我有一个子布局和父布局，如下所示。我需要在子布局中选择多个项目。我可以选择多个项目，但面临两个问题。 1.滚动时，所选项目正在更改。 2.当我在第一行选择项目时，项目4行也在选择中。
这是我的代码。
父级布局：
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent">
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignParentTop="true"
android:id="@+id/formsheader">
<include
android:id="@+id/formToolbar"
layout="@layout/toolbar" />
</RelativeLayout>
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:background="#e9e7e9"
android:layout_above="@+id/formsfooter"
android:layout_below="@+id/formsheader"
android:id="@+id/teamFormsContent">
<GridView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:columnWidth="137dp"
android:numColumns="auto_fit"
android:verticalSpacing="20dp"
android:horizontalSpacing="20dp"
android:stretchMode="columnWidth"
android:layout_marginLeft="23dp"
android:layout_marginRight="23dp"
android:layout_centerHorizontal="true"
android:layout_centerVertical="true"
android:scrollbars="none"
android:id="@+id/form_gridView" />
</RelativeLayout>
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="50dp"
android:layout_alignParentBottom="true"
android:id="@+id/formsfooter"
android:layout_gravity="center"
android:gravity="center"
android:layout_centerHorizontal="true"
android:layout_centerVertical="true"
android:background="#051b2e">
<TextView
android:id="@+id/idletext"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Idle"
android:textColor="#47b8fd"
android:textSize="15dp"
android:textAppearance="?android:attr/textAppearanceMedium" />
<TextView
android:id="@+id/tapToViewText"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Tap to view"
android:textColor="#ffffff"
android:textSize="15dp"
android:layout_marginLeft="20dp"
android:layout_toRightOf="@+id/idletext"
android:textAppearance="?android:attr/textAppearanceMedium" />
</RelativeLayout>
</RelativeLayout>
child_layout：
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:orientation="vertical">
<LinearLayout
android:id="@+id/form_layout"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="30dp"
android:layout_gravity="center"
android:background="@android:color/white"
android:orientation="vertical">
<LinearLayout
android:id="@+id/form_view_layout"
android:layout_width="137dp"
android:layout_height="178dp"
android:orientation="vertical"
android:layout_marginTop="3dp"
android:layout_marginBottom="3dp"
android:layout_marginLeft="3dp"
android:layout_marginRight="3dp"
android:layout_gravity="center"
android:weightSum="100"
android:background="@android:color/white">
<ImageView
android:src="@drawable/image1"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="72"
android:layout_gravity="center"
android:id="@+id/form_Image" />
<TextView
android:text="sometext"
android:textAppearance="?android:attr/textAppearanceSmall"
android:layout_width="match_parent"
android:layout_height="0dp"
android:textColor="#00ccff"
android:textSize="12dp"
android:layout_marginLeft="10dp"
android:layout_marginBottom="5dp"
android:layout_weight="18"
android:id="@+id/heading" />
<TextView
android:text="sometext"
android:textAppearance="?android:attr/textAppearanceSmall"
android:layout_width="match_parent"
android:layout_height="0dp"
android:textSize="12dp"
android:layout_weight="10"
android:layout_marginBottom="10dp"
android:textColor="@android:color/black"
android:layout_marginLeft="10dp"
android:id="@+id/subHeading1" />
</LinearLayout>
</LinearLayout>
<TextView
android:text="sometext"
android:textAppearance="?android:attr/textAppearanceSmall"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:textColor="@android:color/black"
android:textSize="13dp"
android:layout_below="@+id/form_view_layout"
android:layout_marginTop="10dp"
android:layout_gravity="center"
android:gravity="center"
android:id="@+id/subHeading2" />
<TextView
android:text="14/01/1997 5:00"
android:textAppearance="?android:attr/textAppearanceSmall"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:textColor="#696969"
android:textSize="13dp"
android:layout_below="@+id/subHeading2"
android:layout_marginTop="7dp"
android:layout_gravity="center"
android:gravity="center"
android:id="@+id/formupdateddatetime" />
</LinearLayout>
电费率和适配器代码：
namespace FormSample.Activities
{
[Activity(Label = "FormsActivity")]
public class FormsActivity : BaseActivity
{
protected override int Layout => Resource.Layout.Forms;
private FormModel _formModel;
List<Form> formsList = new List<Form>();
List<Form> formsListToDelete = new List<Form>();
private bool _isMultiSelect;
public override void OnBackPressed()
{
FinishAffinity();
}
public static Intent NewIntent(Context context)
{
try
{
var intent = new Intent(context, typeof(FormsActivity));
return intent;
}
catch (Exception exception)
{
return null;
}
}
protected async override void FindViewElements()
{
try
{
_formModel = new FormModel()
{
Form = FindViewById<GridView>(Resource.Id.form_gridView),
FormToolbar = FindViewById<Toolbar>(Resource.Id.formToolbar)
};
formsList = new List<Form>();
var teamForms = new List<Form>();
List<TeamlistResponse> _fromsListFromLocal = await LocalService.Instance.GetFormsCreatedInLocal();
foreach (var form in _fromsListFromLocal)
{
var localForm = ConvertTeamsListDtoToForm(form);
formsList.Add(localForm);
}
formsList = formsList.OrderByDescending(x => x.modified_timestamp).ToList();
InitializeScreen();
LoggingManager.Exit("MethodName:FindViewElements And ActivityName:FormsActivity");
}
catch (Exception exception)
{
LoggingManager.Error(exception, "FindViewElements", "FormsActivity");
}
}
public void InitializeScreen()
{
try
{
LoggingManager.Enter("MethodName:InitializeScreen And ActivityName:FormsActivity");
SetSupportActionBar(_formModel.FormToolbar);
GetListOfForms();
LoggingManager.Exit("MethodName:InitializeScreen And ActivityName:FormsActivity");
}
catch (Exception exception)
{
LoggingManager.Error(exception, "InitializeScreen", "FormsActivity");
}
}
private void GetListOfForms()
{
_formModel.Form.ItemClick += Form_Click;
_formModel.Form.Adapter = new FormAdapter(formsList, this);
}
private async void Form_Click(Object sender, AdapterView.ItemClickEventArgs e)
{
try
{
var selectedItem = formsList[e.Position];
if (selectedItem.Caption != "New Form" && selectedItem.id != null)
{
View selectedForm = e.View;
LinearLayout selectedFormLayout = selectedForm.FindViewById<LinearLayout>(Resource.Id.form_layout);
if (selectedItem.IsSelected)
{
selectedItem.IsSelected = false;
selectedFormLayout.SetBackgroundColor(Color.White);
formsListToDelete.Remove(selectedItem);
}
else
{
selectedItem.IsSelected = true;
selectedFormLayout.SetBackgroundResource(Resource.Drawable.Form_Border);
formsListToDelete.Add(selectedItem);
}
}
}
catch (Exception exception)
{
}
}
}
public class Form
{
private bool _isSelected;
public byte[] ImageResourceId { get; set; }
public string Heading { get; set; }
public string SubHeading { get; set; }
public string Caption { get; set; }
public string UpdatedFormDate { get; set; }
public string id { get; set; }
public bool IsSelected
{
get { return _isSelected; }
set
{
_isSelected = value;
}
}
}
public class FormAdapter : BaseAdapter<Form>
{
private List<Form> formItems;
private Activity context;
public override Form this[int position]
{
get
{
return formItems[position];
}
}
public override int Count => formItems.Count;
public FormAdapter(List<Form> forms, Activity context) : base()
{
try
{
LoggingManager.Enter("ConstructorName:FormAdapter And ActivityName:FormsActivity");
this.context = context;
formItems = forms;
LoggingManager.Exit("ConstructorName:FormAdapter And ActivityName:FormsActivity");
}
catch (Exception exception)
{
LoggingManager.Error(exception, "FormAdapter", "FormAdapter", "FormsActivity");
}
}
public override int GetItemViewType(int position)
{
return position;
}
public override long GetItemId(int position)
{
try
{
return position;
}
catch (Exception exception)
{
return 0;
}
}
public override View GetView(int position, View convertView, ViewGroup parent)
{
try
{
var form = formItems[position];
View view = convertView;
if (view == null)
view = context.LayoutInflater.Inflate(Resource.Layout.Forms_ChildLayout, null);
var imageBitMap = BitmapFactory.DecodeByteArray(form.ImageResourceId, 0, form.ImageResourceId.Length);
view.FindViewById<ImageView>(Resource.Id.form_Image).SetImageBitmap(imageBitMap);
view.FindViewById<TextView>(Resource.Id.heading).Text = form.Heading;
view.FindViewById<TextView>(Resource.Id.subHeading1).Text = form.SubHeading;
view.FindViewById<TextView>(Resource.Id.subHeading2).Text = form.Caption;
view.FindViewById<TextView>(Resource.Id.formupdateddatetime).Text = form.UpdatedFormDate;
return view;
}
catch (Exception exception)
{
LoggingManager.Error(exception, "GetView", "FormsActivity");
return null;
}
}
}
}
通过灼烧，我知道必须使用Viewholder，但是在xamarin.android中成为新手时，我并不真正了解该怎么做。请帮助解决此问题。
答案 0 :(得分：1)
通过搜索，我知道必须使用Viewholder，但是要成为新手 xamarin.android我不是很了解该怎么做
我在这里尝试为您开设Holder类。可能会对您有帮助
在同一文件FormHolder中声明FormAdapter类，并使用所有控件来控制项目布局Forms_ChildLayout中的内容。
public class FormHolder : Java.Lang.Object
{
public ImageView Form_Image { get; set; }
public TextView Heading { get; set; }
public TextView SubHeading1 { get; set; }
public TextView SubHeading2 { get; set; }
public TextView Formupdateddatetime { get; set; }
}
这就是您的FormAdapter的{{1}}
GetView