添加自己的LinearLayout期间无法激活JNI手柄-Xamarin Android

概述我正在XamarinAndroid(基于thistutorial)上创建自己的日历.我将Java所需的所有内容都转换为C#,但是现在当我启动应用程序并打开行中包含自定义日历的片段时：publicoverrideViewOnCreateView(LayoutInflaterinflater,ViewGroupcontainer,BundlesavedInstanceState){

我正在Xamarin Android(基于this tutorial)上创建自己的日历.我将Java所需的所有内容都转换为C#,但是现在当我启动应用程序并打开行中包含自定义日历的片段时：

public overrIDe VIEw OnCreateVIEw(LayoutInflater inflater, VIEwGroup container, Bundle savedInstanceState) {        var vIEw = inflater.Inflate(Resource.Layout.calendar_fragment_main, container, false); //System.NotSupportedException Error        return vIEw;}

我收到一个错误消息：

System.NotSupportedException – Could not activate JNI Handle 0xffcdb7e8 (key_handle 0x741b240) of Java type ‘md57f15d2d0137b5b5d70f719ce3cee21d4/EstiCalendar’ as managed type ‘EstiMOBILE.DroID.Components.EstiCalendar.Component.Layouts.EstiCalendar’.

还有另外两个错误,可能是第一个错误指出：

java.lang.UnsupportedOperationException – Binary XML file line #1: You must supply a layout_wIDth attribute.

AndroID.VIEws.InflateException – Binary XML file line #1: Binary XML file line #1: You must supply a layout_wIDth attribute.

包含自定义日历的片段(calendar_fragment_main.axml)：

    <?xml version="1.0" enCoding="utf-8"?><relativeLayout xmlns:androID="http://schemas.androID.com/apk/res/androID"                 xmlns:esticalendar="http://schemas.androID.com/apk/res-auto"                 xmlns:app="http://schemas.androID.com/apk/res-auto"                xmlns:tools="http://schemas.androID.com/tools"                androID:orIEntation="vertical"                 androID:layout_wIDth="match_parent"                androID:layout_height="match_parent">    <relativeLayout         androID:ID="@+ID/calendar_content_wrapper"        androID:orIEntation="vertical"        androID:layout_wIDth="match_parent"        androID:layout_height="match_parent">        <TextVIEw        androID:ID="@+ID/calendar_Title"        androID:layout_wIDth="match_parent"        androID:layout_height="wrap_content"        androID:layout_alignParenttop="true"        tools:text="Calendar" />        <CalendarVIEw         androID:layout_wIDth="fill_parent"        androID:layout_height="fill_parent"        androID:layout_below="@ID/calendar_Title"        androID:ID="@+ID/calendar_main_object"         androID:visibility="gone" />        <EstiMOBILE.DroID.Components.EstiCalendar.Component.Layouts.EstiCalendar        androID:layout_wIDth="match_parent"        androID:layout_height="match_parent"        androID:ID="@+ID/esti_calendar"        esticalendar:date_format="MMMM yyyy" />    </relativeLayout></relativeLayout>

我的自定义日历类EstiCalendar.cs

using System;using System.Collections.Generic;using AndroID.Content;using AndroID.Content.Res;using AndroID.Graphics;using AndroID.Runtime;using AndroID.Util;using AndroID.VIEws;using AndroID.Widget;using Java.Text;using Java.Util;namespace EstiMOBILE.DroID.Components.EstiCalendar.Component.Layouts{    public class EstiCalendar : linearLayout    {        // how many days to show, defaults to six weeks, 42 days        private static Readonly int DAYS_COUNT = 42;        // default date format        private static Readonly string DATE_FORMAT = "MMM yyyy";        // date format        private string dateFormat;        // current displayed month        private Calendar currentDate = Calendar.Instance;        //event handling        private IEventHandler eventHandler = null;        // internal components        private linearLayout header;        private ImageVIEw btnPrev;        private ImageVIEw btnNext;        private TextVIEw txtDate;        private GrIDVIEw grID;        // seasons' rainbow        int[] rainbow = new int[] {            Resource.color.summer,            Resource.color.fall,            Resource.color.winter,            Resource.color.spring    };        // month-season association (northern hemisphere, sorry australia :)        Readonly int[] monthSeason = { 2, 2, 3, 3, 3, 0, 0, 0, 1, 1, 1, 2 };        public EstiCalendar(IntPtr handle, JniHandleOwnership transfer) : base(handle, transfer)        {        }        public EstiCalendar(Context context, IAttributeSet attrs) : base(context, attrs)        {            InitControl(context, attrs);        }        public EstiCalendar(Context context, IAttributeSet attrs, int defStyleAttr) : base(context, attrs, defStyleAttr)        {            InitControl(context, attrs);        }        /**         * Load control xml layout         */        private voID InitControl(Context context, IAttributeSet attrs)        {            LayoutInflater inflater = (LayoutInflater)context.GetSystemService(Context.LayoutInflaterService);            inflater.Inflate(Resource.Layout.calendar_control, this);            LoadDateFormat(attrs);            AssignUIElements();            AssignClickHandlers();            UpdateCalendar();        }        private voID LoadDateFormat(IAttributeSet attrs)        {            TypedArray ta = Context.ObtainStyledAttributes(attrs, Resource.Styleable.EstiCalendar);            try            {                // try to load provIDed date format, and fallback to default otherwise                dateFormat = ta.GetString(Resource.Styleable.EstiCalendar_date_format);                if (dateFormat == null)                    dateFormat = DATE_FORMAT;            }            finally            {                ta.Recycle();            }        }        private voID AssignUIElements()        {            // layout is inflated, assign local variables to components            header = (linearLayout)FindVIEwByID(Resource.ID.calendar_header);            btnPrev = (ImageVIEw)FindVIEwByID(Resource.ID.calendar_prev_button);            btnNext = (ImageVIEw)FindVIEwByID(Resource.ID.calendar_next_button);            txtDate = (TextVIEw)FindVIEwByID(Resource.ID.calendar_date_display);            grID = (GrIDVIEw)FindVIEwByID(Resource.ID.calendar_grID);        }        private voID AssignClickHandlers()        {            btnNext.Click += (sender, e) =>            {                currentDate.Add(Calendar.Month, 1);                UpdateCalendar();            };            btnPrev.Click += (sender, e) =>            {                currentDate.Add(Calendar.Month, -1);                UpdateCalendar();            };            grID.ItemLongClick += (object sender, AdapterVIEw.ItemLongClickEventArgs e) => {                if (eventHandler != null)                {                    eventHandler.OnDayLongPress((Date)e.position);                }            };        }        public voID UpdateCalendar()        {            UpdateCalendar(null);        }        /**         * display dates correctly in grID         */        public voID UpdateCalendar(HashSet<Date> events)        {            List<Date> cells = new List<Date>();            Calendar calendar = (Calendar)currentDate.Clone();            // determine the cell for current month's beginning            calendar.Set(Calendar.DayOfMonth, 1);            int monthBeginningCell = calendar.Get(Calendar.DayOfWeek) - 1;            // move calendar backwards to the beginning of the week            calendar.Add(Calendar.DayOfMonth, -monthBeginningCell);            // fill cells            while (cells.Count < DAYS_COUNT)            {                cells.Add(calendar.Time);                calendar.Add(Calendar.DayOfMonth, 1);            }            // update grID            grID.Adapter = new Calendaradapter(Context, cells, events);            // update Title            SimpleDateFormat sdf = new SimpleDateFormat(dateFormat);            txtDate.Text = sdf.Format(currentDate.Time);            // set header color according to current season            int month = currentDate.Get(Calendar.Month);            int season = monthSeason[month];            int color = rainbow[season];            header.SetBackgroundcolor(Resources.Getcolor(color));        }        private class Calendaradapter : BaseAdapter<Date>        {            // days with events            private HashSet<Date> eventDays;            private List<Date> days;            // for vIEw inflation            private LayoutInflater inflater;            private Context context;            public Calendaradapter(Context context, List<Date> days, HashSet<Date> eventDays) : base()            {                this.eventDays = eventDays;                this.days = days;                inflater = LayoutInflater.From(context);                this.context = context;            }            public overrIDe Date this[int position] => days[position];            public overrIDe int Count => days.Count;            public overrIDe long GetItemID(int position)            {                return position;            }            public overrIDe VIEw GetVIEw(int position, VIEw convertVIEw, VIEwGroup parent)            {                // day in question                var date = GetItem(position) as Date;                int day = date.GetDate();                int month = date.Month;                int year = date.Year;                // today                Date today = new Date();                // inflate item if it does not exist yet                if (convertVIEw == null)                    convertVIEw = inflater.Inflate(Resource.Layout.control_calendar_day, parent, false);                // if this day has an event, specify event image                convertVIEw.SetBackgroundResource(0);                if (eventDays != null)                {                    foreach (Date eventDate in eventDays)                    {                        if (eventDate.GetDate() == day &&                                eventDate.Month == month &&                                eventDate.Year == year)                        {                            // mark this day for event                            convertVIEw.SetBackgroundResource(Resource.Drawable.reminder);                            break;                        }                    }                }                // clear styling                ((TextVIEw)convertVIEw).SetTypeface(null, TypefaceStyle.normal);                ((TextVIEw)convertVIEw).SetTextcolor(color.Black);                if (month != today.Month || year != today.Year)                {                    // if this day is outsIDe current month, grey it out                    ((TextVIEw)convertVIEw).SetTextcolor(context.Resources.Getcolor(Resource.color.greyed_out));                }                else if (day == today.GetDate())                {                    // if it is today, set it to blue/bold                    ((TextVIEw)convertVIEw).SetTypeface(null, TypefaceStyle.Bold);                    ((TextVIEw)convertVIEw).SetTextcolor(context.Resources.Getcolor(Resource.color.today));                }                // set text                ((TextVIEw)convertVIEw).Text = $"{date.GetDate()}";                return convertVIEw;            }        }        public voID SetEventHandler(IEventHandler eventHandler)        {            this.eventHandler = eventHandler;        }        public interface IEventHandler        {            voID OnDayLongPress(Date date);        }    }}

CalendarFragment.cs包含错误：

using System;using System.Collections.Generic;using AndroID.OS;using AndroID.Runtime;using AndroID.VIEws;using AndroID.Widget;using EstiMOBILE.DroID.Components.EstiCalendar.Component.Layouts;using EstiMOBILE.DroID.Fragments.BaseFragments;using Java.Util;namespace EstiMOBILE.DroID.Fragments.CustomFragments{    public class CalendarFragment : BaseFragment    {        public overrIDe voID OnCreate(Bundle savedInstanceState)        {            base.OnCreate(savedInstanceState);        }        public static CalendarFragment NewInstance()        {            var frag1 = new CalendarFragment { Arguments = new Bundle() };            return frag1;        }        public overrIDe VIEw OnCreateVIEw(LayoutInflater inflater, VIEwGroup container, Bundle savedInstanceState)        {            var vIEw = inflater.Inflate(Resource.Layout.calendar_fragment_main, container, false); //Error            //InitCustomCalendar(vIEw);            return vIEw;        }        public voID InitCustomCalendar(VIEw vIEw)        {            HashSet<Date> events = new HashSet<Date>            {                new Date()            };            EstiCalendar cv = (EstiCalendar) vIEw.FindVIEwByID(Resource.ID.esti_calendar);            cv.UpdateCalendar(events);        }    }}

您有什么帮助,如何摆脱这个错误？

解决方法:

您不需要其他的构造函数

public EstiCalendar(IntPtr handle, JniHandleOwnership transfer) : base(handle, transfer){}

问题是Java和Xamarin之间的名称空间,您应该在XML文件中使用小写字母表示名称空间,使用camelcase表示类名称.更改您的xml文件,例如：

<estimobile.droID.components.esticalendar.component.layouts.EstiCalendar    androID:layout_wIDth="match_parent"    androID:layout_height="match_parent"    androID:ID="@+ID/esti_calendar"    esticalendar:date_format="MMMM yyyy" />

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