
func readValues(){
heroList.removeAll()
let queryString = "SELECT * FROM Heroes"
var stmt:OpaquePointer?
if sqlite3_prepare(db, queryString, -1, &stmt, nil) != SQLITE_OK{
let errmsg = String(cString: sqlite3_errmsg(db)!)
print("error preparing insert: \(errmsg)")
return
}
while(sqlite3_step(stmt) == SQLITE_ROW){
let id = sqlite3_column_int(stmt, 0)
let name = String(cString: sqlite3_column_text(stmt, 1))
let powerrank = sqlite3_column_int(stmt, 2)
heroList.append(Hero(id: Int(id), name: String(describing: name), powerRanking: Int(powerrank)))
}
self.tableView.reloadData()
self.refreshControl.endRefreshing()
}
//MARK: Delete Operation
func deleteItemFromList(itemId: Int32){
let deleteStatementStirng = "DELETE FROM Heroes WHERE id = ?;"
var deleteStatement: OpaquePointer? = nil
if sqlite3_prepare(db, deleteStatementStirng, -1, &deleteStatement, nil) == SQLITE_OK {
sqlite3_bind_int(deleteStatement, 1, itemId)
if sqlite3_step(deleteStatement) == SQLITE_DONE {
print("Successfully deleted row.")
} else {
print("Could not delete row.")
}
} else {
print("DELETE statement could not be prepared")
}
sqlite3_finalize(deleteStatement)
print("delete")
}
@objc private func refreshListData(_ sender: Any) {
readValues()
}
}
extension ViewController : UITableViewDelegate, UITableViewDataSource {
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return heroList.count
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = UITableViewCell(style: UITableViewCell.CellStyle.default, reuseIdentifier: "cell")
let hero: Hero
hero = heroList[indexPath.row]
cell.textLabel?.text = hero.name
return cell
}
func tableView(_ tableView: UITableView, commit editingStyle: UITableViewCell.EditingStyle, forRowAt indexPath: IndexPath) {
if editingStyle == UITableViewCell.EditingStyle.delete {
heroList.remove(at: indexPath.row)
deleteItemFromList(itemId: Int32(heroList[indexPath.row].powerRanking))
tableView.deleteRows(at: [indexPath], with: UITableView.RowAnimation.automatic)
tableView.reloadData()
}
}
func tableView(_ tableView: UITableView, canEditRowAt indexPath: IndexPath) -> Bool {
return true
}
}
class Hero {
var id: Int
var name: String?
var powerRanking: Int
init(id: Int, name: String?, powerRanking: Int){
self.id = id
self.name = name
self.powerRanking = powerRanking
}
}