Question

我刚用PagerAdapter创建了ViewPager，我把它放入了3个项目，但是当我运行程序ViewPager.ChildCount给我2个？当我滚动到第二个视图时，适配器添加第三个项目并给我3个计数，但是当我滚动到最终视图（3）时它给我2个计数，但此时最后2个项目！在我的代码中我试图在布局中的textView中显示位置它在第一个卷轴中给出我的正确数字然后它随机开始混合位置我不知道为什么？请帮助

我正在使用Xamarin 还有我的代码

public class SlidingTabsFragment : Fragment
    {
        private SlidingTabScrollView mSlidingTabScrollView;
        private ViewPager mViewPager;
        protected static View CurrentView;
        protected static int CurrentViewPosition;

        public override View OnCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)
        {
            return inflater.Inflate(Resource.Layout.fragment_sample, container, false);
        }

        public override void OnViewCreated(View view, Bundle savedInstanceState)
        {
            mSlidingTabScrollView = view.FindViewById<SlidingTabScrollView>(Resource.Id.sliding_tabs);
            mViewPager = view.FindViewById<ViewPager>(Resource.Id.viewpager);
            mViewPager.Adapter = new SamplePagerAdapter();
            mViewPager.PageSelected += MViewPager_PageSelected;
            mViewPager.PageScrolled += MViewPager_PageScrolled;
            mSlidingTabScrollView.ViewPager = mViewPager;

        }

        private void MViewPager_PageScrolled(object sender, ViewPager.PageScrolledEventArgs e)
        {
            if (e.Position < mViewPager.ChildCount && e.Position>=0)
            {
                SamplePagerAdapter ad = (SamplePagerAdapter)mViewPager.Adapter;
                TextView txtTitle = mViewPager.GetChildAt(e.Position).FindViewById<TextView>(Resource.Id.item_title);

                int pos = ad.GetItemPosition(CurrentView);
                txtTitle.Text = e.Position.ToString();
            }

        }

        private void MViewPager_PageSelected(object sender, ViewPager.PageSelectedEventArgs e)
        {
            if (e.Position < mViewPager.ChildCount && e.Position >= 0)
            {
                SamplePagerAdapter ad = (SamplePagerAdapter)mViewPager.Adapter;


                TextView txtTitle = mViewPager.GetChildAt(e.Position).FindViewById<TextView>(Resource.Id.item_title);

                txtTitle.Text = e.Position.ToString();
            }
        }


        public class SamplePagerAdapter : PagerAdapter
        {
            List<string> items = new List<string>();
            public override void SetPrimaryItem(ViewGroup container, int position, Java.Lang.Object obj)
            {
                CurrentView = (View)obj;
                CurrentViewPosition = position;
            }
            public SamplePagerAdapter() : base()
            {
                items.Add("Home");
                items.Add("Sell");
                items.Add("Rent");
            }

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

            public override bool IsViewFromObject(View view, Java.Lang.Object obj)
            {
                return view == obj;
            }

            public override Java.Lang.Object InstantiateItem(ViewGroup container, int position)
            {
                View view = LayoutInflater.From(container.Context).Inflate(Resource.Layout.pager_item, container, false);
                container.AddView(view);


                return view;
            }

            public string GetHeaderTitle (int position)
            {
                return items[position];
            }

            public override void DestroyItem(ViewGroup container, int position, Java.Lang.Object obj)
            {
                container.RemoveView((View)obj);
            }
        }

Answer 1

我解决了，这是因为我必须设置OffScreenLimit属性

Android ViewPager.ChildCount给我错误的计数

1 个答案: