当用户点击alertview时从sqlite数据库中删除一条记录

Question

我有一个名为FINALORDER的db表，它填充了一些数据，然后显示在tableview中。

我插入了didSelectRowAtIndexPath内的alertview ..

alert=[[UIAlertView alloc]initWithTitle:@"Cancel Order" message:@"Do you want to cancel the order" delegate:self cancelButtonTitle:@"dismiss" otherButtonTitles:@"Ok",nil]; 
    [alert show]; 
    [alert release]; 

和委托方法如下：

- (void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex 
{ 
const char *dbpath = [databasePath UTF8String]; 
sqlite3_stmt *statement; 
if(buttonIndex==1) 
{ 
    NSString *deleteSQL = @"DELETE FROM FINALORDER WHERE itemname=?"; 

    if (sqlite3_prepare_v2(database, [deleteSQL UTF8String], -1, &statement, NULL) != SQLITE_OK) 
     NSLog(@"%s error preparing %s", __FUNCTION__, sqlite3_errmsg(database)); 
    if (sqlite3_bind_text(statement, 1, [itemname UTF8String], -1, NULL) != SQLITE_OK) 
     NSLog(@"%s error binding %s", __FUNCTION__, sqlite3_errmsg(database)); 
    if (sqlite3_step(statement) != SQLITE_DONE) 
     NSLog(@"%s error executing %s", __FUNCTION__, sqlite3_errmsg(database)); 
    if (sqlite3_finalize(statement) != SQLITE_OK) 
     NSLog(@"%s error finalizing %s", __FUNCTION__, sqlite3_errmsg(database)); 


} 
} 

我怎么得到它可以在取代项目名称问号的地方？请注意，我的数据库包含以下字段itemname,quantity,totalcost

Answer 1

in didSelectRowAtIndexPath 将名称存储在类变量中，然后使用它。

UITableViewCell *cell = [tableView cellForRowAtIndexPath:indexPath]; 
NSArray *names = [cell.textLabel.text componentsSeparatedByString:@" "]; 
NSString *temp; 
for (int i=0; i<[names count]-2; i++) 
{ 
    if (!temp) 
    { 
     temp = [names objectAtIndex:i]; 
    } 
    else 
    { 
     temp = [NSString stringWithFormat:@"%@ %@",temp, [names objectAtIndex:i]]; 
    } 
} 
self.itemName = temp; 

，并用它

NSString *deleteSQL = [NSString stringWithFormat:@"DELETE FROM FINALORDER WHERE itemname=%@",self.itemName]; 

希望它帮助。快乐编码:)

Answer 2

你可以做什么@AnshukGarg建议或者我会这样做。您可以创建自己的自定义类来处理UIAlertView。

例如：

  DataAlertThing.h 

      #import <Foundation/Foundation.h> 

      @protocol DataAlertThingDelegate{ 
      @required 

       -(void)shouldDeleteItem:(ItemType*)itemName; 
      } 

      @interface DataAlertThing : NSObject <UIAlertViewDelegate> 
      @property (nonatomic, weak)id delegate; 
      @property (nonatomic, strong) id itemName; 

      -(id)initWithItemName:(ItemType*)myItemName; 
     @end 

    DataAlertThing.m 

    #import "DataAlertThing.h" 

    @implementation DataAlertThing 



-(id)initWithItemName:(ItemType*)myItemName{ 
    self = [super init]; 
    if (self !=nil{ 
    self.itemName = myItemName; 
    UIAlertView *alert = [UIalertVIew alloc]init...delegate:self..] 
    [alert show]; 
} 
return self; 
} 

- (void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex 
{ 
if(buttonIndex==1) 
{ 

    [delegate shouldDeleteItem:self.itemName]; 

} 
} 

从上面你得到足够的想法，以什么我建议的

希望 - 你封装你的警报逻辑在自己的自定义类。你也可以在这一点上，而不是使用一个块，但我认为一个例子就够了今天:)

请注意，这ARC还利用现代约定，所以你不需要右边的@synthesize

在您初始化警报视图的现有代码中。改为初始化此自定义类。

whatever = [[DataAlertThing alloc]initWithItemName:myItemName]; 
[whatever setDelegate:self]; 

以及与此实现以下

-(void)shouldDeleteItem:(ItemType*)itemName{ 
//do what you need here to delete the record 

}