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1.默认样式

UIAlertController *alertController = [UIAlertController alertControllerWithTitle:@"你好" message:@"这个是UIAlertController的默认样式" preferredStyle:UIAlertControllerStyleAlert];    UIAlertAction *cancleAction = [UIAlertAction actionWithTitle:@"取消" style:UIAlertActionStyleCancel handler:^(UIAlertAction * _Nonnull action) {        NSLog(@"点击了取消");    }];    UIAlertAction *commitAction = [UIAlertAction actionWithTitle:@"确定" style:UIAlertActionStyleDefault handler:^(UIAlertAction * _Nonnull action) {        NSLog(@"点击了确认");    }];    [alertController addAction:cancleAction];    [alertController addAction:commitAction];    [self presentViewController:alertController animated:YES completion:nil];

UIAlertController *alertController = [UIAlertController alertControllerWithTitle:@"文本对话框" message:@"登陆和密码对话框" preferredStyle:UIAlertControllerStyleAlert];    [alertController addTextFieldWithConfigurationHandler:^(UITextField * _Nonnull textField) {        textField.placeholder = @"登陆";        [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(alertTextFieldDidChange:) name:UITextFieldTextDidChangeNotification object:textField];    }];    [alertController addTextFieldWithConfigurationHandler:^(UITextField * _Nonnull textField) {        textField.placeholder = @"密码";        /**         *  是否隐藏输入         */        textField.secureTextEntry = YES;        [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(alertTextFieldDidChange:) name:UITextFieldTextDidChangeNotification object:textField];    }];        UIAlertAction *commitAction = [UIAlertAction actionWithTitle:@"确定" style:UIAlertActionStyleDefault handler:^(UIAlertAction * _Nonnull action) {        /**         *  这里面可以做一些与服务器端交互的事情         */        NSLog(@"%@\n", alertController.textFields.firstObject.text);        NSLog(@"%@", alertController.textFields.lastObject.text);        [[NSNotificationCenter defaultCenter] removeObserver:self];    }];    commitAction.enabled = NO;    UIAlertAction *cancleAction = [UIAlertAction actionWithTitle:@"取消" style:UIAlertActionStyleCancel handler:^(UIAlertAction * _Nonnull action) {        NSLog(@"用户取消了登陆");        [[NSNotificationCenter defaultCenter] removeObserver:self];    }];    /**     *  添加交互按钮     */    [alertController addAction:cancleAction];    [alertController addAction:commitAction];        [self presentViewController:alertController animated:YES completion:nil];

/** *  监听textField是否改变 */- (void)alertTextFieldDidChange:(NSNotification *)nc{    UIAlertController *alertController = (UIAlertController *)self.presentedViewController;    if (alertController) {        UITextField *userField = alertController.textFields.firstObject;        UITextField *passWordField = alertController.textFields.lastObject;        UIAlertAction *commitAction = alertController.actions.lastObject;        commitAction.enabled = userField.text.length > 2 && passWordField.text.length > 6;        NSLog(@"%d", commitAction.enabled);    }}

UIAlertController *alertController = [UIAlertController alertControllerWithTitle:@"保存和删除数据" message:@"删除数据不可恢复" preferredStyle:UIAlertControllerStyleActionSheet];    UIAlertAction *cancleAction = [UIAlertAction actionWithTitle:@"取消" style:UIAlertActionStyleCancel handler:^(UIAlertAction * _Nonnull action) {        NSLog(@"取消");    }];    UIAlertAction *commitAction = [UIAlertAction actionWithTitle:@"确定" style:UIAlertActionStyleDefault handler:^(UIAlertAction * _Nonnull action) {        NSLog(@"确定");    }];    UIAlertAction *saveAction = [UIAlertAction actionWithTitle:@"保存" style:UIAlertActionStyleDefault handler:^(UIAlertAction * _Nonnull action) {        NSLog(@"保存");    }];    [alertController addAction:cancleAction];    [alertController addAction:commitAction];    [alertController addAction:saveAction];    [self presentViewController:alertController animated:YES completion:nil];