objective C: problem with open a second time a subview

I have this code to open a subview

- (IBAction) showList:(id) sender {

if( list == nil){

    list = [[ListClient alloc] initWithNibName:@"ListClient" bundle:nil];
    [list setDelegate:self];
    [self.view addSubview:list.view];
}
}

and this code to close thi开发者_JAVA技巧s subview

-(IBAction) closeListClient {
[self.view removeFromSuperview];

}

it's ok for the first time, but at second time when i want to open the subview, it don't work, why?

Because your list is not nil so it doesn't go inside if (list == nil).

Change it to if (list.superview == nil).

It's because of the if statement. Change it to:

if ( list == nil ) {
    list = [[ListClient alloc] initWithNibName:@"ListClient" bundle:nil];
    [list setDelegate:self];
}
[self.view addSubview:list.view];

And it will work.

PS. To fix the memory management of this, add a retained property list to the class so you can say

self.list = [[[ListClient alloc] initWithNibName:@"ListClient" bundle:nil] autorelease];

And you can say self.list = nil; to release the object when you're done with it. (eg while dismissing or in your dealloc method)

-(IBAction) closeListClient{
[self.view removeFromSuperview];
if ( list != nil ) {
    [list release];
    list=nil;
}}