ios数据处理 使用SQLite保存学生信息

1.新建empty application项目，添加两个UIViewController视图：HomeViewController（主视图，搜索）、AddViewController（添加信息视图）。

 

 

注意：TextField要选择委托（delegate） 

 2.添加支持sqlite3的动态链接库：libsqlite3.dylib。

 

3.主要代码：

//  HomeViewController.h
//  SQLiteDemo
//

#import <UIKit/UIKit.h>
#import "sqlite3.h"

#define kDatabaseName @"database.sqlite"

@interface HomeViewController : UIViewController<UITextFieldDelegate>
{
    sqlite3 *database;
}


@property (retain, nonatomic) IBOutlet UITextField *idTextField;
@property (retain, nonatomic) IBOutlet UILabel *nameLabel;

- (void)createDatabase;
- (IBAction)searchAction:(id)sender;
- (IBAction)addAction:(id)sender;

@end

//  HomeViewController.m
//  SQLiteDemo
//


#import "HomeViewController.h"
#import "AddViewController.h"

@interface HomeViewController ()

@end

@implementation HomeViewController
@synthesize idTextField;
@synthesize nameLabel;


- (void)viewDidLoad
{
    [super viewDidLoad];
    
    [self createDatabase];
}

- (void)viewDidUnload
{
    [self setIdTextField:nil];
    [self setNameLabel:nil];
    [super viewDidUnload];
    // Release any retained subviews of the main view.
    // e.g. self.myOutlet = nil;
}

- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
{
    return (interfaceOrientation == UIInterfaceOrientationPortrait);
}

- (void)dealloc {
    [idTextField release];
    [nameLabel release];
    [super dealloc];
}

- (void)createDatabase
{
    //获取数据库文件路径
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *thePath = [paths objectAtIndex:0];
    NSString *file = [thePath stringByAppendingPathComponent:kDatabaseName];
    
    //创建数据库
    
    if (sqlite3_open([file UTF8String], &database) != SQLITE_OK)
    {
        sqlite3_close(database);
        NSAssert(0, @"未能打开数据库");
    }
    
    //创建表
    char *errmsg;
    NSString *createTableSQL = @"CREATE TABLE IF NOT EXISTS STUDENT(ID INTEGER PRIMARY KEY, NAME TEXT);";
    if (sqlite3_exec(database, [createTableSQL UTF8String], nil, nil, &errmsg) != SQLITE_OK)
    {
        sqlite3_close(database);
        NSAssert1(0, @"未能创建表：%s", errmsg);
        sqlite3_free(errmsg);
    }
}

- (IBAction)searchAction:(id)sender
{
    [idTextField resignFirstResponder];
    BOOL notFound = YES;
    
    NSString *selectSQL = [[NSString alloc] initWithFormat:@"SELECT ID, NAME FROM STUDENT WHERE ID = %@", idTextField.text];
    
    sqlite3_stmt *statement;
    
    if (sqlite3_prepare(database, [selectSQL UTF8String], -1, &statement, nil) == SQLITE_OK)
    {
        while (sqlite3_step(statement) == SQLITE_ROW)
        {
            notFound = NO;
            char *name = (char *)sqlite3_column_text(statement, 1);
            nameLabel.text = [NSString stringWithFormat:@"%s", name];
        }
    }
    
    sqlite3_finalize(statement);
    
    if (notFound)
    {
        nameLabel.text = @"没有记录";
    }
    
    [selectSQL release];
}

- (IBAction)addAction:(id)sender 
{
    AddViewController *addViewController = [[AddViewController alloc] init];
    [self presentModalViewController:addViewController animated:YES];
    [addViewController release];
}

- (BOOL)textFieldShouldReturn:(UITextField *)textField
{
    [textField resignFirstResponder];
    return YES;
}

@end

   在类的实现中，createDatabase方法，完成数据库文件和Student表的创建。

 //  AddViewController.h

//  SQLiteDemo
//

#import <UIKit/UIKit.h>
#import "sqlite3.h"

#define kDatabaseName @"database.sqlite"

@interface AddViewController : UIViewController<UITextFieldDelegate>
{
    sqlite3 *database;
}

@property (retain, nonatomic) IBOutlet UITextField *idTextField;
@property (retain, nonatomic) IBOutlet UITextField *nameTextField;
@property (retain, nonatomic) IBOutlet UIButton *saveButton;
@property (retain, nonatomic) IBOutlet UIButton *cancelButton;

- (void)saveInfoIntoDatabase;
- (BOOL)checkInfo;
- (IBAction)saveAction:(id)sender;
- (IBAction)cancelAction:(id)sender;

@end

 //  AddViewController.m

//  SQLiteDemo
//



#import "AddViewController.h"

@interface AddViewController ()

@end

@implementation AddViewController
@synthesize idTextField;
@synthesize nameTextField;
@synthesize saveButton;
@synthesize cancelButton;



- (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view from its nib.
}

- (void)viewDidUnload
{
    [self setIdTextField:nil];
    [self setNameTextField:nil];
    [self setSaveButton:nil];
    [self setCancelButton:nil];
    [super viewDidUnload];
    // Release any retained subviews of the main view.
    // e.g. self.myOutlet = nil;
}

- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
{
    return (interfaceOrientation == UIInterfaceOrientationPortrait);
}

- (void)dealloc {
    [idTextField release];
    [nameTextField release];
    [saveButton release];
    [cancelButton release];
    [super dealloc];
}

- (void)saveInfoIntoDatabase
{
    //打开数据库，获得数据库文件
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *thePath = [paths objectAtIndex:0];
    NSString *file = [thePath stringByAppendingPathComponent:kDatabaseName];
    if (sqlite3_open([file UTF8String], &database) != SQLITE_OK)
    {
        sqlite3_close(database);
        NSAssert(0, @"未能打开数据库");
    }
    
    NSString *insertSQL = [[NSString alloc] initWithFormat:@"INSERT OR REPLACE INTO STUDENT(ID, NAME) VALUES(%@, '%@');", idTextField.text, nameTextField.text];
    char *errmsg;
    if (sqlite3_exec(database, [insertSQL UTF8String], nil, nil, &errmsg) != SQLITE_OK)
    {
        NSAssert1(0, @"未能插入值：%s", errmsg);
        sqlite3_free(errmsg);
    }
    
    [insertSQL release];
    
    sqlite3_close(database);
                        
}

- (BOOL)checkInfo
{
    if ([idTextField.text isEqual:@""] || [nameTextField.text isEqualToString:@""]) 
    {
        return  NO;
    }
    return YES;
}

- (IBAction)saveAction:(id)sender 
{
    NSLog(@"检查信息：%d", [self checkInfo]);
    //保存
    if (![self checkInfo])
    {
        UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"" message:@"请输入信息" delegate:nil cancelButtonTitle:@"关闭" otherButtonTitles:nil];
        [alert show];
        [alert release];
    }
    else
    {
        //将信息保存到数据库
        [self saveInfoIntoDatabase];
        [self dismissModalViewControllerAnimated:YES];
    }
}

- (IBAction)cancelAction:(id)sender
{
    //取消，重置
    [idTextField setText:@""];
    [nameTextField setText:@""];
    [idTextField resignFirstResponder];
    [nameTextField resignFirstResponder];
    [self dismissModalViewControllerAnimated:YES];
}

- (BOOL)textFieldShouldReturn:(UITextField *)textField
{
    if (textField == idTextField)
    {
        [textField resignFirstResponder];
        [nameTextField becomeFirstResponder];
    }
    else
    {
        [textField resignFirstResponder];
    }
    return YES;
}

@end