单击按钮而不是UIAlertcontroller时创建操作

Question

我创建两个按钮UIAlertcontroller:

One Button - "OpenCamera"
Two button - "OpenGallery"

当我点击其中一个时,我无法理解我是如何创建动作的.

- (IBAction)takePic:(id)sender {


UIAlertController *alert = [UIAlertController alertControllerWithTitle:nil
                                                               message:nil
                                                        preferredStyle:UIAlertControllerStyleActionSheet]; // 1
UIAlertAction *openCamrea = [UIAlertAction actionWithTitle:@"open camrea"
                                                      style:UIAlertActionStyleDefault handler:^(UIAlertAction * action) {
                                                      }];
UIAlertAction *openGallery = [UIAlertAction actionWithTitle:@"open gallery"
                                                       style:UIAlertActionStyleDefault handler:^(UIAlertAction * action) {
                                                       }];

[alert addAction:openCamrea];
[alert addAction:openGallery];

[self presentViewController:alert animated:YES completion:nil];
}

Answer 1

处理程序是在项目选择上执行的块.

UIAlertAction *openGallery = [UIAlertAction
    actionWithTitle:@"open gallery"
    style:UIAlertActionStyleDefault
    handler:^(UIAlertAction * action) {
        // Code to run when the open gallery option is pressed.
    }];

顺便说一下,我认为问题中长期不间断的行确实没有用,因为它们有效地隐藏了关键参数.