UIAlertController的用法

最新推荐文章于 2024-01-15 10:01:16 发布

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本文详细介绍了如何在iOS应用中使用UIAlertController创建登录对话框，包括添加文本输入框、监听输入变化以及处理用户输入。

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UIAlertController 添加alertController

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.
    [self addViews];

}
- (void)addViews{
    _tjView = [[TjjSubView alloc] init];
    [self.view addSubview:_tjView];
}
- (void)viewWillLayoutSubviews{
    _tjView.frame = CGRectMake(20, 100, self.view.bounds.size.width-40, 40);
}
- (void)addAlertController{
    UIAlertController *alertController =[UIAlertController alertControllerWithTitle:@"标题" message:@"这是一个UIAlertController" preferredStyle:UIAlertControllerStyleAlert];

/*typedef NS_ENUM(NSInteger, UIAlertControllerStyle) {
UIAlertControllerStyleActionSheet = 0, 竖排
UIAlertControllerStyleAlert 横排
} NS_ENUM_AVAILABLE_IOS(8_0);

    //添加文本输入框，以登陆和密码对话框例子
    [alertController addTextFieldWithConfigurationHandler:^(UITextField * _Nonnull textField) {
        textField.placeholder =@"登陆";
    }];
    [alertController addTextFieldWithConfigurationHandler:^(UITextField * _Nonnull textField) {
        textField.placeholder = @"密码";
    }];
    //如果要监听uiTextField开始、结束、改变状态、则需要添加监听代码
    [alertController addTextFieldWithConfigurationHandler:^(UITextField * _Nonnull textField) {
        textField.placeholder = @"添加监听代码";
        [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(alertTextFieldDidChange:) name:UITextFieldTextDidChangeNotification object:textField];
    }];
    UIAlertAction * cancelAction = [UIAlertAction actionWithTitle:@"取消" style:UIAlertActionStyleCancel handler:nil];
    //    UIAlertAction * defaultAction = [UIAlertAction actionWithTitle:@"默认Default" style:UIAlertActionStyleDefault handler:nil];
    //    UIAlertAction * resetAction = [UIAlertAction actionWithTitle:@"重置Destructive" style:UIAlertActionStyleDestructive handler:nil];

    UIAlertAction * getAction = [UIAlertAction actionWithTitle:@"好的" style:UIAlertActionStyleDefault handler:^(UIAlertAction * _Nonnull action) {
        UITextField * login =alertController.textFields[0];
        UITextField * password = alertController.textFields[1];
        [self.view endEditing:YES];
        NSLog(@"%@,%@",login,password);
    }];
    [alertController addAction:getAction];
    [alertController addAction:cancelAction];
    //    [alertController addAction:defaultAction];
    //    [alertController addAction:resetAction];

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

}
- (void)alertTextFieldDidChange:(NSNotification *)notification{
    UIAlertController *alertController = (UIAlertController *)self.presentedViewController;
    if (alertController) {
        //下标为2的是添加了监听，也是最后一个alertController.textField.lastObject;
        UITextField * listen = alertController.textFields[2];
        //限制，如果listen输入长度要限制在5个字,否则不允许点击默认Default键
        //当UITextField输入字数超过5个，按钮变灰色，enabled为NO
        UIAlertAction *action = alertController.actions.lastObject;
        action.enabled = listen.text.length<=5;
    }

}