Question

如果用户没有选择选项，我正在尝试在visual studio中的xamarin中验证C＃中的微调器。类似于TextView中的setError，我在SO中看到了例子，但是如果我没有错的话，所有这些都是针对java的。

这是我的微调器

Spinner spinnerJobTypes = FindViewById<Spinner>(Resource.Id.spinnerJobTypes);

这对我不起作用

TextView errorText = (TextView)mySpinner.getSelectedView();

如果用户没有选择任何内容，我想显示此内容

            else if (spinnerJobTypes.SelectedItem.ToString() == "-Select-")
            {
                //Display validation error
            }

感谢任何帮助，

Answer 1

https://developer.xamarin.com/guides/android/user_interface/spinner/

供参考errorText.SetCompoundDrawablesWithIntrinsicBounds(0, 0, Resource.Drawable.errorIcon, 0);

<强>编辑：使用此选项并检查

func makeAddressDefault(_ sender: UIButton) {
        let address = addresses[sender.tag]
        let params:Parameters = ["userid": Globals.sharedInstance.user!.id, "addressid": address.id!]
        let url = "/makeaddressdefault?userid=" + Globals.sharedInstance.user!.id
        RestApiManager.sharedInstance.makePostRequest(vc:self, url: url, post:params, successCompletionHandler:{
            (data) in
            self.addresses.removeAll() // array of addresses
            self.reloadAddresses() // in this reload method in last i have added self.tableview.reload()
        }, failureCompletionHandler:{(data) in })
    }

Answer 2

我的建议是，添加一个＆＃34;没有选择＆＃34;查看Spinner并使用bool参数来识别用户是否选择了某个项目：

SpinnerAdapter.cs

public class SpinnerAdapter : BaseAdapter<String>
{
    Context context;
    List<String> list;
    public SpinnerAdapter(Context c, List<String> list)
    {
        context = c;
        this.list = list;
    }
    public override string this[int position] => list[position-1];

    public override int Count => this.list.Count+1;

    public override long GetItemId(int position)
    {
        return 0;
    }

    public override View GetView(int position, View convertView, ViewGroup parent)
    {
        View view;
        if (position == 0)
        {
            view = LayoutInflater.From(context).Inflate(Resource.Layout.spinner_error,null);
            var txtView = view.FindViewById<TextView>(Resource.Id.tvErr);
            view.FindViewById<TextView>(Resource.Id.tvErr).Text = "None Selected";
            //uncomment the following line if you want to show the error icon inside of spinner
            //view.FindViewById<TextView>(Resource.Id.tvErr).Error = "";
        }
        else
        {
            view = convertView;
            if (view == null|| view.FindViewById<TextView>(Resource.Id.tvItem)==null)
            {
                view = LayoutInflater.From(context).Inflate(Resource.Layout.spinner_item, null);
            }
            view.FindViewById<TextView>(Resource.Id.tvItem).Text = list[position-1];

        }
        return view;
    }
}

MainActivity：

public class MainActivity : Activity
{
    Spinner mSpinner;
    bool validatePass=false;
    TextView tvResult;
    protected override void OnCreate(Bundle bundle)
    {
        base.OnCreate(bundle);

        // Set our view from the "main" layout resource
        SetContentView (Resource.Layout.Main);
        mSpinner = FindViewById<Spinner>(Resource.Id.mSpinner);
        var list = InitList();
        SpinnerAdapter adapter = new SpinnerAdapter(this, list);
        tvResult = FindViewById<TextView>(Resource.Id.tvResult);
        mSpinner.Adapter = adapter;
        mSpinner.ItemSelected += MSpinner_ItemSelected;
    }

    private void MSpinner_ItemSelected(object sender, AdapterView.ItemSelectedEventArgs e)
    {
        //use validatePass to indicate if user has selected something.
        if (e.Position != 0)
        {
            validatePass = true;
        }
        else
        {
            validatePass = false;
        }
        tvResult.Text ="Validate Result: "+ validatePass.ToString();
    }

    private List<string> InitList()
    {
        List<string> list = new List<string>();
        for (int i = 0; i < 15; i++)
        {
            list.Add("Item: " + i);
        }
        return list;
    }
}

但是如果您真的想在微调器内显示错误图标，可以在TextView.Error内设置GetView。

以下是我完整的演示：HelloSpinner。

如何在Xamain Android中验证微调器

2 个答案: