NSOperaionQueue and UIAlertView - ios

Question

The problem is that if I create and display two alert - the second will override the first, and after it closed displayed first. So not pretty.
I'm trying to create a queue alerts with NSOperationQueue. That you could add a few alerts and they show a sequence to close. But I can not do so would be that I add operations are performed sequentially, waiting for the previous one. They are executed in parallel.
AlertOperation.h
#import <Foundation/Foundation.h>
#interface AlertOperation : NSOperation<UIAlertViewDelegate>
#property (nonatomic,assign) BOOL isFinishedAlert;
- (AlertOperation *)initWithAlert:(UIAlertView *)alert;
#end
AlertOperation.m
#import "AlertOperation.h"
#interface AlertOperation()
{
UIAlertView *_alert;
}
#end
#implementation AlertOperation
#synthesize isFinishedAlert = _isFinishedAlert;
- (AlertOperation *)initWithAlert:(UIAlertView *)alert
{
self = [super init];
if (self)
{
_alert = alert;
_alert.delegate = self;
[_alert show];
}
return self;
}
- (void) main
{
_isFinishedAlert = NO;
do {
[[NSRunLoop currentRunLoop] runMode:NSDefaultRunLoopMode beforeDate:[NSDate distantFuture]];
} while (!_isFinishedAlert);
}
- (void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex
{
_isFinishedAlert = YES;
}
- (BOOL) isConcurrent
{
return NO;
}
#end
Here is run code
UIAlertView *u1 = [[UIAlertView alloc] initWithTitle:#""
message:#"Hello i am first alert" delegate:nil
cancelButtonTitle:#"OK" otherButtonTitles:nil];
UIAlertView *u2 = [[UIAlertView alloc] initWithTitle:#""
message:#"Hello i am second alert" delegate:nil
cancelButtonTitle:#"OK" otherButtonTitles:nil];
NSOperation *alertOp1 = [[AlertOperation alloc] initWithAlert:u1];
NSOperation *alertOp2 = [[AlertOperation alloc] initWithAlert:u2];
alertsQueue = [[NSOperationQueue alloc] init];
[alertsQueue setMaxConcurrentOperationCount:1];
[alertsQueue addOperation:alertOp1];
[alertsQueue addOperation:alertOp2];

Answer 1

Make this easier on yourself. Create a mutable array. When you have new alerts to show then push them onto the array. Every time an alert finishes (gets its delegate message), then dispatch the next alert onto the main queue:
NSMutableArray *alerts;
... end of Alert Delegate message
if([alert count]) {
UIAlert *alrt = [alerts objectAtIndex:0];
[alerts removeObjectAtIndex:0];
dispatch_async(dispatch_get_main_queue(), ^{ [alrt show]; } );
}

Answer 2

I moved the [_alert show] to -(void)main method and it worked! Thank you, #phix23 for help!