警報視圖的方法是行不通的

Question

在我的應用程序我有復位按鈕，刪除表中的所有數據，並刪除database.but之前，我必須把警報視圖，並提出這樣的問題如下：

- (IBAction)resetData:(id)sender 
{ 
    UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Bills Data Entry" 
         message:@"Are you sure want to reset data?" delegate:nil 
         cancelButtonTitle:@"No" otherButtonTitles:@"Yes", nil]; 
    [alert show]; 
    [alert release]; 
} 

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

     [self databaseOpen]; 
     NSString *deleteData=[NSString stringWithFormat:@"delete from tbl_Bills"]; 
     [database executeQuery:deleteData]; 
     NSLog(@"inert query: %@",deleteData); 
     NSLog(@"records deleted"); 
     [table reloadData]; 
     [database close]; 

     // DO STUFF 
    } 
} 

這當我點擊是時，方法不會被調用。

Answer 1

如果你想調用它的委託方法，UIAlertView的委託不能爲零。

UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Bills Data Entry" 
         message:@"Are you sure want to reset data?" delegate:self 
         cancelButtonTitle:@"No" otherButtonTitles:@"Yes", nil]; 

Answer 2

如果要調用其委託方法，則必須將UIAlertView委託設置爲self。

UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Bills Data Entry" 
              message:@"Are you sure want to reset data?" 
              delegate:self 
              cancelButtonTitle:@"No" 
              otherButtonTitles:@"Yes",nil]; 

Answer 3

When you are using Delegate method you are supposed to set "delegate: self" instead of nil. 

    UIAlertView *my_Alert = [[UIAlert alloc] initWithTitle:@"Title of Alert" message:@"Your 
          Message" delegate:self cancelButtonTitle:@"OK", 
          otherButtonTitles:nil,nil];