Showing an alert with Cocoa

问题

I have been using VB.NET for a while and I switched to Xcode 4.

In the VB.NET environment, I used to type the following command in a button:

if TextBox1.text="" then
    MessageBox.Show("You can't leave the textbox empty!, "Error!")
else
    Label1.text = TextBox1.text

That is just an example. In Xcode, I want to do the same thing except for I want to have a Pop-Up Alert (in the iPhone) instead of the MessageBox in VB.NET.

Any Ideas?

回答1:

Here you go

if ([TextBox1.text isEqualToString:@""]){
    UIAlertView *errorAlert = [[UIAlertView alloc] initWithTitle:@"Error"
                                                         message:@"You can't leave the textbox empty!"
                                                        delegate:nil
                                               cancelButtonTitle:@"OK"
                                               otherButtonTitles:nil];
    [errorAlert show];
    [errorAlert release];
} else {
    Label1.text = TextBox1.text;
}

来源：https://stackoverflow.com/questions/6424891/showing-an-alert-with-cocoa