UIAlertViewController

一.UIAlertViewController的简单使用

  - (void)setupAlertVcWithTextFiled {

    UIAlertController *alertController = [UIAlertController alertControllerWithTitle:@"文本对话框" message:@"登录和密码对话框示例" preferredStyle:UIAlertControllerStyleAlert];
    [alertController addTextFieldWithConfigurationHandler:^(UITextField *textField){
        textField.placeholder = @"登录";
    }];
    [alertController addTextFieldWithConfigurationHandler:^(UITextField *textField) {
        textField.placeholder = @"密码";
        textField.secureTextEntry = YES;

        // 添加通知观察者,监听文本框值的改变
        [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(alertTextFieldDidChange:) name:UITextFieldTextDidChangeNotification object:textField];
    }];

    // 在“好的”按钮按下时，我们让程序读取文本框中的值。
    UIAlertAction *okAction = [UIAlertAction actionWithTitle:@"好的" style:UIAlertActionStyleDefault handler:^(UIAlertAction *action) {
    // 获得文本框
    UITextField *login = alertController.textFields.firstObject;
        UITextField *password = alertController.textFields.lastObject;

        // 移除通知观察者
        [[NSNotificationCenter defaultCenter] removeObserver:self name:UITextFieldTextDidChangeNotification object:nil];

        NSLog(@"%@----%@",login.text,password.text);
    }];

    // 在显示对话框之前，冻结“好的”按钮
    okAction.enabled = NO;

    [alertController addAction:okAction];

    [self presentViewController:alertController animated:YES completion:nil];
}
// 检查“登录”文本框的内容
- (void)alertTextFieldDidChange:(NSNotification *)notification{
    UIAlertController *alertController = (UIAlertController *)self.presentedViewController;
    if (alertController) {
        UITextField *login = alertController.textFields.firstObject;
        UIAlertAction *okAction = alertController.actions.lastObject;

        // 当输入文字大于2 ,按钮可以点击
        okAction.enabled = login.text.length > 2;
    }
}

- (void)setupAlertVc {
   UIAlertController *alertController = [UIAlertController alertControllerWithTitle:@"标题" message:@"这个是UIAlertController的默认样式" preferredStyle:UIAlertControllerStyleAlert];

    UIAlertAction *cancelAction = [UIAlertAction actionWithTitle:@"取消" style:UIAlertActionStyleCancel handler:nil];
    UIAlertAction *okAction = [UIAlertAction actionWithTitle:@"好的" style:UIAlertActionStyleDefault handler:nil];
    [alertController addAction:cancelAction];
    [alertController addAction:okAction];

    UIAlertAction *resetAction = [UIAlertAction actionWithTitle:@"重置" style:UIAlertActionStyleDestructive handler:^(UIAlertAction * _Nonnull action) {

    }];

    [alertController addAction:resetAction];

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