Question

我正在使用Xamarin.Android开发一个应用程序，它实现了一个viewpager / actionbar选项卡。当我使用相机拍照时，点按“保存”时应用程序会崩溃。出现以下错误。

System.NotSupportedException：无法在App3.ViewPagerFragment类型上找到默认构造函数。请提供缺少的构造函数。

这仅在我使用相机时发生。它会从画廊中选择一张图片就好了。我已经为ViewPagerFragment和FragmentPagerAdapter放置了代码以及我要求摄像头功能的调用。如果有人知道我做错了什么。请告诉我。我一直在靠墙砸墙试图解决这个问题。感谢。

更新：当我的应用程序出现问题时，我也发现了同样的问题。我基本上使用了这个示例应用程序并添加了相机功能。 HelloSwipeViewWithTabs

== ViewPagerFragment ==

class ViewPagerFragment : Android.Support.V4.App.Fragment {

private Func<LayoutInflater, ViewGroup, Bundle, View> _view;

public ViewPagerFragment(Func<LayoutInflater, ViewGroup, Bundle, View> view)
{
    _view = view;
}

public override View OnCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)
{
    base.OnCreateView(inflater, container, savedInstanceState);
    return _view(inflater, container, savedInstanceState);
}

== FragmentPagerAdapter ==

class FragmentPagerAdapter : FragmentPagerAdapter { private List<Android.Support.V4.App.Fragment> _fragmentList = new List<Android.Support.V4.App.Fragment>(); public FragmentPagerAdapter(Android.Support.V4.App.FragmentManager fm) : base(fm) {}

public override int Count
{
    get { return _fragmentList.Count; }
}

public override Android.Support.V4.App.Fragment GetItem(int position)
{
    return _fragmentList[position];
}

public void AddFragment(ViewPagerFragment fragment)
{
    _fragmentList.Add(fragment);
}

public void AddFragmentView(Func<LayoutInflater, ViewGroup, Bundle, View> view)
{
    _fragmentList.Add(new ViewPagerFragment(view));

}
}

public class ViewPageListenerForActionBar : ViewPager.SimpleOnPageChangeListener
{
  private ActionBar _bar;
  public ViewPageListenerForActionBar(ActionBar bar)
  {
      _bar = bar;
  }
  public override void OnPageSelected(int position)
  {
      _bar.SetSelectedNavigationItem(position);
  }
}

public static class ViewPagerExtensions
{
  public static ActionBar.Tab GetViewPageTab(this ViewPager viewPager, ActionBar actionBar, string name)
  {
    var tab = actionBar.NewTab();
    tab.SetText(name);
    tab.TabSelected += (o, e) =>
    {
        viewPager.SetCurrentItem(actionBar.SelectedNavigationIndex, false);
    };
    return tab;
  }
}

==相机意图==

private void TakeAPicture() { Intent pickIntent = new Intent();

    pickIntent.SetType("image/*");
    pickIntent.SetAction(Intent.ActionGetContent);

    Intent takePhotoIntent = new Intent(MediaStore.ActionImageCapture);

    String pickTitle = "Select or take a new Picture"; // Or get from strings.xml
    Intent chooserIntent = Intent.CreateChooser(pickIntent, pickTitle);
    chooserIntent.PutExtra
    (
      Intent.ExtraInitialIntents,
      new Intent[] { takePhotoIntent }
    );

    StartActivityForResult(chooserIntent, 0);
}

从viewpager片段拍照的问题

0 个答案: