c# - 在 Xamarin.Android 中单击 RadioGroup 按钮时未选中 RadioButton

Question

有时我的 RadioGroup 按钮在选择时没有被选中。我正在使用 Xamarin.Android 并且我在 RadioGroup 中有大约 15 个 RadioButtons。奇怪的是，焦点总是设置在点击的 RadioButton 上，但有时同一个 RadioButton 在点击后没有设置为 Checked。这是我目前使用的示例代码:

radioGroup.CheckedChange += delegate
{
    var radioButton = FindViewById<RadioButton>(radioGroup.CheckedRadioButtonId);
    radioButton.Focusable = true;
    radioButton.FocusableInTouchMode = true;
    radioButton.RequestFocus();
    radioButton.Checked = true;
};

如何在每次选择 RadioButton 时将其标记为已选中？提前致谢。

Answer 1

What is strange is that the focus is always set on the RadioButton clicked, but sometimes the same RadioButton is not set as Checked after click.

因为当您点击 RadioButton 时 GetFocus 总是最先发生，因此当您第一次点击 RadioButton 时，CheckedChange 事件永远不会被触发。

因此，正确的做法是为每个 RadioButton 注册 focusChange 事件，并在 focusChange 中将单选按钮设置为选中事件处理程序:

public class MainActivity : Activity
{
    RadioGroup radioGroup;
    protected override void OnCreate(Bundle bundle)
    {
        base.OnCreate(bundle);

        // Set our view from the "main" layout resource
        SetContentView (Resource.Layout.Main);
        radioGroup = FindViewById<RadioGroup>(Resource.Id.mGroup);

        //register focus change event for every sub radio button.
        for (int i = 0; i < radioGroup.ChildCount; i++)
        {
            var child=radioGroup.GetChildAt(i);
            if (child is RadioButton)
            {
                ((RadioButton)child).FocusChange += RadioButton_FocusChange;
            }
        }
    }


    private void RadioButton_FocusChange(object sender, Android.Views.View.FocusChangeEventArgs e)
    {
        //check if the radio button is the button that getting focus
        if (e.HasFocus){
            ((RadioButton)sender).Checked = true;
        }
    }
}