Question

我正在使用简单的警报视图，其中两个按钮名称为ok，取消。

当我按下确定时，取消警报视图退出为一般。

但是我需要在点击警报视图确定按钮时退出警报视图活动指示器将在同一个警报视图上运行2分钟并退出。当我点击取消它正常退出。

任何人都可以帮助我。

提前感谢你。

Answer 1

您可以修改“确定”按钮的UI控件事件，以便为该按钮调用自己的事件处理程序，并且在长时间运行的任务完成之前不会关闭警报视图。在该事件处理程序中，将活动指示符附加到视图并使用GCD异步启动任务。

#import <dispatch/dispatch.h>

// ...

UIAlertView* alert = [[UIAlertView alloc] initWithTitle:@"Test" message:@"Message" delegate:self cancelButtonTitle:@"Cancel" otherButtonTitles:@"OK"    ,nil];

for (UIView *subview in alert.subviews)
{
    if ([subview isKindOfClass:[UIControl class]] && subview.tag == 2) {
        UIControl* button = (UIControl*) subview;
        [button addTarget:self action:@selector(buttonOKPressed:) forControlEvents:UIControlEventTouchUpInside];
        [button removeTarget:alert action:nil forControlEvents:UIControlEventAllEvents];
    }
}
[alert show];
[alert release];

// ...

-(void) buttonOKPressed:(UIControl*) sender {

    [sender removeTarget:self action:nil forControlEvents:UIControlEventAllEvents];
    UIAlertView* alert = (UIAlertView*)[sender superview];
    CGRect alertFrame = alert.frame;
    UIActivityIndicatorView* activityIndicator = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleWhiteLarge];
    activityIndicator.frame = CGRectMake(0,alertFrame.size.height, alertFrame.size.width,30);
    activityIndicator.hidden = NO;
    activityIndicator.alpha = 0.0;
    activityIndicator.contentMode = UIViewContentModeCenter;
    [activityIndicator startAnimating]; 
    [alert addSubview:activityIndicator];
    [activityIndicator release];
    [UIView animateWithDuration:0.3 animations:^{
        alert.frame = CGRectMake(alertFrame.origin.x, alertFrame.origin.y, alertFrame.size.width, alertFrame.size.height+50);
        activityIndicator.alpha = 1.0;

    }];         
    //alert.userInteractionEnabled = NO; // uncomment this, if you want to disable all buttons (cancel button)
    dispatch_async(dispatch_get_global_queue(0,0), ^{
        [NSThread sleepForTimeInterval:5]; // replace this with your long-running task
        dispatch_async(dispatch_get_main_queue(), ^{
            if (alert && alert.visible) {
                [alert dismissWithClickedButtonIndex:alert.firstOtherButtonIndex animated:YES];
            }
        });
    });
}

单击该警报视图的按钮时如何将活动指示器置于警报视图中

1 个答案: